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美国卫生研究院文献>BioMed Research International
>Early Developmental Low-Dose Methylmercury Exposure Alters Learning and Memory in Periadolescent but Not Young Adult Rats
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Early Developmental Low-Dose Methylmercury Exposure Alters Learning and Memory in Periadolescent but Not Young Adult Rats
Few studies have assessed the effects of developmental methylmercury (MeHg) exposure on learning and memory at different ages. The possibility of the amelioration or worsening of the effects has not been sufficiently investigated. This study aimed to assess whether low-dose MeHg exposure in utero and during suckling induces differential disturbances in learning and memory of periadolescent and young adult rats. Four experimental groups of pregnant Sprague-Dawley rats were orally exposed to MeHg or vehicle from gestational day 5 to weaning: (1) control (vehicle), (2) 250 μg/kg/day MeHg, (3) 500 μg/kg/day MeHg, and (4) vehicle, and treated on the test day with MK-801 (0.15 mg/kg i.p.), an antagonist of the N-methyl D-aspartate receptor. The effects were evaluated in male offspring through the open field test, object recognition test, Morris water maze, and conditioned taste aversion. For each test and stage assessed, different groups of animals were used. MeHg exposure, in a dose-dependent manner, disrupted exploratory behaviour, recognition memory, spatial learning, and acquisition of aversive memories in periadolescent rats, but alterations were not observed in littermates tested in young adulthood. These results suggest that developmental low-dose exposure to MeHg induces age-dependent detrimental effects. The relevance of decreasing exposure to MeHg in humans remains to be determined.
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机译:很少有研究评估不同年龄发育性甲基汞(MeHg)暴露对学习和记忆的影响。改善或效果恶化的可能性尚未得到充分研究。这项研究旨在评估子宫内和哺乳期间低剂量MeHg暴露是否会引起青春期和成年幼鼠学习和记忆的差异性干扰。从妊娠第5天到断奶,四个实验组的怀孕Sprague-Dawley大鼠口服MeHg或媒介物:(1)对照(车辆),(2)250μg/ kg /天MeHg,(3)500μg/ kg /天(4)媒介物,并在测试当天用N-甲基D-天冬氨酸受体的拮抗剂MK-801(0.15 mg / kg ip ip)处理。通过露天试验,物体识别试验,莫里斯水迷宫和条件性厌恶对雄性后代的影响进行了评估。对于评估的每个测试和阶段,使用不同的动物组。 MeHg暴露以剂量依赖性方式破坏了青春期大鼠的探索性行为,识别记忆,空间学习和厌恶性记忆的获得,但未在成年后的同窝仔中观察到变化。这些结果表明,低剂量暴露于甲基汞的发育诱导了年龄依赖性的有害作用。减少人体对甲基汞暴露的相关性尚待确定。
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