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BACKGROUND: Eucommia ulmoides has a certain osteogenic effect, which can promote the proliferation and differentiation of osteoblasts. However, it is unclear whether Eucommia ulmoides has effects on alveolar bone formation and Wnt/β-Catenin signaling pathway. OBJECTIVE: To investigate the mechanism by which Eucommia ulmoides promotes alveolar bone formation in ovariectomized rats based on the Wnt/β-Catenin signaling pathway. METHODS: Sixty female Sprague-Dawley rats were selected and randomly divided into five groups: blank control group, sham-operation group, model group, low-dose group Eucommia ulmoides group, and high-dose Eucommia ulmoides group, with twelve rats in each group. Osteoporosis animal models were constructed by bilateral oophorectomy in the model group and the low-dose and high-dose Eucommia ulmoides groups. The sham-operation group underwent the same method to remove adipose tissue of equal mass around the bilateral ovaries. Three months after surgery, the low- and high-dose Eucommia ulmoides groups were given 2.1 g/kg/d and 4.2 g/kg/d Eucommia ulmoides by gavage, respectively. The sham-operation group and model group were given the same amount of physiological saline by gavage. After 12 weeks of drug intervention, the changes in alveolar bone mass of rats in each group were observed through Micro-CT; hematoxylin-eosin staining was used to observe the pathological structural changes of alveolar bone in rats; enzyme linked immunosorbent assay was used to detect the expression levels of alkaline phosphatase and osteocalcin in the serum of rats; western blot was used to detect the expression levels of β-Catenin and Frizzled9 receptor proteins in the alveolar bone of rats; and real-time fluorescence quantitative PCR was used to detect the expression of osteocalcin, Runt-related transcription factor 2 (Runx2), alkaline phosphatase, β-catenin, and frizzled9 mRNAs in alveolar bone tissues of rats. RESULTS AND CONCLUSION: Compared with the blank control group, bone volume fraction, trabecular number, trabecular thickness, and bone mineral density were reduced in the model group (P < 0.05), and trabecular separation was elevated (P < 0.05). Pathological observation showed that the arrangement of trabeculae was disordered and irregular, the trabeculae were thinned or broken, and the marrow cavity was enlarged in the model group, with a significant reduction in bone volume; the level of alkaline phosphatase in the serum was increased (P < 0.05), and the level of osteocalcin was decreased (P < 0.05); mRNA expression of alkaline phosphatase, osteocalcin, Runx2, β-catenin, and frizzled9 were decreased (P < 0.05); protein expression of β-Catenin and Frizzled9 was decreased (P < 0.05). Compared with the model group, the low- and high-dose Eucommia ulmoides groups showed an increase in bone volume fraction, trabecular number, trabecular thickness, and bone mineral density (P < 0.05) and a decrease in trabecular separation (P < 0.05). In the low- and high-dose Eucommia ulmoides groups, bone trabeculae were slightly aligned and thickened, with a significant increase in bone mass. Compared with the model group, the serum level of alkaline phosphatase was reduced (P < 0.05) and the serum level of osteocalcin was elevated (P < 0.05) in the low- and high-dose Eucommia ulmoides groups. Compared with the model group, the mRNA expression of alkaline phosphatase, osteocalcin, Runx2, β-catenin, and frizzled9 were increased in the low- and high-dose Eucommia ulmoides groups (P < 0.05). Compared with the model group, the protein expression of Frizzled9 was increased in the lowdose Eucommia ulmoides group (P < 0.05), while the protein expression of β-Catenin and Frizzled9 was increased in the high-dose Eucommia ulmoides group (P < 0.05). Compared with the low-dose Eucommia ulmoides group, the high-dose Eucommia ulmoides group had a more significant improvement in the above indexes. To conclude, Eucommia ulmoides can effectively promote the alveolar bone formation, and its mechanism of action might be related to the activation of the Wnt/β-catenin signaling pathway [ABSTRACT FROM AUTHOR]

BACKGROUND: Polylactic acid (PLA) has good biocompatibility and a controllable degradation rate and is currently widely used in biomedical engineering. However, PLA has shortcomings such as low mechanical strength and insufficient biological activity, which limits its further application in bone tissue engineering. OBJECTIVE: To construct polylactic acid/polydopamine/tantalum (PLA/PDA/Ta) bone tissue engineering scaffolds, and explore their biosafety and in vitro osteogenesis. METHODS: A PLA scaffold with a porous structure was prepared through liquid crystal display light-curing technology. PLA/PDA scaffolds and PLA/PDA/Ta scaffolds were prepared by soaking PLA scaffolds in dopamine solution and dopamine-tantalum nanoparticle solution, respectively. The microstructure and water contact angle of scaffolds were characterized. MC3T3-E1 cells were co-cultured with PLA, PLA/PDA, and PLA/PDA/Ta scaffolds, respectively, and CCK-8 assay and live/dead cell staining were performed. After osteogenic differentiation, alkaline phosphatase, alizarin red staining, and osteogenic gene detection were performed. RESULTS AND CONCLUSION: (1) The scanning electron microscope results exhibited that the three kinds of prepared scaffolds had an interconnected porous three-dimensional structure, and the average pore diameter was 200 μm. The water contact angle of PLA/PDA/Ta scaffolds was lower than that of PLA and PLA/ PDA scaffolds (P < 0.05). (2) CCK-8 assay showed that compared with PLA and PLA/PDA scaffolds, PLA/PDA/Ta scaffolds could promote cell proliferation (P < 0.05). Live/dead cell staining showed good cell proliferation in the three groups. (3) Alkaline phosphatase and alizarin red staining showed that compared with PLA and PLA/PDA scaffolds, PLA/PDA/Ta scaffolds could promote the expression of alkaline phosphatase and the formation of mineralized nodules. RT-qPCR showed that compared with PLA and PLA/PDA scaffolds, PLA/PDA/Ta scaffolds could enhance the mRNA expression of cell bone morphogenetic protein, Runx- 2, and type I collagen (P < 0.05, P < 0.01). (4) The results showed that the PLA/PDA/Ta scaffold had excellent osteogenic activity and the ability to promote cell proliferation. [ABSTRACT FROM AUTHOR]

BACKGROUND: Existing studies have made significant progress in PIWI-interacting RNAs (piRNAs) against osteoporosis, but the specific targets and related mechanisms by which piRNAs exert their functions remain to be explored. OBJECTIVE: To investigate the effects and downstream mechanisms of piR-7472 on the differentiation of mouse osteoblasts (MC3T3-E1 cells). METHODS: (1) Twelve C57/BL6J mice were randomly divided into a sham-operated and an ovariectomized group, with six mice in each group. Changes in bone mass and the expression of piR-7472 were detected using Micro-CT and RT-qPCR, respectively, at 8 weeks after surgery. (2) MC3T3-E1 cells were divided into NC mimics group, piR-7472 mimics group, NC inhibitor group, and piR-7472 inhibitor group. The mRNA expression of piR-7472, osteopontin, type I collagen, Runt-related transcription factor 2, and potassium voltage-gated channel modifier subfamily F member 1 were detected by RT-qPCR after 7 days of osteogenic induction. The protein expression of osteopontin, Runt-related transcription factor 2, bone morphogenetic protein 2, and potassium voltage-gated channel modifier subfamily F member 1 (KCNF1) was detected using western blot assay. The expression of alkaline phosphatase was detected by alkaline phosphatase staining after 14 days of osteogenic induction, and the number of mineralized nodules was detected by alizarin red staining after 21 days of induction. Whether piR-7472 could bind to KCNF1 was observed by the dual luciferase reporter gene assay. RESULTS AND CONCLUSION: (1) Bone mineral density, bone volume fraction, bone trabecular thickness, bone trabecular number were significantly decreased and bone trabecular separation was significantly increased in ovariectomized mice, and piR-7472 in bone tissue was significantly down-regulated in osteoporotic mice. (2) Compared with the NC group, the mRNA expression of osteopontin, type I collagen, and Runt-related transcription factor 2 were significantly increased, the protein expression of osteopontin, Runt-related transcription factor 2, and bone morphogenetic protein 2 were significantly elevated, and the levels of mineralized deposition and alkaline phosphatase were increased in the piR-7472 mimics group. Compared with the NC inhibitor group, the mRNA expression of osteopontin, type I collagen, and Runt-related transcription factor 2 was significantly downregulated, the protein expression of osteopontin, Runt-related transcription factor 2, and bone morphogenetic protein 2 were significantly decreased, and the levels of mineralized deposition and alkaline phosphatase were reduced in the piR-7472 inhibitor group. (3) piR-7472 was found to interact with the potassium voltage-gated channel modifier subfamily F member 1 as predicted by the miRanda database. The dual luciferase reporter gene assay revealed that piR-7472 mimics could bind to and promote the expression of KCNF1. To conclude, piR-7472 can promote osteogenic differentiation of osteogenic precursor cells MC3T3-E1, and its mechanism of action may be achieved by promoting the expression of KCNF1. [ABSTRACT FROM AUTHOR]

