中文摘要：

应用体外周期性机械拉伸装置研究机械拉伸对大鼠成骨细胞增殖及分化的影响。测试了在应变15％。频率20次／min的拉伸刺激下不同加载时间对成骨细胞增殖及分化的影响。发现在受载12h时，细胞相对增殖指数最大，随受载时间的增加而逐渐趋向于1，受载36h后，碱性磷酸酶活性的相对指数最显著。说明成骨细胞对周期性机械拉伸刺激的响应与受载时间相关联，并且受载的成骨细胞经过自身调控后，逐渐适应于新的力学环境，保持一种新的平衡状态。

英文摘要：

Using a cyclic strain unit, the proliferation and differentiation in rat osteoblasts that underwent mechanical strain were studied. Cells were subjected to 15% elongation at frequency 20 cycles/min at several loading times. Under the action of different loading time, the relative proliferation index of osteoblasts at the 12h of loading time was the biggest, and it gradually tended toward 1 with the increase of the loading time. The relative ALP activity index of osteoblasts increased significantly after being loaded 36h. These results demonstrate that osteoblasts respond to mechanical forces may link to the loading time. Loaded osteoblasts can also adjust themselves to gradually adapt the new mechanical stimulation and maintain a new state of equilibrium.