Cheng Jin-ping, Hu Wei-xuan, Liu Xiao-jie, Zheng Min, Shi Wei, Wang Wen-hua
School of Environmental Science and Engineering, Shanghai Jiaotong University, China.
J Environ Sci (China). 2006;18(4):788-92.
Wanshan mercury mine is the largest mercury deposit in Guizhou Province of China, but there were few reports on mercury toxic effect in the mining area. In order to study the neurotoxicity of food from Wanshan mercury mine area and probe into the effect of food from Wanshan mercury miner area on the changes of brain oxidative damage and expression of c-fos gene. The rats were exposed to mercury contaminated food for 20 d. The content of malondialdehyde (MDA), superoxide dismutase (SOD), GSH-peroxidase (GSH-px) and Glutathione (GSH) in rat brain was measured, and the effect of mercury contaminated rice on the expression of c-fos mRNA in rat brain and the expression of c-FOS protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. The results showed the levels of GSH, MDA, SOD and of GSH-dependent enzymes in the rat brain changed between exposure groups and control group; The mercury polluted rice induced significantly the expression of c-fos mRNA; the c-FOS positive cells in hippocampus and cortex of exposure groups were significant different from control group (P<0.01). It could be concluded that oxidative stress signals could contribute to the induction of immediate early genes (IEGs); free radicals and their by-products might not only cause oxidative damage, but also influenced gene expression; IEGs c-fos participated in the toxicity process of brain injury by mercury polluted food.
万山汞矿是中国贵州省最大的汞矿床，但关于该矿区汞毒性作用的报道较少。为研究万山汞矿区食物的神经毒性，探讨万山汞矿区食物对脑氧化损伤变化及c-fos基因表达的影响。将大鼠暴露于汞污染食物20天。检测大鼠脑内丙二醛（MDA）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-px）和谷胱甘肽（GSH）的含量，采用逆转录聚合酶链反应（RT-PCR）和免疫细胞化学方法观察汞污染大米对大鼠脑内c-fos mRNA表达及皮质、海马区c-FOS蛋白表达的影响。结果显示，暴露组与对照组大鼠脑内GSH、MDA、SOD及谷胱甘肽依赖性酶水平存在差异；汞污染大米显著诱导c-fos mRNA表达；暴露组海马和皮质的c-FOS阳性细胞与对照组有显著差异（P<0.01）。可以得出结论，氧化应激信号可能促成即刻早期基因（IEGs）的诱导；自由基及其副产物不仅可能导致氧化损伤，还可能影响基因表达；IEGs c-fos参与了汞污染食物所致脑损伤的毒性过程。
