The Effect Of Hdac9C On Bone Marrow Mesenchymal Stem Cells In Steroid-induced Osteonecrosis Of The, Femoral Head

Objective:To explore the pathogenesis of steroid-induced osteonecrosis of the femoral head and study the relationship between HDAC9c and steroid-induced osteonecrosis of the femoral head.Methods:Bone marrow mesenchymal stem cells of steroid-induced osteonecrosis of the femoral head, traumatic osteonecrosis and primary osteoarthritis patients were isolated from proximal femoral canal by density gradient centrifugation, Bone marrow mesenchymal stem cells surface antigens were identified by flow cytometry, the mRNA and protein expression of HDAC9c、RUNX2、PPARγ were detected by RT-PCR and western-blot respectively, the osteogenic and adipogenic differentiation of bone marrow mesenchymal stem cells were detected.Results:High purity human MSCs were successfully isolated by density gradient centrifugation, the osteogenic differentiation of BMSCs in steroid-induced osteonecrosis of the femoral head patients was reduced, the adipogenic differentiation of BMSCs in steroid-induced osteonecrosis of the femoral head patients was increased, the mRNA and protein expression of HDAC9c and RUNX2were lower than the other two groups,the difference was statistically significant (P<0.05), the mRNA and protein expression of PPARy were higher than the other two groups, the difference was statistically significant (P <0.05).Conclusion:Abnormal osteonecrosis and adipogenic differentiation of BMSCs in steroid-induced osteonecrosis of the femoral head patients may be the key to the onset of ONFH, low expression HDAC9c can be used as biological markers of steroid-induced ONFH. Objective:To investigate the effect of overexpression of HDAC9c on osteogenic transcription factor RUNX2and adipogenic transcription factor PPARy in BMSCs of steroid-induced osteonecrosis of the femoral head.Methods:Different concentrations of Lentiviral vectors were used to transfect BMSCs of steroid-induced osteonecrosis of the femoral head, protein expression of HDAC9c was detected by western-blot and the optimum concentration of Lentiviral vectors was found, the transfected BMSCs or non-transfected BMSCs combined with gelatin sponge were planted in22B ALB/c mice subcutaneously, protein expression of HDAC9c, RUNX2and PPARy in subcutaneous mass were detected4weeks after being planted.Results:HDAC9c was transfected into the BMSCs of steroid-induced osteonecrosis of the femoral head by lentiviral vector, the expression of HDAC9c was enhanced,4weeks after BMSCs combined with gelatin sponge being planted, subcutaneous mass was formed without rejection, the protein expression of HDAC9c and RUNX2in transfected group were higher than non-transfected group, the differences were statistically significant (P <0.05), the protein expression of PPARy in transfected group was lower than non-transfected group, the difference was statistically significant (P value<0.05).Conclusion:Overexpression of HDAC9c in BMSCs of steroid-induced osteonecrosis of the femoral head can be completed by transfection of lentiviral, the expression of osteogenic transcription factor is enhanced and the expression of the adipogenic transcription factor is reduced after transfected BMSCs and gelatin sponge being planted in BALB/c mice subcutaneously, Objective:To establish a rabbit model of steroid-induced osteonecrosis of the femoral head and observe radiological and histopathological changes, to explore the pathogenesis of steroid-induced osteonecrosis of the femoral head and evaluate of the effect of treatment of rabbit model of steroid-induced osteonecrosis of the femoral head with reinfusion of autologous BMSCs.Methods:40healthy New Zealand white rabbits were randomly divided into three groups,10rabbits in saline group (A),14rabbits in model group (group B),and16rabbits in reinfusion of autologous BMSCs group (group C), toxins and methylprednisolone were used to build model, histopathological detection and X-ray, MRI examination were executed before and after modeling4w,8w,12w, group C reinfusion of autologous BMSCs in necrotic femoral head8weeks after modeling, the histopathological detection and X-ray, MRI examination were executed4weeks after reinfusion.Results:Decreased bone density in the femoral head was showed in x ray after modeling, low signal mixed in femoral head in MRI, increased empty lacunae and fat cells in tissue sections of HE staining were also showed. Increased density of the femoral head in X-ray, enhanced signal in the femoral head in MRI, decreased empty lacunae and fat cells in tissue sections of HE staining were obversed4weeks after modeling.Conclusion:Rabbit model of steroid-induced osteonecrosis of the femoral head can be successfully induced by using toxins and methylprednisolone, the osteogenic and adipogenic differentiation in femoral head is related to incidence of steroid-induced osteonecrosis of the femoral head, Reinfusion of autologous BMSCs inhibit fat cell proliferation, promote bone cell formation, is effective in treatment of steroid-induced osteonecrosis of the femoral head.