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Understanding the anatomy behind a pelvic fracture can be a significant challenge to medical students. Recent advances in three-dimensional printing technology offers a novel approach to facilitate the learning of complex fracture. We have described here how the 3-dimension printing (3Dp) models can help medical students improve their understanding in and identification of pelvic fractures.One hundred students were randomized into 2 teaching module groups (with or without 3Dp models). Prior to randomization assignment, a 50-minute didactic lecture covering elementary knowledge of anatomy, Young-Burgess classification, and traumatic mechanism of pelvic fracture was delivered to all students. The 3Dp group received X-rays, CT images, and 3Dp models of the eight pelvic fractures during presentation, while the students in the control group only obtained X-rays and CT scans of the same 8 pelvic fractures. Young-Burgess classification system and injury mechanism of pelvic fracture, time for evaluation, and subjective questions were conducted to assess the learning outcomes.A medical student program based in a LevelⅠtrauma center PARTICIPANTS: One hundred students in their 4th year of a 5-year clinical medicine program (for a medical bachelor degree) RESULTS: Students receiving 3Dp model had a higher rate of identifying the correct pelvic fracture via Young-Burgess identification compared to these without 3Dp model. Moreover, the accuracy of identifying the injury mechanism was significantly higher in the 3Dp group than that in group without 3Dp model. Participant in 3Dp group had faster assessment time compared to the control group. Subjective survey results suggested that 3Dp model would increase the learning interest and enhance the understanding of pelvic fracture. In addition, majority of students (83%) reported that they would like to use 3Dp model in other surgical course education.3Dp model increased the perceived accuracy of pelvic fracture identification and understanding of injury mechanism. Moreover, 3Dp model promoted the subjective interest and motivation of students in pelvic fracture learning. Therefore, 3Dp model can be considered as a valuable educational tool for learning pelvic fracture in medical students.

BACKGROUND: Congenital pseudarthrosis of the clavicle (CPC) is a rare congenital entity with unresolved aetiology and pathogenesis. Nearly 250 cases have been reported to date. CPC is characterized by a definite defect in the mid-clavicle at birth and is usually diagnosed when the deformity becomes evident in late childhood or adolescence. Surgical management is controversial, especially in asymptomatic children, with various techniques reported in the literature. CASE REPORT: We report a case of a 6-year-old boy who was diagnosed with CPC during a medical examination for primary school enrollment. Operative treatment included debridement of pseudoarthrosis, internal fixation with third tube plate, and barrel-shaped mono-cortical iliac crest autograft. RESULTS: A complete bone union was obtained 9 months after the operation, and satisfactory function and cosmetic appearance were observed 4 years and 3 months postoperatively. CONCLUSION: In our opinion, reconstruction with barrel-shaped mono-cortical iliac crest autograft was an effective and reproducible surgical technique to treat CPC.

Introduction：Published studies have suggested a potential association between diabetes mellitus (DM) and RA, with glycated hemoglobin (HbA1c) serving as an important biomarker for DM. The purpose of this study was to investigate the causal relationship between HbA1c levels and RA risk using Mendelian randomization (MR) analysis. methods：A two-sample Mendelian randomization (MR) study was conducted using genetic variants as instrumental variables (IVs) related to HbA1c. Summary statistics from genome-wide association studies (GWAS) were obtained from the publicly accessible Integrative Epidemiology Unit (IEU) OpenGWAS database. A systematic selection process was employed to identify high-quality instrumental single-nucleotide polymorphisms (SNPs) strongly associated with the exposure. Various MR methodologies, such as inverse-variance weighted (IVW) and MR-Egger, were implemented to determine causal effects. The MR-Egger intercept test, Cochran's Q test, and leave-one-out sensitivity analysis were used to evaluate horizontal pleiotropy, heterogeneities, and stability of the association. Odds ratios (OR) and 95% confidence intervals (CI) were computed. Results：A total of 9 SNPs were identified as final IVs. The MR analysis demonstrated a significant causal relationship between elevated HbA1c levels and an increased risk of seronegative RA [odds ratio (OR) = 1.358, 95% confidence interval (CI), 1.044-1.767]. However, no significant evidence of a causal relationship was observed between HbA1c and seropositive RA [OR = 1.033, 95% CI, 0.850-1.257] or overall RA [OR = 1.093, 95% CI, 0.935-1.278]. Sensitivity analyses supported the robustness of the findings, with no significant evidence of heterogeneity or bias and no potential SNPs affecting the causal link. Conclusions:This study provides evidence of a causal relationship between HbA1c levels and seropositive RA risk, emphasizing the importance of closely monitoring and managing HbA1c levels in patients. Further research is needed to elucidate shared pathophysiological mechanisms between DM and RA, which may lead to novel therapeutic strategies.

Background Obturator dislocation is a rare type of hip dislocation, accounting for about 2%-5% of all hip dislocations. The occurrence of old unreduced obturator dislocation is even more infrequent, with only 17 cases reported in nine studies, most of which were from the 1950s to 1980s in developing countries. Case summary A 38-year-old woman from Hunan Province, China presented with stiffness of the left hip in abduction, flexion, and external rotation after falling from a 2-meter-tall tree onto her left knee 1.5 mo prior. Pelvic radiograph and computed tomography revealed obturator dislocation of the left hip accompanied by impaction fracture at the superolateral aspect of the left femoral head without associated acetabulum fracture. Open reduction was performed, resulting in restoration of the concentric alignment of the left hip. After surgery, 6-wk skin traction was applied and the patient was kept in bed for an additional 2 wk. At 3 mo after surgery, the patient reported experiencing some pain, which did not affect the function of the affected limb, and some movement restriction but no abduction deformity or claudication was present. An X-ray showed that the left hip was homocentric, and there was no sign of posttraumatic arthritis or avascular necrosis. Conclusion Open reduction may be an effective treatment strategy for the rare condition of old unreduced obturator dislocation with short neglect time.

Purpose: To investigate the effect of cyclopentadione-aniline conjugate (CAC) on proliferation of liver cancer cells. Methods: MTT assay and flow cytometry were used for the determination of the effect of CAC on cell proliferation and apoptosis. Western blotting was used to measure the influence of CAC on the expressions of various proteins, while Matrigel-coated Transwell assay was used for assessment of cell invasion. Results: CAC inhibited proliferation of liver cancer cells in a concentration-dependent manner. The degree of proliferation of HepG2 cells was 98, 89, 76, 66, 51, 42 or 36 %, on treatment with 0.25, 0.5, 1.0, 1.5, 2.0, 2.5 or 3.0 µM CAC, respectively. In H4TG cells, treatment with 0.25, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 µM CAC decreased proliferation of cells to 99, 91, 79, 70, 54, 46 and 40 %, respectively. Apoptosis was induced in 34.56, 37.37 and 52.98 % cells, on treatment with 2.0, 2.5 and 3.0 µM CAC, respectively. The invasive potential of HepG2 cells was significantly decreased by CAC (p < 0.05). Marked decreases were observed in Bcl-2, MMP-2, MMP-9, c-ERK1/2 and phospho-Akt levels in CACtreated HepG2 cells. CAC treatment markedly upregulated Bax and phospho ERK1/2, but significantly downregulated phospho PI3K, phospho mTOR and phospho Akt in HepG2 cells (p < 0.05). However, the level of phospho p38 was decreased in CAC-treated cells. Conclusion: These results demonstrate that CAC inhibits proliferation of liver cancer cells via apoptosis induction. Thus, CAC can potentially be used for the treatment of liver cancer in humans

