波动性高糖对人脐静脉内皮细胞中NO合成的影响及作用机制(英文)

Effect of intermittent high glucose on synthesis of nitric oxide in human umbilical vein endothelial cells and its mechanism

目的:探索波动性与持续性高糖对人脐静脉内皮细胞合成血管舒张因子一氧化氮( NO)的影响及其作用机制。方法:以体外培养人脐静脉内皮细胞( HUVECs)为研究对象,分别测定波动性高浓度葡萄糖(5.5或20 mmol /L)与持续性高浓度葡萄糖(20 mmol /L)环境下NO浓度,RT-PCR及Western印迹方法检测磷脂酰肌醇-3激酶( PI3K)、蛋白激酶B( PKB /AKT)、内皮型一氧化氮合酶( eNOS) mRNA及蛋白表达水平。结果:波动性高糖组NO均明显低于持续高糖组和正常组(P<0.05 ) ;波动组,持续高血糖组的PI3K,PKB,eNOS mRNA及蛋白表达水平均较正常组下调(P<0.01 ) ,而波动组又低于持续组(P<0.05)。结论:波动性高血糖较持续性高血糖可能对血管内皮细胞具有更强的损伤效应,并可能通过影响信号通路PI3K/PKB /eNOS导致NO合成减少。

Objective To compare the effect of intermittent and constant high glucose media on the synthesis of vascular relaxing factor nitric oxide （NO） in cultured human umbilical vein endothelial cells （HUVECs）,and to investigate its mechanism.Methods HUVECs were exposed to 5.5 mmol/L glucose （normal control）,20 mmol/L glucose （constant high glucose）,and 5.5 mmol/L alternating with 20 mmol/L glucose （intermittent high glucose） for 7 days.The NO level was measured using Griess Reaction in cell culture supernatants;the expressions of PI3K,PKB and eNOS mRNA and protein were measured with RT-PCR or Western blot.Results NO level in the intermittent high glucose group was significantly lower than that in the constant high glucose group （P〈0.05）.The expression of PI3K,PKB,and eNOS in the intermittent high glucose group was significantly lower than that in the constant high glucose group （P〈0.05）.Conclusion Intermittent high glucose could be more deleterious to endothelial cells than constant high glucose,and may lead to decrease synthesis of NO by inhibiting PI3K/PKB/eNOS pathway activation.