BACKGROUND: Although aromatase inhibitors significantly improve the clinical benefit of patients with hormone receptor-positive breast cancer, its associated adverse event - osteoporosis seriously affects the quality of life of patients. Huangqi Bushen Huoxue Decoction can effectively prevent the occurrence of aromatase inhibitor-induced osteoporosis, but its mechanism of action is unclear. OBJECTIVE: To investigate the effects of Huangqi Bushen Huoxue Decoction on osteoclast activity in a mouse model of osteoporosis induced by aromatase inhibitors and relevant mechanisms. METHODS: Sixty 8-week-old female C57BL/6J mice were randomly divided into sham operation group, model group, high-, medium- and low-dose Huangqi Bushen Huoxue Decoction, and positive control group, with 10 mice in each group. Bilateral ovaries were removed to establish postmenopausal animal models in all the groups except for the sham operation group. After 1 week of recovery, letrozole was injected subcutaneously to establish postmenopausal osteoporosis models via subcutaneous injection of letrozole (an aromatase inhibitor). The high-, medium- and low-dose Huangqi Bushen Huoxue Decoction groups were intragastrically given 19.24, 9.62 and 4.81 g/kg/d Huangqi Bushen Huoxue Decoction (once a day), respectively. The positive control group was given alendronate 5mg/kg once a week. After 3 months of administration, Micro-CT was used to detect tibial bone mineral density and bone microstructure. Hematoxylin-eosin staining and tartrate-resistant acid phosphatase staining of the femur were performed. Immunohistochemistry was used to detect the protein expression of receptor activator of nuclear factor-κB ligand and osteoprotectin in the femur. ELISA was used to detect the serum levels of carboxyterminal cross-linked telopeptides of type I collagen and tartrate-resistant acid phosphatase 5b. RESULTS AND CONCLUSION: (1) Compared with the sham operation group, the model group showed a significant decrease in bone mineral density, sparse and fractured trabecular morphology, and a significant increase in serum levels of carboxyterminal cross-linked telopeptides of type I collagen and tartrateresistant acid phosphatase 5b, indicating that the model of aromatase inhibitor-induced osteoporosis was successfully constructed. (2) Compared with the model group, the high-, medium-, and low-dose Huangqi Bushen Huoxue Decoction groups showed significant improvement in bone mineral density and bone microstructure, thickening and densification of trabecular morphology, significantly decreased serum levels of carboxyterminal cross-linked telopeptides of type I collagen and tartrate-resistant acid phosphatase 5b, a decrease in the number of osteoclasts and the expression of receptor activator of nuclear factorκB ligand proteins, and an increase in the expression of osteoprotegerin. To conclude, Huangqi Bushen Huoxue Decoction may regulate the receptor activator of nuclear factor-κB ligand/receptor activator of nuclear factor-κB/osteoprotegerin signaling pathway, inhibit osteoclast activity, improve trabecular morphology and bone microstructure, and increase bone mineral density, thus preventing the occurrence and development of aromatase inhibitor-induced osteoporosis. [ABSTRACT FROM AUTHOR]

BACKGROUND: The research of dental stem cells in the fields of regenerative medicine and tissue engineering has been deepening, bringing hope for the repair of tooth-related tissues and the treatment of systemic diseases. However, there is a lack of systematic research and analysis on the biological characteristics of dental stem cells in different age groups. OBJECTIVE: To explore the biological characteristics of the human deciduous tooth and permanent tooth pulp stem cells cultured in umbilical cord blood platelet lysate to provide a reliable basis for human platelet lysates to replace fetal bovine serum. METHODS: The pulp tissues of deciduous teeth, juvenile permanent teeth and adult permanent teeth were taken out and cultured in DMEM/F-12 medium supplemented with 10% fetal bovine serum or different concentrations (5%, 10% and 15%) of human platelet lysates. Cell proliferation in the four groups was detected by cytometry. The optimal concentration of human platelet lysates was selected for subsequent experiments. Under the optimal concentration of human platelet lysates, human deciduous tooth and juvenile and adult permanent tooth pulp stem cells were cultured in vitro. The cell growth status was observed under the microscope. The specific antigen on the cell surface was detected by flow cytometry. The cell proliferation ability was tested by the cell counting method and CCK-8 assay. The cell differentiation ability in vitro was observed by a three-line differentiation assay. RESULTS AND CONCLUSION: (1) The cell proliferation rate of the 10% human platelet lysate group was the highest. (2) In all three groups, fusiform fibrous cells grew and expanded from around the tissue block. There was no significant difference between deciduous teeth and juvenile permanent tooth cells, but the adult permanent tooth cells were larger than the deciduous and juvenile permanent tooth cells of the same generation. (3) The results of flow cytometry showed that deciduous teeth, juvenile permanent teeth and adult permanent teeth conformed to the phenotypic characteristics of mesenchymal stem cells. (4) The proliferative capacity of adult permanent dental pulp stem cells was significantly lower than those of deciduous teeth and juvenile permanent dental pulp stem cells (P < 0.01). (5) mRNA expressions of osteoblast-related genes alkaline phosphatase and bone morphogenetic protein 2, lipoprotein lipase and peroxisome proliferator-activated receptor γ2, mRNA expressions of chondroblast related gene type II collagen α1 and cartilage oligomeric matrix protein in adult pulp stem cells of permanent teeth were significantly lower than those of deciduous teeth and juvenile permanent teeth pulp stem cells (P < 0.01). (6) Compared with adult dental pulp stem cells, human deciduous teeth and juvenile permanent teeth dental pulp stem cells have the stronger proliferative capacity and multidirectional differentiation potential, and are more suitable for clinical research and disease treatment. [ABSTRACT FROM AUTHOR]

BACKGROUND: Natural bone morphogenetic protein 2 disperses and degrades rapidly in vivo, reducing local concentration and therapeutic efficacy. Simply combining bone morphogenetic protein 2 with tissue engineering scaffolds could not stay in vivo for a long time, making it difficult to achieve good sustained and controlled release effects. OBJECTIVE: To prepare and test the biological properties and chondrogenic induction effect of collagen-binding domain-bone morphogenetic protein 2-collagen cartilage scaffold. METHODS: SD rat tail collagen was extracted and a collagen cartilage scaffold was prepared using a vacuum freeze-drying machine chemical crosslinking method. The plasmid expressing collagen-binding domain-bone morphogenetic protein 2 was constructed by rapid cloning C112 homologous recombination, constructed by genetic engineering, and introduced into E. coli, and then collagen-binding domain-bone morphogenetic protein 2 was isolated and purified. Natural bone morphogenetic protein 2 and collagen-binding domain-bone morphogenetic protein 2 were combined with collagen cartilage scaffolds, respectively, to detect the release level of bone morphogenetic protein 2 in the scaffolds. The biocompatibility of collagen-binding domain-bone morphogenetic protein 2-collagen cartilage scaffold was detected by CCK-8 assay and F-Actin staining. Bone marrow mesenchymal stem cells were implanted on two kinds of collagen cartilage scaffolds for chondrogenic induction, and their chondrogenic induction activity was tested. RESULTS AND CONCLUSION: (1) The binding rate of collagen-binding domain-bone morphogenetic protein 2 to collagen cartilage scaffolds was higher than that of natural bone morphogenetic protein 2 (P < 0.05). After being immersed in PBS for 7 days in vitro, the release of bone morphogenetic protein 2 in the collagen-binding domain bone morphogenetic protein 2-collagen cartilage scaffold was smaller than that in the natural bone morphogenetic protein 2-collagen cartilage scaffold (P < 0.05). The results of the CCK-8 assay and F-Actin staining showed that the collagen-binding domain-bone morphogenetic protein 2-collagen cartilage scaffold had no obvious cytotoxicity and had good biocompatibility. (2) After 14 days of chondrogenic induction, ELISA detection demonstrated that the expressions of agglutincan and type II collagen A1 in the collagen-binding domain-bone morphogenetic protein 2-collagen cartilage scaffold group were higher than those in the natural bone morphogenetic protein 2-collagen cartilage scaffold group (P < 0.05). Under scanning electron microscopy, more bone marrow mesenchymal stem cells were observed on the inner wall of the pores of the two groups of scaffolds, and the cell morphology and size were the same, and the cells were closely arranged, without cell fragmentation or abnormal morphology. (3) The results indicate that the collagen-binding domain-bone morphogenetic protein 2-collagen cartilage scaffold has good biological properties and chondrogenic induction activity. [ABSTRACT FROM AUTHOR]

BACKGROUND: As a member of bone morphogenetic proteins, growth differentiation factor-5 shows promising potential in the application of cartilage and bone repair. The affinity of growth differentiation factor-5 onto bone tissue determines protein use efficiency, so it is of great significance to prepare growth differentiation factor-5 with bone targeting capability. OBJECTIVE: To modify growth differentiation factor-5 using bisphosphonates and investigate the effects of modified protein on the growth of preosteoblasts in mice. METHODS: Pamidronate disodium/growth differentiation factor-5 complex was prepared using chemical crosslinking to couple growth differentiation factor-5 with pamidronate disodium. The functional groups and structures of the complex were characterized using Fourier transform infrared spectroscopy and circular dichromatography. To determine the bone targeting in vitro, the binding of the modified growth differentiation factor-5 with calcium phosphate and in vitro release amount of growth differentiation factor-5 were measured with an ELISA kit. Growth differentiation factor-5 (control group) and the pamidronate disodium/growth differentiation factor-5 complex (experimental group) were co-cultured with preosteoblasts MC3T3-E1. Individually cultured cells were blank controls. The effect of the complex on cell proliferation and differentiation was evaluated. RESULTS AND CONCLUSION: (1) The infrared spectroscopy and circular dichromatography results indicated that the bisphosphonate/growth differentiation factor-5 complex was successfully prepared without significant changes in the protein secondary structure. In vitro protein adsorption results showed that growth differentiation factor-5 adsorption on calcium phosphate was increased by about one time after coupling with a bisphosphonate. In the presence of cysteine, growth differentiation factor-5 could be released from the bisphosphonate/growth differentiation factor-5 complex. (2) CCK-8 assay results showed that the absorbance value of the experimental group cultured for 4 and 7 days was higher than that of the control group and blank control group (P < 0.000 1). After 7 days of culture, the expression of alkaline phosphatase in the experimental group was significantly higher than that in the control group and blank control group (P < 0.000 1). After 13 days of culture, the content of calcium nodules in the experimental group was significantly higher than that in the control group and the blank control group (P < 0.000 1). The results of qRT-PCR showed that the mRNA expression of alkaline phosphatase, osteocalcin and Runx2 in the experimental group was higher than that in the control group and the blank control group after 7 days of culture (P < 0.01, P < 0.001, P < 0.000 1). (3) These findings exhibit that bisphosphonate modification can enhance the binding capacity of growth differentiation factor-5 to calcium phosphate as well as improve its biological activity. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study is based on the evidence that bone morphogenetic protein 2 plays an important role in osteogenesis and bone repair, and Schnurri3 can regulate the transforming growth factor-β signal transduction. OBJECTIVE: To investigate the effect of inhibiting Schnurri3 on bone morphogenetic protein 2-induced osteogenic differentiation of C3H10T1/2 cells. METHODS: Mouse mesenchymal stem cell line C3H10T1/2 cells were used as research materials. Four groups were set in this study: adenovirus-green fluorescent protein, adenovirus-bone morphogenetic protein 2, adenovirus-Simshn3 and adenovirus-bone morphogenetic protein 2+adenovirus-Simshn3. The expression of bone morphogenetic protein 2 was enhanced and the expression of Schnurri3 was inhibited. Alkaline phosphatase staining was used to detect the expression of alkaline phosphatase. The mRNA transcriptional levels of bone morphogenetic protein 2, Schnurri3, osteogenic and angiogenic markers were determined by RT-qPCR. Immunohistochemical staining was used to detect the expression of type I collagen, vascular endothelial growth factor and endothelial mucin. Alizarin red staining and semiquantitative analysis were used to detect calcium salt deposition levels. Subcutaneous stem cell implantation in nude mice was used to measure ectopic bone. RESULTS AND CONCLUSION: (1) Recombinant adenovirus-bone morphogenetic protein 2 could induce osteogenic differentiation of C3H10T1/2 cells. Compared with the adenovirus-bone morphogenetic protein 2 group, mRNA transcription levels of osteogenic markers alkaline phosphatase, type I collagen, osteoblast-specific transcription factor, osteocalcin, Runt related transcription factor 2 and angiogenic markers neurite guidance factor, vascular endothelial growth factor, von Willebrand factor, angiopoietin and endothelial mucin were significantly increased in the adenovirus-bone morphogenetic protein 2+adenovirus-Simshn3 group (P < 0.001). Simultaneously, it significantly enhanced the expression of type I collagen, vascular endothelial growth factor and endothelial mucin at the protein level (P < 0.05), and the calcium salt deposition level (P < 0.05). (2) The application of bone morphogenetic protein 2 and Schnurri3 alone could act on C3H10T1/2 cells to form ectopic bone blocks subcutaneously in nude mice. Bone morphogenetic protein 2 combined with Schnurri3 could form more significant ectopic bone blocks. (3) The results showed that inhibition of Schnurri3 significantly enhanced the osteogenic differentiation of C3H10T1/2 cells induced by bone morphogenetic protein 2, and enhanced the expression of angiogenesis factors mRNA and protein to regulate angiogenesis. [ABSTRACT FROM AUTHOR]