Distally based sural fasciocutaneous (DBSF) flaps are widely used for reconstructing soft tissue defects of the foot. The purpose of this paper was to compare the clinical efficacy of the use of flaps to repair defects in areas proximal and distal to the level of the tarsometatarsal joints in a relatively large number of patients and to analyze the effects of factors on the risk of developing partial necrosis of the flaps. Between April 2001 and December 2019, a total of 355 DBSF flaps were utilized to cover soft tissue defects in the foot. According to the furthest location of the defects reconstructed with the flaps, the flaps were divided into the proximal foot group (n = 260) and the distal foot group (n = 95). The partial necrosis rates, their influencing factors, and the clinical outcomes of the procedure were compared between the two groups. In the proximal foot group, the partial necrosis rate (6.2%, 16 of 260) was significantly lower than that in the distal foot group (14.7%, 14 of 95) ( P .05). The ratio of unfavorable conditions in the distal foot group was higher than that in the proximal foot group ( P

Pauwels III fracture is a kind of femoral neck fractures, in which the angle of the fracture line in the coronal plane and the upper edge of the acetabulum is more than 50°. Internal fixation for the treatment of femoral neck fractures is largely performed by cannulated compression screw (CCS), dynamic hip screw, or locking plate. This study aims to compare the biomechanical properties of parallel CCS combined with medial buttress plate fixation and F-type CCS fixation in the treatment of Pauwels III femoral neck fracture by finite element modeling and to determinate the most suitable procedure for such fractures.A 52-year-old male volunteer, 176 cm in height and 72 kg in weight, with no history of hip joint, was selected. X-ray and CT examination confirmed that the morphology and bone condition of the right hip of the volunteer were normal. A simulation model of Pauwels III femoral neck fracture was established from the collected CT data of the right proximal femur of the volunteer by the finite element method. Four internal fixations were developed to treat the finite element model: Three CCSs in an inverted triangular parallel configuration combined with medial buttress plate model served as Group A, 2 CCSs in a vertical parallel configuration combined with medial buttress plate model served as Group B, 2 CCSs in a horizontal parallel configuration combined with medial buttress model served as Group C, and the "F" shaped CCS model served as Group D. The distribution of stress, the peak stress, the distribution and maximum of displacement of internal fixations and fracture ends in different models were evaluated.For Groups A, B, C, and D, the peak stresses on the internal fixation were 362.74, 586.84, 558.25, and 208.66 mPa, respectively, all of which occurred near the fractures and the stress distribution in Group D was the most uniform. The maximum displacements of internal fixations in Groups A, B, C, and D were 0.39, 0.45, 0.44, and 0.41 mm, respectively; the peak stresses on the fracture ends were 70.62, 98.48, 55.84, and 65.39 mPa, respectively, all of which were concentrated on the base of femoral neck and lateral cortex of the femoral shaft, and the stresses of Groups C and D were more evenly distributed than those of Groups A and B. The maximum displacements of fracture ends in Groups A, B, C, and D were 0.44, 0.52, 0.50, and 0.44 mm, respectively.The biomechanical stability of F-type CCS fixation is similar to that of 3 CCSs in an inverted triangular parallel configuration combined with medial buttress plate, with a better dispersion of stress. F-type CCS fixation may be a well option for the treatment of femoral neck fracture of Pauwels III.

Background No large series have analysed distally based sural fasciocutaneous (DBSF) flaps in paediatric patients. The aims of this study were to assess the reliability and analyse the potential risk factors for these flaps and to describe complications in the donor site and the functional follow-up results. Methods Between June 2002 and November 2017, 88 DBSF flaps were used to reconstruct soft tissue defects in paediatric patients. Potential risk factors, reconstruction outcomes, and complications in the donor site of the flaps were analysed. Results Among the 88 flaps, partial necrosis developed in 8 flaps (9.1%). The partial necrosis rate was significantly higher in flaps with the top edge located in the 9th zone (26.1%), with a length-width ratio (LWR) ≥ 5:1 (28.6%), and with a dimension of the skin island ≥ 100 cm2 (22.7%). Partial necrosis did not occur in flaps with a dimension of the skin island < 80.0 cm2 or with a skin-island width < 7.0 cm. The reconstruction outcomes in most paediatric patients were evaluated as “excellent” or “good”. The incidence of obvious scarring was higher in the donor site. Conclusions Partial necrosis of DBSF flaps will significantly increase when the top edge of the flap is located in the 9th zone, when the LWR of the flap is ≥ 5:1, or when the dimension of the skin island is ≥ 100.0 cm2. Flaps with a skin-island width < 7.0 cm or with a dimension of the skin island < 80 cm2 are relatively safe and reliable.

Distally based peroneal artery perforator-plus fasciocutaneous (DPAPF) flaps are widely used to reconstruct soft tissue defects of the lower extremity. Treatment for soft tissue defect combined with chronic osteomyelitis in the lateral malleolus has rarely been reported. The aim of this study was to elaborate the superiority of the DPAPF flap and provide referential experience for using the DPAPF flap in this situation. Between June 2010 and December 2017, soft tissue defects in the setting of chronic osteomyelitis in the lateral malleolus were reconstructed with DPAPF flaps in 17 patients. After thorough debridement, the defect was repaired with the DPAPF flap, and patients subsequently followed an antibiotic regimen for 6 weeks. Follow-up periods for all patients were at least 24 months. The reconstruction outcomes and the satisfaction of the 17 patients were evaluated. Of the 17 flaps, 16 survived uneventfully, except one occurrence of partial necrosis. No infection occurred in the follow-up period. In the study, 17 patients except one were satisfied with flap appearance. All the patients were satisfied with the reconstruction outcomes. In a one-stage procedure, the use of DPAPF flaps is ideal for reconstructing soft tissue defects in the setting of chronic osteomyelitis in the lateral malleolus.

BACKGROUND Acetabular anterior wall fracture with preservation of the pelvic brim is extremely rare. It is different from anterior wall fracture classified by Judet and Letournel. Few studies have reported cases treated by open reduction and internal fixation via the Smith-Petersen or iliofemoral approach. CASE SUMMARY We report a 48-year-old Chinese woman who had difficulty moving her right hip from abduction and external rotation after falling from 3 m. Pelvic radiograph and three-dimensional reconstruction of computed tomography revealed acetabular anterior wall fractures combined with fractures of the anterior inferior iliac spine and the iliac wing but not involving the pelvic brim. First, the patient underwent interim management by closed reduction of the hip dislocation and skin traction for 6 d. Then, we used a modified pararectus approach for treatment to fix the acetabular fractures with a reconstruction plate and nonlocking T-shape plate. At the 9-mo follow-up, the patient could walk painlessly without necrosis of the femoral head or heterotopic ossification, and the X-rays and computed tomography scan reconstructions showed good bone union. CONCLUSION The modified pararectus approach described here can facilitate exposure, reduction, and osteosynthesis for atypical acetabular fracture with less invasiveness.

