Extracorporeal Shock Wave Promotes Postnatal Human Bone Marrow Stromal Cells Osteogenesis In vivo

It is known that extracorporeal shock wave (SW) may promote healing of fracture. A previous study reported that SW promoted human bone marrow stromal cells (hMSCs) towards osteoblasts in vitro. To study the osteogenesis ability of hMSCs treated by shock wave in porous hydroxyapatite (HA) in vivo, primary hMSCs of SW group and control group were cultured in the porous HA for 2 weeks and then implanted into subcutaneous sites of nude mouse. These implants were harvested and prepared for the biochemical analysis of alkaline phosphatase activity by AKP kit, histological analysis of decalcified and undecalcified sections and morphology by scan electric microscope (SEM), as well as osteocalcin mRNA expression by RT- PCR 4 weeks and 8 weeks after implantation. It showed that cells of SW and control group almost covered the rough surface of HA before implantation and the extracelluar matrix of SW group was abundant by SEM photomicrograph . The histological analysis and SEM photomicrograph showed active bone formation 4 weeks and 8 weeks after implantation, as well as tetracycline labeling under fluoroscopy analysis in SW group. Alkaline phosphatase in supernatants of the implants detected 4 weeks and 8 weeks after implantation in SW group was higher than in control group (P 0.001). The expression of osteocalcin mRNA was found 4 weeks and 8 weeks after implantation in SW group. The results suggest that postnatal hMSCs treated by SW could form bone tissue in vivo using tissue engineering technique, and this new method would be applied in the field of bone tissue engineering.