BACKGROUND: Less is reported about the effect of transforming growth factor-beta 3 and bone morphogenetic protein-2 on the proliferation and osteogenic differentiation of dental pulp stem cells. OBJECTIVE: To explore the effect of transforming growth factor-beta 3 and bone morphogenetic protein-2 on the osteogenic differentiation of dental pulp stem cells and its preliminary mechanism. METHODS: Dental pulp stem cells were isolated from the pulp tissue of New Zealand rabbit by the enzymatic digestion method. Dental pulp stem cells at passage 3 were divided into the blank group, bone morphogenetic protein-2 group (80 μg/L) and transforming growth factor-beta 3 group (80 μg/L). The cell proliferation activity in each group was tested by MTT assay. After 7 and 14 days of culture, alkaline phosphatase activities were measured. Runt-related transcription factor 2 and bone sialoprotein protein expression levels were conducted by immunocytochemical staining. Osteogenesis-related gene expression was tested through RT-qPCR method. Alizarin red S staining was conducted after 14 and 21 days of culture to observe mineralized nodules. RESULTS AND CONCLUSION: (1) Dental pulp stem cell proliferation activity and alkaline phosphatase activity were higher in the bone morphogenetic protein-2 and transforming growth factor-beta 3 groups than those in the blank group (P < 0.05). The alkaline phosphatase activity of the transforming growth factor-beta 3 group on day 7 was higher than that of the bone morphogenetic protein-2 group (P < 0.05). (2) The expression levels of Runt-related transcription factor 2 and bone sialoprotein in the transforming growth factor-beta 3 group and the bone morphogenetic protein-2 group were higher than those in the blank group (P < 0.05). The protein expression of Runt-related transcription factor 2 in the transforming growth factor-beta 3 group on day 7 was higher than that in the bone morphogenetic protein-2 group (P < 0.05). (3) The expression levels of alkaline phosphatase, type I collagen A1, Runt-related transcription factor 2, osteocalcin, osteopontin and Osx genes in the transforming growth factor-beta 3 group and bone morphogenetic protein-2 group were higher than those in the blank group (P < 0.05). On day 7, the expression levels of alkaline phosphatase, type I collagen A1, and Runt-related transcription factor 2 genes of transforming growth factor-beta 3 group were higher than those of bone morphogenetic protein-2 group (P < 0.05). (4) The mineralized nodules in the transforming growth factor-beta 3 group and bone morphogenetic protein-2 group were more obvious than those in the blank group. (5) The results show that transforming growth factor-beta 3 and bone morphogenetic protein-2 can improve the proliferation and osteogenic differentiation of dental pulp stem cells. The osteogenic induction ability of transforming growth factor-beta 3 on dental pulp stem cells was better than that of bone morphogenetic protein-2 at the early stage of osteogenesis. [ABSTRACT FROM AUTHOR]

BACKGROUND: How to effectively repair and reconstruct critical bone defects has become a difficult problem in clinical medicine. Dental pulp stem cells have certain advantages as transgenic target cells to repair damaged tissues or organs. OBJECTIVE: To investigate the effect of hypoxia-inducible factor-1α on osteogenesis and angiogenesis of dental pulp stem cells in vitro. METHODS: The pulp tissues of healthy and intact bicuspid teeth extracted by orthodontic treatment in patients aged 12 to 18 years were isolated to culture dental pulp stem cells. The hypoxia-inducible factor-1α gene was transfected into dental pulp stem cells in the experimental group. The control group did not do any treatment. The expression of the hypoxia-inducible factor 1α gene was detected by qPCR and the expression of osteogenic and angiogenic factors was detected by western blot assay. RESULTS AND CONCLUSION: (1) Dental pulp stem cells were short spindle-shaped fibroblast-like cells, and the cells grew in colonies. (2) Hypoxia-inducible factor-1α gene was stably transfected into dental pulp stem cells. The expression of the hypoxia-inducible factor-1α gene increased gradually with the extension of time, reached a peak at 14 days, and significantly decreased at 21 days. (3) Compared with the control group, the expression level of angiogenesis-related factors in the experimental group was higher. The protein expression levels of vascular endothelial growth factor, stromal cell-derived factor 1, angiopoietin 2, and placental growth factor were significantly increased at 1 day after gene transfection and reached a peak at 4 days. After that, the expression of angiogenesis-associated protein in the experimental group decreased slightly, but was significantly higher than that in the control group. (4) Compared with the control group, the expression level of osteogenic-related factors in the experimental group was higher. The protein expression levels of human bone morphogenetic protein 2, osteocalcin, and Runt-related transcription factor 2 were significantly increased at 1 day after gene transfection, with the highest protein expression at 4 days. (5) It is concluded that hypoxia-inducible factor-1α can promote the osteogenesis and the expression of angiogenic factors in dental pulp stem cells. [ABSTRACT FROM AUTHOR]

BACKGROUND: Repair of osteochondral defects is a major challenge that orthopedic surgeons face today, because current treatments fail to achieve satisfactory results. With the development of tissue engineering in recent years, new hope has been brought for the repair of osteochondral defects. Bone morphogenetic protein 2 is an important factor involved in bone growth, development, and repair, with good osteoinductive effects. In recent years, it has been found that bone morphogenetic protein 2 also has an effect on cartilage development. OBJECTIVE: To investigate the research progress of bone morphogenetic protein 2 in the repair of osteochondral defects in recent years and to provide new ideas and strategies for the treatment of osteochondral defects by summarizing the application of bone morphogenetic protein 2 in the repair of various types of bone defects. METHODS: WanFang, CNKI, and PubMed databases were searched for literature regarding the mechanism of bone morphogenetic protein 2 in the repair of osteochondral defects and its application in osteochondral tissue engineering published between January 1, 2012 and July 1, 2022. The search terms were “Bone morphogenetic protein 2, Chondrocytes, Cartilage defects, Bone defects, Mesenchymal stem cells, MSC, Signaling pathways” in Chinese and English. RESULTS AND CONCLUSION: Bone morphogenetic protein 2 promotes chondrogenic differentiation of mesenchymal stem cells and can maintain the chondrocyte phenotype to maintain cartilage properties. Bone morphogenetic protein 2 controls chondrogenesis by regulating chondrocyte glucose metabolism. Bone morphogenetic protein 2 acts on osteogenesis through the classical Smad 1/5/8 signaling pathway, but the mechanism of chondrogenesis is not clear. The current research and application of bone morphogenetic protein 2 in tissue engineering mainly focus on the field of bone defect repair, and less is reported on cartilage defect repair. How to prevent bone morphogenetic protein 2 from promoting the transformation of chondrocytes to hypertrophic chondrocytes will be the focus of future research. [ABSTRACT FROM AUTHOR]

