H_2O_2诱导的线粒体损伤神经元内硫氧还蛋白mRNA水平的变化

CHANGES OF THIOREDOXIN mRNA LEVEL IN NEURONS WITH MITOCHONDRIAL DYSFUNCTION INSULTED BY H_2O_2

线粒体缺陷和氧化应激参与了神经退行性疾病的发病机制。叠氮钠(NaN_3)是线粒体细胞色素C氧化酶(COX)的特异性抑制剂,能诱导线粒体缺陷。本实验通过细胞活性检测(MTT法),形态学观察,分析H_2O_2对原代培养的正常神经元及NaN_3诱导的线粒体缺陷神经元的损伤作用的差异。并通过RT-PCR半定量法检测H_2O_2损伤后两类神经元内硫氧还蛋白(Thioredoxin,Trx)mRNA水平的变化,以阐明细胞内这一重要氧化还原调节蛋白在神经元损伤时的作用机制。实验表明,在正常神经元内,H_2O_2的损伤对Trx表达量的改变似乎不明显;而线粒体缺陷神经元内Trx的表达量下降,且对于H_2O_2的损伤具有浓度、时间依赖性。提示:在线粒体功能缺陷神经元中,Trx似乎发挥更重要的作用。

Oxidative stress and mitochondrial deficiency have been considered to be associated with the mechanisms of many neurodegenerative diseases. Sodium azide (NaN3) is a special inhibitor of mitochondrion cytochrome c oxidase (COX),which can be used to mimic neuronal damage induced by mitochondrial deficiency. In this experiment, the neurotoxic effects of H2O2 on primary cultured neurons and NaN3-induced mitochondrial dysfunctional neurons were detected by means of cell viability measurement (MTT) and analyzed through morphological observation. Furthermore, the changes of thioredoxin mRNA level in both normal and abnormal cultured neurons insulted by H2O2 were analyzed by semiquantitative RT-PCR in order to explore the role of Trx, an important redox regulatory protein, in modulating the process of neuronal injury. It was found that mitochondrial dysfunctional neurons could be damaged by H2O2 in a dose-and time-dependent manner and the expression of Trx decreased during certain dose (0-200 μmol/L) and time (0-4 h) of H2O2 treatment. But in normal neurons the effects of H2O2 treatment seemed to be less evident. It suggests that in neurons with mitochondrial dysfunction, the redox modulation of thioredox seems to be more prominent.