Extracorporeal shock wave effects on osteogenic differentiation of bone marrow mesenchymal stem cells at the non-necrotic area of patients with steroid-induced avascular necrosis of the femoral head

BACKGROUND: Avascular necrosis of the femoral head involves pimelosis changes of bone marrow progenitor cells on the proximal end of the femur, and leads to difficulties in repairing the bone remodeling. It still remains unclear whether bone marrow mesenchymai stem cells (BMSCs) can be induce-differentiated into osteoblast precursor at autologous non-osteonecrosis region using in vitro extracorporeal shock wave therapy, and then transplanted in autologous osteonecrosis region, contributing to bone remodeling in the zone of necrosis. OBJECTIVE: To investigate the effect of extracorporeal shock wave on the BMSC differentiation in the non-necrotic area of steroid-induced osteonecrosis of the femoral head in patients. METHODS: This study took the bone marrow of steroid-induced osteonecrosis of the femoral head patients who donated voluntarily. BMSCs were isolated and cultured in vitro by density gradient centrifugation and adherence method. Primary cultured BMSCs were cultured with serum-free medium for 24 hours, and intervened by extracorporeal shock wave of 5 kV/500 frequency for 10 minutes. No extracorporeal shock wave was given in the blank control group. RESULTS AND CONCLUSION: Cells after passage in the extracorporeal shock wave group entered the peak phase of proliferation early, showing osteogenic differentiation trend. Ceils in the blank control group presented multi-directional differentiation into other cell types. Proliferation speed was significantly greater in the extracorporeal shock wave group than in the blank control group at various time points (except at day 1) (P < 0.01). Mean positive rate of alkaline phosphatase was about 90% at day 24 in the extracorporeal shock wave group, and about 50% at day 36 in the blank control group. At day 20, alizarin red staining exhibited that mineralized nodules in the extracorporeal shock wave group was (7.0 plus or minus 1.3) per field, but no obvious mineralized nodules were found, and staining was always negative in the blank control group. Core binding factor alpha 1 mRNA expression in the extracorporeal shock wave group was significantly stronger than the blank control group at various time points (except at day 3) (P < 0.01). Osteocalcin mRNA expression was significantly stronger in the extracorporeal shock wave group than in the blank control group at various time points (except at days 3 and 6) (P < 0.01). Results have suggested that appropriate intensity of extracorporeal Shockwave can promote pro