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BACKGROUND: Cartilage decellularized extracellular matrix (dECM) is an ideal biomaterial for the preparation of cartilage tissue engineering scaffolds, which can be used to repair cartilage defects. OBJECTIVE: To use polyvinyl alcohol (PVA) as the loading material of dECM and poly3-hydroxybutyrate 4-hydroxybutyrate (P34HB) as the frame material to prepare P34HB-PVA-dECM composite nanofiber scaffolds by two-needle electrospinning, and preliminarily explore the bioactivity of the scaffolds in vitro. METHODS: The cellular components in the cartilage tissue were removed by a combination of enzyme, chemical, and ultrasonic concussion cleaning methods to prepare cartilage dECM. P34HB, P34HB-PVA, and P34HB-PVA-dECM scaffolds were prepared by two-neezle electrospinning. The fiber morphology, composition, hydrophilicity, and mechanical properties of the scaffolds were characterized. Human bone marrow mesenchymal stem cells were co-cultured with the three kinds of scaffolds. The viability of cells on scaffolds was evaluated by the Live/Dead staining. The adhesion morphology of the cells on the scaffolds was observed by scanning electron microscopy. The proliferation performance of the cells on the scaffolds was detected by the alamar blue kit. The chondrogenic differentiation of human bone marrow stem cells on the scaffolds was evaluated by type II collagen immunofluorescence. RESULTS AND CONCLUSION: (1) Scanning electron microscopy results showed that the scaffold fibers in each group were randomly distributed and the interconnections between the fibers showed a porous structure. The fiber diameter of P34HB-PVA-dECM scaffolds was the smallest. The P34HB-PVA-dECM scaffolds had the smallest water contact angle (P < 0.05) and the highest water absorption rate compared with the P34HB and P34HB-PVA scaffolds (P < 0.05). The elastic modulus of the P34HB-PVA-dECM scaffolds was higher than that of the P34HB and P34HB-PVA scaffolds (P < 0.05). (2) Live/Dead staining showed that most cells survived well on the three groups of scaffolds. The scanning electron microscope observation showed that the bone marrow mesenchymal stem cells on P34HB-PVA-dECM scaffolds extended pseudopod more fully and fused better with the scaffolds. Alamar blue staining exhibited that the proliferation rate of bone marrow mesenchymal stem cells on the P34HB-PVA-dECM scaffolds was faster than that on the P34HB and P34HB-PVA scaffolds (P < 0.05). The immunofluorescence staining results showed that more type II collagen produced after chondrogenic induction on the P34HB-PVA-dECM scaffolds was more than that on the P34HB and P34HB-PVA scaffolds (P < 0.05). (3) To sum up, the P34HB-PVA-dECM composite nanofiber scaffolds have smaller fiber structure, more optimized hydrophilicity and mechanical properties, which is more favorable for the adhesion, proliferation, and differentiation into chondrocytes of bone marrow mesenchymal stem cells. [ABSTRACT FROM AUTHOR]

BACKGROUND: Recently, decellularized dermal matrix hydrogel has broad application prospects in tissue filling and repair because of its injectable and filling irregular space. Cytocompatibility and biocompatibility are the key to tissue repair. It is significant to explore the compatibility of decellularized dermal matrix hydrogel. OBJECTIVE: To construct a decellularized dermal matrix hydrogel scaffold for tissue filling and repair. METHODS: An injectable decellularized dermal matrix hydrogel was prepared, and its microscopic morphology was observed under a scanning electron microscope. The decellularized dermal matrix hydrogels with a concentration of 8 and 10 g/L were co-cultured with bone marrow mesenchymal stem cells, separately, and the cell proliferation and cytocompatibility were tested. The decellularized dermal matrix hydrogels with a protein concentration of 0.25 and 0.5 g/L were injected into different subcutaneous parts of the back of the same SD rat separately, and the degradation of the hydrogels was observed 2 and 4 weeks after the operation. Decellularized dermal matrix hydrogels with protein concentrations of 1, 1.5, and 2 g/L were injected into different subcutaneous parts of the back of the same SD rat separately. At 8 and 16 weeks after the operation, the degradation of the hydrogel was observed and histological analysis was performed. RESULTS AND CONCLUSION: (1) Scanning electron microscopy analysis showed that the decellularized dermal matrix hydrogel exhibited an irregular and randomly oriented porous fibrous structure with different pore sizes. (2) After 1, 3, and 5 days of co-culture, the hydrogels with the two concentrations had no effect on the proliferation of bone marrow mesenchymal stem cells. Live/Dead staining after 1, 2, and 3 days of co-culture showed that the hydrogels with the two concentrations had no effect on the proliferation of bone marrow mesenchymal stem cells, but the cell morphology on the hydrogel changed to some extent. (3) The hydrogel with a protein concentration of 0.25 g/L was degraded after subcutaneous injection for 2 weeks; the hydrogel with a protein concentration of 0.5 g/L was degraded after subcutaneous injection for 4 weeks; the hydrogels with a protein concentration of 1, 1.5, and 2 g/L did not degrade after subcutaneous injection for 16 weeks, and possibly even longer. Hematoxylin-eosin staining showed that after subcutaneous injection for 8 weeks, the hydrogel tissue of the three protein mass concentrations was relatively dense, with a small amount of inflammatory infiltration, and the 2 g/L group had microangiogenesis. After 16 weeks, the hydrogel tissue became loose, and the 1 g/L group was more obvious, and the inflammatory infiltration was alleviated. Immunohistochemical staining showed that the number of microvessels in the hydrogel increased with the increase of injection time. The number of microvessels in the hydrogel increased with the increase of protein concentration. (4) The results confirmed that the injectable decellularized dermal matrix hydrogel had good cytocompatibility and biocompatibility. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bone tissue engineering scaffolds with modified growth factors have promising applications in bone repair materials, but the rapid release of growth factors leads to composite scaffolds that can promote bone repair only at an early stage, and the coating process provides a new idea to solve this problem. OBJECTIVE: To prepare Mg-F membrane/icaritin/β-tricalcium phosphate scaffold to characterize the biological properties of the new scaffold. METHODS: The β-tricalcium phosphate scaffold was prepared by applying 3D printing technology, and the icaritin/β-tricalcium phosphate scaffold was prepared by low energy electron beam deposition technology. Mg-F membrane/icaritin/β-tricalcium phosphate scaffolds were fabricated by pulsed laser deposition technology. The microstructure, pore diameter, porosity, wire diameter, compressive strength, and elemental composition of the scaffolds were examined, and the icaritin binding force and slow-release properties were analyzed. Rabbit bone marrow mesenchymal stem cells were co-cultured with β-tricalcium phosphate scaffold, icariin/β-tricalcium phosphate scaffold and Mg-F membrane/icariin membrane/β-tricalcium phosphate scaffold extract. Cell proliferation was measured by CCK8 assay. Rabbit bone marrow mesenchymal stem cells were co-cultured with the above three scaffolds, separately, and osteogenic induction medium was added, and the osteogenic differentiation ability was observed by alizarin red staining. RESULTS AND CONCLUSION: (1) Scanning electron microscope showed that the structure of β-tricalcium phosphate scaffold was relatively regular and the pore connectivity rate was good; the surface of the icariin membrane/β-tricalcium phosphate scaffold had relatively dense icariin membrane covering the original microscopic pores; Mg-F membrane was deposited on the surface of the icariin membrane, leaving a relatively rough and loose surface with microscopic pores. The differences in pore diameter, porosity, wire diameter, and compressive strength of three kinds of scaffolds were not statistically significant (P > 0.05). (2) The icariin binding force of Mg-F membrane /icariin membrane /β-tricalcium phosphate scaffold was better than that of icariin membrane /β-tricalcium phosphate scaffold (P < 0.05), and slow release of icariin lasted longer. (3) The results of CCK8 assay showed that the three kinds of scaffold extracts did not affect the growth of bone marrow mesenchymal stem cells. Alizarin red staining showed that at 21 days of osteogenic induction, the number of calcium nodules and the maturity of calcium nodules in the Mg-F membrane/icariin membrane/β-tricalcium phosphate scaffold group and the icariin membrane/ β-tricalcium phosphate scaffold group were better than those in the β-tricalcium phosphate scaffold group. (4) The results show that the Mg-F membrane/ icariin membrane / β-tricalcium phosphate scaffold has good cytocompatibility, osteogenic ability, drug binding and sustained release properties. [ABSTRACT FROM AUTHOR]

