铅对大鼠海马C-fos基因表达及学习记忆的影响
Effect of lead exposure on expression of C-fos gene and capacity of learning and memory of rats
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摘要:目的 观察和探讨铅对大鼠海马C-fos基因表达及学习记忆的影响.方法 选用健康大鼠30只, 每天给醋酸铅灌胃1次, 高剂量组0.2g/(kg·d), 低剂量组0.1g/(kg·d), 连续染毒3个月后, 用Y型迷宫试验测试大鼠学习记忆能力; 最后处死大鼠, 用原位杂交法观察各组大鼠海马C-fosmRNA的表达状况.结果 (1) 2个染铅组大鼠主被动回避反应正确次数显著低于对照组(P < 0.01);(2)光镜下观察高铅组海马切片着色很浅, C-fosmRNA阳性细胞很少; 低铅组着色较浅, 可见少数C-fosmRNA阳性细胞; 对照组着色较深, C-fos阳性细胞密集, 阳性锥体细胞呈多角形, 胞体较大, 胞浆染色呈不规则的环形.结论 C-fos基因表达水平下降可能是亚慢性铅染毒致大鼠学习记忆障碍的重要环节, 是铅对学习记忆损害的分子机制之一.Abstract:Objective To observe the effect of subchronic lead contaminant on the expression of C-fos mRNA in hippocampus and the capacity of learning and memory of rats.Methods Subchronic acetic lead contaminant was applied on rats(0.2g·kg-1·d-1 as the high dose and 0.1g·kg-1·d-1 as the low dose)for three months.The Y-maze test was used to measure the capacity of learning and memory of each group.At the end of the experiment, the ISH(in situ hybridization) was used to observe the expression of C-fos mRNA in hippocampus after the induction of Y-maze test.Results (1) In step down test the correct percentage of lead group significantly decreased compared with the control(P < 0.01).(2)Results of C-fos mRNA ISH: There were few positive cells of deep colouring in hippocampus of high lead group.A few was observed in low lead group.The C-fos positive cells of deep colouring in hippocampus of control group was concentrated.Conclusion The decrease of C-fos gene expression level in hippocampus had a great link with the impairment of learning and memory induced by lead in rats, and this may be one of the molecule mechanism of lead-induced impairment of learning and memory.
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