BACKGROUND: Chlorogenic acid is the most abundant polyphenol in dried plums, which, as a food-derived drug, is expected to be used in the treatment of osteoporosis. OBJECTIVE: To investigate the effect of chlorogenic acid on osteogenic differentiation of osteogenic precursor cells and its mechanism and to verify its effect on bone loss in a mouse model of osteoporosis. METHODS: (1) In vitro test: MC3T3-E1 cells were cultured in vitro with different concentrations of chlorogenic acid (0, 0.1, 1, 10, 100 mg/L) and cell proliferation was detected using cell counting kit-8. MC3T3-E1 cells were cultured in osteogenic induction media containing 0, 10, 20 mg/L chlorogenic acid, followed by alkaline phosphatase staining, alizarin red staining, and detection of osteogenic genes and BMP-2/RUNX2/SMAD4 signaling pathway-related proteins. (2) In vivo test: Thirty-two female C57BL/6 mice were randomly divided into four groups, sham operation group, ovariectomized group, and low- and high-dose chlorogenic acid groups, with 8 mice in each group. An ovariectomized mouse model was established, and chlorogenic acid was then administered at high (50 mg/kg/d) and low (25 mg/kg/d) concentrations in the latter two groups for 8 continuous weeks, respectively. Micro-CT scan and histomorphology analysis were performed on the femur and tibia of the mice 8 weeks later. RESULTS AND CONCLUSION: (1) In vitro test: Chlorogenic acid at a concentration of ≤ 10 mg/L had no obvious effects on the proliferation of MC3T3-E1 cells. With the increased concentration of chlorogenic acid, the alkaline phosphatase activity, calcium deposition and calcium nodule formation ability of MC3T3-E1 cells increased; the mRNA expression levels of osteogenesis-related genes, alkaline phosphatase, osteopontin, osteocalcin, bone morphogenetic protein 2, RUNX2 and SMAD4 increased; and the protein expression levels of bone morphogenetic protein 2, RUNX2, and SMAD4 increased. (2) In vivo test: Micro-CT scan results showed that compared with the sham operation group, the bone mineral density, bone volume fraction, thickness and number of trabecular bone were significantly lower in the ovariectomized group (P < 0.05) and trabecular separation degree was significantly higher in the ovariectomized group (P < 0.05). Treatment with different concentrations of chlorogenic acid could certainly improve the above-mentioned indicators and the high-dose chlorogenic acid group showed significant changes in these indicators (P < 0.05). Hematoxylin-eosin staining showed less bone mass in the ovariectomized group than the sham operation group, and the bone mass increased after chlorogenic acid intervention. (3) To conclude, chlorogenic acid may promote osteogenic differentiation through the BMP-2/RUNX2/SMAD4 signaling pathway and prevent bone loss in ovariectomized mice. [ABSTRACT FROM AUTHOR]

BACKGROUND: Previous studies have confirmed that miR-27b at the lipid level can control multiple genes that have an important impact on dyslipidemia. It is speculated that miR-27b may function in osteoporosis by targeting peroxisome proliferators-activated receptors γ2 (PPARγ2). OBJECTIVE: To investigate the effect of miR-27b/PPARγ2 axis in the dexamethasone-induced osteoporosis model in mouse embryonic osteogenic precursor cells MC3T3-E1 and related mechanisms of action. METHODS: After MC3T3-E1 cells were dexamethasone-induced and cultured in vitro, miR-27b mimic, miR-27b inhibitor, NC-mimic, NC-inhibitor, siPPARγ2, and siNC were transfected with Lipofectamine®2000, and dimethyl sulfoxide was used as a control. After the cells were induced and cultured, the cell viability and alkaline phosphatase activity were detected to determine the osteogenesis and differentiation levels of the cells. The mRNA and protein expression levels of osteogenic differentiation genes miR-27B, PPARγ2, Runt-related transcription factor 2 (Runx2), bone morphogenetic protein 2 and osteocalcin were detected by real-time fluorescence quantitative PCR and western blot methods. Bioinformatics analysis predicted the downstream target genes of miR-27b followed by verification with dual luciferase gene reporter experiments. RESULTS AND CONCLUSION: Dexamethasone treatment significantly reduced cell viability and miR-27b expression levels in MC3T3-E1 pre-osteoblasts. Compared with dimethyl sulfoxide, dexamethasone significantly inhibited MC3T3-E1 cell viability and downregulated miR-27b expression levels at 24 and 48 hours. miR-27b could directly regulate PPARγ2. Compared with the corresponding NC-mimic, the miR-27b mimic significantly upregulated the expression level of miR-27b, while the miR-27b inhibitor significantly downregulated the expression level of miR-27b. Furthermore, PPARγ2 miRNA and protein expression levels were inhibited by the miR-27b mimic and significantly enhanced by the miR-27b inhibitor. miR-27b overexpression attenuated the inhibitory effect of dexamethasone on the proliferation and osteogenic differentiation of MC3T3-E1 pre-osteoblasts. Dexamethasone significantly inhibited osteoblast differentiation compared with the dimethyl sulfoxide + NC-mimic group. In contrast, the dexamethasone-mediated inhibition was reversed by the miR-27b mimic. Cellular alkaline phosphatase activity and bone morphogenetic protein 2, Runx2 and osteocalcin protein expression levels were partially restored. Inhibition of miR-27b suppressed proliferation and osteogenic differentiation of MC3T3-E1 pre-osteoblasts through the upregulation of PPARγ2. Knockout of miR-27b significantly increased PPARγ2 expression and decreased cell viability, osteoblast differentiation, alkaline phosphatase activity, and expression levels of bone morphogenetic protein 2, Runx2 and osteocalcin. PPARγ2 may be a direct target of miR-27b. [ABSTRACT FROM AUTHOR]

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BACKGROUND: At present, human placental mesenchymal stem cells are rarely used in bone tissue engineering research, and the use of human placental mesenchymal stem cells in the treatment of osteoporotic fractures is likely to open new horizons for their therapeutic methods. OBJECTIVE: To investigate the mechanism of human placenta-derived mesenchymal stem cells in the treatment of tree shrews with osteoporotic fracture, and the effect of different drug delivery methods on the efficacy of tree shrews with osteoporotic fracture. METHODS: Bilateral ovaries and uterus were removed from female tree shrews to simulate postmenopausal osteoporosis, and they were naturally fed for 180 days. The osteoporotic fracture tree shrew model was established by performing a right femoral fracture. The 24 tree shrews with osteoporotic fracture were randomly divided into four groups. We adjusted the concentration of the human placenta-derived mesenchymal stem cells to 1×109 L-1. In the tail vein injection group, human placenta-derived mesenchymal stem cells were injected with 1 mL in the tail vein. In the tail vein combined with fracture injection group, human placenta-derived mesenchymal stem cells were injected with 0.5 mL in the tail vein and 0.5 mL at the fracture site. In the tail vein combined with intraperitoneal injection group, human placenta-derived mesenchymal stem cells were injected with 0.5 mL in the enterocoelia and 0.5 mL in the tail vein. In the model group, 1 mL physiological saline was injected through tail vein. From the 3rd day after the fracture, tree shrews were injected once a week and three times in a row. Eight weeks after the last treatment, bone mineral density was tested in tree shrews of each group. Three-point bone biomechanics and hematoxylin-eosin staining experiments were performed on the femurs of tree shrews in each group. The expression levels of osteocalcin, estrogen, bone alkaline phosphatase and tartrate resistant acid phosphatase were measured by ELISA in all groups. The mRNA expression levels of bone morphogenetic protein-2, osteoprotegerin and receptor activator of nuclear factor-κB ligand were measured by quantitative real time polymerase chain reaction. RESULTS AND CONCLUSION: (1) Eight weeks after the last treatment, compared with the model group, the other three groups showed increased bone mineral density, maximum load, structural stiffness and energy absorption, with tail vein injection group showed the most significant increase. (2) Serum estrogen, bone alkaline phosphatase and osteocalcin expression levels in tail vein injection group, tail vein combined with fracture injection group, and tail vein combined with intraperitoneal injection group increased significantly compared with the model group. Serum tartrate resistant acid phosphatase levels decreased significantly in the tail vein injection group, tail vein combined with fracture injection group, and tail vein combined with intraperitoneal injection group compared with the model group. These serum detection results showed the most obvious improvement in tail vein injection group. (3) Hematoxylineosin staining showed significant improvement of pathological changes in tail vein injection group and tail vein combined with fracture injection group. (4) The expression level of osteoprotegerin and bone morphogenetic protein-2 mRNA in tail vein injection group, tail vein combined with fracture injection group, and tail vein combined with intraperitoneal injection group increased to varying degrees compared with model group; the tail vein combined with fracture injection group had the highest level. (5) The expression level of receptor activator of nuclear factor-κB ligand mRNA in tail vein injection group, tail vein combined with fracture injection group, and tail vein combined with intraperitoneal injection group decreased to different degrees compared with model group, with tail vein combined with fracture injection group having the lowest level. (6) It is concluded that human placenta-derived mesenchymal stem cell transplantation can effectively improve the symptom of tree shrews with osteoporotic fracture, increase bone formation indexes such as bone alkaline phosphatase, osteocalcin and osteoprotegerin, decrease bone resorption indexes such as tartrate resistant acid phosphatase and receptor activator of nuclear factor-κB ligand, and improve bone mineral density and bone biomechanics of tree shrews. Tail vein injection group had the best results for systemic treatment and tail vein combined with fracture injection group showed better results for treatment at the fracture site. [ABSTRACT FROM AUTHOR]

BACKGROUND: Exercise training can maintain bone mass and improve bone mineral density. However, its effect on senile osteoporosis and its possible mechanism are not clear. OBJECTIVE: To study the effects of exercise training on senile osteoporosis and to explore its possible molecular mechanism. METHODS: Sixteen Sprague-Dawley rats aged 24 months old were regarded as the model of senile osteoporosis and randomly divided into elderly model group (n=8) and exercise training group (n=8), while eight young Sprague-Dawley rats of 3 months old were randomly selected as young control group. All rats moved freely in their cages and those in the exercise training group underwent exercise training every day for 8 weeks. After 8 weeks of intervention, serum bone-specific alkaline phosphatase, type I procollagen amino-terminal peptide, tartrate-resistant acid phosphatase 5b and type I collagen aminoterminal peptide were detected using ELISA assay. Bone mineral density of the femur and the fourth lumbar vertebra were measured by dual energy X-ray absorptiometry, while bone microstructural parameters of the tibia and the fifth lumbar vertebra were determined by Micro-CT in each group. mRNA and protein expressions of bone morphogenetic protein 2, Runt-related transcription factor 2, Osterix, and peroxisome proliferator-activated receptor γ in bone marrow of the femur were detected by reverse transcriptase polymerase chain reaction and western blot. RESULTS AND CONCLUSION: Compared with the elderly model group, the serum levels of bone-specific alkaline phosphatase and type I procollagen aminoterminal peptide (P < 0.05), bone mineral density of the femur (P < 0.05) but not that of the fourth lumbar vertebra (P > 0.05), bone volume fraction and trabecular number of the tibia (P < 0.05), and the mRNA and protein expression of bone morphogenetic protein 2, Runt-related transcription factor 2, and Osterix in the femur (P < 0.05) were significantly increased in the elderly model group, while the serum levels of tartrate-resistant acid phosphatase 5b and type I collagen amino-terminal peptide (P < 0.05), trabecular separation of the tibia and the fifth lumbar vertebra (P < 0.05), and the mRNA and protein expression of peroxisome proliferator-activated receptor γ were significantly decreased (P < 0.05). In addition, exercise training could improve the bone volume fraction, trabecular number and trabecular thickness of the fifth lumbar vertebra in rats with senile osteoporosis, although the differences in changes were not always statistically significant (P > 0.05). The trabecular thickness of the tibia had no significant changes after exercise training (P > 0.05). To conclude, exercise training can significantly improve bone mineral density and bone microstructure, promote osteogenic differentiation, and inhibit adipogenic differentiation in aged osteoporotic rats. The mechanism may be related to the bone morphogenetic protein 2/Runt-related transcription factor 2/Osterix signaling pathway. [ABSTRACT FROM AUTHOR]