BACKGROUND: During stem cell transplantation, the generation of a large number of free radicals damages the cells in situ, and then reducing the cell survival. In the past decade, the emergence of nanozymes provides a new method for scavenging excess free radicals. Among them, manganese oxide (Mn3O4) is one of the promising nanomaterials, because it could provide Mn trace elements in human body as well as its well antioxidative stress properties and biodegradability. Mn3O4 can be used as a new type of nanomaterial to protect the extension function of stem cells. OBJECTIVE: To produce Mn3O4 nanoparticles for detecting its effect on scavenging and spreading function of bone marrow mesenchymal stem cells during oxidative stress. METHODS: Mn3O4 nanoparticles were prepared by hydrothermal method. Scanning electron microscope and X-ray diffraction were used to characterize the morphology and structure of Mn3O4, respectively. The particle size and zetapotential data of the nanoparticle in human-simulated environment were detected by the dynamic light scattering. The antioxidant capacity of Mn3O4 was tested in neutral environment. The CCK-8 and live-dead staining assays were utilized to verify the biological toxicity of Mn3O4 to bone marrow mesenchymal stem cells. H2O2 was used to induce oxidative stress of bone marrow mesenchymal stem cells. The effect of Mn3O4 on antioxidant ability and spreading ability of bone marrow mesenchymal stem cells was detected under oxidative stress. RESULTS AND CONCLUSION: (1) The results of scanning electron microscope and X-ray diffraction exhibited that the material was Mn3O4 with average particle size about 70-80 nm. The dynamic light scattering showed that the particle size of the nanoparticles in PBS solution was about 100 nm, and the Zeta potential was about +20 mV. Antioxidant performance experiments showed that Mn3O4 had a certain antioxidant capacity. (2) The CCK-8 assay, live-death staining and reactive oxygen scavenging experiment demonstrated that Mn3O4 did not show biotoxicity and exhibited a certain level of reactive oxygen scavenging ability under 40 mg/L. (3) The cell spreading analysis showed that H2O2 had a significant inhibitory effect on the spreading function of bone marrow mesenchymal stem cells. After adding Mn3O4 into the cell culture microenvironment, the cell spreading area had no significant difference compared with the control group (P > 0.05). Moreover, the single use of Mn3O4 did not inhibit the spreading function of bone marrow mesenchymal stem cells (P > 0.05). (4) The results have shown that the addition of Mn3O4 nanoparticles in the cell microenvironment can resist oxidative stress and have a certain protective effect on the spreading function of bone marrow mesenchymal stem cells. [ABSTRACT FROM AUTHOR]

BACKGROUND: Titanium as a bone substitute material has been widely used in the field of oral implant devices, but its bioinert would affect the stable combination with bone tissue at the early stage of implantation. Therefore, exploring to improve the osteogenic properties of titanium through surface modification is necessary. OBJECTIVE: To investigate the effect of composite coating of aspirin loaded chitosan nanoparticles and polydopamine on the viability of osteoblasts in vitro. METHODS: The titanium sheets modified by polydopamine coating as well as aspirin loaded chitosan nanoparticles and polydopamine composite coating were constructed. The surface morphology and microstructure of the coatings were characterized by scanning electron microscopy. In vitro sustained-release properties of aspirin nanosphere coatings on pure titanium were detected. Rat bone marrow mesenchymal stem cells were seeded and cultured on the pure titanium sheet and the two kinds of modified titanium sheets. The spreading morphology of rat bone marrow mesenchymal stem cells on the surface of titanium sheets was observed by cytoskeleton staining. Cell proliferation was determined by CCK-8 assay. The osteogenic differentiation of rat bone marrow mesenchymal stem cells on titanium sheets was measured using alkaline phosphatase staining and immunofluorescence staining. RESULTS AND CONCLUSION: (1) Scanning electron microscope images showed that the pure titanium surface was relatively smooth, and deposits as well as grain appeared after the dopamine polymerization. Aspirin microspheres were spherical with uniform size distribution. The hydrophilicity of the nanoparticles immobilized titanium surfaces and the polydopamine coating modified titanium surfaces were better than that of the pure titanium sheets (P < 0.05). The aspirin appeared to be slow and sustained under the encapsulation of chitosan nanoparticles. (2) As observed by cytoskeleton staining, the cells showed insufficient cell expansion on the surface of the pure titanium sheets and formed a few filopodia on the dopamine modified titanium sheets. The cells on nanoparticles modified sheets showed perfect expansion. (3) CCK-8 assay showed that the titanium sheets had no obvious cytotoxicity, and the cell proliferation rate of the nanoparticles modified titanium sheets displayed higher rates of proliferation than that of the dopamine coated and pure titanium sheets with increasing cell culture time (P < 0.05). (4) Alkaline phosphatase activity was highest on the surfaces of nanoparticles modified sheets. Immunofluorescence showed that the fluorescence intensity of alkaline phosphatase was strongest. (5) The results showed that the sustained-release coating of aspirin loaded chitosan nanoparticles on the titanium surfaces could enhance the proliferation and adhesion of rat bone marrow mesenchymal stem cells and promote osteogenic differentiation. [ABSTRACT FROM AUTHOR]

