Regulation system of differentiation from mesenchymal stem cells to bone, vascular, and fatty tissues by mechanical loading and unloading

我们用运动负荷小鼠和由于尾部悬吊而卸车的小鼠进行了研究。我们证明了在负载条件下，通过PTH/PTHrP受体的信号促进了间充质干细胞的成骨分化并抑制了成脂分化。该信号是促进骨膜骨形成和横切面皮质壳扩大所必需的。CD31及其受体CD38的表达在卸载后下降，重新加载后恢复到正常加载水平。成骨细胞与CD38阳性细胞共培养实验表明，血管内皮因子是成骨分化所必需的。

We performed studies using exercise loading mice and unloading mice due to tail suspension. We demonstrated that the signal through PTH/PTHrP receptors promoted osteogenic differentiation and suppressed adipogenic differentiation from mesenchyman stem cells under loading condition. This signal is necessary for promotion of periosteal bone formation and enlargement of cross-sectional cortical shell. The expressions of CD31 and its receptor CD38 decreased after unloading and recovered to the normal loading levels after reloading. Co-culture experiments of osteoblasts and CD38 positive cells revealed that vascular endothelial factors are necessary for osteogenic differentiation.