Protective role of glutathione reductase in paraquat induced neurotoxicity
Protective role of glutathione reductase in paraquat induced neurotoxicity
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DOI：
10.1016/j.cbi.2012.05.008
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发表时间：
2012-08-30
影响因子：
5.1
通讯作者：
Vekic, Jelena
中科院分区：
文献类型：
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作者：
Djukic, Mirjana M.;Jovanovic, Marina D.;Vekic, Jelena
百草枯（Paraquat，PQ）是一种广泛使用的除草剂，也是一种自由基产生剂。PQ神经毒性的机制途径进行了检查，通过评估氧化/亚硝化应激标志物。重点是谷胱甘肽（GSH）循环的作用，并检查与酶谷胱甘肽还原酶（GR）的预处理是否可以保护脆弱的大脑区域（VBR）对PQ有害的氧化作用。实验选用Wistar大鼠，随机分为5组：正常对照组（n = 8）和4个实验组（n = 24）。所有测试化合物均在24小时内纹状体内（i.s.）一次注射在处理后30 min、24 h和7 d，测量纹状体、海马和皮质中的以下氧化状态参数：超氧阴离子自由基（O-2（中心点-））、硝酸根（NO3-）。丙二醛（MDA）、超氧化物歧化酶（SOD）、总谷胱甘肽（tGSH）及其氧化型二硫键（GSSG）和谷胱甘肽过氧化物酶（GPx）。给药途径不会影响结果的可靠性。此外，在检查的VBR的同侧和对侧之间观察到类似的变化模式，表明氧化应激的快速空间扩散。仅在PQ组中观察到24 h内动物死亡（10%），沿着帕金森综合征症状，从麻醉中苏醒2-3 h后。在处理后30 min，测定到O2（中心点-）、NO3-和MDA水平升高，GSSG/GSH比值升高，GPx活性相当高。PQ的细胞毒性效应通过所有测量参数的急剧下降和PQ i.s.后24小时GSSG/GSH比值的极高高峰来记录。注射在GR + PQ组中，整个实验过程中GPx活性和NO3-（纹状体和皮层）含量均较低，而仅在第7天观察到O-2（中心点-）含量的增加，说明氧化/亚硝化应激和兴奋性毒性是PQ引起神经毒性早期最重要的事件。根据GSSG/GSH的比值，GSH氧化为GSSG可能是GHS耗竭的主要途径，也是PQ有害氧化作用的抗氧化防御能力降低的主要原因。GR预处理导致大鼠没有帕金森病样症状和死亡率。此外，在GR + PQ中未发生氧化/亚硝化应激，并且在第24小时VBR代谢几乎减少（如PQ组中所记录的），表明GR在PQ诱导的神经毒性中具有神经保护作用。(c)2012爱思唯尔爱尔兰有限公司保留所有权利。
Paraquat (PQ), a widely used herbicide is a well-known free radical producing agent. The mechanistic pathways of PQ neurotoxicity were examined by assessing oxidative/nitrosative stress markers. Focus was on the role of glutathione (GSH) cycle and to examine whether the pre-treatment with enzyme glutathione reductase (GR) could protect the vulnerable brain regions (VBRs) against harmful oxidative effect of PQ. The study was conducted on Wistar rats, randomly divided in five groups: intact-control group, (n = 8) and four experimental groups (n = 24). All tested compounds were administered intrastriatally (i.s.) in one single dose. The following parameters of oxidative status were measured in the striatum, hippocampus and cortex, at 30 min, 24 h and 7 days post treatment: superoxide anion radical (O-2(center dot-)), nitrate (NO3-). malondialdehyde (MDA), superoxide dismutase (SOD), total GSH (tGSH) and its oxidized, disulfide form (GSSG) and glutathione peroxidase (GPx).Results obtained from the intact and the sham operated groups were not statistically different, confirming that invasive i.s. route of administration would not influence the reliability of results. Also, similar pattern of changes were observed between ipsi- and contra- lateral side of examined VBRs, indicating rapid spatial spreading of oxidative stress. Mortality of the animals (10%), within 24 h, along with symptoms of Parkinsonism, after awakening from anesthesia for 2-3 h, were observed in the PQ group, only. Increased levels of O2(center dot-), NO3- and MDA, increased ratio of GSSG/GSH and considerably high activity of GPx were measured at 30 min after the treatment. Cytotoxic effect of PQ was documented by drastic drop of all measured parameters and extremely high peak of the ratio GSSG/GSH at 24th hrs after the PQ i.s. injection. In the GR + PQ group, markedly low activity of GPx and low content of NO3- (in striatum and cortex) were measured during whole experiment, while increase value was observed only for O-2(center dot-), at 7th days.We concluded that oxidative/nitrosative stress and excitotoxicity are the most important events since the early stage of PQ induced neurotoxicity. Based on the ratio GSSG/GSH, the oxidation of GSH to GSSG is probably dominant way of GHS depletion and main reason for reduced antioxidative defense against PQ harmful oxidative effect. The GR pre-treatment resulted in the absence of Parkinson's disease-like symptoms and mortality of the rats. Additionally, oxidative/nitrosative stress did not developed, as well as almost diminished metabolism of the VBRs at 24th hours (as has been documented in the PQgroup) did not occurred in the GR + PQ suggesting a neuroprotective role for the GR in PQ induced neurotoxicity. (c) 2012 Elsevier Ireland Ltd. All rights reserved.