【作者】 朱波； 薛耀明； 高方； 周琳； 曹瑛； 陆雯； 连欣；

【Author】 Bo Zhu;Yaoming Xue;Fang Gao;Lin Zhou;Wen Lu;Xin Lian;Department of Endocrinology and Metabolism of Nanfang Hospital;

【机构】 南方医科大学南方医院内分泌科；

【摘要】 目的:探讨高糖条件下内皮细胞超氧化物歧化酶(SOD)活性变化及其可能机制。方法:以牛主动脉内皮细胞(BAEC)作为实验对象,BAEC细胞用含有10%胎牛血清的DMEM完全培养基,置于370C、5%CO2的孵箱内培养。不同浓度葡萄糖处理分为5.5mmol/l组和25 mmol/l组,以19.5mmol raffinose和5.5mmol葡萄糖作为渗透压对照组,干预时间72小时。以DCFDA检测细胞ROS生成水平,8-异构前列腺素(8-I)和TBARS反应氧化应激水平,生化法检测葡萄糖-6-磷酸脱氢酶(G6 PD)活性、过氧化氢酶(catalase,CAT)活性、SOD活性、还原型谷胱甘肽(GSH)和NADPH水平。以G6PD编码的腺病毒感染BAEC,过表达G6PD水平,检测上述指标变化。结果:与5.5 mmol/l葡萄糖的对照组相比,25mmol/l可显著增高BAEC的ROS水平及8-I和TBARS水平。GSH、NADPH水平显著下降,G6PD、CAT、SO D活性均显著降低。渗透压对照组与5.5mmol/L组无显著差异。G6PD过表达组可显著降低高糖诱导的ROS水平,升高GSH和NADPH水平,改善氧化应激指标8-I和TBARS。G6PD过表达同样可改善细胞内抗氧化酶SOD和CAT活性。结论:高糖条件下,BAEC细胞内抗氧化酶活性显著下降并发生氧化应激损伤。高糖条件下细胞内抗氧化系统的损伤依赖于磷酸戊糖通路G6PD活性的抑制,G6PD活性的改善可显著升高NADPH水平并回复被高糖抑制的抗氧化酶活性。SOD和CAT在清除过氧化物的级联反应中关系密切,相互影响。G6PD产生的NADPH对维持CAT的结构和生理活性具有重要作用,高糖导致的G6PD活性抑制和NADPH水平下降可影响CAT的活性,进而抑制SOD活性。提高G6PD活性可通过增高NADPH水平升高CAT活性,从而改善SOD活性,对抗氧化应激的发生。更多还原

【Abstract】 Objective: To explore the changes of SOD activity induced by high glucose and its mechanism in BAEC. Methods Bovine aortic endothelial cells(BAEC) were treated with 5.5 mM and 25 mM glucose and raffinose as the osmotic control. DCFDA was used to detect the ROS level and 8-isoprostane and TBARs were determined as the marker of oxidative stress.GSH and NADPH were also determined to assess the redox status of BAEC. G6 PD activity, catalase cativity and SOD activity was determined to assess the antioxidant system in the cells. Results: 25 mM glucose significantly incrased ROS, 8-isporostane and TBARs level and decreased GSH and NADPH level.High glucose also decreased SOD and catalase activity as well as G6 PD activity. Overexpressed G6 PD restored the increased oxidative stess markers and the increased antioxidant levels such as GSH and NADPH, which in turn increased SOD and catalase activity significantly. Conclusions: High glucose induced oxidative stress in BAEC and decreased SOD activity, which was at least partly by decreased G6 PD activity.更多还原