Cheng Jinping, Yang Yichen, Ma Jing, Wang Wenhua, Liu Xiaojie, Sakamoto Mineshi, Qu Yiya, Shi Wei
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Environ Int. 2009 Apr;35(3):619-25. doi: 10.1016/j.envint.2008.12.006. Epub 2009 Jan 22.
Polychlorinated biphenyls and methylmercury are two of the most ubiquitous environmental contaminants in Guizhou province. Rice is eaten with almost every meal and provides more calories than any single food in Guizhou province. The estimated tolerable daily intake of total mercury, MeHg, Se and PCBs from Guizhou contaminated rice by Chinese people showed that MeHg and/or PCBs exceeded the corresponding limits. The aim of this study was to characterize the effects of exposure to environmental contaminated rice on neurobehavioral development and neurobiological disruptions in mice. Animals were treated from postnatal day (PND) 22 to 91. At PND 26-91 days of age, mice were tested for neurobehavioural development and neurochemical level changes. We showed that dietary exposure to environmentally contaminated rice gave rise to different changes in antioxidants. Reduced superoxide dismutase (SOD) activity and excess increased nitric oxide (NO) indicated aggravation of oxidative status after long-term dietary intake of Hg and PCBs. Neurobehavioral derangement in the central nervous system and significant delay in the Morris water maze test response on PND 91 are correlated with the increased of c-fos/c-jun expression levels in the cerebral cortex. These results suggest that MeHg neurotoxicity might be a greater hazard than that associated with PCB, but PCB may augment the neurobehavioral deficits caused by increased levels of mercury exposure. The simultaneous intake of selenium might have a protective effect on Hg accumulation in the body, and vitamin C might protect mice against the toxic effects of PCBs. However, the protective role of Se and vitamin C is very limited for multiple-agent pollution. Immediately early genes in the brain response to contaminated rice might be dependent on interaction among NO, NO synthase (NOS), SOD and reduced glutathione (GSH). We should be alert to mental health problems in human beings when any kind of Hg- and PCB-polluted food is consumed.
多氯联苯和甲基汞是贵州省最普遍存在的两种环境污染物。贵州几乎每餐都吃米饭，米饭提供的热量比该省任何一种单一食物都多。中国人从贵州受污染大米中摄入的总汞、甲基汞、硒和多氯联苯的每日估计耐受摄入量表明，甲基汞和/或多氯联苯超过了相应限值。本研究的目的是描述暴露于受环境污染的大米对小鼠神经行为发育和神经生物学破坏的影响。动物从出生后第22天（PND）至91天接受处理。在出生后第26 - 91天，对小鼠进行神经行为发育和神经化学水平变化测试。我们发现，饮食中暴露于受环境污染的大米会导致抗氧化剂发生不同变化。超氧化物歧化酶（SOD）活性降低和一氧化氮（NO）过量增加表明，长期摄入汞和多氯联苯后氧化状态加剧。中枢神经系统的神经行为紊乱以及出生后第91天在莫里斯水迷宫试验中的反应显著延迟与大脑皮质中c - fos/c - jun表达水平升高相关。这些结果表明，甲基汞的神经毒性可能比多氯联苯更大，但多氯联苯可能会加剧汞暴露水平升高引起的神经行为缺陷。同时摄入硒可能对体内汞的积累有保护作用，维生素C可能保护小鼠免受多氯联苯的毒性影响。然而，对于多种污染物污染，硒和维生素C的保护作用非常有限。大脑中立即早期基因对受污染大米的反应可能取决于NO、一氧化氮合酶（NOS）、SOD和还原型谷胱甘肽（GSH）之间的相互作用。当食用任何受汞和多氯联苯污染的食物时，我们都应该警惕人类的心理健康问题。
