蛋白酶体抑制剂诱导多巴胺能神经元变性伴包涵体形成

The degeneration of dopaminergic neuron and inclusion-like formation induced by the inhibitor of proteasome

目的观察蛋白酶体抑制剂诱导黑质多巴胺(DA)能神经元变性伴胞浆内包涵体形成,探讨蛋白酶体功能在帕金森病发病机制中的作用。方法将蛋白酶体抑制剂Lactacystin立体定向注射至大鼠黑质部位。免疫荧光观察黑质区DA神经元变性缺失及胶质细胞变化。免疫荧光双标法观察DA能神经元内蛋白聚集的包涵体及其主要成分α-共核蛋白(α-synuclein)、Parkin和泛素(ubiquitin)的表达。同时观察DA能神经元发生细胞凋亡。结果注射Lactacystin第7天大鼠开始出现自发性活动减少,阿扑吗啡可诱导出旋转行为;3周后黑质部位酪氨酸羟化酶(TH)阳性细胞减少,呈剂量依赖性;小胶质细胞增生明显。TH与硫磺素、硫磺素与α-synuclein、硫磺素与Parkin、以及硫磺素与ubiquitin复合染色呈阳性;TH与TUNEL双染亦呈阳性。结论Lactacystin对多巴胺能神经元具有毒性作用,且导致蛋白聚集,包涵体形成。蛋白酶体功能异常可能在帕金森发病机制中起重要作用。

Objective To observe the degeneration of dopaminergic neuron and inclusion-like formation induced by the inhibitor of proteasome in the substantia nigra,and to investigate the role of ubiquitin proteasome system (UPS) in the pathogenesis of Parkinson's disease.Methods Lactacystin, a proteasome inhibitor,was unilateral infused stereotaxically into the substantia nigra of rats.The loss of dopaminergic neurons and the secondary change of glia activity induced by Lactacystin in the substantia nigra were detected by imunofluorescence staining.The double labeling fluorescence staining was used to observe costain of TH and Thioflavine,Thioflavine and α-synuclein/ Parkin/ ubiquitin.The apoptosis of neurons was also examined by double TH and TUNEL stain.Results The rats began to display spontaneous and apomorphine induced rotation 7 days after Lactacystin injection into the substantia nigra.On the 21 day after the injection of Lactacystin,the loss of TH positive neurons in substantia nigra was observed in the dose-dependent manner,with the microglia activated.The colocalization positive neurons of TH and Thioflavine,Thioflavine and α-synuclein/Parkin/ ubiquitin was observed in the imaging of double labeling immunofluorescence.The TUNEL positive neurons were also observed to express TH with double staining.Conclusions Lactacystin is neurotoxic to dopaminergic neurons,with the protein aggregation and inclusion-like formation.UPS maybe act as a main role in the pathogenesis of Parkinson's disease.