BACKGROUND Congenital radioulnar synostosis (CRUS) is a rare deformity of the upper extremity. It is characterized by loss of rotation of the involved forearm and functional limitations in daily activities. No studies on CRUS with osteoporosis have been reported to date, and osteoporosis is usually recognized as an important dimension of genetic disorder in children. We discuss the possible relationship among this disorder, osteoporosis and fracture nonunion, investigate the strict surgical indications and recommended treatments. CASE SUMMARY A 14-year-old male patient with bilateral CRUS with osteoporosis, fragility fracture and nonunion of fractures in ulna and radius presented our institution for further treatment, complaining of limitation in rotation. The bone mineral density of the hip and lumbar spine was 0.687 g/cm2 and 0.705 g/cm2, respectively, and the Z-score for both was -2.1, which revealed osteoporosis and a high risk of fracture. Tow serum bone turnover markers indicated an imbalance of bone metabolism. Reoperation for ulna fracture with autogenous bone grafting and a postoperative physiotherapy program were adopted rather than the separation of pathological synostosis. Radiological examination, observational posture assessment and limb function scale were evaluated before and 1 year after surgery. At 1 year, the fracture nonunion had almost recovered, forearm movement function on the fracture side was restored, and function on the healthy side was significantly improved compared with that before rehabilitation. CONCLUSION Surgical indications for CRUS vary from person to person. Surgery should not be the first choice of treatment, and physiotherapy is not inferior to surgical treatment.

Distally based peroneal artery perforator-plus fasciocutaneous (DPAPF) flaps and distally based posterior tibial artery perforator-plus fasciocutaneous (DPTAPF) flaps are widely used to reconstruct soft-tissue defects of the distal lower leg, ankle, and foot. However, a comparative study of both flaps in a considerable sample size is lacking. This retrospective study aimed to compare the efficacy of the flaps and provide referential evidence for selection of flaps.Between April 2001 and October 2016, 227 patients underwent reconstruction with DPAPF flaps (peroneal group; n = 150) or DPTAPF flaps (posterior tibial group; n = 82). The distal lower leg, ankle, and foot were divided into Zones I and II. Flap viability-related complications and their risk factors, reconstruction outcomes, and donor-site morbidities were compared.In Zone I, the partial necrosis rate was lower in the peroneal group than in the posterior tibial group (p 0.05). In Zone II, the partial necrosis rate was significantly lower in the peroneal group (p 0.05). Significantly lower incidences of donor-site morbidities in terms of hypertrophic scarring, itching, and pigmentation were observed in the peroneal group (p 0.05).The DPAPF flap was superior to the DPTAPF flap with respect to reliability and decreased donor-site morbidities. The former is the recommended preferential choice between the two.

We have previously demonstrated the pivotal role of Jnk-mediated Irf-3/c-Jun in regulating nuclear factor kappa-Β ligand (RANKL)-induced osteoclastogenesis. Here, we demonstrated that proanthocyanidins (PACs) target Irf-3 to alleviate breast cancer-induced activation of osteoclasts. We also found that PACs induced apoptosis of osteoclast precursors by upregulating the ratio of bax/bcl-2 and activating caspase-3 activity. Such bone protective effect also could be observed in a bone metastasis model of breast cancer. These findings provided a novel therapeutic intervention targeting abnormal bone metabolism to alleviate bone metastasis of breast cancer.

BACKGROUND Joint stiffness after elbow surgery is not a rare complication, and is always accompanied by deformity. The causes of joint stiffness are multiple in different patients, and divided into intrinsic and extrinsic causes. Herein, we report an unusual case of posttraumatic elbow stiffness due to multiple and rare causes. CASE SUMMARY A 19-year-old male was hospitalized with the loss of motion of the left elbow for over ten years. Left limb computed tomography revealed left elbow stiffness with bony block and connection. The patient underwent surgery, and the etiology of joint stiffness was found to be a rare combination of common and uncommon causes. During an 18-mo follow-up period, the patient’s left elbow had normal motion and he was symptom-free. CONCLUSION However, this case combined with multiple and rare causes highlights that the patient with scar physique is likely to be accompanied with more severe soft tissue, nerve contracture, and heterotypic ossification, even during recurrence.

BackgroundOsteoporosis is a common complication of acute fracture, which can lead to fracture delayed union or other complications and resulting in poor fracture healing. Bisphosphate is a common anti-osteoporosis drug, but its application in fracture patients is still controversial because of its inhibitory effect on bone resorption.MethodStudies were acquired from literature databases in accordance with established inclusion criteria. Standard mean difference (SMD) and 95% confidence intervals (Cls) were calculated to evaluate the effectiveness of the bisphosphonates treatment in fracture patients. Data analysis was conducted with the Review Manager 5.4.1 software.ResultsA total of 16 studies involving 5022 patients obtained from selected databases were examined. As expected, bisphosphate had no significant effect on fracture healing time, but it could significantly increase BMD and prevent osteoporosis. Meanwhile, bisphosphate can inhibit both bone resorption and bone formation markers, resulting in low bone turnover state.ConclusionThis meta-analysis showed that bisphosphonate have no significant effect on fracture healing time but they do increase the changes in BMD and reduce bone synthesis and resorption markers. Early application of bisphosphonates after injury in the appropriate patient population should be considered.

Glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH) accounts for a big portion of non-traumatic ONFH; nevertheless, the pathogenesis has not yet been fully understood. GC-induced endothelial dysfunction might be a major contributor to ONFH progression. The Gene Expression Omnibus (GEO) dataset was analyzed to identify deregulated miRNAs in ONFH; among deregulated miRNAs, the physiological functions of miR-122-5p on ONFH and endothelial dysfunction remain unclear. In the present study, miR-122-5p showed to be under-expressed within GC-induced ONFH femoral head tissues and GC-stimulated bone microvascular endothelial cells (BMECs). In human umbilical vein endothelial cells (HUVECs) and BMECs, GC stimulation significantly repressed cell viability, promoted cell apoptosis and increased the mRNA expression of proinflammatory cytokines, such as TNF-α, IL-1β, and IFN-γ. After overexpressing miR-122-5p, GC-induced endothelial injuries were attenuated, as manifested by rescued cell viability, cell migration, and tube formation capacity. Regarding the BMP signaling, GC decreased the protein levels of BMP-2/6/7 and SMAD-1/5/8, whereas miR-122-5p overexpression significantly attenuated the inhibitory effects of GC on these proteins. Online tool and experimental analyses revealed the direct binding between miR-122-5p and GREM2, a specific antagonist of BMP-2. In contrast to miR-122-5p overexpression, GREM2 overexpression aggravated GC-induced endothelial injury; GREM2 silencing partially eliminated the effects of miR-122-5p inhibition on GC-stimulated HUVECs and BMECs. Finally, GREM2 silencing reversed the suppressive effects of GC on BMP-2/6/7 and SMAD-1/5/8, and attenuated the effects of miR-122-5p inhibition on these proteins upon GC stimulation. Conclusively, the present study demonstrates a miR-122-5p/GREM2 axis modulating the GC-induced endothelial damage via the BMP/SMAD signaling. Considering the critical role of endothelial function in ONFH pathogenesis, the in vivo role and clinical application of the miR-122-5p/GREM2 axis is worthy of further investigation.

