蛋白酶体抑制剂诱导大鼠黑质变性伴包涵体形成

目的 观察蛋白酶体抑制剂Lactacystin诱导大鼠黑质变性伴包涵体形成及运动行为学的改变,探讨蛋白酶体功能下降在帕金森病(PDl发病机制中的作用. 方法 24只SD大鼠采用随机数字表法分为kactacystin实验组和生理盐水组.每组12只,Lactacystin实验组将蛋白酶体抑制剂Lactacystin立体定向注射人大鼠左侧黑质致密部(SNc).生理盐水组注射等体积生理盐水;观察大鼠自主行为和阿朴吗啡(APO)诱导的旋转行为的改变;Nissl染色法观察SNc病理改变;免疫组化法观察SNc及纹状体酪氨酸羟化酶(TH)和SNc中α-共核蛋白的表达;透射电镜观察SNc超微结构的改变. 结果 Lactacystin实验组大鼠给药7 d后出现自发性活动减少、动作缓慢、震颤、且症状逐步加重.APO可诱导出向健侧的旋转运动;Nissl染色发现Lactacystin实验组左侧SNc神经元数量减少,尼氏体结构松散;免疫组化结果表明21 d后Lactacystin实验组左侧SNc出现变性,TH免疫阳性神经元数量减少,α-共核蛋白表达增强,纹状体内TH免疫阳性纤维数量减少;电镜观察到蛋白质聚集形成的包涵体. 结论 Lactacystin单侧SNc注射可以诱导大鼠黑质变性伴包涵体形成及大鼠行为改变.蛋白酶体功能下降可能在PD发病机制中起重要作用.

Proteasome inhibitor induces substantia nigra degeneration and inclusion body formation in rats

Objective To observe nigral degeneration with inclusion body formation in rats and their behavioral changes after treatment with proteasome inhibitor, and investigate the role ofproteasomal dysfunction in the pathogenesis of Parkinson disease. Methods Lactacystin, a selective proteasome inhibitor, was injected stereotaxically into the lett substantia nigral pars compacta of the rats, and an equal volume of saline was injected in the control group. Spontaneous behavioral abnormalities and apomorphine-induced contralateral rotations of the rats were observed after the injection. The pathological changes in the substantia nigra were detected using Nissl staining, and the expressions of tyrosine hydroxylase (TH) and a-synuclein in the substantia nigra and TH expression in the striatum were investigated by immunohistochemistry. The ultrastructural changes in the substantia nigral pars compacta were observed with transmission electron microscope. Results Seven days after lactacystin injection, the rats exhibited reduced apontaneous activities, tremor, progressive bradykinesia, and apomorphine-induced contralateral rotation. Nissl staining 3 weeks after lactacystin injection revealed significantly reduced neurons in the lett substantia nigra pars compacta and loosened structures of the Nissl bodies;immunohistochemistry demonstrated obvious degeneration in the lett substantia nigra pars compacta, where the TH-positive cells were significantly decreased with enhanced expression of a-synuclein. The number of TH-positive fibers in the striamm was significantly reduced 3 weeks afterlactacystin injection, and electron microscopy revealed the formation of inclusion bodies as a result of protein aggregation. Conclusion Lactacystin injected stereotaxically into the lett substantia nigrai pars compacta can induce substantia nigra degeneration, inclusion body formation and behavioral changes in rats, suggesting the applicability of lactacystin for establishment of animal models of Parkinson disease. Proteasomal dysfunction may play an important role in the pathogenesis of Parkinson disease.