BACKGROUND: Injectable sodium alginate hydrogel can repair bone defects by non-invasive or minimally invasive methods, but the mechanical properties are poor and polyethylene glycol-based hydrogel has elasticity. The composite of materials is expected to improve the mechanical properties and cellular biocompatibility of hydrogel scaffolds. OBJECTIVE: To investigate the physical and chemical properties of glucolactone-sodium alginate/β-tricalcium phosphate-polyethylene glycol hydrogel and its effect on the proliferation and differentiation of murine bone marrow mesenchymal stem cells. METHODS: Gluconolactone as cross-linking agent was set to prepare glucolactone-sodium alginate/β-tricalcium phosphate-polyethylene glycol hydrogel (concentrations of cross-linking agent were 5, 10, and 20 g/L, respectively, which were marked as groups A, B, and C) and glucolactone-sodium alginate/ β-tricalcium phosphate hydrogel (concentration of cross-linking agent was 10 g/L, which was marked as group D). The morphology, mechanical properties, and gelation time of hydrogels in the four groups were characterized. Rat bone marrow mesenchymal stem cells were co-cultured with four groups of hydrogels. The proliferation of cells was detected by CCK-8 assay. Cell survival was observed by Live/Dead fluorescence staining. Osteogenic differentiation was detected by immunocytochemical staining of type I collagen. RESULTS AND CONCLUSION: (1) The filamentous structure similar to adhesion was observed by scanning electron microscope in the groups A, B and C. The pore size distribution of group A was uneven. The pore size of group B was uniform and the porosity was high. The group C had high porosity but different pore sizes. The group D had uneven pore size distribution and low porosity. (2) Physicochemical properties: The compressive stress in group B was higher than that in group D (P < 0.05). With the increase of gluconolactone concentration, the compressive stress of hydrogel in groups A, B and C increased (P < 0.05). The macroscopic performance of hydrogel after 50% compression showed that there were larger cracks in group D and only smaller cracks in group B after compression. The gelation time of groups A, B and C shortened with the increase of gluconolactone concentration, and the gelation time of group B was slightly longer than that of group D (P < 0.05). (3) CCK-8 assay showed that the cell proliferation rate of groups A and B was higher than that of group C (P < 0.05), and that of group B was higher than that of group D (P < 0.05). Live/Dead staining showed that the cell survival rate of each group was higher, but the number of dead cells was more in group C than that in the other three groups. (4) Immunocytochemical staining showed that the cells in groups A, B, and D were polygonal, and the cells in group C were partially round. The green fluorescence intensity in group B was higher than that in the other three groups, and the morphology of the cytoskeleton and microfilaments and the number of cells were also better than those in the other three groups. (5) The results show that the glucolactone-sodium alginate/β-tricalcium phosphate-polyethylene glycol hydrogel has perfect mechanical properties and stability; hydrogel prepared with 10 g/L gluconolactone can effectively promote the proliferation and differentiation of murine bone marrow mesenchymal stem cells. [ABSTRACT FROM AUTHOR]

BACKGROUND: The human umbilical cord mesenchymal stem cells isolation methods mainly include enzymatic digestion and tissue attachment. It is important to understand the biological characteristics of the two methods isolated cells in two-dimensional and three-dimensional culture conditions; it is of great significance to the selection of cell isolation methods and culture condition in tissue engineering. OBJECTIVE: To compare the biological characteristics of human umbilical cord mesenchymal stem cells from the enzymatic digestion and tissue attachment methods in two-dimensional and three-dimensional culture conditions. METHODS: Human umbilical cord mesenchymal stem cells were isolated by digestion method and tissue attachment method, amplified and cultured to passage 3 and divided into two-dimensional and three-dimensional culture. Scanning electron microscope was used to observe the cell spheroids. Live\dead staining was utilized to detect cell spheroid survival. Alamar Blue was applied to detect cell proliferation. Flow cytometry was used to detect the expression of immunophenotypes CD34, CD44, CD45, CD90, and CD105. Immunofluorescence and western blot assay were used to detect the expression of pluripotent transcription factors Sox2, Nanog, and Oct4. RESULTS AND CONCLUSION: (1) Enzymatic digestion method took shorter time to obtain cells than the attachment method. The cell proliferation ability of the attachment method was better than that of the enzyme digestion under two-dimensional culture, but the proliferation was slow and there was no difference under three-dimensional culture conditions. After 3 days of spheroid culture, the cells became compact spheroids and survived well. (2) The cells isolated by the two methods all expressed CD44, CD90, and CD105 under two-dimensional and three-dimensional culture conditions, but did not express CD34 and CD45. Under two-dimensional culture, the expression of CD105 cells isolated by enzymatic digestion was higher than that of tissue attachment method; under threedimensional culture, the expression of CD90 and CD105 cells isolated by enzymatic digestion was also higher than that of tissue attachment method. (3) Both isolation methods under two-dimensional and three-dimensional culture expressed pluripotency transcription factors Sox2, Nanog, and Oct4. Under the twodimensional culture, the expression of the three transcription factors of the cells extracted by the enzymatic digestion method was higher than that of the tissue attachment method. However, under the three-dimensional culture, the expression of Sox2 in the tissue attachment method was higher than that of the enzymatic digestion method, and the expression levels of Nanog and Oct4 were not different between the two groups. [ABSTRACT FROM AUTHOR]