The immune system mediates inflammation, vascularization and the first response to injuries or implanted biomaterials. Although the function of neutrophils in tissue repair has been extensively studied, its complete role in the tissue regeneration of biomaterials, specifically the resolution of inflammation and promotion of angiogenesis, is unclear. Here, we fabricate nanofibrous gelatin scaffolds containing 10% (w/w) strontium-hydroxyapatite (SrHA) via phase-separation methods to investigate Sr-mediated regulation of neutrophil polarization and, subsequently, the effects on angiogenesis and macrophage polarization. Compared with neutrophils cultured on pure gelatin or HA-incorporated gelatin scaffolds, neutrophils on SrHA-incorporated gelatin scaffolds show more N2 polarization in vitro and in vivo and significantly greater production of immunomodulatory and angiogenic factors. The Sr-induced immunomodulatory and proangiogenic functions of neutrophils are mediated through NF-κB pathway downregulation and increased STAT3 phosphorylation. Thus, neutrophils play a vital role in tissue engineering, and Sr-incorporated scaffolds efficiently promote neutrophil polarization to the N2 phenotype, enhancing resolution of inflammation and ultimately promoting angiogenesis and tissue regeneration. Thus, incorporation of neutrophils in analyses of the immune characteristics of scaffolds and the development of immunomodulatory biomaterials that can regulate neutrophils are novel and promising strategies in tissue engineering.

Background Osteoarthritis (OA) is the most common articular disorder, leading to joint malfunction and disability. Although the incidence of OA is increasing globally, the treatment of OA is very limited. LncRNA CIR has been implicated in OA through unclear mechanisms. Here, we investigated the role of lncRNA CIR in chondrogenic differentiation. Methods Human umbilical-cord-derived mesenchymal stem cells (hUC-MSCs) were obtained from human umbilical cords. Flow cytometry was used to analyze the surface markers of hUC-MSCs. Various culture conditions and corresponding staining assays were employed to assess the differentiation abilities of hUC-MSC. qRT-PCR, western blot, and immunostaining were used to measure expression levels of related genes and proteins such as lncRNA CIR, ATOH8, EZH2, and H3K27me3. RNA immunoprecipitation assay, biotin pull-down, and chromatin immunoprecipitaion assay were performed to analyze the interactions of lncRNA CIR, EZH2, H3K27me3 and ATOH8 promoter. Results hUC-MSCs exhibited MSCs features and could differentiate into chondrocytes under specific conditions. LncRNA CIR was downregulated while ATOH8 was upregulated during the chondrogenic differentiation of hUC-MSCs. Knockdown lncRNA CIR or overexpression of ATOH8 promoted chondrogenic differentiation. Further, lncRNA CIR bound to EZH2 and repressed ATOH8 expression via EZH2-mediated H3K27me3, which promotes the methylation of ATOH8. Inhibition of ATOH8 reversed the effects of knockdown lncRNA CIR on chondrogenic differentiation. Conclusion LncRNA CIR suppresses chondrogenic differentiation of hUC-MSCs. Mechanistically, lncRNA CIR could inhibit ATOH8 expression that functions to promote chondrogenic differentiation through EZH2-mediated epigenetic modifications.

Suture is one of the basic surgical skills. The needle and suture are equally important as basic materials. Surgical sutures retain in the tissues for varying lengths of time, while needles pass through the tissues for only a few seconds. If needles are not ideal, it is difficult for the suture to play its role well. Whether the needle is stable on the needle holder and the size of the wound caused by the needle both influence the suture effect. Hence suture needles are quite important especially for delicate surgeries. Under the premise of ensuring strength, the needle should be as thin and sharp as possible and can be firmly held by the needle holder. The suture needle guided through the tissue under minimum resistance causes minimum damage. The rigidity and flexibility of the needle should be well matched and can resist both bending and breakage. It should also be easy to be disinfected, resist corrosion, and effectively prevent microorganisms or foreign bodies from entering the wound. Suture needles with corresponding shape and diameter can be designed and manufactured according to the suture diameter and different surgical procedures. The sutures are used for suturing tissues and ligating blood vessels, which should have certain tension, easy knotting, minor tissue reaction, no toxicity, no sensitization, no carcinogenicity, and easy sterilization and preservation. The sutures are divided into absorbable sutures and non-absorbable sutures. New suture materials can meet different surgical needs.

Background Distally based peroneal artery perforator-plus fasciocutaneous (DPAPF) flaps are widely used for reconstructing soft-tissue defects of the lower extremity. However, reports on the reconstruction of the defects over the distal forefoot using the DPAPF flaps are scarce. Herein, we describe our experience on the reconstruction of these defects using DPAPF flaps in a considerable sample size. Methods Between February 2005 and August 2019, a total of 56 DPAPF flaps in 56 patients were used to reconstruct soft-tissue defects in the forefoot. In order to reduce the length of fascial pedicle and the total length of the DPAPF flaps, the ankles were fixed in dorsiflexion using a Kirschner wire before designing the flaps. The flaps were elevated by the anterograde–retrograde approach. Patient factors and flap factors were compared between the “survival” and “partial necrosis” groups. Results Overall, 47 flaps had survived completely in one stage. Partial necrosis developed in nine flaps, with only one remnant defect covered using a local flap. By fixing the ankles in dorsiflexion, the length of the fascial pedicle was reduced approximately 2.35 ± 0.58 cm, the total length of the flap was simultaneously shortened by the same amount as the length of the fascial pedicle. The width of the fascia pedicle varied from 3.0 cm to 6.0 cm. The fascial pedicle width > 4 cm was found in 21 flaps. The partial necrosis rate of the DPAPF flaps with the top edge located in the 8th zone was significantly lower than that in the 9th zone (p < 0.05). Conclusions The DPAPF flaps can be effectively used to reconstruct the defects over the distal forefoot because of convenient harvest and reliability. By fixing the ankle in dorsiflexion with Kirschner wire and widening the fascial pedicle appropriately, the top edge and LWR of the flaps will be decreased, and thus the procedures are helpful for the flaps survival.

Osteoarthritis (OA) is a high prevalent musculoskeletal problem, which can cause severe pain, constitute a huge social and economic burden, and seriously damage the quality of life. This study was intended to identify genetic characteristics of subchondral bone in patients with OA and to elucidate the potential molecular mechanisms involved. Data of gene expression profiles (GSE51588), which contained 40 OA samples and 10 normal samples, was obtained from the Gene Expression Omnibus (GEO). The raw data were integrated to obtain differentially expressed genes (DEGs) and were further analyzed with bioinformatic analysis. The protein–protein interaction (PPI) networks were built and analyzed via Search Tool for the Retrieval of Interacting Genes (STRING). The significant modules and hub genes were identified via Cytoscape. Moreover, Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analysis were performed. Totally 235 DEGs were differentially expressed in the subchondral bone from OA patients compared with those of normal individuals, of which 78 were upregulated and 157 were downregulated. Eight hub genes were identified, including DEFA4, ARG1, LTF, RETN, PGLYRP1, OLFM4, ORM1, and BPI. The enrichment analyses of the DEGs and significant modules indicated that DEGs were mainly involved in inflammatory response, extracellular space, RAGE receptor binding, and amoebiasis pathway. The present study provides a novel and in-depth understanding of pathogenesis of the OA subchondral bone at molecular level. DEFA4, ARG1, LTF, RETN, PGLYRP1, OLFM4, ORM1, and BPI may be the new candidate targets for diagnosis and therapies on patients with OA in the future.

