The regulation of cell proliferation and differentiation of bone cells after the change of gravity loading

我们从组织、细胞和分子水平全面阐明了骨骼加载和卸载后骨骼轮廓、转换和强度的顺序变化。与有氧运动（跑步）相比，抗阻运动（跳跃）通过促进皮质漂移和增加骨形成，在生长期大鼠中更有效地增加了骨体积和骨强度。我们最初创建了自愿攀爬动物模型。运动后2周和4周，胫骨近端骨小梁体积增加。运动后2周破骨细胞表面减少，4周骨形成增加。在细胞培养研究中，从2周运动小鼠胫骨获得的骨髓细胞显示碱性磷酸酶阳性CFU-f增加和TRAP阳性多核细胞减少。我们还发现，一氧化氮是必不可少的松质骨形成在卸载后重新加载。

We comprehensively clarified the sequential changes of bone contour, turnover, and strength after skeletal loading and unloading at the tissue, cellular and molecular levels. The resistant exercise (jumping) increased bone volume and bone strength more effectively by promoting cortical drift and by increasing bone formation, compared to the aerobic exercise (running), in the growing rats.We originally created the voluntarily climbing-up animal model. The trabecular bone volume of the proximal tibia was increased at 2 and 4 weeks after the exercise. Osteoclast surface was decreased at 2 weeks and bone formation was increased at 4 weeks after the exercise. In the cell culture study, the bone marrow cells obtained from the tibias of 2-week exercise mice showed the increase of alkaline phosphatase-positive CFU-f and the decrease of TRAP-positive multinucleated cells. We also revealed that nitric oxide is essential for trabecular bone formation at the reloading after unloading.