BACKGROUND: Osteoclasts are the only known type of bone resorption cells, and its life activities are essential to the normal development of bones and the repair of bone damage. Osteoclasts show abnormal proliferation and differentiation and increased bone resorption activity in most bone diseases, while receptor activator of nuclear factor-kappa B (RANK) is a key signal pathway that regulates osteoclastogenesis. OBJECTIVE: To summarize the latest research progress on the downstream targets of osteoclast RANK signal and DNA transcription factors at home and abroad, and provide a basis for the research and treatment of related diseases. METHODS: A computer-based retrieval was conducted in CNKI, WanFang, VIP, PubMed, Embase and Web of Science databases. The search terms were “osteoclasts, osteoclast precursor cells, osteoporosis, bone metabolism, pathogenesis, epigenetics, signaling pathway, signal transduction, transcription factors, tissue engineering” in Chinese and English. The retrieval time was set to 2017-2021. Finally 52 articles were included according to the inclusion and exclusion criteria. RESULTS AND CONCLUSION: The special structure of RANK determines that its signal transduction needs to be combined with tumor necrosis factor receptorassociated factor 6 to recruit a variety of proteins, active enzymes and cytokines to form a RANK complex with intrinsic enzyme activity. This complex then activates nuclear factor-κB, mitogen-activated protein kinase and other signal pathways, ultimately regulating osteoclast differentiation, proliferation, and bone resorption. [ABSTRACT FROM AUTHOR]

BACKGROUND: Endplate chondrocytes are regulated by many factors in the microenvironment of the intervertebral disc and the influence of microenvironmental changes inside the intervertebral disc caused by abnormal stress on endplate chondrocytes still needs to be explored. OBJECTIVE: To observe the exosome secretion of nucleus pulposus cells under cyclic mechanical tension conditions and the effect of exosomes on endplate chondrocytes under this condition. METHODS: Nucleus pulposus cells were isolated and cultured from the nucleus pulposus of patients undergoing lumbar surgery in vitro. The cells were loaded with cyclic mechanical tension by FX-5000T system. Exosomes secreted from nucleus pulposus cells under stress and non-stress conditions were extracted by magnetic bead method. Purity and concentration of nucleus pulposus cells-derived exosomes were identified by flow cytometry. The exosomes were labeled with PKH67 fluorescent dye and incubated with endplate chondrocytes for 24 hours. Endplate chondrocytes cultured alone were used as control. The uptake of exosomes by endplate chondrocytes was observed under inverted fluorescence microscope. Then the apoptosis and activity of endplate chondrocytes were observed. Type II collagen, depolymerized protein like metalloproteinase 5, matrix metalloproteinase 3, bone morphogenetic protein 2, and β-catenin mRNA expression were detected. RESULTS AND CONCLUSION: Under certain cyclic mechanical tension conditions, nucleus pulposus cells could be promoted to secrete exosomes, and the particle concentration of nucleus pulposus cells-derived exosomes was higher than that under non-stress conditions. Under the inverted fluorescence microscope, both stress and non-stress nucleus pulposus cells-derived exosomes could be ingested by endplate chondrocytes. Compared with the control group, the viability of endplate chondrocytes decreased significantly (P < 0.05) and the apoptosis rate increased in the stress group (P < 0.05). Compared with the control group, the mRNA expression of matrix metalloproteinase 3 and bone morphogenetic protein 2 in endplate chondrocytes decreased significantly in the non-stress group (P < 0.05). Compared with the control group, the mRNA expression of type I collagen decreased significantly in the stress group (P < 0.05), while the mRNA expression of depolymerized protein like metalloproteinase 5, matrix metalloproteinase 3 and β-catenin increased significantly in the stress group (P < 0.05). Compared with the non-stress group, the mRNA expression of type II collagen decreased significantly in the stress group, while the mRNA expression of depolymerized protein like metalloproteinase 5, matrix metalloproteinase 3 and bone morphogenetic protein 2 increased significantly in the stress group (P < 0.05). Therefore, abnormal stress could promote the exosome secretion of nucleus pulposus cells, and the exosomes under this condition could inhibit the viability of endplate chondrocytes and cause the disorder of cell matrix synthesis and catabolism. [ABSTRACT FROM AUTHOR]

【Objective】 Cloning and bioinformatics analysis of Bone morphogenetic protein receptor II (BMPRII)gene were carried out, and its expression differences in different tissues of Tibetan sheep were detected, which provided a reference for studying the biological function of BMPRII gene in Tibetan sheep.【Method】 In the present experiment, six Tibetan sheep with similar age and body weight were randomly selected for slaughter and samples of each tissue were collected. RNA was extracted and quality detection was performed, and Real-time qPCR was used to detect the expression levels of BMPRII gene in 13 tissues, including hypothalamus, pituitary, heart, liver, spleen, lung, kidney, ovary, uterus, oviduct, rumen, duodenum and longissimus dorsi of Tibetan sheep, and to analyze the specific expression and distribution of BMPRII gene in different tissues of Tibetan sheep. Coding region of BMPRII gene sequence in Tibetan sheep was amplified and analyzed through PCR, cloning, sequencing and the bioinformatics tools.【Result】BMPRII gene was expressed widely in all the above 13 tissues. The expression in liver was higher than that in uterus, ovary and spleen, but did not reach a significant level (P＞0.05), and significantly higher than that in other tissues (P＜0.05). The lowest expression was found in the longissimus dorsi. The CDS sequence of Tibetan sheep BMPRII gene was 3117 bp, encoding 1038 amino acids. The amino acid sequence of BMPRII was most closely related to sheep, cattle and yaks, and the furthest from zebras and chickens. Tibetan sheep BMPRII protein was a hydrophilic secretory protein with instability, containing 1 transmembrane structure and signal peptide, with 127 potential phosphorylation sites and 14 potential N-glycosylation sites, mainly distributed outside the cell. The secondary structure of Tibetan sheep BMPRII protein was mainly random coiling, followed by α-helix, extended chain and β-angle, and the prediction results of the tertiary structure were consistent with the secondary structure. 【Conclusion】BMPRII gene plays an important role in various physiological activities of Tibetan sheep. The results of experiment provide basic data for further research on the regulation mechanism of BMPRII gene of Tibetan sheep on reproductive performance of Tibetan sheep. [ABSTRACT FROM AUTHOR]

BACKGROUND: Signal peptide-CUB-EGF-like domain-containing protein (SCUBE) can act as a coreceptor and/or a ligand to activate signaling pathways, such as bone morphogenetic protein, vascular endothelial growth factor, transforming growth factor β, and hedgehog, and plays an important role in a variety of physiological and pathological processes OBJECTIVE: To review relevant literature worldwide and summarize the research progress in the structure and function of SCUBE family, as well as their roles in embryonic development and disease occurrence. METHODS: The first author used a computer to search for related articles included in PubMed and CNKI databases from 2000 to 2021. The search terms were “SCUBE, EGF family, structure and function, coreceptor, signaling pathways, embryonic development, disease, mechanism, tumor, protein, gene” in English and Chinese, respectively. According to the inclusion criteria, 68 articles were selected for review. RESULTS AND CONCLUSION: The SCUBE family includes three independent members, SCUBE1, SCUBE2, and SCUBE3. SCUBE family members share five similar domains, including one amino-terminal signal peptide sequence, nine tandemly arranged epidermal growth factor-like repeats, one amino glycosylation spacer, three cysteine-rich domains, and one carboxy-terminal CUB-like domain. SCUBE family members can act as coreceptors and/or ligands, binding through their special CUB-like domains to activate multiple signaling pathways including bone morphogenetic protein, transforming growth factor β and vascular endothelial growth factor and produce corresponding biological effects. SCUBE family members are widely expressed in a variety of tissues and organs, and have a dynamic expression pattern during vertebrate embryonic development. The SCUBE family is closely related to the occurrence of diseases, and can be used as key therapeutic targets for diseases such as bone and tooth dysplasia, vascular dysplasia, autoimmune diseases and tumors. SCUBE family members play an important role in embryonic development and disease occurrence. They can not only be used as therapeutic targets for diseases, but also have broad application prospects in the field of tissue engineering regeneration in the future. However, their specific functions and mechanisms still need to be further studied. [ABSTRACT FROM AUTHOR]

