中文摘要：

目的探讨铅对中枢神经系统神经细胞内转录因子Brn-3a表达的影响。方法雌性大鼠在围产期经饮水染铅（对照组蒸馏水、染铅组低0.5g/L、中1.0g/L、高2.0g/L）,观察21日龄仔鼠脑组织,采用逆转录-聚合酶链反应（RT-PCR）半定量检测Brn-3a的mRNA转录水平,采用免疫组织化学方法检测Brn-3a蛋白表达水平。结果RT-PCR凝胶成像系统结果分析表明,各染铅剂量组脑组织海马区扩增产物的电泳条带密度与对照组相比其差异有显著性（P〈0.05）,表明mRNA的表达量减弱。免疫组织化学图像分析表明,各染铅组脑组织皮层、海马及小脑的Brn-3a蛋白表达的阳性面积比[Aa（%）]、平均灰度与对照组相比其差异有不同程度的显著性（P〈0.05或P〈0.01）,并呈剂量-依赖性的变化。染铅组Brn-3a表达低于对照组。结论本研究的铅暴露动物模型脑组织观察到,大鼠脑组织基因转录水平和蛋白表达水平有所下降,表明铅干扰了Brn-3a蛋白的正常表达模式,因此干扰了神经细胞的正常分化。

英文摘要：

Objective To explore the effects of lead on the transcription factor Brn-3a expression level in the neurons of central nervous system. Methods The pregnant rats were randomly divided into 4 groups, which were provided with distilled water, 0.Sg/L, 1.0g/L, 2.0g/L lead actate solution via drinking water respectively, the lead-exposed period for exposure groups was limited from the 15th day after pregnancy to the 21st day when the offspring began to weaned and various brain regions were obtained. Brn-3a mRNA transcription level were observed by polymerase chain reaction （RT- PCR） and Brn-3a proteins expression level were observed by immunohistochemistry method. Results The RT-PCR results showed that Brn-3a mRNA transcription level decreased significantly in neural cells from cerebral hippocampus in every lead treatment group compared with the control group（ P 〈 0.05）. The immunohistochemistry results showed that Brn-3a decreased significantly in lead poisoning groups compared with that of control group （ P 〈 0.05 or P 〈 0.01 ）. Conclusion Brn-3a mRNA transcription level and protein expression level were decreased in brain regions in this study. The results showed that lead-exposure might interfere the normal model of Brn-3a protein expression, so it interfered the differentiation of neuronal cells.