BACKGROUND: The pore-forming technology of silk fibroin scaffolds is mostly prepared by freezing or freeze-drying methods, but different concentrations and temperatures have an impact on the physical and biological properties of the scaffold. There is no clear study on which freezing method or concentration is used for the preparation of the bone tissue scaffold. OBJECTIVE: To study the effects of concentration, freezing condition and 10 g/L polyethylene glycol on the properties of silk fibroin scaffolds under the condition of pore-induced water, and to select the suitable production conditions for the fabrication of bone tissue engineering scaffolds.METHODS: The silk fibroin protein solutions of 30, 60, 90 g/L were prepared. After pre-frozen at - 20.c, the silk fibroin solution of each mass concentration was divided into four groups t o prepare porous scaffolds: -20.c freezing treatment group, -60.c freezing treatment group, - 20.c lyophilization treatment group, and-60.c lyophilization treatment group. The pore size, hydrophilicity, porosity and compression strength of the scaffolds and cell compatibility were determined in each group. The surface morphology of the material was observed by scanning electron microscope. Based on the above results, the optimal freezing conditions and the mass concentration of silk fibroin solution for preparing porous scaffolds were obtained. Polyethylene glycol and 60 g/L silk fibroin solution were mixed uniformly, and lyophilized method at -60.c was used to prepare silk fibroin porous scaffolds. The compressive strength, tensile strength and cell compatibility of the composite scaffold were tested. RESULTS AND CONCLUSION: (1) The pore size, porosity, hydrophilicity, compressive strength and cell compatibility results showed that 60 g/ L silk fibroin solution was pre-frozen at-20c and t hen lyophilized at-60.c to obtain the best porous scaffold. The scaffold had a po re size of (213.07±37.89) µm and a porosity rate of 85%, which could promote the proliferation of bone marrow mesenchymal stem cells. (2) The addition of polyethylene glycol cou ld increase the compressive and tensile strength of the silk fibroin scaffold (P < 0.05). (3) Bone marrow mesenchymal stem cells were seeded on a polyet hylene glycolsilk fibroin composite scaffold. Scanning electron microscopy for 7 days of co-cultivation showed that the cells ad hered to the scaffold sufficiently and the synapses on the cell surface were fully stretched. Hematoxylin-eosin staining at 2 weeks of co-cultivation showed that the cells adhered to the stent wall and the nuclei were deeply stained. At 4 weeks, the cells adhered tightly in the channel of the stent hole, filled the entire channel, and proliferated faster. lmmunohistochemica l staining for 2 weeks of co-culture showed that type I collagen, RUNX2, and osteocalcin were negatively expressed. RT-PCR detection of co-culture for 3 weeks showed that the composite scaffold had no effect on the differentiation of bone m arrow mesenchymal stem cells. (4) It is concluded that at -60°C, 60 g/L silk fibroin freeze-dried porous scaffold is suitable for bone tissue engineering. 10 g/L polyethylene glycol can increase the tensile and compressive strength of the material. Silkfibroin scaffold has no induction effect on cell differentiation. [ABSTRACT FROM AUTHOR]

BACKGROUND: The polycaprolactone nanofiber scaffolds prepared by electrostatic spinning have a structure resembling extracellular matrix, but it is not conducive to cell adhesion, migration, proliferation and differentiation due to the poor hydrophilicity. OBJECTIVE: To fabricate attapulgite/polycaprolactone scaffolds via three-dimensional (3D) electrohydrodynamic printing and evaluate the biological effects and osteogenic induction ability on mouse bone marrow mesenchymal stem cells. METHODS: Attapulgite/polycaprolactone scaffolds with different concentration of attapulgite (0%, 0.5%, 1%, 2%) were prepared by 3D electrohydrodynamic, and the morphology and structure were observed by scanning electron microscope. The mouse bone marrow mesenchymal stem cells were co-cultured with four groups of scaffolds. The growth and morphology of bone marrow mesenchymal stem cells were observed with scanning electron microscope and Live/ Dead staining at 7 and 2 days, respectively. The proliferation of bone marrow mesenchymal stem cells was detected by CCK-8 assay at 1, 3 and 5 days. The mRNA expression levels of osteogenic marker genes were detected by real-time PCR at 3, 7, and 14 days. Alkaline phosphatase activity was detected at 3, 7 and 10 days of co-culture. RESULTS AND CONCLUSION: (1) Scanning electron microscopy results showed that four groups of scaffolds presented macropore morphology with the pore size of about 450 μm, and the surfaces of 0% and 0.5% attapulgite were smooth, while the scaffold surfaces in 1% and 2% attapulgite groups were rough. (2) Scanning electron microscopy showed that cells adhered and grew well on the surface of these scaffolds, and there were more cells grow in 1% attapulgite group than in other groups. (3) Live/Dead staining showed that cells adhered and grew well on the surface of four groups of scaffolds, among which 2% attapulgite group had the least cells. (4) The results of CCK-8 assay showed that the cell proliferation rate of 0.5% attapulgite group was higher than that of the other groups. (5) Real-time PCR showed that the expressions of alkaline phosphatase, osteocalcin, osteoblast-specific transcription factor and Runx-2 genes in 0.5% attapulgite group for 14 days were higher than those in the other groups. (6) The alkaline phosphatase activities of 0.5%, 1% and 2% attapulgite groups were all higher than 0% attapulgite group, in which the 0.5% attapulgite group was the highest at 3 and 7 days but 1% and 2% attapulgite groups were higher than other groups at 10 days of co-culture. (7) The 0.5% attapulgite scaffold has better biocompatibility and osteogenic induction potential. [ABSTRACT FROM AUTHOR]

BACKGROUND: With its excellent biocompatibility and osteoconductivity, hydroxyapatite is widely used as a material coating in tissue engineering, and its biological properties are strongly associated with the morphology caused by the manufacturing process. OBJECTIVE: To investigate the effects of plasma spraying and electrochemical deposition on the stent of hydroxyapatite coating on the proliferation, adhesion and osteogenic differentiation of bone marrow mesenchymal stem cells. METHODS: Hydroxyapatite coating was prepared on titanium stent using plasma spraying and electrochemical deposition. The titanium stent without coating was used as a control. Rat bone marrow mesenchymal stem cells were cocultured with three kinds of stents for 1, 3, 5, and 7 days. Cell proliferation was detected using CCK-8 assay for 5 days. Cell adhesion was observed using scanning electron microscope and confocal laser microscope. At 14 days, alkaline phosphatase staining was conducted; at 21 days, alizarin red staining was performed. At 14 and 21 days, real-time quantitative fluorescent polymerase chain reaction was conducted to analyze osteogenic differentiation of bone marrow mesenchymal stem cells. RESULTS AND CONCLUSION: (1) With the extension of the culture time, the cell proliferation rate of each group increased. The cell proliferation rate of the plasma spraying group was higher than that of the electrochemical deposition group and the control group (P < 0.05). (2) Scanning electron microscopy showed that cell adhesion was seen on the stents in the three groups. The plasma spraying group had the largest cell spreading area, and the control group had the smallest cell spreading area. The laser confocal microscope showed that the actin fibers in the plasma spraying group were the densest and the cells were in good extension; the electrochemical deposition group was relatively dense and the cells were in normal extension. In the control group, cytotactin was relatively sparse and the cells were not fully extended. (3) The alkaline phosphatase activity of the plasma spraying group was higher than that of the electrochemical deposition group and the control group, and calcium nodules were formed more than that of the electrochemical deposition group and the control group. (4) Real-time quantitative fluorescent polymerase chain reaction showed that the expression levels of osteopontin, type I collagen, osteocalcin and Runx2 mRNA in plasma spraying group were higher than those in electrochemical deposition group at the same time except that there was no difference between osteocalcin mRNA expression at 7 days and Runx2 mRNA expression at 14 days (P < 0.05). (5) The results showed that the morphology of plasma sprayed hydroxyapatite coating is more conducive to proliferation, adhesion and osteogenic differentiation of bone marrow mesenchymal stem cells. [ABSTRACT FROM AUTHOR]