BACKGROUND: Xianling Gubao Capsules (a commonly used Chinese medicine in orthopedic surgery) can improve bone metabolism and prevent osteoporosis; however, whether it has a preventive effect or a possible mechanism on osteoporosis complicated by diabetes has been rarely reported. OBJECTIVE: To investigate the effects of Xianling Gubao Capsules on bone metabolism and related osteogenic marker factors Wnt3a, β-catenin and bone morphogenetic protein-2 in rats with diabetes mellitus complicated by osteoporosis and to explore their mechanisms of action. METHODS: Thirty-six male healthy 8-week-old Sprague-Dawley rats were treated with streptozotocin at a dose of 60 mg/kg to establish a diabetes mellitus model and were then randomly divided into model group, Xianling Gubao Capsule group and alendronate group, with 12 rats in each group. Another 12 normal rats were used as the normal group. Rats in the Xianling Gubao Capsule group and alendronate group were given Xianling Gubao Capsule and alendronate sodium suspension by gavage for 12 weeks, respectively. Rats in the normal and model groups were gavaged with the same amount of double-distilled water for 12 weeks. Blood glucose level of model rats was measured once a week during the administration period to ensure the accuracy of the experiment. Femur, tibia and systemic bone mineral density in each group were measured by dual energy X-ray absorptiometry. Hematoxylin-eosin staining was used to observe the morphological changes of the right femur in each group. Immunohistochemistry and RT-PCR were applied to detect the expression of osteogenic marker factors Wnt3a, β-catenin, and bone morphogenetic protein-2 at protein and mRNA levels. RESULTS AND CONCLUSION: Compared with the model group, the femur, tibia and systemic bone mineral density values of rats increased significantly in the Xianling Gubao Capsule group (P < 0.05). The mRNA and protein expressions of Wnt3a, β-catenin, and bone morphogenetic protein-2 in bone tissues decreased significantly in the model group (P < 0.05). While compared with the model group, the mRNA and protein expressions of Wnt3a, β-catenin, and bone morphogenetic protein-2 were significantly increased in the Xianling Gubao Capsule group (P < 0.05). In addition, there was no significant difference in the expressions of above-mentioned indicators between the Xianling Gubao Capsule group and alendronate group. These findings confirmed that Xianling Gubao Capsules exert a protective effect on bone metabolism in diabetic rats by the Wnt /β-catenin signaling pathway. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Clinical studies have shown that Guyuling capsule is effective in the treatment of osteoporosis, but the mechanism is not clear. OBJECTIVE: To screen out the active components acting on osteoporosis-related target proteins in Guyuling capsule by molecular docking technique in bioinformatics. METHODS: The chemical components of Guyuling capsule were screened by Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform database (TCMSP) and traditional Chinese medicine comprehensive database (TCMID). The screening conditions were bioavailability ≥ 20% and drug likeness ≥ 0.18. The target protein library related to osteoporosis was constructed according to the literature and database. Drug absorption, distribution, metabolism, excretion and toxicity (ADMET) prediction and molecular docking were carried out by Discovery Studio 2016 software. RESULTS AND CONCLUSION: (1)In total 130 potential active components with good bioavailability of Guyuling capsule were screened and downloaded from traditional Chinese medicine database. Sixty-three active components with good absorption and low toxicity were screened by ADMET prediction function of Discovery Studio 2016, such as L-α-glycerol palmitate, sesamin and so on. (2)By consulting the literature and database, 17 membrane protein receptors were selected, such as extracellular signal-regulated kinase 1/2, protein kinase, and glycogen synthase kinase-3, which are definitely related to osteoporosis. It is mainly related to mitogen-activated protein kinase signal pathway and bone morphogenetic protein signal pathway, which may promote bone formation by regulating the growth and differentiation of mesenchymal stem cells. (3)The results of molecular docking showed high docking scores between Sudihydrodehydropineol, (23E)-20, 25-dihydrodama-23-en-3-one, L-α-glycerol palmitate, sesamin, (24S)-20, 24-epoxy-25-hydroxydama resin-3-one and extracellular signal-regulated kinase 1/2, protein kinase, glycogen synthase kinase-3 and other membrane proteins. Osteoporosis may be treated by mainly regulating mitogen-activated protein kinase signaling pathway. (4)The above results confirm that the active components of Guyuling capsule, such as Su-typedihydrodehydropineol, (23E)-20, 25-dihydroxydama-23-en-3-one, L-α-glycerol palmitate, sesamin, (24S)-20, 24-epoxy-25-hydroxydama resin-3-one, may bind to membrane proteins such as extracellular signal-regulated kinase 1/2, protein kinase and glycogen synthase kinase-3 beta to regulate mitogen-activated protein kinase, bone morphogenetic protein, Wnt, estrogen receptor and other signal pathways, and then play the therapeutic efficacy on osteoporosis, thereby providing big data analysis basis and ideas for further experimental research. [ABSTRACT FROM AUTHOR]

BACKGROUND: It is of great significance for the design, processing and clinical application of medical metal implant materials to study the molecular mechanism of bone marrow mesenchymal stem cell osteogenic differentiation induced by different medical metal implant materials and to organize and analyze the comprehensive gene regulatory network of multiple osteogenic signaling pathways. OBJECTIVE: To review possible molecular mechanisms of bone marrow mesenchymal stem cell osteogenic differentiation induced by medical metal implant materials to provide theoretical basis for clinical application of different medical metal implant materials. METHODS: The articles were searched in PubMed, CNKI, and Wanfang databases with the key words of “osteogenic differentiation, signaling pathways, bone marrow mesenchymal stem cells, bone defect, bone repair materials, oral and maxillofacial restoration, implant, alloys” in Chinese and English, separately. Finally, 51 articles met the criteria for review. RESULTS AND CONCLUSION: (1) Bone marrow mesenchymal stem cells are a kind of pluripotent adult stem cells and an important source of stem cells for tissue engineering. The Wnt/β-catenin pathway, MAPK pathway and bone morphogenetic protein/Smad pathway can regulate and induce osteogenic differentiation of bone marrow mesenchymal stem cells. After implanted into human body, medical metal implant materials can release metal ions or stimulate the body to produce various cytokines and produce cascading effects to promote osteogenic differentiation of bone marrow mesenchymal stem cells, so as to promote bone regeneration and repair bone defects. (2) This review summarized and analyzed the osteogenic signaling pathways (Wnt/β-catenin pathway, MAPK pathway, bone morphogenetic protein/Smad pathway, integrin pathway, phosphatidylinositol 3-kinase pathway, osteoprotegerin/RANKL/RANK pathway) involved in the promotion of osteogenic differentiation of bone marrow mesenchymal stem cells by different medical metal implant materials and bone repair materials with different surface treatments. (3) At present, many researches on the promotion of bone marrow mesenchymal stem cell osteogenic differentiation by medical metal materials in vitro and in vivo are mainly focused on a single signaling pathway, while multiple pathways related to osteogenic differentiation interact with each other and constitute a complex network. Current studies have not been able to fully reveal the specific mechanism of osteogenic differentiation. (4) From the perspective of osteogenic differentiation of bone marrow mesenchymal stem cells, we discussed and summarized the possible molecular mechanisms of different new medical metal implants regulating the induction of osteogenic differentiation of bone marrow mesenchymal stem cells, as well as the relationships among multiple signaling pathways and their roles. For example, when the Wnt/β-catenin signaling pathway is activated, it will stimulate cells to produce MAPK pathway and bone morphogenetic protein/Smad pathway initiating factors, such as epidermal growth factor and bone morphogenetic protein. These three signaling pathways work simultaneously. After entering the nucleus, it induces the transcription of osteogenic effect genes, thereby promoting the osteogenic differentiation of bone marrow mesenchymal stem cells, and forming a comprehensive gene regulatory network mechanism of multiple osteogenic signal pathways. [ABSTRACT FROM AUTHOR]

BACKGROUND: Type 2 diabetes mellitus is a disease caused by energy metabolism disorder. Muscles and bones participate in the body’s energy metabolism regulation through their endocrine function under the condition of exercise stimulation. Currently there are few studies on the mechanism of “Muscle-Bone” Crosstalk mediated exercise regulating bone metabolism in type 2 diabetes mellitus. OBJECTIVE: By analyzing how exercise regulates the expression level of “Muscle-Bone” Crosstalk secretion-related factors and acting on the pathological reasons of bone tissue, to explore the mechanism of bone metabolism mediated by “Muscle-Bone” Crosstalk exercise in type 2 diabetes mellitus. METHODS: CNKI, WanFang, and PubMed were searched for relevant literatures published in recent 10 years. The keywords were “exercise, type 2 diabetes mellitus, bone metabolism, “Muscle-Bone” Crosstalk, muscle factor” in Chinese and English, respectively. After screening, 50 eligible articles were analyzed and discussed. RESULTS AND CONCLUSION: Some of bioactive factors in muscles and bones act on the bones in an endocrine manner, such as myostatin, bone morphogenetic protein, musclin, etc., and the others act on the bones in a paracrine manner, such as insulin-like growth factor 1, interleukin 6, irisin, etc. These factors participate in the regulation of bone metabolism, balance the bone formation of osteoblasts and bone resorption of osteoclasts in bone tissue, and become the messenger factors of exercise-mediated musculoskeletal system. Exercise is an important means to regulate energy metabolism. Exercise-mediated internal stimulus changes can trigger the signal response of muscle cells and bone cells, activate Wnt, bone morphogenetic protein/Smads, transforming growth factor-β and other signal pathways, thereby regulating the endocrine function of the musculoskeletal system, promoting metabolic adaptation and influencing bone metabolism in type 2 diabetes mellitus. [ABSTRACT FROM AUTHOR]

