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目的探讨凝血酶诱导小胶质细胞激活与黑质多巴胺(DA)能神经元变性的关系。方法采用脑立体定向术将凝血酶注射入大鼠黑质,采用尼氏(Nissl)染色、酪氨酸羟化酶(TH)及特异性小胶质细胞表面补体受体(CR3)单克隆抗体(OX-42)标记免疫组织化学染色,观察凝血酶注射入大鼠黑质后不同时间点TH阳性多巴胺能神经元数量及小胶质细胞的激活情况。结果凝血酶注入黑质4h后小胶质细胞开始呈现“灌木丛样”或少量呈现阿米巴样;12h小胶质细胞数目明显增加且绝大部分呈现阿米巴样;24h已完全激活,“阿米巴样”细胞达高峰;3d维持高峰;14d后小胶质细胞染色变淡,体积变小,阿米巴样细胞数目下降。TH阳性细胞数在第3d开始下降,第7d有大量的TH阳性细胞丢失,与对照侧相比下降达约53%(P<0.01),高倍镜下可见胞体皱缩、突起明显缩短或减少,14d时细胞数下降至21%,30d时约为12%(P<0.01)。结论凝血酶对DA能神经元具有一定的损毁作用,小胶质细胞的激活先于DA能神经元变性,其活化可能参与DA能神经元变性。
Objective To investigate the relationship between thrombin-induced microglial activation and degeneration of dopaminergic neurons in substantia nigra. Methods Thrombin was injected into the substantia nigra of rats by stereotactic technique. Nissl staining, tyrosine hydroxylase (TH) and monoclonal antibody against specific microglial surface complement receptor (CR3) (OX-42) immunohistochemical staining was performed to observe the number of TH positive dopaminergic neurons and the activation of microglial cells at different time points after thrombin injection into rat substantia nigra. Results After 4h injection of thrombin into the substantia nigra, microglia began to show “shrub-like” or a small amount of amoeba-like; 12h microglia significantly increased and most of the amoeba-like; 24h completely Activated, “” amoeba-like "cells peaked; 3d peak; 14d after microglial staining fades, smaller, amoeba-like cells decreased. The number of TH positive cells began to decrease at the 3rd day. On the 7th day, a large number of TH positive cells were lost, about 53% (P <0.01) decreased compared with the control side. Under high magnification, the cell body was shrunk and the protrusions were significantly shortened or reduced. The number of cells decreased to 21% on day 14 and 12% on day 30 (P <0.01). Conclusion Thrombin has a certain damaging effect on DA neurons. The activation of microglia precedes the denaturation of DA neurons, which may be involved in the degeneration of DA neurons.