BACKGROUND: Relevant studies have shown that adding an appropriate amount of graphene oxide can improve the mechanical properties, hydrophilicity, and cell compatibility of the fiber scaffold, and has a certain ability to promote bone formation. OBJECTIVE: To prepare egg white/polyvinyl alcohol/graphene oxide composite fiber scaffolds with different concentrations of graphene oxide and preliminary explore the biocompatibility of composite fiber scaffold in vitro. METHODS: Electrospinning was used to prepare egg white/polyvinyl alcohol/graphene oxide composite fiber scaffolds containing 0, 0.5, 1, and 1.5 g/L graphene oxid. The morphology of the scaffold was observed by scanning electron microscope, and the mechanical properties, contact angle and equilibrium swelling ratio of the scaffold were also tested. Human umbilical vein endothelial cells and human bone marrow mesenchymal stem cells were respectively inoculated on the surface of four groups of scaffolds. The CCK-8 assay was used to detect the proliferation of the two types of cells. Live/Dead fluorescent staining was used to observe the viability of the two types of cells. The scratch test and rhodamine phalloidin staining were used to observe the migration and morphology of human umbilical vein endothelial cells. RESULTS AND CONCLUSION: (1) Scanning electron microscope showed that with the increase of graphene oxid content, the fiber diameter of the composite scaffold increased. (2) With the increase of graphene oxid content, the hydrophilicity of the composite scaffold first decreased and then increased, and the hydrophilicity of the composite scaffold containing 0.5 g/L graphene oxid was the lowest. (3) With the increase of graphene oxid content, the Young's modulus and tensile strength of the composite scaffold first increased and then decreased, and the Young's modulus and tensile strength of the composite scaffold containing 0.5 g/L graphene oxid were the largest. (4) CCK-8 assay showed that the proliferation rate of human bone marrow mesenchymal stem cells on the composite scaffold containing 1.5 g/L graphene oxid was faster than that of the other three groups of scaffold (P < 0.05), and the proliferation rate of human umbilical vein endothelial cells on the composite scaffold containing 1 g/L graphene oxid was faster than the other three groups of scaffolds (P < 0.05). (5) With the increase of graphene oxid content, the survival rate of human bone marrow mesenchymal stem cells on the composite scaffold increased; the survival rate of human umbilical vein endothelial cells on the composite scaffold containing 1 g/L graphene oxid was the highest. (6) Scratch experiment and rhodamine phalloidin staining proved that the composite scaffold containing 1 g/L graphene oxid was most conducive to the migration and morphological expansion of human umbilical vein endothelial cells. (7) The results show that the egg white/polyvinyl alcohol/graphene oxide fiber scaffold containing 1 g/L graphene oxid has excellent fiber structure, hydrophilicity, mechanical properties and cell compatibility. [ABSTRACT FROM AUTHOR]

BACKGROUND: Based on the need of in situ tissue engineering regeneration in the field of meniscus regeneration, three-dimensional (3D) bioprinting technology can be used to construct a scaffold which can effectively combine recruitment bioactive factors and excellent materials. OBJECTIVE: To optimize the preparation process of polycaprolactone/methacrylate anhydride gelatin/meniscus extracellular matrix (PCL/GelMA/MECM) 3D bioprinting scaffold loaded with platelets derived growth factor-BB (PDGF-BB), and to test the sustained release properties of the growth factor and its effect on the migration and proliferation of the synovial mesenchymal stem cells. METHODS: Photosensitive bio-ink was prepared by GelMA/MECM. PCL scaffold and PCL/GelMA/MECM bio-scaffold were prepared by 3D bioprinting technology. Finally, PDGF-BB was loaded to fabricate functional bioprinting PCL/GelMA/MECM/PDGF scaffold, and then its mechanical properties and sustained release properties were tested. New Zealand white rabbit synovial mesenchymal stem cells were isolated and cultured. Transwell and CCK-8 assays were used to explore the effects of PCL scaffold, PCL/GelMA/MECM scaffold and PCL/GelMA/MECM/PDGF scaffold on the migration and proliferation of synovial mesenchymal stem cells, and single medium cultured cells were used as negative control. The third passage of synovial mesenchymal stem cells was inoculated on PCL scaffold, PCL/GelMA/MECM scaffold and PCL/GelMA/MECM/PDGF scaffold respectively. The viability, adhesion and growth of the cells on the three scaffolds were observed by confocal microscope and scanning electron microscope. RESULTS AND CONCLUSION: (1) There was no significant difference in tensile modulus and compression modulus between PCL/GelMA/MECM scaffolds and PCL scaffolds (P > 0.05). (2) PCL/GelMA/MECM/PDGF scaffolds had good sustained release performance, and PDGF-BB could be released continuously for up to 28 days. (3) Compared with the negative control group, PCL/GelMA/MECM scaffolds and PCL/GelMA/MECM/PDGF scaffolds could promote the migration of synovial mesenchymal stem cells, among which PCL/GelMA/MECM/PDGF scaffolds were more effective. (4) Compared with the negative control group, the cells cultured with PCL/GelMA/MECM scaffolds and PCL/GelMA/MECM/PDGF scaffolds proliferated faster after 4 and 7 days (P < 0.001), and the proliferative effect of PCL/GelMA/MECM/PDGF scaffolds was more obvious. (5) Dead/Live staining showed that the cells in each group had good activity, and the number of cells on the PCL/GelMA/MECM/PDGF scaffold was the highest. (6) Scanning electron microscope showed that the cells were attached to the surface of the three groups of scaffolds, and the cells on PCL/GelMA/MECM scaffolds and PCL/GelMA/MECM/PDGF scaffolds adhered to a large number of cells and secreted a large amount of extracellular matrix. (7) These results showed that the 3D bioprinted meniscus scaffold loaded with PDGF-BB had good mechanical properties and biocompatibility and could promote the migration and proliferation of synovial mesenchymal stem cells. [ABSTRACT FROM AUTHOR]

