铅对大鼠海马一氧化氮合酶基因表达的影响

Effect of Lead Exposure on Gene Expressions of Neuron Nitric Oxide Synthase in Hippocampus of Rat

目的 探讨铅对海马一氧化氮合酶 (nNOS)基因的mRNA和蛋白表达的影响。方法 1 2只大鼠饮用含 0 2 %醋酸铅 (PbAc)水 3个月后 ,作为铅染毒组进行实验。用ABC免疫组织化学和半定量逆转录 -聚合酶链式反应 (RT PCR)方法测定大鼠海马nNOS阳性神经元数量和nNOSmRNA含量的变化。结果 铅染毒组大鼠海马CA1 区、齿状回nNOS阳性神经元数目分别为 4 6 6 7± 9 0 4和 30 5 3± 7 0 8,较对照组的6 0 6 7± 1 3 4 8和 5 7 0 7± 1 1 1 4明显减少 ,差异有显著性 (P <0 0 5 ) ;铅染毒组大鼠海马CA3 区nNOS阳性神经元数目与对照组比较 ,差异无显著性 (P >0 0 5 ) ;铅染毒组大鼠海马nNOSmRNA含量 (0 0 71± 0 0 2 5 )比对照组 (0 4 5 4± 0 0 4 5 )显著减少 (P <0 0 1 )。结论 铅对大鼠海马各区nNOS阳性神经元数和mRNA表达降低 。

Objective To investigate the effect of lead on the protein and gene expressions of neuron nitric oxide synthase(nNOS)in hippocampus of rat.Methods 12 Wistar rats were exposed to lead by drinking 0 2% lead acetate solution for three months.Study the changes of nNOS positive neuronal numbers and mRNA content in nNOS in hippocampus of rat by immunohistochemical and semi quantitative reverse transcription polymerase chain reaction(RT PCR) method.Results Compared with the control group,the number of nNOS positive neurons in CA 1 area and dentate gyrus of lead exposed rats(46 67±9 04 and 30 53±7 08 respectively)were significantly decreased than the control rats(60 67±13 48 and 57 07±11 14,P<0 05 respectively); the numbers of nNOS positive neurons in CA 3 area of lead exposed rats showed no obvious difference with those of control rats.In comparison with control group(0 454±0 045), the nNOS mRNA content of hippocampus(0 071±0 025)decreased notably(P<0 01).Conclusions These results suggest that the expression reduction of nNOS positive neuron in hippocampus might be related to the effect of lead on learning and memory.