Proliferation and differentiation of rat bone marrow mesenchymal stem cells under different mechanical strains / 中国组织工程研究

ABSTRACT

BACKGROUND:In vitro and in vivo studies of cel response to a variety of mechanical loadings have demonstrated the stimulation of bone formation by loads. However, the effects of different mechanical strains on the same cel s have never been adequately studied by far. OBJECTIVE:To investigate the effects of different mechanical strains on rat bone marrow mesenchymal stem cel s. METHODS:Rat bone marrow mesenchymal stem cel s were isolated and cultured in vitro. Bone marrow mesenchymal stem cel s were subjected to different stimulations including dynamic stretch, static stretch and hybrid stretch through the use of custom-made mechanical stretch device. Cel ular proliferation, alkaline phosphatase activity and mRNA expression of Runx2 of bone marrow mesenchymal stem cel s were detected and the secretion of osteocalcin was evaluated under three different stretch modes respectively. RESULTS AND CONCLUSION:Compared to the control group, cel proliferation increased by 18.67%, however, alkaline phosphatase activity, Runx2 expression and osteocalcin secretion were not changed obviously in the static stretchgroup. Compared to the control group, alkaline phosphatase activity, Runx2 expression and osteocalcin secretion increased by 60.33%, 49.67%and 48%respectively;however, cel proliferation was inhibited, in the dynamic stretch group. Compared to the control group, cel proliferation was slightly, but not significantly, increased in the hybrid stretch group, and the alkaline phosphatase activity, Runx2 expression and osteocalcin secretion increased although the increases were not as apparent as those in the dynamic stretch group. These findings suggest that static mechanical strain can significantly promote cel proliferation, the dynamic mechanical strain more greatly promotes osteogenic differentiation of bone marrow mesenchymal stem cel s, and the hybrid mechanical strain promotes the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cel s.