流体切应力下血管内皮单核细胞趋化蛋白-1的表达

Influence of fluid shear stress on the expression of monocyte chemotactic protein 1 by vascular endothelial cells

目的 研究流体切应力对人血管内皮细胞的单核细胞趋化蛋白 1(MCP 1)表达的影响 ,探讨血流动力在动脉粥样硬化 (AS)发生早期中的作用。方法 利用平行板流动腔对血管内皮细胞施加不同切应力 ,分别采用夹心酶联免疫吸附测定 (ELISA)及逆转录 聚合酶链反应 (RT PCR)法检测MCP 1蛋白及mRNA水平。结果 以 0 .72Pa切应力进行不同时间作用 ,0 .5h后MCP 1mRNA即达到静态时 (0 16 0± 0 0 37)的 4倍 (0 .6 84± 0 .0 33) ,5h时略有升高 ,达 0 .70 7± 0 .0 89,12h后下降到低于对照组的水平 (0 .0 36± 0 .0 0 6 ,P <0 .0 0 1)。灌流液中MCP 1蛋白时间依赖性增加 ,但 5h后增长趋缓 ;而在不同切应力 (0 .30、0 .72、2 .40Pa)相同时间 (5h)下 ,0 .72Pa的作用最显著 ,MCP 1蛋白比静态对照增加了 2倍多 ,mRNA水平则升高达 4倍。结论 MCP 1的表达对切应力的变化反应强烈 ,持续稳定的切应力则下调MCP 1的表达 ,此研究结果表明血流紊乱可促进AS病变的发生发展。

Objective To study the effect of fluid shear stress on the expression of monocyte chemotactic protein 1(MCP 1) by vascular endothelial cells and its role in the early stages of atherogenesis(AS). Methods Parallel plate flow chamber was used to expose vascular endothelial cells to different shear stress. Sandwich ELISA (enzyme linked immunosorbent assay) and RT PCR (reverse transcription polymerase chain reaction) were applied to detect MCP 1 protein and mRNA respectively. Results Under 0.72 Pa shear stress, MCP 1 mRNA expression in endothelial cells reached a high level in 5 hours, but decreased to below the control level ( P <0.001) after 12 hours. The expression of MCP 1 mRNA showed a time dependent increase, which became slower 5 hours later. When different shear stress (0.30, 0.72, 2.40 Pa) was loaded for the same period of time (5 h), MCP 1 increased to above twice the control level, while its mRNA expression increased threefold as compared to the static control. Conclusions The expression of MCP 1 reacts strongly to fluid shear stress. The steady laminar flow down regulates the gene expression of MCP 1. These results may help to explain why AS lesions tends to occur at the site of turbulent blood flow.