流体切应力对人内皮细胞迁移和整合素基因表达的影响

目的研究流体切应力空间梯度和均匀切应力对内皮细胞（ECs）迁移和整合素基因表达的影响，为阐明应力诱导血管重建的分子机制提供一些实验依据。方法将脐静脉内皮细胞置于平行平板流动腔系统，分别施加11dyn／cm^2的均匀切应力（矩形组）和5～14dyn／cm^2的切应力梯度（梯度组）为受力组，以静态条件下培养的ECs为对照组（静止组）。Transwell方法检测切应力对ECs迁移能力的影响；半定量RT-PCR测定ECs整合素α3β1、α5β1mRNA3、6和12h的表达情况。结果①同静止组相比，切应力梯度组ECs3h的迁移（88±4 vs 23±3，P〈0．01，n=3）能力显著提高；而均匀切应力组ECs3h迁移（21±3VS23±3）同静止组相比，差异无统计学意义（P〉0．05，n=3）；②ECs受切应力梯度作用3h即可诱导ECs整合素α3β1、α5β1mRNA表达（P〈0．01，P〈0．05）；均匀切应力于6h激活ECs整合素理，亚型表达（P〈0．01），α3 、β1亚型表达延迟到12h激活（P〈0．01）。结论切应力通过上调整合素基因表达促进了ECs迁移，提示整合素信号通路参与了切应力条件下ECs迁移过程的信号转导。

Effects of Shear Stress on Cell Migration and Integrin Gene Expression in Human Endothelial Cells

Objective By observing the cell migration and expression of integrin gene in human umbilical wein endothelial cells（HUVECs） after gradient shear stress and steady flow shear stress stimulation to provide some experimental evidences for molecular mechanisms of shear stress-induced vascular remodeling. Methods The endothelial cells were subjected to different fluid shear stress in the flow chamber, and then divided into three different experimental groups： static group, gradient shear stress group（5 ～ 14 dyn/cm2） and steady flow shear stress group（11dyn/cm^2）. The effects of shear stress on the migration of ECs for 3 hours were assessed by Transwell cell migration; the expression of integrin α3,β1, α5,β1 for 3, 6 and12 hours was examined by RT-PCR. Results ① Gradient shear stress promotes ECs migration（88 ±4 vs. 23 ± 3, P 〈 0.01, n = 3） compared with that in static group at 3 hours; whereas steady flow shear stress group compared with static group, there was no significant increase（21 ±3 vs. 23 ±3, P 〉0.05, n =3）. ②Increased integrinoα3,α5,β1 expression in gradient shear stress group was detectable as early as 3 hours（ P 〈 0.01, P 〈 0.05） ; instead, in steady flow shear stress group integrin α5 was induced at 6 hours（P 〈0.01）, integrinoα3,β1 was activated at 12 hours（ P 〈 0.01）. Conclusion Integrin activation could be enhanced by shear stress to promote ECs migration,suggesting that integrin may be involved in ECs migration signaling pathway.