The Hedgehog (Hh) signaling pathway is highly conserved signaling pathway in cells. Steroids was found to play a vital role in Hh signaling pathway and aberrant Hh signaling was found to lead a series of disease correlate with abnormal lipid metabolism. This paper aimed to elucidate the relationship between lipid metabolism and Hedgehog signaling pathway.

This study aimed to investigate the mechanism of the ubiquitinase Aurora kinase A (AURKA) in the occurrence of osteoarthritis (OA) by mediating mitochondrial stress. Bioinformatic predictions revealed 2247 differentially expressed genes (DEGs) in the normal and OA tissues. According to the UbiNet database, 39 DEGs that code for ubiquitination enzymes was screened. AURKA was highly expressed in OA tissues and cells. AURKA interference inhibited the elevation of matrix metalloproteinase-13 (MMP-13). (MMP13), sex determining region Y-box 9 (Sox9), and a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS5) expression and the reduction of collagen type IIα (Col2a1) and Aggrecan expression in interleukin-1 β (IL-1β) induced chondrocytes. The animal experiments proved that depleting AURKA could repress the occurrence of OA. Superoxide dismutase 2 (SOD2) was determined to be AURKA ubiquitination substrate via AURKA expression and bioinformatic prediction experiments. SOD2 expression was lower in OA tissues, but higher in normal joint tissues. AURKA interference activates SOD2. Meanwhile, the IP results confirmed that AURKA could bind to SOD2 and degrade it through K48 ubiquitination. Modification and overexpression of AURKA reduce SOD2 levels. AURKA interference can reverse the reactive oxygen species elevation caused by SOD2 overexpression or lysine-48 (K48) mutation, respectively, leading to mitochondrial dysfunction. Furthermore, AURKA silencing suppressed the occurrence of OA induced by mitochondrial activation. These findings suggest that ubiquitination of AURKA lowers SOD2 expression and affects mitochondrial dysfunction to repress the occurrence of OA. The results of the current study reveal that AURKA ubiquitination influences mitochondrial dysfunction and suppresses the occurrence of OA via degradation of SOD2. These data reveal novel potential targets for OA treatment.

Osteosarcoma is a malignant bone tumour with the lowest survival rates out of all paediatric cancers and is primarily diagnosed in children and adolescents. MNAT1 is a subunit in the cyclin-dependent kinase-activating kinase complex. Abnormal up-regulation of MNAT1 has been associated with the poor prognosis of multiple cancers. Bioinformatics analysis showed that has-circ-0001146 and miR-26a-5p were involved in the regulation of MNAT1 in osteosarcoma. The present study investigated the regulatory effects of has-circ-0001146 and miR-26a-5p on MNAT1 expression using luciferase reporter and RNA-pull down assays. The effects of the has-circ-0001146/miR26a-5p/Mnat1 network on the proliferation and invasion of osteosarcoma were evaluated by cell viability, apoptosis, migration, and invasion assays. Osteosarcoma tissues showed higher MNAT1 and has-circ-0001146 expression than adjacent normal tissues, although the expression of MNAT1 was not significantly up-regulated in sarcomas according to TCGA databases. As indicated by luciferase reporter and RNA-pull down assays, miR-26a-5p was able to bind to both has-circ-0001146 and MNAT1 mRNA. The depletion of has-circ-0001146 as well as the increase of miR-26a-5p decreased MNAT1 expression in osteosarcoma cells, while the reduction of miR-26a-5p was associated with increased MNAT1 expression. These data suggested that has-circ-0001146 promoted MNAT1 expression by competitively binding to miR-26a-5p with MNAT1 mRNA. The depletion of has-circ-0001146 or MNAT1 or the increase of miR-26a-5p inhibited osteosarcoma cell viability and invasion, and increased apoptosis. Reduction of miR-26a-5p conversely promoted osteosarcoma cell viability and invasion. The present study confirmed that has-circ-0001146 blocked miR-26a-5p targeting MNAT1 in osteosarcoma cells, thereby promoting the malignant behaviours of osteosarcoma cells.

Cladribine (2CdA), a synthetic purine analog interfering with DNA synthesis, is a medication used to treat hairy cell leukemia (HCL) and B-cell chronic lymphocytic leukemia. Entinostat, a selective class I histone deacetylase (HDAC) inhibitor, shows antitumor activity in various human cancers, including hematological malignancies. The therapeutic potential of cladribine and entinostat against multiple myeloma (MM) remains unclear. Here we investigate the combinatorial effects of cladribine and entinostat within the range of their clinical achievable concentrations on MM cells. While either agent alone inhibited MM cell proliferation in a dose-dependent manner, their combinations synergistically induced anti-proliferative/anti-survival effects on all MM cell lines (RPMI8226, U266, and MM1.R) tested. Further studies showed that the combinations of cladribine and entinostat as compared to either agent alone more potently induced mitotic catastrophe in the MM cells, and resulted in a marked increase of the cells at G1 phase associated with decrease of Cyclin D1 and E2F-1 expression and upregulation of p21waf−1. Apoptotic ELISA and western blot analyses revealed that the combinations of cladribine and entinostat exerted a much more profound activity to induce apoptosis and DNA damage response, evidenced by enhanced phosphorylation of histone H2A.X and the DNA repair enzymes Chk1 and Chk2. Collectively, our data demonstrate that the combinations of cladribine and entinostat exhibit potent activity to induce anti-proliferative/anti-survival effects on MM cells via induction of cell cycle G1 arrest, apoptosis, and DNA damage response. Regimens consisting of cladribine and/or entinostat may offer a new treatment option for patients with MM. Abbreviations: MM, multiple myeloma; HCL, hairy cell leukemia; HDAC, histone deacetylase; Ab, antibody; mAb, monoclonal Ab; FBS, fetal bovine serum; CI, combination index; PAGE, polyacrylamide gel electrophoresis; ELISA, enzyme-linked immunosorbent assay; PARP, poly(ADP-ribose) polymerase; MTS, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium,inner salt

