剪切力对大鼠肺微血管内皮细胞细胞骨架的影响

目的 观察不同的剪切力对体外培养的大鼠肺微血管内皮细胞(PMVECs)细胞骨架蛋白(F-actin)的影响，探讨高血流性肺动脉高压的早期发病机制。方法 用自制的多层流动腔对体外培养的大鼠PMVECs施加剪切力作用，以异硫氰酸荧光素-毒蕈肽标记F-actin，采用共聚焦显微镜扫描观察F-actin的变化并记录相应的荧光值。结果 剪切力引起PMVECs骨架内的微丝重排，向着剪切力的方向出现与细胞长轴一致的应力纤维，且剪切力越大、作用时间越长，这种现象越明显，直至细胞内几乎所有的微丝F-actin都沿着细胞长轴形成应力纤维。结论 PMVECs细胞骨架在受到剪切力作用后会形成应力纤维，该现象在剪切力作用早期即可发生，并且对作用时间及剪切力大小具有依赖性，这可能与高血流性肺动脉高压的早期发病机制密切相关。

Effects of shear stress on the cytoskeleton in rat pulmonary microvascular endothelial cells

Objective To observe the effects of shear stress on rat pulmonary microvascular endothelial cells (PMVECs) cultured in vitro and to elucidate the early pathogenesis of pulmonary hypertension induced by high pulmonary flow. Methods Rat PMVECs were cultured with conventional methods. Self-made perfusion system was used to exert different shear stresses on rat PMVECs. The dynamic changes of F-actin stained by FITC-phalloidin were observed through laser scanning confocal microscope. Results Microfilament rearrangement (compliant changed from former disorderliness into orderliness) occurred in PMVECs due to the shear stress, towards the direction of the shear force. Stress fibers appeared along the cell long axis. This change was time and stress strength dependent. With the extension of treatment time, the phenomena became more obvious， until nearly all the F-actin changed to be stress fibers. ConclusionThe cytoskeleton of the PMVECs will rearrange to be stress fibers according to the shear stress it endured. This phenomenon is both time and stress strength dependent, and occurs at the early stage. This may be closely related to the early pathogenesis of pulmonary hypertension induced by high pulmonary flow.