蛋白酶体抑制剂诱导多巴胺能神经元变性及诱导型一氧化氮合酶变化

目的探讨蛋白酶体（proteasome）功能下降在帕金森病（PD）发病机制中的作用，以及模型大鼠脑内黑质部位诱导型一氧化氮合酶（iNOS）是否参与蛋白酶体抑制剂Lactacystin诱导的多巴胺能神经元变性。方法将30只健康雄性SD大鼠分为5组（生理盐水对照组，1d组、3d组、1周组、3周组），每组6只。将蛋白酶体抑制剂Lactacystin立体定向注射至大鼠黑质部位，记录大鼠在不同时间点的行为学改变，并用免疫组化方法观察生理盐水对照组及不同时间点组（1d、3d，1周、3周）大鼠黑质区多巴胺能神经元变性及iNOS变化。结果Lactacystin注射1周后大鼠开始出现自发性活动减少，阿朴吗啡可诱导出旋转行为；3周后，30min旋转次数为258．90±11．56；实验3周组黑质部位TH阳性细胞减少。1d后iNOS阳性细胞明显增多，3d时达高峰，1周后开始下降，3周时基本消失。结论蛋白酶体功能下降可能是多巴胺能神经元变性的始动因素，而iNOS上调可能是多巴胺能神经元变性的重要过程。

Degeneration of dopaminergic neurons and changes of inducible nitric oxide synthase induced by a proteasome inhibitor

Objective To investigate the role ofproteasomal dysfunction in the pathogenesis of Parkinson disease and whether the changes of inducible nitric oxide synthase in the substantia nigra of model rats are involved in the degeneration of dopaminergic （DA） neurons induced by proteasome inhibitor lactacystin. Methods Thirty healthy SD male rats are equally divided into 5 groups （saline control and 1-day, 3-day, 1-week and 3-week groups）. Lactacystin was stereotaxically infused unilaterally into the substantia nigra of the rats, and the behavioral alterations of rats at different time points were recorded. The degeneration of DA neurons and the changes of inducible nitric oxide synthase in the substantia nigra of all the groups were detected by immunohistochemistry. Results The rats presented with reduction of spontaneous activity and apomorphine-induced contralateral rotation on the 7th day after lactacystin injection. On the 2 lth day after the injection of lactacystin, the number of apomorphine-induced contralateral rotations in 30 minutes was 258.90 ± 1.56. The number of TH-positive cells in the central nervous system was decreased significantly in the 3-week group. The numbers of iNOS positive cells in the central nervous system was increased dramatically after 1 day with lactacystin injection and peaked on the 3rd day, started to decrease on the 7th day and virtually disappeared at the 21th day. Conclusion The dysfunction of proteasome may play a trigger role in the pathogenesis of Parkinson disease. Up-regulation of iNOS may be one of the crucial mechanisms in Lactacystin-induced degeneration of DA neurons.