BACKGROUND: Adequate bone grafting is very necessary during spinal fusion. However, due to the limited number of osteoblasts and the function of the bone microenvironment in elderly patients, as well as the in vivo application of bone morphogenetic protein 2 will cause adverse effects such as ectopic bone. The current method can cause nonunion and other complications. In this case, Nel-like molecule-1 (Nell-1) has entered the field of vision of researchers. Nell-1 is not only equivalent to BMP-2 in osteogenic activity, but also has anti-fat, anti-inflammatory, and pro-vascular properties. These laid the foundation for clinical trial approval of Nell-1 in promoting spinal fusion. OBJECTIVE: To review the effect and mechanism of Nell-1 on bone fusion after spinal fusion. METHODS: Relevant documents were retrieved in Baidu Academic, PubMed, Web of Science, Wanfang, and CNKI. The Chinese and the English search terms were “Nell-1, spinal fusion, bone fusion, pre-osteoblast differentiation, neovascularization, progenitor cell migration”. Finally, 68 articles were included for review. RESULTS AND CONCLUSION: Autologous bone grafting has complications and supply problems related to bone grafting. Bone graft replacement therapy represented by bone morphogenetic protein 2 will produce many non-target effects. Therefore, neither can meet the increasing demand for spinal fusion. In this context, the emergence of Nell-1 provides the possibility to solve this dilemma. Although the role of Nell-1 in promoting bone fusion after spinal fusion is still in the preliminary stage of research, there are still deficiencies in the lack of an optimal route of administration; the molecular mechanism is not fully understood; and whether there are adverse reactions related to the application. Nevertheless, it has the triple effect of promoting progenitor cell migration, pre-osteoblast differentiation, and vascularization, so it has great potential for promoting bone fusion after spinal fusion. Future research should further reveal the detailed underlying mechanism, optimize the dosage and schedule, explore the combined effect with other osteogenic growth factors and stem cells, and translate the potential of Nell-1 for promoting spinal fusion into clinical practice. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bone morphogenetic protein 9 (BMP9) possesses the potential to regulate the osteogenic differentiation of stem cells. A large number of studies have shown that BMP9 can promote the repair of bone defects in animals. OBJECTIVE: To explore the mechanism of BMP9 regulating stem cell differentiation, to discuss the potential factors affecting the promotion of stem cell osteogenic differentiation by BMP9, and to explore the application perspective of BMP9 in bone tissue engineering. METHODS: In PubMed, Web of Science, Wanfang, Weipu and CNKI, the authors searched the relevant literature from 1990 to 2020 with the keywords "bone morphogenetic protein 9/BMP9, mesenchymal stem cell, stem cell, bone regeneration, bone reconstruction". According to the inclusion and exclusion criteria, the repetitive, unrelated, or low-quality articles were excluded. Finally, 67 articles were summarized and analyzed. RESULTS AND CONCLUSION: As a key molecule of bone morphogenetic protein family, BMP9 has a strong ability to promote stem cell differentiation and bone tissue regeneration. BMP9 regulates stem cell differentiation mainly through BMP9-SMAD signal pathway and BMP9-MAPK signal pathway. TGFβ, Wnt/β-catenin and Notch signaling pathways can regulate the expression of key molecules in BMP9 signaling pathway to indirectly affect the osteogenic differentiation of BMP9. In oral and maxillofacial bone tissue engineering and osteoarticular disease model, BMP9 can significantly promote bone tissue regeneration, bone defect repair and bone tissue reconstruction. However, with the limitations of the existing research, the specific mechanism of BMP9 regulating stem cell differentiation and bone tissue regeneration remains to be further explored, and the toxic and side effects of stimulating BMP9 on other tissues and organs still need to be evaluated. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Regeneration of periosteal osteoblasts is essential for fracture healing. Runx2 is crucial for bone cell development and even for bone formation. OBJECTIVE: To review relevant domestic and foreign literatures, summarize the relationship between Runx2 gene and fracture healing, and understand the mechanism and prospect of Runx2 gene in fracture healing. METHODS: CNKI, WanFang, VIP, and PubMed databases were retrieved with the keywords of “runx2, fracture healing, osteoblasts, chondrocytes, osteoclasts” in Chinese and English, respectively. Literature reports related to the mechanism of Runx2 gene in fracture healing were included. According to the selection criteria, the literature was screened, and the repetitive research and the long-standing literature were excluded. A total of 52 articles were included for review and analysis. RESULTS AND CONCLUSION: Runx2 plays important roles in regulation of skeletal development-related genes. Runx2 regulates the processes of bone resorption, formation and remodeling by regulating osteoblasts, chondrocytes, osteoclasts and other bone cells. It also can maintain the formation and differentiation of osteoblasts by interaction with Wnt, bone morphogenetic protein/transforming growth factor β signaling pathways, parathyroid hormone and fibroblast growth factor molecules. Runx2 has been confirmed by a number of animal experiments that it can effectively regulate the transcription and related factors of osteocyte differentiation and proliferation. However, the mechanism of Runx2 in cytokines and signal pathways still remains unclear. [ABSTRACT FROM AUTHOR]

BACKGROUND: MicroRNAs (miR) is an important endogenous non-coding small RNA that regulates the expression of genes by regulating the translation of mRNA. In recent years, it has been found that miR-214 plays an important role in related bone metabolic signaling pathways, which can regulate bone resorption and bone formation by targeting related genes. OBJECTIVE: To review the new progress in the regulatory mechanism and possible application of miR-214 in bone metabolism. METHODS: The first author searched PubMed, Web of Science, and Medline with the keywords of “miRNA, miR-214, osteogenesis, osteoblast,” “miR-214, bone remodeling,” and “miR-214, osteoclast, tissue engineering” respectively for relevant literature published from 2005 to 2020. A total of 761 articles were preliminarily searched, and 63 articles that were related to the research purpose were selected and analyzed. RESULTS AND CONCLUSION: MiR-214 can promote osteoclast differentiation by targeting phosphatase-tensin homolog and tumor necrosis factor receptor associated factor 3, and inhibit osteoblast differentiation by targeting transforming growth factor β activated kinase 1 binding protein 2, cadherin protein β1, Osterix, activating transcription factor 4, α1 type IV collagen, baculovirus IAP repeat containing 7, fibroblast growth factor receptor 1, TAFA chemokine-like family member 5, and bone morphogenetic protein 2. Many studies have proved that silencing or overexpression of miR-214 can regulate bone metabolism. It is also found that miR-214 in serum or extracellular vesicles may be a marker for the diagnosis and prognosis of some diseases. It is the focus of its application research to combine miR-214 antagonists with bioscaffold materials to form a stable, efficient and safe sustained release system. Therefore, miR-214 may have great potential in the treatment of bone metabolic diseases in the future. [ABSTRACT FROM AUTHOR]

BACKGROUND: Demineralized bone matrix contains many kinds of active factors such as bone morphogenetic protein 2, which can promote bone marrow mesenchymal stem cells to transform into chondrocytes and promote their proliferation under specific joint microenvironment.OBJECTIVE: To explore the osteogenic differentiation of bone marrow mesenchymal stem cells in vitro induced by demineralized bone matrix and its research value as cell carrier scaffold in the treatment of bone defect. METHODS: Rat femur bone marrow mesenchymal stem cells were isolated and adhered with whole bone marrow. Bone marrow mesenchymal stem cells at passage 3 were selected and cultured with complete medium and 50 mg/L demineralized bone matrix inducer. The proliferation and viability of bone marrow mesenchymal stem cells were determined by CCK-8 assay. Alkaline phosphatase activities were quantitatively measured by enzyme labeling at 7 and 14 days after culture. Calcium nodule formation was observed by alizarin red staining 21 days after culture. The expression of osteogenesis-related factors was detected by qRT-PCR 21 days after culture. Demineralized bone matrix and bone marrow mesenchymal stem cells were cultured for 21 days. The adhesion of them was observed by ordinary optical inverted phase contrast microscope and scanning electron microscope. RESULTS AND CONCLUSION: (1) The number of cells on days 5 and 6 in the demineralized bone matrix group was higher than that in the complete medium group (P < 0.05). (2) Alkaline phosphatase activities were significantly higher in the demineralized bone matrix group than in the complete medium group at 7 and 14 days (P < 0.05). (3) Calcium nodules were more in the demineralized bone matrix group than in the complete medium group. (4) The expression of RUNX2, ALP, OCN and OPN was significantly higher in the demineralized bone matrix group than in the complete medium group (P < 0.05). (5) The adherence of bone marrow mesenchymal stem cells was good on the demineralized bone matrix; cells were distributed in the space between scaffolds and crawled with each other. (6) The results showed that demineralized bone matrix could induce bone marrow mesenchymal stem cells to differentiate into osteoblasts, and the adhesion was good, which provided theoretical reference for the research of tissue engineering composite materials. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bone morphogenetic proteins have strong bone induction properties and have been proved to promote bone healing in fracture, bone defect and other diseases. However, few studies are reported on the use of bone morphogenetic proteins in the treatment of bone nonunion, and the results of various studies remain controversial, which makes the role of bone morphogenetic proteins in the treatment of limb long bone nonunion unclear. OBJECTIVE: Meta-analysis was used to systematically evaluate the advantages and disadvantages of bone morphogenetic protein versus autogenous bone grafting in the treatment of limb long bone nonunion. METHODS: PubMed, Elsevier, Web of Science, Cochrane Library, CNKI and WanFang databases were searched to retrieve the randomized controlled trials and non-randomized controlled trials of bone morphogenetic proteins for limb long bone nonunion published before April 2019. Quality evaluation and data extraction of the included literatures were performed. Meta-analysis of outcome indicators was perfonned using RevMan 5.1 software provided by Cochrane system. RESULTS AND CONCLUSION: Eight articles were enrolled, including 4 randomized controlled trials and 4 non-randomized controlled trials, all of which were small sample-size studies involving 30-124 cases. A total of 613 cases of nonunion were included. In the study group, patients received bone morphogenetic proteins or bone morphogenetic proteins in combination with bone grafting. In the control group, patients received autologous bone grafting. Meta-analysis results showed that there were no significant differences in postoperative healing rate, infection rate, secondary operation rate, and postoperative improvement in limb function between study and control groups (P > 0.05). The mean healing time in the study group was significantly shorter than that in the control group [WMD=-1.24, 95%C/(-1.70, -0.79), P < 0.01]. Intraoperative blood loss in patients receiving simple bone morphogenetic protein was less than that in patients receiving autologous bone grafting (P < 0.05). The hospitalization cost of bone morphogenetic protein in combination with autologous bone grafting was significantly higher than that of autologous bone grafting (P < 0.01 ). There was no significant difference in hospital stay between patients receiving simple bone morphogenetic protein and patients receiving autologous bone grafting (P > 0.05). These results suggest that bone morphogenetic protein can provide a viable alternative to autologous bone grafting, and it is also a safe adjuvant for autologous bone grafting, which has the potential advantage of accelerating fracture healing, but the current evidence does not support bone morphogenetic protein in combination with autologous bone grafting. [ABSTRACT FROM AUTHOR]

