NMDA受体NR2A亚基在脑缺血后处理中的保护作用

Neuroprotective effect of NMDA receptor NR2A subunit in brain ischemic postconditioning

①目的研究NMDA受体NR2A亚基在脑缺血后处理中的保护作用。②方法采用四动脉阻塞模型((four-vessel occlusion,4-VO)大鼠全脑缺血(global cerebral ischemia,GCI)模型,动物随机分为假手术组(sham),Sh+NVP-A组,缺血再灌注组(I/R),缺血后处理组(Postc,Postc+Veh),NR2A抑制剂组(Postc+NVP),溶剂对照组。采用Western blot法检测大鼠海马CA1区NR2A的表达,采用焦油紫染色观察大鼠海马CA1区神经元的存活情况。③结果焦油紫染色显示:与I/R组相比,Postc组再灌注5d海马CA1区存活的神经元显著增加(P<0.05),而NR2A抑制剂NVPAAM077可显著废除Postc的神经保护作用,海马CA1区存活的神经元显著减少(P<0.05)。与I/R组相同时间点相比,Postc组海马CA1区神经元细胞膜NR2A的蛋白表达于缺血后处理后的3h,6h,24h和72h显著增加,而NR2A抑制剂可显著抑制缺血后处理后24h NR2A的蛋白水平的升高(P<0.05)。④结论 NR2A亚基在脑缺血后处理中具有神经保护作用。

Objective To investigate the role of NMDA receptor NR2A subunit in the neuroprotection induced by cerebral iscbemic postconditioning. Methods The SD rats were subjected to global cerebral ischemia by four - vessel occlusion and randomly divided into five groups：sham,ischemia/reperfusion（I/R） ,ischemic postconditioning（Postc） , NVPAAM077 （a specific inhibitor of NR2A） ,vehicle（ I/R ＋ 1% DMSO）. Cresyl violet was used to observe neuronal damage and the protein level of NR2A was detected by Western blotting in hippocampal CA1 region. Results Cresyl violet staining showed that in Postc group the number of surviving neurons after 5d reperfusion significantly increased compared with I/R group in hippocampal CA1 region（P 〈 0.05 ）, more importantly NVPAAM077 almost abolished the neuroprotective role induced by Postc. Compared with I/R group at the same time point, protein expression of NR2A at 3h,6h,24h or 72h after Postc was significantly increased in hippocampal CAI region（P 〈0. 05 ） ,whereas the NR2A inhibitor significantly inhibited the increase at 24h after Postc （ P 〈 0. 05 ）. Conclusion NMDA receptor NR2A subunit plays a neuroprotective role in cerebral isehemic postconditioning.