Department of Biochemistry and Nutrition, Central Food Technological Research Institute, Council of Scientific and Industrial Research, Mysore, India.
Arch Insect Biochem Physiol. 2013 May;83(1):25-40. doi: 10.1002/arch.21094. Epub 2013 Apr 5.
Paraquat (PQ; 1, 1'-dimethyl-4-4'-bipyridinium), an herbicide and model neurotoxicant, is identified to be one of the prime risk factors in Parkinson's disease (PD). In the Drosophila system, PQ is commonly used to measure acquired resistance against oxidative stress (PQ resistance test). Despite this, under acute PQ exposure, data on the oxidative stress response and associated impact on mitochondria among flies is limited. Accordingly, in this study, we measured markers of oxidative stress and mitochondrial dysfunctions among adult male flies (8-10 days old) exposed to varying concentrations of PQ (10, 20, and 40 mM in 5% sucrose solution) employing a conventional filter disc method for 24 h. PQ exposure resulted in significant elevation in the levels of oxidative stress biomarkers (malondialdehyde: 43% increase: hydroperoxide: 32-39% increase), with concomitant enhancement in reduced glutathione and total thiol levels in cytosol. Higher activity of antioxidant enzymes were also evident along with increased free iron levels. Furthermore, PQ exposure caused a concentration-dependent increase in mitochondrial superoxide generation and activity of manganese-superoxide dismutase (Mn-SOD). The activity levels of complex I-III, complex II-III, and Mg+2 adinosine triphosphatase (ATPase) were also decreased significantly. A robust diminution in the activity of succinate dehydrogenase and moderate decline in the citrate synthase activity suggested a specific effect on citric acid cycle enzymes. Collectively, these data suggest that acute PQ exposure causes significant oxidative stress and mitochondrial dysfunction among flies in vivo. It is suggested that in various experimental settings, while conducting the "PQ resistance stress test" incorporation of selected biochemical end points is likely to enhance the quality of the data.
百草枯（PQ；1,1'-二甲基-4-4'-联吡啶𬭩），一种除草剂和模式神经毒物，被认为是帕金森病（PD）的主要危险因素之一。在果蝇系统中，PQ 通常用于测量对氧化应激的获得性抗性（PQ 抗性测试）。尽管如此，在急性 PQ 暴露下，关于 flies 中氧化应激反应及其对线粒体的影响的数据仍然有限。因此，在这项研究中，我们使用常规滤纸片法在 5%蔗糖溶液中测量了不同浓度的 PQ（10、20 和 40 mM）暴露 24 小时后成年雄性果蝇（8-10 天大）中的氧化应激标志物和线粒体功能障碍。PQ 暴露导致氧化应激生物标志物水平显著升高（丙二醛：增加 43%；氢过氧化物：增加 32-39%），同时细胞质中还原型谷胱甘肽和总巯基水平升高。抗氧化酶的活性也明显增强，游离铁水平升高。此外，PQ 暴露导致线粒体中超氧阴离子生成和锰超氧化物歧化酶（Mn-SOD）活性呈浓度依赖性增加。复合物 I-III、复合物 II-III 和 Mg+2 三磷酸腺苷酶（ATPase）的活性水平也显著降低。琥珀酸脱氢酶的活性显著降低，柠檬酸合酶的活性中度降低，表明对柠檬酸循环酶有特异性影响。总的来说，这些数据表明急性 PQ 暴露导致体内 flies 发生显著的氧化应激和线粒体功能障碍。建议在各种实验设置中，在进行“PQ 抗性应激测试”时，结合选定的生化终点可能会提高数据质量。
