宫内接触氯化甲基汞对发育阶段小鼠学习记忆能力和海马神经元超微结构的影响

目的　研究宫内接触氯化甲基汞对发育阶段小鼠学习记忆能力及海马神经元超微结构的影响.方法　对妊娠7～10天的小鼠每天灌胃给予0和4mg kgbw氯化甲基汞。以出生6周龄仔鼠进行学习记忆能力测试及透射电镜技术观察宫内接触氯化甲基汞对发育阶段小鼠学习记忆能力及海马神经元超微结构的影响。结果　氯化甲基汞暴露组学习记忆能力显著低于对照组(P <0 . 0 5 )。超微结构显示海马神经元细胞膜结构不清,部分核膜消失,核膜皱缩,核孔不清,染色质淡染;线粒体肿胀变大、粗面内质网扩张、空泡变性,核糖体减少;轴突环出现分层;有髓神经纤维脱髓鞘、板状分离。结论　甲基汞可致小鼠学习记忆障碍和海马神经元超微结构改变;宫内接触氯化甲基汞引起海马神经元超微结构的改变与小鼠学习记忆障碍密切相关。

Effects of prenatal methylmercury exposure on learning and memory ability of mice and ultrastructure of hippocampus neurons in mice

OBJECTIVE: To study the effects of prenatal methylmercury exposure on learning and memory ability of mice and ultrastructure of hippocampus neurons in mice. METHODS: Methylmercury in doses of 0 and 4mg/(kg x d) were fed to pregnant mice at 7th-9th day after conception. Learning and memery ability of the mice offspring was detected. The ultrastructure of hippocampus neurons was observed by electron microscope after the completion of the experiment. RESULTS: The learning and memery ability of the mice offspring of 4 mg/(kg x d) dose group was lower than those of 0 mg/(kg x d) dose group (P < 0.05). Changes in the ultrastructure of hippocampus neurons were obvious in 4 mg/(kg x d) dose group as compared with the 0 mg/(kg x d) dose group. CONCLUSION: Methylmercury could affect the growth and development of central nerve system. The learning and memory ability of mice offspring was greatly damaged and the ultrastructure of hippocampus neurons was changed by methylmercury.