Roles of Cytoskeletal Components for the Orientation and the Permeability of Cultured Endothelial Cells Exposed to Shear Stress

采用平行平板流动室培养猪主动脉内皮细胞（PAECs），并将其暴露于剪切应力下。与对照相比，观察细胞的伸长和取向。这种效应高度依赖于剪切应力水平和暴露持续时间等参数。内皮细胞的肌动蛋白丝染色显示，细胞骨架结构的变化之前，细胞形状的形态变化在早期阶段的剪切应力负荷。流动实验后，使用微量吸管技术研究的机械性能。暴露于剪切应力的细胞表现出机械刚度显著大于对照细胞。切应力对内皮细胞机械刚度的影响可能与细胞骨架结构的改变有关。利用同样的技术，肌动蛋白丝也被证明在细胞的粘弹性行为中起重要作用。 ...更多信息 s）对PAECs细胞形态和细胞骨架结构的影响。所用ECM的成分为IV型胶原、硫酸乙酰肝素、硫酸软骨素和硫酸皮肤素。在混合ECM上培养的PAEC即使在无流动条件下也表现出明显的伸长和节段性取向，细胞轴呈随机分布。肌动蛋白丝大多与细胞轴平行。这些结果表明，ECM是与切应力共同作用引起内皮细胞形态变化的重要因素之一，荧光染色法观察到血小板在PAEC上粘附，并在细胞的光照射区域生长。在体外血栓模型中，扫描电镜显示血小板直接粘附在PAEC上，而没有被剥脱。少

Porcine aortic endothelial cells (PAECs) were cultured and exposed to shear stress using the parallel plate flow chamber. The elongation and orientation of the cells were observed as compared to controls. This effect was highly dependent on such parameters as the level of shear stress and the duration of exposure. Staining of actin filament of endothelial cells showed changes in cytoskeletal structure prior to morphological changes of cell shape at an early stage of shear stress loading. After the flow experiment the mechanical properties were studied using the micropipette technique. The cells exposed to shear stress demonstrated a mechanical stiffness was significantly greater than that of control cells. The influence of shear stress on endothelial cell mechanical stiffness may be related to alteration in cytoskeletal structure. Using the same technique actin filaments were also shown to play important roles in viscoelastic behavior of the cells.Effects of extracellular matrices (ECM … More s) on the cell shape and the cytoskeletal structure were analyzed on PAECs. The components of ECM used were type IV collagen, heparan sulfate, chondroitin sulfate and dermatan sulfate. The PAECs cultured on the mixed ECMs showed marked elongation and segmental orientation with randomly distributed cell axis even under a no-flow condition. The actin filaments were mostly observed in parallel with the cell axis. These findings suggest that ECM is one of the most important factors that acts together with shear stress to induce the variation of endothelial cell configuration in vivo.Using the fluorescent dye-light technique platelet adhesion was found to be induced on PAECs and the platelet deposition grew on the light-irradiated area of the cells. In this in vitro thrombus model, a scanning electron microscopy showed that the platelets directly adhered to PAECs without the denudation.Experiments on the permeability through PAECs are still continued while we have tried to remodel the apparatus. Less