BACKGROUND: Insufficient local effective drug concentration after debridement of spinal tuberculosis lesions and repair of residual bone defects are the current problems in the treatment of spinal tuberculosis. New anti-tuberculosis drugs combined with bone morphogenetic protein 2 (BMP-2) have become a new idea to solve this problem, which can effectively promote bone defect repair. OBJECTIVE: To observe the effect of PA-824, moxifloxacin and pyrazinamide (PaMZ)/BMP-2/nano-hydroxyapatite (nHA) anti-tuberculosis artificial bone on osteogenic differentiation and adhesion of rabbit bone marrow mesenchymal stem cells. METHODS: Rabbit bone marrow mesenchymal stem cells were extracted and purified. The nHA was used to fabricate the three-dimensional printed artificial bone containing anti-tuberculosis drugs PA-824, moxifloxacin, pyrazinamide and BMP sustained-release microspheres (PaMZ/BMP-2/nHA), and co-cultured with the third generation of bone marrow mesenchymal stem cells as the experimental group. BMP-2 was co-cultured with bone marrow mesenchymal stem cells as a positive control group. Bone marrow mesenchymal stem cells were cultured separately as blank control group. The proliferation, osteogenesis and cell adhesion effects of rabbit bone marrow mesenchymal stem cells were respectively tested at 1, 3, 7, 14, and 21 days of culture to evaluate the influence of the artificial bone on the osteogenic differentiation of rabbit bone marrow mesenchymal stem cells. The cell proliferation and cytotoxicity were detected by CCK-8 assay. The degree of calcium nodule deposition and alkaline phosphatase expression activity were measured to evaluate the influence of osteogenic differentiation. Fluorescence quantitative PCR and western blot assay were used to detect the expression levels of osteogenicgenes and proteins, respectively. The adhesion characteristics of cells were observed by scanning electron microscopy. RESULTS AND CONCLUSION: (1) The newly synthesized anti-tuberculosis artificial bone showed good spatial microstructure, which was conducive to cell attachment. (2) CCK-8 assay showed that the cells in each group proliferated well. Among them, the experimental group and the positive control group showed a proliferation state for 14 days, and the blank control group became stable after 7 days, indicating that the artificial bone had good biocompatibility. (3) The alkaline phosphatase activity appeared a trend of increasing first and then decreasing, reaching a peak at 14 days. At 7 and 14 days, the alkaline phosphatase activity of the positive control group was higher than that of the experimental group (P < 0.05), but the activity of the experimental group was higher than that in the positive control group at 21 days. The change was not obvious in the blank control group at each time point. (4) Alizarin red staining experiments revealed that calcium nodules were formed in the experimental group and the positive control group, and the differences in the number and size of calcium nodules between the experimental group and the positive control group were not obvious. The expression levels of bone-related genes and proteins (Runx2 and collagen I) were higher in the two groups than those in the blank control group (P < 0.05). (5) Under the scanning electron microscope, it was observed that the cells adhered tightly to the scaffold and showed “Eight Claws” or long fusiform growth. (6) It is concluded that the newly synthesized anti-tuberculosis artificial bone has a unique spatial structure and good biocompatibility, which can promote the proliferation and osteogenesis of bone marrow mesenchymal stem cells, and is an ideal bone tissue engineering material. [ABSTRACT FROM AUTHOR]

BACKGROUND: Regeneration and repair of the injured meniscus remain scientific challenges. It is of significance to construct a tissue-engineered scaffold with good biomechanical performance and cytocompatibility. OBJECTIVE: To prepare decellularized porcine skin matrix scaffold and evaluate its biomechanical properties and cytocompatibility. METHODS: Porcine skin was decellularized with the combination of trypsin, Triton X-100 and sodium dodecyl sulfate to obtain decellularized porcine skin matrix. DAPI staining was used to observe whether the cells were well removed and scanning electron microscope to observe its microstructure. The decellularized porcine skin matrix was compared with natural meniscus in term of histological staining, contents of collagen and glycosaminoglycans, and biomechanical properties. The third-generation bone marrow mesenchymal stem cells were seeded on the decellularized porcine skin matrix. After 3 days of culture, the scanning electron microscopy, dead/live cell staining and phalloidin staining were used to observe cytocompatibility of the decellularized porcine skin matrix. RESULTS AND CONCLUSION: (1) DAPI staining showed that no cell nucleus was found in the decellularized porcine skin matrix. Scanning electron microscopy showed that the surface of the decellularized porcine skin matrix was rough, and the surface fibers showed a topological structure. (2) Histological staining showed that the natural meniscus tissue was rich in extracellular matrix, and the meniscus cells were evenly distributed in the matrix. The collagen fibers were dense and arranged regularly, and the collagen composition was mainly type I collagen fibers and contained glycosaminoglycan components. The decellularized porcine skin matrix had no cell nucleus and was in the shape of loose fiber strips with more pore structure, and its collagen component was mainly type I collagen fiber and contained glycosaminoglycan components. (3) There was no significant difference in collagen content and tensile modulus between decellularized porcine skin matrix and natural meniscus (P > 0.05), while the glycosaminoglycan content and compression modulus were lower than those of the natural meniscus (P < 0.05). The biomechanical properties of the decellularized porcine skin matrix are sufficient to bear the load of the knee joint and maintain the integrity of the scaffold. (4) Scanning electron microscope showed that bone marrow mesenchymal stem cells adhered to the pore structure of porcine skin matrix, and the cells were elliptical and grew in clusters. (5) Dead/live cell staining showed that the bone marrow mesenchymal stem cells on the decellularized porcine skin matrix had high activity (94.0±3.8)%. (6) Phalloidin/DAPI staining showed that bone marrow mesenchymal stem cells showed good spreading on the decellularized porcine skin matrix. (7) The results showed that decellularized porcine skin matrix has similar collagen components as the natural meniscus, and presents good biomechanical performance and cytocompatibility, and is conducive to cell adhesion and growth. [ABSTRACT FROM AUTHOR]

