中文摘要：

目的：观察神经细胞黏附分子（NCAM）和酪氨酸羟化酶（TH）在大鼠黑质致密部（SNc）多巴胺（DA）能神经细胞表达的变化，探讨其发生机制。方法：健康雄性SD大鼠24只，分为成年组（4—5月龄）和老年组（≥24月龄），取中脑黑质，分别进行TH和NCAM的免疫组织化学染色及免疫印迹检测蛋白表达，显微镜下计数免疫组化染色阳性神经细胞，灰度分析电泳条带。结果：SNc的DA能神经细胞几乎都表达NCAM，老年大鼠SNcTH阳性细胞总数及蛋白量均无减少（P〉0．05），但尾侧段TH阳性细胞减少（P〈0．05）；NCAM在阳性细胞总数及蛋白量均减少（P〈0．05），但各段阳性细胞的减少无统计学意义（P〉0．05）。结论：正常老化后大鼠的SNcDA能神经细胞DA合成降低，并且NCAM可能参与了这种DA的合成下降。

英文摘要：

Aim： To observe the expression changes of neural ceil adhesion molecule （NCAM） and tyrosine hydroxylase（TH） in dopamine（DA） neurons of the rat substantia nigra compact（SNc） during normal aging, and to discuss the mechanism of the change. Methods：24 male healthy SD rats were divided into two groups： 4-5 months group and above 24 months group. Routine paraffin sections were made for TH and NCAM imrnunohistochemical staining, and expressions of the proteins were detected by Western blot. The number of positive neurons was counted under microscope and the gray scales of electrophoresis strips were analyzed. Results：There was coexpression of TH with NCAM in dopamine neurons of SNc, and the total number of TH-positive neurons and the amount of TH-protein had no change with aging （P〉0.05）, but the number of TH-positive neurons decreased in the caudal of substantia nigra compact of aged rats （P〈0.05）, meanwhile, the expression of NCAM decreased in aged rats（P〈0.05）, although there was no decrease in every fragment（P〈0.05）. Conclusion： The product of DA descended in substantia nigra compact during normal aging, moreover, NCAM may be participated in the descent.