氧化型低密度脂蛋白对剪切力诱导的人主动脉内皮细胞一氧化氮合酶表达的影响

Effect of oxLDL on expression of shear stress-induced endothelial NO synthase in human aortic endothelial cells

目的探讨氧化型低密度脂蛋白(oxLDL)对剪切力诱导的人主动脉内皮细胞(HAEC)内皮型一氧化氮合酶(eNOS)表达的影响。方法将HAEC分为对照组和实验组,2组均采用精密输液泵施加剪切力,实验组同时给予oxLDL 100μg/ml共刺激。2组根据剪切力施加梯度,又各分为3个亚组:无剪切力组(n=5)、低剪切力组(n=5)和高剪切力组(n=5),剪切力分别为0、4、15dyn/cm2(1dyn/cm2=0.1Pa)。采用RT-PCR及Western blot技术检测eNOS mRNA和蛋白的表达,采用硝酸盐还原酶法测定NO含量。结果实验组、对照组的NO、eNOS mRNA和eNOS蛋白的表达量低剪切力组明显低于无剪切力组,高剪切力组明显高于无剪切力组和低剪切力组;实验组无剪切力组、低剪切力组及高剪切力组NO[(1.09±0.33)μmol/L vs(2.27±0.90)μmol/L、(0.20±0.08)μmol/L vs(0.71±0.36)μmol/L、(3.03±0.71)μmol/L vs(4.93±1.16)μmol/L]、eNOS mRNA(0.65±0.20 vs 1.11±0.32、0.22±0.13 vs 0.49±0.22、1.05±0.22 vs 1.90±0.56)和eNOS蛋白(0.50±0.19 vs 1.10±0.26、0.18±0.52 vs 0.62±0.19、1.07±0.20 vs 1.70±0.38)的表达量均明显低于对照组相同亚组,低剪切力组NO下降率明显高于无剪切力组,高剪切力组eNOS蛋白、eNOS mRNA和NO下降率明显低于低剪切力组。结论 oxLDL可削弱高梯度剪切力诱导的内皮细胞活性,也可加剧低梯度剪切力诱导的内皮细胞功能紊乱。

Objective To study the effect of oxLDL on expression of shear stress（SS）-induced endothelial NO synthase（eNOS）in human aortic endothelial cells.Methods Culturaled human aortic endothelial cells were divided into control group and experimental group.SS was enforced in two groups with a precision infusion pump and experimental group was stimulated with 100μg/ml oxLDL.Each of the two groups was divided into SS-free group（n=5）,low SS group（n=5）and high SS group（n=5）with a SS of 0dyn/cm2,4dyn/cm2,and 15dyn/cm2 respectively.Expressions of eNOs mRNA and protein were detected by RT-PCR and Western blot respectively.Serum NO level was measured using nitrate reductase method.Results The serum NO level and eNOS mRNA and protein expression levels were significantly lower in low SS group than in SSfree group,significantly higher in high SS group than in SS-free group and low SS group,the serum NO level and eNOS mRNA and protein expression level were significantly lower in SS-free group,low SS group and high SS group than in control group.The serum NO level was significantly lower in low SS group than in SS-free group.Conclusion oxLDL reduces high SS-induced activity of endothelial cells and aggravates low SS-induced dysfunction of endothelial cells.