The aim of this study is to investigate the role of tumor necrosis factor-α (TNF-α) in apoptosis and autophagy of mouse osteoblast MC3T3-E1 cells, as well as the crosstalk between autophagy and apoptosis. Mouse osteoblast MC3T3-E1 cells were cultured in vitro and treated with 5-fluorouracil (5-FU), rapamycin, 3-methyl adenine (3-MA) and TNF-α either alone or in combination, respectively. MTT assays were used to monitor the cell viability upon different treatments. Annexin-V-FITC/propidium iodide (PI) staining was used to detect the apoptotic rate of osteoblasts. Autophagic structure and apoptotic bodies were visualized by transmission electron microscopy (TEM). Western blot analysis was performed to detect the autophagic marker LC3-II/I, p62 and apoptotic marker cleaved caspase-3. TNF-α inhibits MC3T3-E1 cell viability in a dose-dependent and time-dependent manner. Annexin-V-FITC/PI staining, coupled with TEM, showed that TNF-α induced cell apoptosis and autophagy in MC3T3-E1 cells. The autophagy inducer rapamycin ameliorated TNF-α-induced apoptosis. In contrast, 3-MA, which is an autophagy inhibitor, caused an exaggerated induction of TNF-α-induced apoptosis. TNF-α upregulated autophagy marker LC3-II/I, but downregulated p62 in osteoblasts. Combined treatment of rapamycin and TNF-α further exaggerated this effect, whereas co-treatment of 3-MA and TNF-α decreased LC3-II/I, but increased p62 compared with TNF-α alone. In addition, TNF-α caused an induction of apoptotic marker cleaved caspase-3. TNF-α-mediated induction of cleaved caspase-3 was downregulated by rapamycin, but upregulated by 3-MA, respectively. TNF-α induced both autophagy and apoptosis in osteoblasts, and upregulated autophagy protects the cell by reducing TNF-α-induced apoptosis.

Background The aim of this study was to compare the clinical results between double reverse traction repositor and traction table used for the treatment of unstable intertrochanteric femur fracture. Methods This retrospective study included 95 patients with AO/OTA 31- A2 and A3 proximal femur fracture, who underwent double reverse traction repositor or traction table facilitated Asian proximal femoral nail antirotation (PFNA-II) nailing. The demographics, duration of operation, blood loss, part loading time after surgery, the period of union of fracture, complication were assessed. Clinical and radiological outcomes were evaluated. Results There were no significant differences in respect to demographics and fracture characteristics. Duration of patient positioning and total operative time were significant longer in traction table group than that in double reverse traction repositor group(p

Background Hip fractures are common and account for a large proportion of orthopedic surgical admissions in elderly patients. However, determining the timing for surgery has been controversial for patients who develop hip fractures while on antiplatelet treatment. Methods Computerized databases for studies published from the inception date to January 2020, including the Cochrane Library, PubMed (Medline), EMBASE, Web of ScienceTM, ClinicalTrials, ClinicalKey, and Google Scholar, were searched using the keywords “Hip AND Fracture”, “Antiplatelet”, “Antithrombocyte”, “Platelet aggregation inhibitors”, “Aspirin”, “Plavix”, and “Clopidogrel”. Results In total, 2328 initial articles were identified. Twenty-four studies with 5423 participants were ultimately included in our analysis. Early surgery was associated with an increased transfusion rate in the antiplatelet group compared to the non-antiplatelet group (OR = 1.21; 95% CI, 1.01 to 1.44; p = 0.03). Early surgery for hip fracture patients on antiplatelet therapy was associated with a greater decrease in hemoglobin compared to delayed surgery (WMD = 0.75; 95% CI, 0.50 to 1.00; p < 0.001). However, early surgery appeared to decrease the length of hospitalization (WMD = − 6.05; 95% CI, − 7.06 to − 5.04; p < 0.001) and mortality (OR = 0.43; 95% CI, 0.23 to 0.79; p = 0.006). Conclusion It is unnecessary to delay surgery to restore platelet function when patients with hip fractures receive antiplatelet therapy. Furthermore, early surgery can significantly reduce mortality and hospital stay, which is conducive to patient recovery. Future randomized trials should determine whether the results are sustained over time.

There remain unmet clinical needs for safe and effective bone anabolic therapies to treat aging-related osteoporosis and to improve fracture healing in cases of nonunion or delayed union. Wnt signaling has emerged as a promising target pathway for developing novel bone anabolic drugs. Although neutralizing antibodies against the Wnt antagonist sclerostin have been tested, Wnt ligands themselves have not been fully explored as a potential therapy. Previous work has demonstrated Wnt7b as an endogenous ligand upregulated during osteoblast differentiation, and that Wnt7b overexpression potently stimulates bone accrual in the mouse. The earlier studies however did not address whether Wnt7b could promote bone formation when specifically applied to aged or fractured bones. Here we have developed a doxycycline-inducible strategy where Wnt7b is temporally induced in the bones of aged mice or during fracture healing. We report that forced expression of Wnt7b for 1 month starting at 15 months of age greatly stimulated trabecular and endosteal bone formation, resulting in a marked increase in bone mass. We further tested the effect of Wnt7b on bone healing in a murine closed femur fracture model. Induced expression of Wnt7b at the onset of fracture did not affect the initial cartilage formation but promoted mineralization of the subsequent bone callus. Thus, targeted delivery of Wnt7b to aged bones or fracture sites may be explored as a potential therapy.

Background: We aimed to carry out a comprehensive multiple-center epidemiological study of post-traumatic related limb osteomyelitis (PTRLO) in China. Methods: Approved by the Institutional Research Board (IRB), 3,526 PTRLO patients were identified from 212,394 traumatic limb fracture patients from 21 hospitals between January 1st, 2008- December 31st, 2017 to conduct an epidemiological retrospective analysis, which includes dynamic changes of infection rate (IR), pathogens, infection risk factors, and antibiotics resistant and sensitivity during the past decade. Findings: The IR of PTRLO gradually increased from 0.93% to 2.16% (Z=14.392, p 0.05). The dominant strains of GP are MSSA (17.03%), MRSA (10.46%), E. faecalis (5.19%), and S. epidermidis (4.87%). The dominant strains of GN are Pseudomonas Aeruginosa (10.92%), E. cloacae (10.34%), E.coli (9.47%), Acinetobacter Baumannii (7.92%) & Klebsiella Pneumoniae (3.33%). Overall, the high-risk factors of PI are open-fracture (odds ratio, 2.223), hypoproteinemia (odds ratio, 2.328), and multiple fractures (odds ratio, 1.465). The antibiotic-resistance and sensitivity analysis of the pathogens could be influenced by the complications or comorbidities. Interpretation: The current study demonstrates the epidemiology of PTRLO of a patient population in China, and provides a useful information for patient care and clinical practice. Trial Registration: The study is registered with the Chinese clinical trials registry (ChiCTR1800017597). Funding: National Natural Science Foundation of China, Technological Innovation Projects of Southwest Hospital of China, and AO Trauma Clinical Priority Program on Bone Infection. Declaration of Interests: All other authors declare no competing interests. Ethics Approval Statement: Approved by the Institutional Research Board (IRB)

Additional file 1.

