神经细胞黏附分子在胶质细胞系源性神经营养因子保护多巴胺能神经元中的作用

The role of NCAM in the mechanism of GDNF protection of dopaminergic neurons

目的研究神经细胞黏附分子(neural cell adhesion molecule,NCAM)在胶质细胞系源性神经营养因子(glial cell line-derived neurotrophic factor,GDNF)保护1-甲基-4-苯基-1,2,3,6-四氢吡啶(1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine,MPTP)损伤的多巴胺(dopamine,DA)能神经元中的作用。方法以原代培养的小鼠腹侧中脑神经细胞作为观察对象,实验分4组:空白对照组、MPTP组(在无血清培养基内加入10μmol/LMPTP)、GDNF+MPTP组(在无血清培养基内加入GDNF保护的基础上,再加入MPTP)、抗-NCAM+GDNF+MPTP组(在无血清培养基内加入NCAM封闭抗体阻断GDNF保护作用的基础上,再加入MPTP)。采用免疫细胞化学染色技术,观察各组酪氨酸羟化酶(tyrosine hydroxylase,TH)、钙结合蛋白D28K(calbindin D28K,CB)表达的变化。结果MPTP组TH阳性神经元胞体明显小于空白对照组;CB阳性神经元数目减少,有统计学意义。GDNF+MPTP组TH阳性神经元胞体与MPTP组有明显差别;CB阳性神经元数目与MPTP组有显著性差异。抗-NCAM+GDNF+MPTP组上述指标与MPTP组无显著性差异。结论NCAM参与了GDNF保护DA能神经元的作用,该保护作用可能是通过增加CB的表达而完成的。

Objective To explore the possible role of neural cell adhesion molecule （NCAM） in mediating the protective effect of glial cell line - derived neurotrophic actor （GDNF） on dopaminergic （DA） neurons in the mesencephlic cell culture injured by 1 - methyl - 4 - phenyl - 1,2,3,6 - tetrahydropyfidine （ MPTP）. Methods Primary culture of ventral mesencephalic neurons was established. The neurons were studied in four groups, normal control group, MPTP control group, MPTP plus GDNF test group, and anti - NCAM plus MPTP and GDNF test group. On the 8th day, TH and CB immunohistochemistry was performed. The morphologic indexes were measured and statistic analysed. Results The long diameter of TH positive neurons in the MPTP control group was significantly shorter than that in the normal control group. The density of CB positive neurons was also decreased in the MPTP injury control group. GDNF could protect the DA neurom against the injury of MPTP. However, the protective effect of GDNF on DA neurons was canceled, when the NCAM pathway was blocked by adding anti - NCAM in the fourth group of the present experiment. Conclusion NCAM can mediate the protective effect of GDNF on DA neurons, and this role may be related to the increase of CB expression.