Visualizing superoxide production in normal and diabetic rat islets of Langerhans
Visualizing superoxide production in normal and diabetic rat islets of Langerhans
复制标题
DOI：
10.1074/jbc.m206913200
复制
发表时间：
2003-03-14
影响因子：
4.8
通讯作者：
Philipson, LH
中科院分区：
文献类型：
--
作者：
Bindokas, VP;Kuznetsov, A;Philipson, LH
氧自由基与1型和2型糖尿病相关的β细胞功能障碍和细胞凋亡有关。自由基在糖尿病中的作用迄今为止已经通过监测氧化性组织损伤和抗氧化剂、自由基清除剂和超氧化物歧化酶的过度表达的影响来间接地定义。我们采用超氧化物介导的氧化氢乙啶乙锭动态和直接评估的相对速率的线粒体超氧阴离子的产生在孤立的胰岛响应于葡萄糖刺激。在葡萄糖刺激下，离体胰岛的超氧化物含量增加。我们接下来通过数字成像显微荧光测定法比较了Zucker瘦对照和Zucker糖尿病脂肪大鼠胰岛中的氧自由基水平。Zucker糖尿病脂肪胰岛的超氧化物含量显着高于Zucker瘦对照胰岛在静息条件下，相对不敏感的葡萄糖浓度升高，并在时间上与葡萄糖诱导的线粒体膜超极化的减少。重要的是，在来自年轻的糖尿病前期Zucker糖尿病脂肪动物的胰岛中，超氧化物水平升高。超氧化物的过度产生与线粒体形态学紊乱有关，并可能导致2型糖尿病Zucker糖尿病脂肪模型中发现的异常葡萄糖信号传导。
Oxygen free radicals have been implicated in beta-cell dysfunction and apoptosis associated with type 1 and type 2 diabetes mellitus. The roles of free radicals in diabetes have thus far been defined indirectly by monitoring oxidative tissue damage and the effects of antioxidants, free radical scavengers, and overexpression of superoxide dismutase. We employed the superoxide-mediated oxidation of hydroethidine to ethidium to dynamically and directly assess the relative rates of mitochondrial superoxide anion generation in isolated islets in response to glucose stimulation. Superoxide content of isolated islets increased in response to glucose stimulation. We next compared the oxyradical levels in Zucker lean control and Zucker diabetic fatty rat islets by digital imaging microfluorometry. The superoxide content of Zucker diabetic fatty islets was significantly higher than Zucker lean control islets under resting conditions, relatively insensitive to elevated glucose concentrations, and correlated temporally with a decrease in glucose-induced hyperpolarization of the mitochondrial membrane. Importantly, superoxide levels were elevated in islets from young, pre-diabetic Zucker diabetic fatty animals. Overproduction of superoxide was associated with perturbed mitochondrial morphology and may contribute to abnormal glucose signaling found in the Zucker diabetic fatty model of type 2 diabetes mellitus.