血管壁切应力变化对动脉内皮细胞间连接的影响

目的：探讨动脉血流受阻后管壁切应力变化对动脉内皮细胞连接的影响。方法：60只实验兔建立颈总动脉血流减少模型，在术后0至30天8个不同时相点，制作血流减小后的颈总动态超薄切片，透射电镜下观察内皮细胞间连接和细胞形态学变化。结果：动脉内皮细胞间连接结构及稳定性随血管壁切应力的变化而发生相应改变。3天后，在部分细胞间近腔面出现间隙；细胞间紧密连接不象正常对照那样完好而致密，胞质内未见微丝附着；可见部分动脉壁内皮细胞脱离基底膜或完全脱落人管腔。在血管壁切应力递增阶段，近腔面内皮细胞间隙消失，可见窄而短的闭锁带。结论：血管壁切应力的降低可导致动脉内皮细胞间连接结构发生改变，细胞稳定发生减小。提示低血流的切应力变化可能破坏动态内皮细胞屏蔽的完整性。

INFLUENCE OF CHANGES OF WALL SHEAR STRESS ON ARTERIALENDOTHELIAL CELL JUNCTIONS

Objective:To explore the effect of changes of wall shear stress(WSS)on endothelial cell (EC) junction after reducing arterial flow.Methods:The reducing flow model was established in 60 rabbits:Arterial ultrathin sections were made at 8 different time intervals from 0 to 30 days Arterial endothelial cell (AEC) junctions were observed under transmission electron microscope.Results:AEC junction and its stability adapted to the changes of WSS.An obvious gap occured in some intercellular junctions near the luminal side after 3 days.Tight junctions were not so well developed and not associated with microfilament bundles compared with that of control.Some cells were found to detach partly from the basement membrane or fully drop into the luminal cavity.With increasing of WSS,the gap disappeared and replaced by a thin and short tight junction.Conclusion:Reduced WSS results in the changes of junction and decrease in cell stability,suggesting that lower flow shear may damage the integrity of AEC barrier.