Extracorporeal Shock Wave Promotes Differentiation Of Postnatal Human Bone Marrow Stromal Cells Towards Osteoprogenitors

Bone defects and nonunion are common problem in orthopaedic surgery, the management for these conditions is traditionarily autogenous bone graft, which is defect on the aspect of local complication and limited by bone volume in donor sites. Bone induction is an important theory in the early 20th century. Urist found that bone morphogenetic protein (BMP) could promote mesenchymal cell to differentiate into osteoprogenitors and chondroblast in 1965, thence many scholars went in for the significant work in this research field. It is known that bone marrow stromal cells (BMSCs) have the potential to differentiate into several cell lineages, e.g. , osteoblasts, chondrocytes, neuron, hepatocytes, retinal cells, skeletal muscular cells and tendocytes. Extracorporeal shock wave (ESW) therapy is used routinely for urolithiasis, has gained increasing acceptance for bone nonunion, but it is not clear in the mechanism. Bone marrow in postnatal human being is main composed of hematopoietic cells and stromal cells. Our aim was to investigate whether ESW could promote BMSCs to differentiate into osteoprogenitor cells in vitro and in vivo.Part I In vitro Objective: To study the characteristics in differentiation andv 4proliferation of postnatal human bone marrow stromal cells (hMSCs) and ESW to promote hMSCs to differentiate into osteoprogenitor cells. Methods: hMSCs were source of the bone marrow collected from healthy human donors and cultured according to Majumdar's method in vitro. An optimal dose of SW was selected to treat primary MSCs on the authority of hMSCs proliferation and colony-forming unit (CFU-F). We evaluated that hMSCs differentiated into osteoprogenitor cells by morphology, TGF- P i and Alkaline phosphatase in the culture supernatants, calcium node formation, Alkaline phosphatase Ca-Co staining, osteocalcin mRNA expression. Results: The optimal energy of ESW treated MSCs is 10KV (500), which had the best promoting effect on the CFU-F and cell proliferation .There was not difference in cell morphology between SW group and control group before 3th subculture ,but the cells of S W group tended to osteoblast in morphology after 4th subculture . We found that alkaline phosphatase activity in SW group was increase than control group's every subculture (p<0.01). It show that osteogenesis was clear in SW group by histochemistry and tetracycline fluorescence staining . The expression of osteocalcin mRNA was found in 10 days and TGF- P i was induced after SW treatment. Conclusion: ESW could promote postnatal hMSCs differentiation toward osteogenic lineage associated with induction of TGF- P i. The optimal dose of ESW is 10 KV(500).