葡萄糖对人血管内皮细胞多元醇通路的激活作用及其机理

Activation of Polyol Pathway and Its Mechanisms Induced by Glucose in Human Vascular Endothelial Cells

观察葡萄糖对人血管内皮细胞多元醇通路的影响 ,并探讨其作用机理。体外培养人脐静脉内皮细胞 ,加不同浓度葡萄糖或作用不同时间 ,采用高效液相色谱仪、硝酸还原酶法、生物化学检测及逆转录聚合酶链反应等方法测定内皮细胞山梨醇、一氧化氮、醛糖还原酶活性及醛糖还原酶基因mRNA。结果发现 ,经高浓度葡萄糖处理的人脐静脉内皮细胞山梨醇浓度明显高于对照组 (P <0 .0 5) ,一氧化氮浓度明显低于对照组 (P <0 .0 5)。醛糖还原酶基因mRNA水平及其活性均呈浓度及时间依赖性 ,但是内皮细胞经 2 2mmol L葡萄糖作用 48h或 44mmol L葡萄糖作用 2 4h后 ,醛糖还原酶基因mRNA水平及其活性均不再升高 ,而呈下降趋势 (P <0 .0 5)。结果提示 ,高浓度葡萄糖能引起内皮细胞功能改变 ,其机制可能是高浓度葡萄糖能增强醛糖还原酶基因的转录并提高其活性 ,从而活化多元醇通路。

Aim To observe the influence of glucose on the polyol pathway in human vascular endothelial cells and to investigate its potential mechanisms. Methods Human umbilical vein endothelial cells were cultured in vitro with glucose at different concentrations or for different cultural time. The level of nitric oxide (NO) and sorbitol, aldose reductase (AR) AR activity and the expression of AR mRNA level were detected with high performance liquid chromatography (HPLC), nitrate reductase method,biochemical assay and reverse transcription polymerase chain reaction (RT PCR). Results The levels of sorbitol in high glucose groups were higher than in control group (P<0.05 or P<0.01), but the levels of NO in high glucose groups were lower than in control group (P<0.05 or P<0.01). Both AR mRNA expression and its activity were dependent on glucose concentrations or cultural times (P<0.05 or P<0.01) AR mRNA expression and its activity with glucose at 22 mmol/L for 48 h or at 44 mmol/L for 24 h did not increase accordingly, but began to decrease(P<0.05). Conclusion Glucose can affect the function of endothelial cells such as the increasing prodction of sorbitol and the decreasing systhesis of NO. The mechanisms may be that glucose can upregulate AR gene expression and enhance its activity, then activates the polyol pathway in endothelial cells.