周期性应变对血管平滑肌细胞形态和生长的影响

Effects of cyclic strain on morphology and growth of vascular smooth muscle cells

目的 :研究周期性应变条件下血管平滑肌细胞 (vascular sm ooth m uscle cells,VSMCs)形态和生长的变化。 方法 :利用脉动膜式张应力系统 ,给 VSMCs施加周期性应变 ,运用相差显微镜、计算机图像捕获系统及图像处理分析软件观察和分析 VSMCs的形态变化 ;用 3HTd R掺入率测定法检测 VSMCs的 DNA合成变化。 结果 :VSMCs承受 14 %的周期性应变后 ,细胞发生重排并与应力加载方向垂直 ,细胞形态指数减小 ,铺展面积、周长、细胞长轴在加载 6 h时明显增加 ,12～ 2 4 h逐渐减小并趋向于稳定。8%的周期性应变抑制 VSMCs生长和 DNA合成 ;14 %的周期性应变使 VSMCs生长和 DNA的合成明显增加 ,2 4 h和 4 8h时其 DNA合成分别是对照组的 1.4和 1.8倍。结论 :周期性应变不但影响 VSMC的形变 ,且会导致 VSMCs的重排。近生理条件下的周期性应变抑制 VSMCs的生长 ,超生理范围的应变促进 VSMCs的生长。

Objective:To investigate the effects of cyclic strain on the morphology and growth of vascular smooth muscle cells(VSMCs). Methods: A pulsatile membrane cyclic strain system was used to perform cyclic strain on VSMCs from adult SD rats. Microscopy and computer image capture system were used to investigate morphological change in VSMCs. The growth of VSMCs and their DNA synthesis were indicated by 3HTdR method. Results: Under 14% cyclic strain, VSMCs re-aligned gradually and were finally vertical to the direction of stress; the shape index decreased. However, the spreading area, perimeter and long axis of stretched VSMCs increased within 6 h, then decreased to a relatively stable level from 12 to 24 h. The growth and 3H thymidine incorporation of VSMCs under 8% cyclic strain were arrested, but accelerated under 14% cyclic strain.The 3H thymidine incorporation had a significant difference in 12 h and increased by 1.4-fold and 1.8-fold in 24 and 48 h respectively compared with control group. Conclusion: The cyclic strain not only affects the morphology of VSMCs, but leads to rearrangement of VSMCs. It can inhibit cell growth under physiological condition but promote cell growth beyond physiological condition in cultured VSMCs.