代谢型谷氨酸受体1阻滞剂LY367385对NMDA所致神经元损伤的保护作用

Neuroprotective effects of mGluR1 antagonist LY367385 against NMDA-induced neuronal injury in rat cortical neurons

目的探讨代谢型谷氨酸受体1在神经系统兴奋性损伤中的作用。方法用代谢型谷氨酸受体1特异性阻滞剂LY367385预处理神经元细胞1 h,加入N-甲基-D-门冬氨酸(NMDA)造成兴奋性损伤;采用甲基噻唑基四唑(MTT)比色实验检测细胞活性; LDH试剂盒检测培养基中乳酸脱氢酶(LDH)活性;转移酶介导的三磷酸脱氧鸟苷-生物素刻痕末端标记(TUNEL)法检测细胞凋亡指数;免疫共沉淀和免疫印迹实验检测NMDA受体2B亚基(NR2B)和突触后致密物质95(PSD95)相互作用。结果 MTT、LDH和TUNEL实验显示,LY367385能减轻NMDA造成的神经元损伤(P <0. 05);免疫共沉淀和免疫印迹实验显示,NMDA受体与PSD95存在相互关系,LY367385可以减轻兴奋性损伤造成的NMDAR-PSD95表达增高(P <0. 05)。结论 LY367385能够明显减轻NMDA造成的神经元损伤,其机制可能与阻断代谢型谷氨酸受体1可以减少NMDA受体与PSD95连接相关。

Objective The role of metabotropic glutamate receptors 1 in the excitotoxic neuronal injury was investigated. Methods Neurons were pretreated with a specific metabotropic glutamate receptor 1 antagonist LY367385 for 1 h before exposed to N-methyl-D-aspartic acid（NMDA） to cause excitotoxicity. Neuroactivity was measured by methyl thiazolyl tetrazolium（MTT） and the lactate dehydrogenase（LDH） activity was in culture medium was detected with LDH detection kit. Apoptosis index of neurons was measured by transferase-mediated deoxyuridine triphosphate-biotin nick end labeling（TUNEL） assay. The interactions of NMDA receptor 2 B（NR2 B）and postsynaptic density 95（PSD95） were detected by co-immunoprecipitation and Western blotting. Results MTT,LDH and TUNEL experiments indicated that LY367385 might reduce NMDA-induced neuronal injury. Coimmunoprecipitation and Western blotting showed that NMDA receptors and PSD95 might interact with each other,and LY367385 could reduce the increased expression of NMDAR-PSD95 caused by NMDA-induced excitotoxicity.Conclusion LY367385 can attenuate NMDA-induced neuronal excitotoxicity significantly,which may be related to the reduced connection between NMDA receptor and PSD95 by blocking metabotropic glutamate receptor 1.