不同切应力下血管内皮整合素αVβ_3的表达

Expression of Integrin-αVβ_3 in Vascular Endothelium Cultured in Vitro Under Different Level of Shear Stress

目的对离体培养血管施加不同水平切应力,观察不同时间点整合素αVβ3(αVβ3-Integrin)的表达水平。方法 (1)建立血管体外应力培养系统,检测不同切应力时流场的稳定性;(2)将家兔50只按完全随机分组方式分为两组(n=25):低切应力组(5 dyn/cm2)和正常切应力组(20 dyn/cm2),每组再完全随机等分为2 h、4 h、8 h、16 h和24 h共5个时间点(n=5),取兔降主动脉并将其置于应力培养系统进行离体培养,采取免疫组织化学染色法观察两组5个不同时间点的整合素αVβ3表达部位及强度。结果建立的体外血管应力培养系统运行稳定,能够提供实验所需的各种切应力。低切应力组的整合素αVβ3在5个时间点都有较高程度的表达,并在16 h时达到高峰,其平均光密度值[MOD=(1.995±0.194)×10-2]明显增高(P<0.05);正常切应力组随时间的增加逐渐减少,2 h[(0.059±0.005)×10-2]、4 h[(0.049±0.002)×10-2]时分别与其他时间点相比差异有统计学意义(P<0.05)。低切应力组的整合素αVβ3MOD值与正常切应力组相同时间点比较明显增高(P=0.000)。结论低切应力可引起αVβ3明显表达,而正常切应力抑制αVβ3的表达。

Objective To observe the expression of integrin αVβ3 in vascular endothelium cultured in vitro at different time points under different level of shear stress.Methods（1） We established a vascular culture system in vitro which could provide steady flow with different level of shear stress,and tested the flow stability when loading different level of shear stress.（2） A total of 50 rabbits were randomly divided into low shear stress group（5 dyn/cm2,n=25） and normal shear stress group（20 dyn/cm2,n=25）.Rabbits in each group were further randomly divided into five different time points as 2 h,4 h,8 h,16 h and 24 h（n=5 at each time point）.The descending aorta of rabbits were harvested and cultured in the vascular culture system in vitro under different level of shear stress.The expression sites and intensity of αVβ3-Integrin in vascular endothelium were examined at 5 different time points in both groups by immunohistochemical staining.Results The vascular culture system in vitro was stable in providing laminar flow with different level of shear stress required for the experiment.Vascular endothelium expressions of αVβ3-Integrin in the low shear stress group were in high level at all the 5 time points and reached its summit at 16 h,when the mean optical density（MOD） value was（1.995±0.194）×10-2.In the normal shear stress group,the MOD value decreased time-dependently at the 5 time points.The MOD values at 2 h（0.059±0.005）×10-2 and 4 h（0.049±0.002）×10-2 were significantly higher than those at other time points（P0.05）.The αVβ3-Integrin MOD values of the low shear stress group were significantly higher than those of the normal shear stress group at all the 5 respective time points（P=0.000）.Conclusion Low shear stress can significantly promote the expression of αVβ3-Integrin while normal shear stress decreases the expression of αVβ3-Integrin in vascular endothelium cultured in vitro.