成梯度增加的拉伸刺激对成骨细胞胶原合成的影响

Effect of Step Increased Stretching on Osteoblasts Collagen Synthesis

使用四点弯曲加载装置研究机械拉伸对成骨细胞胶原合成的影响 ,在生理应变范围 (5 0 0～ 15 0 0 με)研究了不同加载时间、不同应变水平对成骨细胞胶原合成的影响 .发现在 5 0 0 με下的拉伸刺激提高了成骨细胞合成胶原的能力 ,而在 10 0 0 με和 15 0 0 με下的拉伸刺激使成骨细胞的胶原合成受到了明显抑制 (P <0 0 1) .设计了应变成梯度增加的加载方式 :使细胞在 5 0 0 με加载一段时间后 ,将应变增加到 10 0 0 με加载同样长的时间 ,最后将应变增加到 15 0 0 με加载同样长的时间 .在梯度加载实验中发现 ,成骨细胞接收到有利于其胶原蛋白合成的信号时 ,大量地吸收用于合成胶原的脯氨酸 ,当力学刺激变为抑制信号时 ,储存在胞内的3 H 脯氨酸又重新释放回溶液中 .说明在应变逐渐增加的加载过程中 。

A four-point bending device was used to investigate the effect of stretching on osteobtasts collagen production. Cells were stretched with different strain level and loading time. Cyclic stretching of the cells with a strain magnitude of 500 muepsilon resulted in an increased collagen production while collagen synthesis was significantly reduced with a strain magnitude of 1 000 muepsilon and 1 500 muepsilon ( P < 0.01). A new loading method, step increased stretching was also used. Cells were stretched at 500 &mu;&epsilon; firstly, followed by stretching at 1 000 &mu;&epsilon; for the same hours. Then the strain level was raised to 1 500 &mu;&epsilon; and cells were stretched for the same hours. The step increased stretching experiment showed that osteobtasts absorbed proline to synthesize collagen when received an appropriate signal (500 &mu;&epsilon;). When the strain magnitude was raised, that is to say, the mechanical stimulation was turned into an inhibiting signal, intracellular H-3-proline was released into solution again. These results demonstrate that osteoblasts can adjust themselves to adapt the new mechanical stimulation during the step increased stretching course.