BACKGROUND: Adipose mesenchymal stem cells are currently recognized as excellent seed cells for tissue engineering cartilage. Gene transfection technology can effectively induce them to differentiate into cartilage. The bioreactor is used to simulate the mechanical environment in vivo. It is a new idea for the majority of scholars to explore the construction of tissue engineering cartilage in vitro. OBJECTIVE: To investigate the effects of cyclic dynamic compressive stress combined with insulin-like growth factor-1 gene transfection on the proliferation and elastic modulus of rabbit adipose mesenchymal stem cells implanted in chitosan/gelatin scaffold.METHODS: Rabbit adipose mesenchymal stem cells were transfected with pcDNA3.1-IGF-1 gene mediated by liposome. The stable transfected cell lines were screened by G418. The adipose mesenchymal stem cells transfected with or without insulin-like growth factor-1 gene were inoculated in chitosan/gelatin scaffold at the density of 5×1010 L-1 for 2 days, and cultured under dynamic pressure (2% at 1 Hz, 4 hours per day) or static culture conditions for 7 days, respectively. The morphological changes of the cell/scaffold complex were observed by scanning electron microscope, Masson trichrome staining and alcian blue staining. The cell proliferation curve was drawn by MTT assay. The cell proliferation efficiency and distribution were evaluated by CM-Dil fluorescence-labeling method, and the content of total glycosaminoglycan was quantitatively determined by DMMB. The differences of type II collagen among different groups were compared with real time PCR. Compressive mechanical properties of the cell/scaffold constructs were assessed using a BioDynamicTM mechanical tester, and the corresponding elastic modulus was calculated.RESULTS AND CONCLUSION: Dynamic pressure combined with insulin-like growth factor-1 transfection could significantly improve the cell proliferation ability of the cell/scaffold complex; the cell distribution was more uniform; glycosaminoglycan and collagen secretion in the cartilage-specific extracellular matrix were increased; the expression levels of type II collagen were up-regulated; and the mechanical properties were significantly improved. The cell proliferation and elastic modulus of insulin-like growth factor-1 group were better than those of single pressure group, but the distribution of cells in scaffolds was more uniform under dynamic pressure. The results indicate that both dynamic pressure and insulin-like growth factor-1 gene transfection can significantly improve the proliferation and mechanical properties of rabbit adipose mesenchymal stem cells; the two have synergistic effect. [ABSTRACT FROM AUTHOR]

In this study, rod like hydroxyapatite (HAp) with a length of 25 —35 nm and a width of 10 —20 nm was synthesized by chemical precipitation method. Then the HAp was doped in situ into the nano-disk osteogenic Laponite (LP) matrix. A type of injectable composite with high bioactivity was prepared by a single-step ultrasonic mixing method by leveraging Laponite’s good water solubility and in situ gelation property. The prepared gel material showed good injectability and thixotropic properties. A comparative study was conducted between pure LP injectable material (LIM) and LP/HAp injectable material (LHIM). The results of X-Ray Energy Spectrum showed that the HAp in the LHIM was well dispersed. The results of Scanning Electron Microscope (SEM) showed that the introduction of HAp increased the surface roughness of LHIM compared with LIM. The results of rabbit bone marrow mesenchymal stem cells (rBMSCs) in vitro showed that both LHIM and LIM had good cytocompatibility, and more rBMSCs adhered to the surface of LHIM in one day. The results of transwell showed that compared with LIM, LHIM could further improve the migration ability of rBMSCs. The results of osteogenic activity in vitro showed that LHIM can increase rBMSCs alkaline phosphatase (ALP), Runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) activity. LHIM has the advantages of simple preparation, rapid gelation, no cross linking agent, easy storage and good osteogenic activity. Therefore, LHIM is expected to be a bone repair material for clinical use. The current study provides a potential therapeutic tool for bone repair and regeneration [ABSTRACT FROM AUTHOR]

BACKGROUND: Human amniotic mesenchymal stem cells (hAMSCs) are a kind of adult stem cells that can be extracted from discarded placenta. Compared with other mesenchymal stem cells, hAMSCs have many advantages such as noninvasive isolation, low immunogenicity and short growth cycle, and thus hAMSCs are an important source of tissue engineering seed cells. Currently, hAMSCs have been applied in the clinical treatment of diabetes. OBJECTIVE: To explore a simple method to fabricate hAMSC sheets and to study their potential to differentiate into osteocytes. METHODS: Passage 3 hAMSCs were seeded into culture plates at a high density, and the sheet-forming medium was added to fabricate hAMSC sheet. The structural characteristics of hAMSC sheets were evaluated by histological staining and scanning electron microscopy. The sheet-forming induction medium was added to the passage 3 hAMSCs for 7 continuous days, and then replaced by the osteogenic induction medium for 14 days to construct osteogenic-induced hAMSC sheets. The potential for osteogenic differentiation of hAMSC sheets was assessed by alizarin red staining, immunohistochemical staining, alkaline phosphatase activity, RT-PCR, and western blot assay. RESULTS AND CONCLUSION: Hematoxylin-eosin staining results indicated that hAMSC sheets had a multi-layered structure with the cells stacked layer-by-layer and evenly distributed. Under the scanning electron microscope, the hAMSC sheets had a multi-layered structure, and a large amount of extracellular matrices that enveloped the fusiform cells were produced. After 14 days of osteogenic induction, orange-red precipitation was observed by alizarin red staining. Immunohistochemical staining results showed a large amount of type II collagen. Compared with non-induced hAMSC sheet, alkaline phosphatase activity was significantly increased in the osteogenic induced sheet (P < 0.01). The expression levels of type I collagen, osteocalcin, and Runt-related transcript factor 2 mRNA and protein were significantly higher in the osteogenic-induced hAMSC sheet group than the non-induced hAMSC sheet group (P < 0.05). Our findings indicate that this is a simple and economic method to construct the hAMSC sheets in the normal culture medium. Moreover, hAMSC sheets have a good osteogenic differentiation potential that has been confirmed in vitro. [ABSTRACT FROM AUTHOR]

