中文摘要：

目的研究断乳后不同浓度慢性铝暴露的大鼠海马细胞内钙调神经磷酸酶（caleineurin，CaN）表达变化，探讨铝损害学习记忆的突触机制。方法对照组、低剂量和高剂量组大鼠从断乳后分别自由饮用蒸馏水、Al^3＋浓度为15mmol·L^-1和30mmol·L^-1的AICl，水溶液；采用跳台法测试大鼠学习记忆能力；Western blot法测定大鼠海马内CaN蛋白表达；免疫组化方法测定大鼠海马CA1、CA3区的CaN阳性细胞平均积分光密度。结果与对照组相比，两铝暴露组大鼠跳台实验反应时间明显延长而潜伏期明显缩短，5min内错误次数明显增加，且两铝暴露组间的差异具有显著性；与对照组相比，两铝暴露组大鼠海马内CaN蛋白表达明显增加、CaN阳性神经元平均积分光密度明显增加，且两铝暴露组间差异亦具有显著性。结论断乳后铝暴露损害了大鼠的学习与记忆行为，可能与海马内CaN的表达增加有关。

英文摘要：

Aim To study the effects of CaN in hippocampus of rats after postweaning chronic aluminum exposure, and to investigate the synaptic mechanism of the impairment of learning and memory after aluminum administration. Methods Postweaning rats of control, low-dose and high-dose groups were treated with distilled water and AlCl3 water solution with concentration of 15 mmol·L^-1 or 30 mmol · L^-1 Al^3＋ respectively. The step-down test was used to determine the learning and memory ability. Western blot measured the expression of CaN in hippocampus. The Integrated OD Average of CaN positive cells were observed with immunohistochemistry. Results Compared with the control group,in the Al^3＋ exposed groups, the escape latency was remarkably prolonged, the step-down latency was remarkably decreased, and the number of errors both in learning and memory were significantly increased. Moreover, the expression of CaN in hippocampus and the Integrated OD Average of CaN in hippocampus increased. Conclusion Postweaning aluminum exposure after ablaetation could impair the learning and memory ability of rats, which might be related to the increase of the expression of CaN in the hippoeampus.