Methylmercury exposure during the vulnerable window of the cerebrum in postnatal developing rats.
Methylmercury exposure during the vulnerable window of the cerebrum in postnatal developing rats.
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出生后发育中的大鼠大脑脆弱窗口期间的甲基汞暴露。
DOI：
10.1016/j.envres.2020.109776
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Nakamura M.
中科院分区：
文献类型：
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作者：
Sakamoto M;Kakita A;Sakai K;Kameo S;Yamamoto M;Nakamura M.
众所周知，发育中的大脑对甲基汞 (MeHg) 的毒性作用很敏感。在大脑看似最脆弱的窗口期间，甲基汞暴露的毒性水平的影响尚未得到充分研究。在这项研究中，我们旨在研究甲基汞毒性水平对幼鼠大脑神经行为、神经变性和硒酶活性的具体影响。雄性 Wistar 大鼠（n = 8/组）从出生后第 14 天开始连续 10 天以急性毒性剂量（8 mg Hg/kg/天）口服 MeHg（P14）。暴露于甲基汞的大鼠在第 8 天后表现出体重显着下降，并在第 12 天表现出类似于肌张力障碍的严重神经系统症状 (P25)。在第 11 天（P24），在暴露于甲基汞的大鼠中观察到使用旋转杆性能测试确定的运动协调缺陷和使用 Y 迷宫任务确定的短期记忆损伤。第12天处死的甲基汞暴露大鼠出现严重的脑神经元变性、反应性星形细胞增多和TUNEL阳性凋亡细胞核，脑汞浓度为15.0±1.6μg/g。此外，甲基汞暴露大鼠大脑中谷胱甘肽过氧化物酶和硫氧还蛋白还原酶的活性低于对照组。这些结果表明，幼鼠接触甲基汞将有助于预测甲基汞对人类大脑生长突增的影响。
The developing brain is known to be sensitive to the toxic effects of methylmercury (MeHg). The effects of toxic levels of MeHg exposure during the most seemingly vulnerable window of the cerebrum are not well studied. In this study, we aimed to examine the specific effects of toxic levels of MeHg on neurobehavior, neurodegeneration, and selenoenzyme activity in the cerebrum of infant rats. Male Wistar rats (n = 8/group) were orally treated with MeHg at an acute toxic dose (8 mg Hg/kg/day) for 10 consecutive days starting on postnatal day 14 (P14). The MeHg-exposed rats showed a significant reduction in body weight after day 8 and severe neurological symptoms similar to dystonia on day 12 (P25). Motor coordination deficits determined using the rotarod performance test and short-term memory impairment determined using the Y-maze task were observed in the MeHg-exposed rats on day 11 (P24). The MeHg-exposed rats sacrificed on day 12 showed severe cerebral neuronal degeneration, reactive astrocytosis, and TUNEL-positive apoptotic nuclei, with the cerebral Hg concentration of 15.0 ± 1.6 μg/g. Furthermore, the activities of glutathione peroxidase and thioredoxin reductase in the cerebrum in MeHg-exposed rats were lower than those in control. These results indicate that MeHg exposure to infant rats will be useful to predict the effects of MeHg at the cerebral growth spurt in humans.