Rösen Peter, Wiernsperger Nicolas F
German Diabetes Center, Leibniz Institute at the Heinrich-Heine University, Auf'm Hennekamp 65, D-40225 Düsseldorf, Germany.
Diabetes Metab Res Rev. 2006 Jul-Aug;22(4):323-30. doi: 10.1002/dmrr.623.
This study was undertaken to test the hypothesis that hyperglycaemia induces the generation of reactive oxygen species (ROS) by mitochondria and that the oxidative stress thereby exerted is diminished by treatment with metformin. As a parameter of mitochondrial ROS formation, the activity of mitochondrial aconitase activity was determined using Goto-Kakizaki (GK) rats as model of type 2 diabetes.
In parallel with the development of diabetes (glucose, insulin), the generation of oxidative stress was determined in aortic tissue, heart and kidney of GK rats by measurement of lipid peroxides, oxidized proteins (carbonyl activity) and mitochondrial aconitase activity. Vascular activity was determined in aortae by measuring the endothelium-dependent vasodilatation in response to acetylcholine, and vasoconstriction in response to phenylephrine.
At the age of 12-14 weeks, blood glucose levels rose dramatically from 7.5 up to 16.2 mM, indicating the manifestation of an overt diabetes. In addition, the glucose tolerance was impaired. The increase in blood glucose was not accompanied by changes in plasma insulin. Whereas the lipid peroxides in plasma only showed a tendency to increase, the amount of oxidized proteins (carbonyl moieties) increased from 4.6 to 10.9 micromol/mg protein (2.4 fold). In addition, the lipid peroxides in tissue were increased. Mitochondrial aconitase activity was reduced in the aorta and kidney, but not in the heart of diabetic animals. Treatment with metformin nearly normalized the hyperglycaemia and prevented the rise in carbonyl, tissue lipid peroxides and the fall in aconitase activity. Whereas the endothelium-dependent vasodilatation was not affected by the diabetes, the reaction of aortae in response to phenylephrine was strongly enhanced, changes which were prevented by treatment with metformin.
These observations provide in vivo evidence that the generation of ROS plays an important role in the onset of diabetes and the development of vascular dysfunction in GK rats with type 2 diabetes.
本研究旨在验证以下假说，即高血糖会诱导线粒体产生活性氧（ROS），且二甲双胍治疗可减轻由此产生的氧化应激。以Goto-Kakizaki（GK）大鼠作为2型糖尿病模型，测定线粒体乌头酸酶活性，以此作为线粒体ROS生成的参数。
在GK大鼠糖尿病发展过程中（监测血糖、胰岛素水平），通过测量脂质过氧化物、氧化蛋白（羰基活性）和线粒体乌头酸酶活性，测定主动脉组织、心脏和肾脏中的氧化应激。通过测量乙酰胆碱引起的内皮依赖性血管舒张和去氧肾上腺素引起的血管收缩，测定主动脉的血管活性。
在12 - 14周龄时，血糖水平从7.5 mM急剧升至16.2 mM，表明明显糖尿病的出现。此外，糖耐量受损。血糖升高并未伴随血浆胰岛素的变化。血浆中的脂质过氧化物仅呈现增加趋势，而氧化蛋白（羰基部分）的量从4.6微摩尔/毫克蛋白增加至10.9微摩尔/毫克蛋白（增加了2.4倍）。此外，组织中的脂质过氧化物增加。糖尿病动物主动脉和肾脏中的线粒体乌头酸酶活性降低，但心脏中未降低。二甲双胍治疗使高血糖几乎恢复正常，并防止了羰基、组织脂质过氧化物的增加以及乌头酸酶活性的降低。糖尿病未影响内皮依赖性血管舒张，但主动脉对去氧肾上腺素的反应显著增强，而二甲双胍治疗可防止这些变化。
这些观察结果提供了体内证据，表明ROS的产生在2型糖尿病GK大鼠糖尿病的发生和血管功能障碍的发展中起重要作用。
