流体切应力对衰老内皮祖细胞血管内皮修复能力的影响及机制研究

Effect of fluid shear stress on vascular endothelial repair in aging endothelial progenitor cells and its mechanism

目的探讨体外流体切应力对老年志愿者内皮祖细胞(EPC)功能活性的影响及可能的分子机制。方法抽取老年志愿者外周血20ml,采用密度梯度离心法分离提取EPC。在体外采用生理范围(0.15mN/cm2)流体切应力处理培养后的老年志愿者EPC 24h,观察EPC体外的迁移、黏附能力的变化。通过建立裸鼠颈动脉拉脱损伤模型,观察流体切应力对老年志愿者EPC裸鼠颈动脉内皮损伤修复能力的影响。实时RT-PCR和Western blot检测EPC表面相关基因和蛋白的表达情况。结果体外切应力干预明显提高老年志愿者EPC体外的迁移、黏附能力,0.15mN/cm2体外切应力干预24h能提高EPC修复损伤血管内皮的能力[干预前:(33.1±5.9)%;干预后:(49.1±7.1)%,P<0.01]。基因和蛋白水平检测显示,EPC表面的趋化生长因子受体4(CXCR4)信号通路明显上调(P<0.01)。结论流体切应力干预显著改善老年志愿者EPC血管内皮损伤修复能力,其机制可能与EPC表面的CXCR4信号通路密切相关。

Objective To study the effect of fluid shear stress on vascular endothelial repair in endothelial progenitor cells（EPC）and its molecular mechanism.Methods EPC isolated from 20 ml peripheral blood of elderly volunteers by density gradient centrifugation were cultured in vitro by exposing them to fluid shear stress（0.15mN/cm^2）for 24 h.Their migration and adhesion ability were detected.A carotid artery sprain model of nude mice was established to observe the effect of fluid shear stress on the ability of EPC to repair the carotid artery endothelial injury of nude mice.Expressions of EPC surface-related genes and proteins were detected by RT-PCR and Western blot,respectively.Results Fluid shear stress pretreatment significantly increased the in vitro migration and adhesion of EPC.The ability of EPC to repair vascular endothelial injury was significantly higher after 24 hintervention with 0.15mN/cm^2 fluid shear stress than before intervention with 0.15mN/cm^2 fluid shear stress（49.1%±7.1%vs 33.1%±5.9%,P〈0.01）.The signaling pathway of CXCR4 on EPC was markedly upregulated after shear stress pretreatment（P〈0.01）.Conclusion Fluid shear stress can effectively improve the ability of EPC to repair vascular endothelial injury,which is closely related with the signaling pathway of CXCR4 on EPC.