BACKGROUND: Our previous study confirmed that BTO/P(VDF-TrFE) piezoelectric nanocomposita membrane containing 5%BTO (BaTO3, BTO) nanoparticles could significantly promote bone marrow mesenchymal stem cells (BMSCs) adhesion, growth, osteogenic differentiation and repair of bone defects due to its bionic potential. However, for clinical applications, it is not clear whether there is any difference between the bone repair effect of this material as a guide for tissue regeneration and that of the existing clinically non-degradable membrane products. OBJECTIVE: To compare the effects of BTO/P(VDF-TrFE) piezoelectric nano-composne membrane materials with commercial PTFE membrane in repairing critical-sized defects of SD rat skull. METHODS: BTO/P(VDF-TrFE) piezoelectric nanocomposne membrane containing 5% BTO nanoparticles was prepared by solution casting method. Scanning electron microscope, atomic force microscope and water contact angle measuring instrument were used to observe the surface morphology, measure the surface roughness and surface hydrophilicity and hydrophobicity of the material. In SD rats (purchased from the Laboratory Animal Center, Beijing University Hospital of Stomatology, China), a 5-mm sized full-thick bone defect was made on both sides of the sagittal suture of the skull. The left bone defect was covered with PTFE membrane (control group). The right bone defect was covered with BTO/P(VDF-TrFE) piezoelectric nano-composita membrane (experimental group). At postoperative 4 and 12 weeks, micro-CT and histological methods were used to evaluate the repair of the skull defect in rats. This study was approved by Animal Ethics Committee, Beijing University Hospital of Stomatology. RESULTS AND CONCLUSION: The piezoelectric nanocomposite membrane had smooth and dense surface and BTO nanoparticles were evenly distributed. PTFE membrane was composed of loose coarse fibers. The piezoelectric nanocomposite membrane had lower surface roughness (P< 0.001) and higher hydrophilicity (P< 0.001) than PTFE membrane. Micro-CT and histological results showed that at 4 weeks after surgery, new bone formation was found in both groups, but new bone formation was more obvious in the center of the defect in the experimental group than in the control group. At 12 weeks after surgery, bone defects healed in both groups, but the maturity of newly formed bone in the experimental group was greater than that in the control group. These results suggest that BTO/P(VDF-TrFE) piezoelectric nanocomposite membrane containing 5%BTO (BaTO3, BTO) nanoparticles can be used as a membrane guiding tissue regeneration. [ABSTRACT FROM AUTHOR]

BACKGROUND: Our previous studies have found that silk fibroin-chitosan scaffold carrying bone marrow mesenchymal stem cells can repair cartilage defect in rabbits, but further exploration on the biocompatibility of tissue engineered cartilage is yet to be done. OBJECTIVE: To explore the biocompatibility of tissue engineered cartilage that is constructed in vitro by silk fibroin-chitosan scaffold with bone marrow mesenchymal stem cells. METHODS: Three-dimensional silk fibroin-chitosan scaffolds were prepared in a ratio of 1:1. Rabbit bone marrow mesenchymal stem cells were extracted, induced and seeded onto the silk fibroin-chitosan scaffold to construct the cell-scaffold composite. The composite was then implanted into a rabbit joint defect model for cartilage repair. There were three groups in the present study: experiment group with implantation of induced bone marrow mesenchymal stem cells+silk fibroin-chitosan scaffold into the cartilage defect model, control group with implantation of silk fibroin-chitosan scaffold into the cartilage defect model, and blank group without implantation. RESULTS AND CONCLUSION: The three-dimensional silk fibroin-chitosan scaffolds were successfully prepared and combined with bone marrow mesenchymal stem cells (BMSCs) to construct the tissue engineered cartilage for repair cartilage defects in rabbits. Blood routine parameters, procalcitonin levels, erythrocyte sedimentation rates and C-reactive protein levels detected at 2, 4, 8, and 12 weeks post-implantation indicated no obvious signs of systemic infection, and there was no damage to liver and kidney functions in the three groups. There were also no significant differences between the three groups in terms of blood routines and liver and kidney functions (P > 0.05). As shown by gross observation, hematoxylin-eosin staining and scanning electron microscope, in the experimental group, cartilage defects were repaired, with scaffold degradation, no presence of inflammatory cells, and good integration with surrounding tissues. Therefore, tissue engineered cartilage constructed in vitro by silk fibroin-chitosan scaffolds carrying bone marrow mesenchymal stem cells has good biocompatibility, which provides an experimental basis for tissue engineering approaches to cartilage repair. [ABSTRACT FROM AUTHOR]

BACKGROUND: Nanosized cell-type tissue-engineered bone is a good scaffold material possessing the merits of stem cells and nanomaterials to fabricate bone and soft tissue formation. OBJECTIVE: To explore the method of constructing nano-sized cell-type tissue-engineered bone and to explore its application in the repair of mandibular bone defects. METHODS: One New Zealand white rabbit was taken to isolate bone marrow stromal stem cells by centrifugation. Then, the cells were induced to differentiate into osteoblasts. Osteoblasts (3×108 /L, 10 μL) were inoculated into the prepared nano-phase hydroxyapatite/collagen composite to produce the nano-sized cell-type tissue-engineered bone. Another 20 New Zealand white rabbits were taken to make a unilateral puncture-type bone defect model of 15 mm×8 mm. These model rabbits were thereafter randomized into control and artificial bone groups (n=10 per group), followed by no intervention and implantation of nano-sized cell-type tissue-engineered bone, respectively. Repair effects were compared between the two groups. RESULTS AND CONCLUSION: (1) Under the inverted microscope, osteoblasts grew along the material in each group, and the number of cells increased with the prolongation of the culture time. (2) Under the scanning electron microscope, a large number of spindle- or polygon-shaped adherent cells grew well on the surface of the tissue-engineered bone. (3) The defect in the artificial bone group was lessened at 4 weeks after implantation and disappeared at 8 weeks after implantation, and there was no clear boundary with the surrounding tissue. In the control group, the defect size changed little at 4 weeks and reduced at 8 weeks after implantation, and a clear boundary with the surrounding tissue was observed. (4) Bone density, trabecular thickness and trabecular number were significantly higher in the artificial bone group than the control group at 4 and 8 weeks after implantation (P < 0.05). (5) At 4 weeks after implantation, many new bones at the defect site were detected in the artificial bone group, and a large number of mature bone cells were visible at 8 weeks. In the control group, a few osteoblasts were found at the defect site with low bone maturation at 4 and 8 weeks after implantation. These findings suggest that the implantation of nanosized cell-type tissue-engineered bone into the defect site can considerably promote defect healing and achieve ideal repair effects. [ABSTRACT FROM AUTHOR]