流体切应力与内皮祖细胞铜锌超氧化物歧化酶基因表达及活性*****☆

背景：流体切应力是调控内皮祖细胞的重要非药理学手段，但目前其对内皮祖细胞抗氧化功能的作用尚不清楚。目的：观察不同切应力对内皮祖细胞铜锌超氧化物歧化酶(Cu/Zn-superoxide dismutase，Cu/Zn-SOD)基因表达和活性的影响，以探讨流体切应力对内皮祖细胞抗氧化功能的调节作用。方法：健康成人外周血的单个核细胞诱导分化为内皮祖细胞，分为静态组、低切应力组、中切应力组和高切应力组4组进行观察。结果与结论：外周血单个核细胞分化成为内皮祖细胞，倒置荧光显微镜下呈典形的“纺锤样”梭形细胞，ac-LDL吞噬及lectin抗体荧光标记双阳性，FLK-1和VWF免疫荧光抗体染色均为阳性。各切应力组内皮祖细胞CuZn-SOD活性均高于静态组，并且切应力越大，内皮祖细胞Cu/Zn-SOD分泌水平越高。荧光定量RT-PCR表明，切应力处理能上调内皮祖细胞CuZn-SOD mRNA表达，并且切应力水平越高，CuZn-SOD mRNA表达越强。说明切应力能上调内皮祖细胞Cu/Zn-SOD基因表达，增强内皮祖细胞Cu/Zn-SOD活性，提高内皮祖细胞的抗氧化活性。因此，在生理范围内增加体外切应力，能上调内皮祖细胞的功能活性。 关键词：内皮祖细胞；切应力；超氧化物歧化酶；内皮；基因表达doi:10.3969/j.issn.1673-8225.2012.10.035

Effect of shear stress on the copper-zinc superoxide dismutase gene expression and activity in human endothelial progenitor cells

BACKGROUND: Shear stress is an important non-pharmacological method to regulated endothelial progenitor cells (EPCs). However, the effect of shear stress on the anti-oxidative activity of EPCs is not clear. OBJECTIVE: To observe the effect of shear stress on the copper-zinc superoxide dismutase (Cu/Zn-SOD) gene expression and activity in EPCs, in order to investigate the regulatory effects of shear stress on the EPCs function. METHODS: The peripheral blood mononuclear cells of healthy adult were inducted into EPCs. Then, they were divided into four different experimental groups which included stationary group, low-flow shear stress group (0.05 mN /cm2), medium-flow shear stress group (0.15 mN/cm2) and high-flow shear stress group (0.25 mN/cm2). RESULTS AND CONCLUSION: The peripheral blood mononuclear cells were differentiated into EPCs. They presented typical “spindle-shaped” appearance, and were positively labeled by acetylated-LDL, lectin, FLK-1 and VWF. The Cu/Zn-SOD activity of human EPCs in shear stress treatment groups was higher than that in stationary group. The higher the shear stress, the higher the Cu/Zn-SOD activity of human EPCs. Quantitative real-time PCR indicated that shear stress could increase the CuZn-SOD mRNA expression of EPCs, the higher the shear stress, the stronger the CuZn-SOD mRNA expression of EPCs. In vitro shear stress could upregulate the gene expression of Cu/Zn-SOD in EPCs, increase the Cu/Zn-SOD activity in human EPCs, which contributes to enhance the anti-oxidative activity of EPCs. Therefore, enhanced shear stress within the physiological range could regulate the function of EPCs, which can act as an important strategy of enhancing their therapeutic approach for vascular endothelial injury.