慢性低灌注脑缺血损伤中GABA_B受体激动剂通过调节自噬介导的神经元保护作用的机制研究

发布时间：2018-11-16 15:07

【摘要】：目的：本实验旨在观察慢性低灌注脑缺血(2VO)大鼠海马CA1区自噬水平变化对神经元凋亡的影响,探讨2VO大鼠海马CA1区GABAB受体、GABAA受体和自噬相互关联及其可能的作用机制。方法：采用大鼠双侧颈总动脉永久性结扎慢性低灌注脑缺血模型；应用水迷宫实验评价其认知功能的变化：采用免疫荧光技术检测自噬表达和分布的变化；采用HE染色观察海马形态学改变及CA1区神经元丢失情况；TUNEL染色检测神经元凋亡；Western blot检测相关蛋白的变化：①LC3-Ⅱ、p-mTOR、Beclin 1等自噬相关蛋白；Bcl-2和cleaved caspase-3等凋亡相关蛋白；③GABAA受体；④Akt、GSK-3p和ERK1/2；⑤线粒体和细胞膜上缝隙连接蛋白CX43、 CX36;⑥自噬体转运相关蛋白MAPK8IP1/JIP1、DUSP1/MKP1;⑦溶酶体相关蛋白LAMP-1、cathepsin L。结果：2VO模型组大鼠空间学习记忆能力受损；海马皱缩、CA1区神经元数量显著减少、自噬水平显著增加且分布紊乱；Bcl-2/Bax比率降低,cleaved caspase-3增多：GABAA受体膜表达减少；线粒体和胞膜上的CX43和CX36表达增加。GABAB受体激动剂baclofen可明显减轻神经元损伤。同时,baclofen可上调Bcl-2/Bax比率、激活Akt、GSK-3β和ERK而抑制细胞破坏性自噬。另外,我们还发现baclofen可改善慢性低灌注脑缺血引起的GABAA受体膜表达减少,进而下调细胞膜及线粒体膜CX43和CX36的表达,促进保护性自噬。我们的实验还发现,baclofen可改善2VO诱导大鼠海马CA1区自噬体逆向轴突运输障碍和溶酶体功能受损,其具体机制还有待进一步研究。结论：在慢性低灌注脑缺血情况下,激动GABAB受体通过双重调节自噬、改善自噬体逆向转运障碍、恢复溶酶体功能而减轻神经元损伤及认知功能障碍。
[Abstract]:Aim: to investigate the effect of autophagy on apoptosis of hippocampal CA1 in rats with chronic hypoperfusion cerebral ischemia (2VO), and to explore the relationship among GABAB receptor, GABAA receptor and autophagy in CA1 area of 2VO rats and its possible mechanism. Methods: the rat model of chronic hypoperfusion cerebral ischemia was established by permanent ligation of bilateral common carotid artery, the changes of cognitive function were evaluated by water maze test, and the changes of autophagy expression and distribution were detected by immunofluorescence technique. Hippocampal morphological changes and neuronal loss in CA1 region were observed by HE staining, and apoptotic; Western blot was detected by TUNEL staining: 1autophagy related proteins such as LC3- 鈪，

本文编号：2335855