BACKGROUND: Osteoporotic fracture combined with type 2 diabetic mellituus in female patients is often accompanied by dyslipidemia and hyperglycemia. In addition to insulin treatment, statins are often prescribed for combination therapy, but the combined effect of these two drugs on fracture healing has not been reported in such patients. OBJECTIVE: To investigate the effect of lovastatin combined with insulin on the fracture healing of bilateral ovariectomized rats suffering from type 2 diabetic mellitus. METHODS: The study was approved by the Ethical Committee of North China University of Science and Technology. Thirty-two female Sprague-Dawley rats were divided into control, diabetic ovariectomized, insulin and combined groups. A model of type 2 diabetes and osteoporosis fracture was established in all rats except for the control group. At 7 days after the type 2 diabetic model was successfully established by injection of streptozotocin, the rats in the insulin and combined groups received the subcutaneous injection of insulin (2-4 U in the morning, and 4-6 U in the evening) until the end of the experiment. The rats in the combined group were given 20 mg/kg lovastatin via gavage daily, and those in the other two groups were not treated. All rats were sacrificed at 3 weeks after fracture. Radiographic, clinical and histomorphometric detections of the callus were performed. The expression levels of bone morphogenetic protein 2, vascular endothelial growth factor and collagen type II were detected. All above results were used to analyze the fracture healing in each group. RESULTS AND CONCLUSION: (1) The radiographic score, micro-CT index, histologic score and the expression levels of vascular endothelial growth factor and collagen type II in the diabetic ovariectomized group were significantly poorer than those in the control group (P < 0.05). (2) All above indexes in the insulin group were significantly improved compared with the diabetic ovariectomized group (P < 0.05), which promoted the fracture healing of model rats. (3) After combined with lovastatin, although the expression levels of vascular endothelial growth factor and bone morphogenetic protein 2 in the callus were significantly increased (P < 0.05), there was no significant improvement in the radiographic appearance and microstructure of the callus. [ABSTRACT FROM AUTHOR]

BACKGROUND: Long-term use of dexamethasone as a glucocorticoid will destroy the dynamic balance of osteogenesis and osteoclastation, reduce bone mineral density, damage bone biomechanics. A regulation of receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG) protein pathway may be an approach to improve bone mineral density and bone biomechanics in dexamethasone-induced osteoporosis rats. OBJECTIVE: To investigate the effects of psoralen corylifolia extract on bone mineral density and bone biomechanics in dexamethasone-induced osteoporosis rats based on RANKL/OPG pathway. METHODS: Osteoporosis models were established in Wistar rats, SPF grade, using intramuscular injection of dexamethasone. Lentiviral vectors containing OPG gene interference fragments at concentration of 1×107 TU/mL were selected for subsequent experiments. The model rats were randomly divided into model group, no-load group (lentivirus empty vector), OPG silencing group (lentivirus vector containing OPG gene interference fragment), psoralen corylifolia extract group, psoralen corylifolia extract+OPG silencing group, with 12 rats in each group. Another 12 rats were selected as the control group. After drug treatment, bone mineral density of the left femur in rats was measured by bone densitometer; the elastic modulus, maximum load and yield load of the right femur of rats were measured by mechanical testing machine; the mineral salt content in the femur of rats was determined; the levels of RANKL and OPG in the serum of rats were detected by ELISA kit; and the expression levels of RANKL and OPG in bone tissues of rats were detected by western blot. The study protocol was approved by the Animal Ethics Committee of Qinghai University Medical School with an approval No. 2017081501. RESULTS AND CONCLUSION: (1) Bone mineral density, modulus of elasticity, maximum load, yield load, bone mineral salt content, serum OPG level and OPG protein expression in bone tissues were measured, which were lower in the model group than the control group, lower in the OPG silencing group than the model group, higher in the psoralea corylifolia extract group than the model group, and higher in the psoralen corylifolia extract+OPG silencing group than the OPG silencing group, but lower than the psoralea corylifolia extract group (all P < 0.05). (2) The level of RANKL in serum and the expression of RANKL in bone tissue were measured, which were higher in the model group than the control group, higher in the OPG silencing group than the model group, lower in the psoralea corylifolia extract group than the model group, and lower in the psoralen corylifolia extract+OPG silencing group than the OPG silencing group, but higher than the psoralea corylifolia extract group (all P < 0.05). (3) There was no significant difference in each index between model group and no-load group (P > 0.05). (4) All these findings indicate that psoralea corylifolia extract can increase bone mineral density and improve bone biomechanics in dexamethasone-induced osteoporosis rats, possibly by up-regulating the expression of OPG and down-regulating the expression of RANKL. [ABSTRACT FROM AUTHOR]

BACKGROUND: Psoralen is a plant estrogen, and a large number of studies have confirmed its role in promoting cell proliferation and differentiation. OBJECTIVE: To construct a cell-scaffold composite bone using psoralen, rabbit endosteal mesenchymal stem cells and polycaprolactone and to explore its effect on the treatment of rabbit nonunion. METHODS: (1) Rabbit endosteal mesenchymal stem cells were cultured and cultured until the third generation for each experiment. Passage 3 cells were seeded onto culture plates containing 50 mg/L bone morphogenetic protein 2 (positive control), 10-8, 10-7 and 10-6 mol/L psoralen (low-, middle-, and high-concentration psoralen groups) or the same volume of purified water (control group). The cell proliferation of each group was detected on the 3rd, 5th and 7th days after intervention using MTT method. (2) The three-dimensional polycaprolactone scaffold was added to the bottom of the cell culture plate, and rabbit endosteal mesenchymal stem cells were seeded into the scaffold at a density of 1×10³ per well. Then, 10-6 mol/L of psoralen was added. Cell-scaffold composite bone was taken after 21 days of culture. (3) Animal models of radial nonunion were established in 27 New Zealand white rabbits, and were then randomized into experimental, scaffold and control groups followed by implantation of cell-scaffold composite bone, simple scaffold, and nothing, respectively. Pathological hematoxylin-eosin staining for observation of bone healing was performed at the 2nd, 4th, and 8th weeks after surgery. Healing of nonunion was observed on the X-ray films that were taken at the 4th week after surgery. RESULTS AND CONCLUSION: (1) Three concentrations of psoralen could induce the proliferation of rabbit endosteal mesenchymal stem cells. Compared with the control group, 10-6 mol/L psoralen exerted the strongest stimulation effect on rabbit endosteal mesenchymal stem cells (P < 0.05), whereas there was no significant difference between high-concentration psoralen group positive control group (P > 0.05). (2) Pathological hematoxylin-eosin staining of radial nonunion showed that the number of osteoblasts in the experimental group was higher than that in the scaffold and control groups (P < 0.05). (3) The X-ray films revealed bone healing in the experimental group, partial healing in the scaffold group and non-healing in the control group. Overall findings indicate that psoralen can promote the proliferation of rabbit endostealmesenchymal stem cells, and the effect is certainly related to the concentration of psoralen. Psoralen can be combined with rabbit endosteal mesenchymal stem cells and polycaprolactone scaffold to form composite bone, achieving good outcomes in the treatment of nonunion in animals. [ABSTRACT FROM AUTHOR]

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PURPOSE: To Investigate the mechanism of bone morphogenetic protein receptor (BMP-R) on inducing the osteogenesis of rat bone marrow stromal cells. METHODS: BMSCs were harvested from rats and induced in control medium (CM), osteogenic medium (OM), BMP-2, and OM with BMP-2. Alkaline phosphatase (ALP) activity assay and Von Kossa staining were used to assess the differentiation. BMP receptor (BMP-R) was also assessed using RT-PCR.SPSS 16.0 software package was used for data analysis with one-way ANOVA. RESULTS: BMSCs underwent osteogenic differentiation in OM group, showing high level of ALP activity and matrix mineralization. BMP-2 increased osteogenesis of BMSCs induced by OM. Significant BMP-R I A, BMP-R II expression could be detected in BMSCs in OM after 3 days of stimulation, while BMP receptors were later detected in BMSCs in BMP-2. CONCLUSIONS: BMP-2 can increase osteogenesis of BMSCs induced by OM. BMP receptors have a strong effect on the osteogenic differentiation of BMSCs. Supported by Natural Science Foundation of Guangdong Province (9151008901000035) and Project of Science and Technology plan of Guangdong Province (200813080701002). [ABSTRACT FROM AUTHOR]

Objective: Conventional deletion of ALK3, also termed as bone morphogenetic protein (BMP) receptor IA, in mice might result in early embryonic lethality. To investigate the function of ALK3 in cardiac development, the cardiac-specific deletion of ALK3 in mice was made by Dr. Schneider, using Cre recombinase driven by the alpha-MHC promoter that Dr. Fukushipe worked out. Such specific deletion of ALK3 caused death in mid-gestation with defects in the trabeculae, interventricular septum, and endocardial cushion. Since ALK3 is not a cardiac-specific gene, it is extremely important to identify ALK3 downstream genes., Methods: Alpha-MHC Cre+/-, ALK3 F/- and alpha-MHC Cre+/-, ALK3 F/+ embryos were obtained after 20 alpha-MHC Cre+/-, ALK3 +/- mice and 20 ALK3 F/F mice were mating. The ALK3 downstream genes were screened using microarray made in Germany that could identify 25000 genes in mouse. Two populations of mRNA, one derived from the embryonic heart (11.5 days) of alpha-MHC Cre+/-, ALK3 F/- mice, and the other derived from the alpha-MHC Cre+/-, ALK3 F/+ mice, were compared. Cardiac-specific ALK3 downstream genes were identified using real time quantitative RT-PCR and in situ hybridization., Results: The expression of 12 genes, such as Pax-8 and Hox-3.5 were down-regulated in alpha-MHC Cre+/-, ALK3 F/- mouse heart. The expression of 16 genes including Ras-related protein Rab-5b and EPS-8 protein was up-regulated in the group of alpha-MHC Cre+/-, ALK3 F/-. It was found that the Box protein Pax-8 gene was down-regulated by 7.1 fold (P < 0.001) in the alpha-MHC Cre+/-, ALK3 F/- mice by real time quantitative RT-PCR. It was also revealed that the Box protein Pax-8 gene was expressed stronger in alpha-MHC Cre+/-, ALK3 F/+ than alpha-MHC Cre+/-, ALK3 F/- E11.5 days mouse heart by means of in situ hybridization., Conclusion: The Box protein Pax-8 gene is an important and cardiac-specific ALK3 downstream gene in the BMP signaling pathway during inter-ventricular septum development.