成年与老年大鼠中脑黑质致密部多巴胺能神经元形态学研究

Age-related change of dopaminergic neuron in the substantia nigra of rat

目的研究大鼠中脑黑质致密部多巴胺能神经元随年龄老化的形态学变化规律，探讨其退行性变的形态学依据。方法SD大鼠16只，雄性，分为成年组（4-5月龄）和老年组（≥18月龄）。取中脑黑质，常规制片，连续冠状切片，分别进行焦油紫染色和TH免疫组化染色，用图像分析仪分别对Nissl染色细胞、TH免疫组化染色阳性神经元进行计数，透射电镜观察神经元的超微结构变化。结果老年大鼠中脑黑质神经元数量减少（P〈0．05），TH阳性神经元也同时减少（P〈0．05），且在超微结构上老年大鼠多巴胺能神经元出现内质网扩张及多量脂褐素形成。结论老年黑质退行性病变可能与中脑黑质致密部多巴胺能神经元数量减少有关。

Objective To study the rule of age - related morphological changes of dopaminergic neurons in substantia nigra compact of midbrain in rats to explore the morphological basis of the degenerative process. Methods SD rats for the present study were of two groups： 4 -5 months and above 18 months （n = 8 each）. Routine paraffin sections were made for Nissl staining, TH immunohistochemical staining and electron microscopy. The neurons and the TH positive cells in the substantia nigra compact were counted by using morphometric technique; the uhrastructure of TH positive neurons was studied under electron microscope. Results The total number of neurons and the proportion of the TH positive neurons in the substantia nigra compact were both less in the aged rats than in the younger adult ones （ P 〈 0.05 ）. Electron microscopy showed swelling of endoplasmic reticulum and accumulated pigment formation in the TH positive cells of aged rat. Conclusion There may exist a relation between age - related degenerative diseases and the numeral reduction of dopaminergic neurons in the substantial nigra compact of midbrain.