Sp1 activated FOXC1 and they both directly transactivated HOTTIP, which recruited enhancer of zeste homolog 2 and lysine‐specific demethylase 1 to silence LATS2 and thus activated YAP/β‐catenin signaling. In summary, we showed that the Sp1/FOXC1/HOTTIP/LATS2/YAP/β‐catenin cascade presented oncogenic activities in OS cells., The prognosis for osteosarcoma (OS) is dismal due to the aggressive tumor growth and high incidence of metastasis. The long noncoding RNA human homeobox A transcript at the distal tip (HOTTIP) and the transcription factor forkhead box C1 (FOXC1) present oncogenic activities in OS. Here, we aimed at gaining insights into the underlying mechanisms and their crosstalk. The expression of FOXC1 and HOTTIP in OS tissues or cell lines was examined by real‐time PCR (RT‐PCR) and western blot. The in vitro effects of FOXC1 or HOTTIP on cell viability, proliferation, migration, invasion, and expression of target genes were examined using MTT, colony‐forming assay, wound‐healing, Transwell invasion, and western blot, respectively; the in vivo effects were examined using xenograft and experimental metastasis models. Molecular control of HOTTIP on large tumor suppressor 2 (LATS2) or transactivation of FOXC1 or Sp1 on HOTTIP was assessed by combining RNA immunoprecipitation, qRT‐PCR, western blot, ChIP, and luciferase assay. Both FOXC1 and HOTTIP were potently up‐regulated in OS tissues and cell lines. FOXC1 and HOTTIP essentially maintained viability, proliferation, migration, and invasion of OS cells in vitro and contributed to xenograft growth or lung metastasis in vivo. Mechanistically, HOTTIP recruited enhancer of zeste homolog 2 (EZH2) and lysine‐specific demethylase 1 (LSD1) to silence LATS2 and thus activated YAP/β‐catenin signaling. Upstream, Sp1 activated FOXC1 and they both directly transactivated HOTTIP. In summary, we showed that the Sp1/FOXC1/HOTTIP/LATS2/YAP/β‐catenin cascade presented oncogenic activities in OS cells. Targeting FOXC1 or HOTTIP may therefore prove beneficial for OS treatment.

Objective To study roles of lncRNA-MALAT1 and miR-214 in steroid-induced avascular necrosis of the femoral head (SANFH). Methods MALAT1, miR-214 and osteogenic-related genes (Runx2, ALP, and OCN) expressions were determined in SANFH tissue samples and human bone marrow stromal cells (BMSC) by RT-qPCR. BMSCs were verified by flow cytometry. The ATF4 level was determined by western blotting and RT-qPCR. Osteogenesis induced by osteogenic medium (OM) in BMSCs and dexamethasone (DEX) was used to inhibit osteogenesis. The alkaline phosphatase (ALP) activity was measured and ALP staining and alizarin red staining were conducted for evaluation of osteogenic differentiation. MTT assay was used for cell proliferation. The dual luciferase reporter assay was used to confirm binding between MALAT1 and miR-214, as well as miR-214 and ATF4. Results MALAT1 was down-regulated and miR-214 was up-regulated in SANFH tissues. DEX inhibited osteogenic differentiation of BMSC in a dose-dependent manner, leading to decreased MALAT1, increased miR-214, as well as reduced ALP activity and decreased expression of RUNX2, ALP and OCN. Either overexpression of MALAT1 or inhibition of miR-214 improved DEX-induced inhibition of BMSC osteogenic differentiation. The overexpression of miR-214 reversed the effects by MALAT1. MALAT1 directly sponged miR-214 and miR-214 directly targeted ATF4. Conclusion MALAT1 was down-regulated, while miR-214 was elevated in SANFH tissues. MALAT1 promoted osteogenesis differentiation by sponging miR-214 to upregulate ATF4.

To investigate the effect of miR-30a/HMGA2-mediated autophagy in osteosarcoma cells on apoptosis induced by chemotherapeutics. Methods: A total of 30 osteosarcoma tissues of sensitive and resistant to chemotherapeutics were divided into a chemotherapy-sensitive group and a chemotherapy-resistant group. The mRNA expression levels of miR-30a and high mobility group protein A2 (HMGA2) in the chemotherapy-sensitive group and the chemotherapy-resistant group, and the mRNA expression levels of miR-30a in osteosarcoma U2-OS cells treated by cisplatin, doxorubicin and methotrexate at different concentrations were detected by real-time PCR. The expression levels of autophagy related protein Beclin 1, microtubule associated protein 1 light chain 3B (LC3B) and autophagy factor P62 were detected by Western blotting. The osteosarcoma U2-OS cells were transfected with miR-30a mimics and miR-30a inhibitors to construct a miR-30a high expression group, a miR-30a low expression group and a control group. The expression levels of Beclin 1, LC3B and P62 in osteosarcoma U2-OS cells after treatment of cisplatin and doxorubicin in these 3 groups were detected by Western blotting; the level of autophagy was detected by monodansylcada (MDC) staining; the level of ROS was detected by dihydroethidium (DHE); the level of cell surviving rate was detected by cell counting kit-8 (CCK-8); the level of apoptosis was detected by annexin APC/PI double staining; the level of mitochondria oxidative damage was detected by mitochondrial membrane potential assay kit with JC-1 (JC-1 method). The interaction between miR-30a and HMGA2 was detected by dual luciferase reporter assay. The osteosarcoma U2-OS cells were transfected with HMGA2 mimics and HMGA2-shRNA to construct a high HMGA2 group, a low HMGA2 group, and a control group. The expression levels of Beclin 1, LC3B and P62 in osteosarcoma U2-OS cells after the treatment of cisplatin were detected by Western blotting. Results: The level of miR-30a in the chemotherapy-resistant tissues was significantly lower than that in the chemotherapy-sensitive tissues (P0.05), and the expression of HMGA2 was opposite comparing to that of miR-30a (P0.05). After the treatment by low concentration (5 μmol/L) of chemotherapeutics, the level of miR-30a was down-regulated in osteosarcoma U2-OS cells, accompanied with up-regulation of Beclin 1 and LC3B (P0.01) and down-regulation of P62 (P0.01). Compared with the control group, the expression levels of Beclin 1 and LC3B were significantly decreased (P0.05), and the expression level of P62 was significantly increased (P0.05) in the miR-30a high expression group, which was opposite in the miR-30a low expression group. In the miR-30a high expression group treated by chemotherapeutics, the level of autophagy and the cell survival rate were lower than those in group with low expression of miR-30a, while the levels of ROS, the mitochondrial oxidative damage and the apoptosis were higher than those in group with low expression of miR-30a (all P0.05). The targeting interaction between HMGA2 and miR-30a were verified by dual luciferase reporter assay. Compared with the control group, the expression levels of Beclin 1 and LC3B were significantly increased (P0.05), and the expression level of P62 was significantly decreased (P0.05) in the HMGA2 high expression group, which was opposite in the HMGA2 low expression group. Conclusion: Suppression of miR-30a/HMGA2-mediated autophagy in osteosarcoma cells is likely to enhance the therapeutic effect of chemotherapeutics.目的：探讨微小RNA(microRNA，miR)-30a/高迁移率族蛋白A2(high mobility group protein A2，HMGA2)介导的骨肉瘤细胞自噬对化学药物治疗(以下简称化疗)药物诱导的细胞凋亡的影响。方法：随机选取30例经化疗药物治疗后表现为化疗敏感和化疗抵抗的骨肉瘤患者组织，分为化疗敏感组(n=15)和化疗抵抗组(n=15)，采用real-time PCR检测两组中miR-30a和HMGA2的mRNA表达水平，以及骨肉瘤细胞U2-OS经不同浓度的化疗药物(顺铂、阿霉素、氨甲蝶呤)处理后miR-30a的mRNA表达水平；采用蛋白质印迹法检测细胞内自噬相关因子Beclin 1，自噬微管相关蛋白1轻链3B(microtubule associated protein 1 light chain 3B，LC3B)、自噬抑制因子P62的表达情况。在骨肉瘤细胞U2-OS中转染miR-30a模拟物和抑制剂，构建miR-30a高表达组、低表达组和对照组，采用蛋白质印迹法检测经过顺铂和阿霉素处理后上述3组细胞内Beclin 1，LC3B和P62的表达情况；采用单丹磺酰尸胺(monodansylcada，MDC)染色法检测细胞内自噬水平，ROS荧光探针-二氢乙啶(dihydroethidium，DHE)检测细胞内ROS水平，细胞计数试剂盒8(cell counting kit-8，CCK-8)检测细胞存活率，流式细胞术检测细胞凋亡程度，线粒体膜电位荧光探针JC-1检测细胞线粒体氧化损伤程度；采用双荧光素酶法检测miR-30a与HMGA2的相互作用，同时通过转染HMGA2模拟物和HMGA2-shRNA干扰质粒载体，构建HMGA2高表达组、低表达组和对照组，采用蛋白质印迹法检测经过顺铂和阿霉素处理后上述3组细胞内Beclin 1，LC3B和P62的表达情况。结果：化疗抵抗组中miR-30a的mRNA水平显著低于化疗敏感组(P0.05)，HMGA2的表达与miR-30a相反(均P0.05)。在相对低浓度(5 μml/L)的化疗药物刺激下，骨肉瘤细胞U2-OS内的miR-30a mRNA表达下调，Beclin 1和LC3B均显著上调(均P0.01)，P62显著下调(P0.01)。在miR-30a高表达组中，与对照组相比，Beclin 1和LC3B的表达水平与miR-30a明显下降(P0.05)，P62的表达水平明显升高(P0.05)，在miR-30a低表达组中则相反；在经过化疗药物处理后的miR-30a高表达组中，细胞自噬水平更低，细胞存活率更低，ROS水平更高，线粒体氧化损伤程度更高，细胞凋亡水平更高(均P0.05)，miR-30a低表达组则相反(均P0.05)。双荧光素酶报告基因检测验证了miR-30a与HMGA2的靶向互补配对关系；与对照组相比，HMGA2高表达组中Beclin 1和LC3B的表达水平与HMGA2明显升高(P0.05)，P62的表达水平明显下降(P0.05)，在HMGA2低表达组中则相反。结论：积极发挥miR-30a/HMGA2抑制骨肉瘤细胞自噬的功能，能够破坏细胞应对ROS介导的自噬与凋亡的平衡，增强化疗药物对细胞的杀伤作用。.

Sexually transmitted infection with Chlamydia trachomatis may lead to fibrotic blockage in women’s upper genital tracts, resulting in tubal infertility. Intravaginal inoculation with C. muridarum readily induces fibrotic blockage or hydrosalpinx in mice and is used for investigating C. trachomatis pathogenicity. Using this model in combination with an antibody depletion approach, we confirmed CD4(+) T cell-mediated protective immunity and a CD8(+) T cell-dependent pathogenic mechanism during chlamydial infection in C57BL/6J mice. However, when mice genetically deficient in CD8(+) T cells were evaluated, we found, surprisingly, that these mice were still able to develop robust hydrosalpinx following C. muridarum infection, both contradicting the observation made in C57BL/6J mice and suggesting a pathogenic mechanism that is independent of CD8(+) T cells. We further found that depletion of CD4(+) T cells from CD8(+) T cell-deficient mice significantly reduced chlamydial induction of hydrosalpinx, indicating that CD4(+) T cells became pathogenic in mice genetically deficient in CD8(+) T cells. Since depletion of CD4(+) T cells both promoted chlamydial infection and reduced chlamydial pathogenicity in CD8(+) T cell-deficient mice, we propose that in the absence of CD8(+) T cells, some CD4(+) T cells may remain protective (as in C57BL/6J mice), while others may directly contribute to chlamydial pathogenicity. Thus, chlamydial pathogenicity can be mediated by distinct host mechanisms, depending upon host genetics and infection conditions. The CD8(+) T cell-deficient mouse model may be useful for further investigating the mechanisms by which CD4(+) T cells promote chlamydial pathogenicity.

Simvastatin is demonstrated to be a potent stimulator for bone formation. However, a high dosage of simvastatin is required to induce bone regeneration in systematic administration, which may result in various side effects. Here we achieved the local administration of simvastatin through fabricating core/shell microspheres. Meanwhile, the addition of platelet derived growth factor (PDGF) encapsulated in core/shell microspheres was explored for a better outcome of bone regeneration. The microspheres composed of poly-L-lactide (PLLA) core and alginate shell were formulated via coaxial electrohydrodynamic atomization (CEHDA). The simvastatin and PDGF were incorporated in following models: (1) simvastatin was loaded in the core layer alone (core-simvastatin/shell, M1); (2) simvastatin was encapsulated in the core layer and PDGF was loaded into the shell layer (core-simvastatin/shell-PDGF, M2). Well-formed microspheres with distinct core–shell structures were successfully formulated. In vitro, simvastatin in the core layer displayed a near-zero-order release pattern within 40 days. In contrast, the release profile of PDGF in the shell layer was characterized with a strong initial burst release and being almost depleted in as early as 9 days. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed good biocompatibility with PLLA–alginate microspheres. In in vivo experiments, both the M1 and M2 groups showed greater new bone formation, with significantly increased bone mineral density (BMD), the ratio of mineralized bone volume of the defect tissue volume (BV/TV) and trabecula thickness (Tb.Th) of neogenesis bone, while little newly formed bone was found in sham surgery controls and blank microsphere groups. More importantly, the enhancement of bone regeneration was significantly greater in the M2 group. Thus, we suggested that the core/shell microspheres could be a promising delivery system for simvastatin combined with PDGF to improve bone regeneration.

Osteosarcoma is the most common primary malignant bone tumor, and the frequent acquisition of chemoresistance is often an obstacle to achieving favorable outcomes during chemotherapy. Recently, Krüppel‐like factor 4 (KLF4) has been shown to be associated with chemotherapy resistance in a few tumors; however, the involvement of KLF4 in chemotherapy resistance in osteosarcoma cells remains unknown. In this study, quantitative real‐time PCR and western blot analysis revealed that KLF4 expression was significantly increased in response to cisplatin, methotrexate and doxorubicin treatment in osteosarcoma cells, and knockdown of KLF4 increased sensitivity to these anticancer drugs by decreasing cellular clonogenic ability and increasing apoptosis. Moreover, our data suggest that KLF4‐regulated drug resistance might, at least partially, positively regulate high‐mobility group box 1 (HMGB1), which was found to be a significant contributor to chemoresistance in osteosarcoma cells in our previous study. In summary, this study highlights the significance of KLF4/HMGB1 interaction in regulating chemotherapy resistance, and suggests that targeting KLF4/high‐mobility group box 1 may be a therapeutic strategy for osteosarcoma chemotherapy.