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目的探讨脑缺血再灌注大鼠半暗带皮质中谷氨酸受体相互作用蛋白(GRIP)表达变化的规律。方法 SD雄性大鼠,随机分为脑缺血2h后再灌注1、3、6、12、24、72h组和假手术组(每组6只大鼠),采用线栓-再通法制作大脑中动脉闭塞模型,于再灌注后相应时间点处死大鼠取脑,免疫组织化学方法观察GRIP在皮质中的表达及分布,免疫荧光双标记法观察GRIP阳性神经元与谷氨酸受体2(GluR2)阳性神经元的关系。结果假手术组大鼠皮质内罕见GRIP阳性神经元,缺血再灌注3h后大鼠半暗带皮质中GRIP阳性神经元数量明显增加,早期主要为树突阳性染色,后期主要为胞体阳性染色。免疫荧光双标记结果显示,GRIP与GluR2在皮质神经元中表现为共定位。结论脑缺血再灌注后半暗带皮质中GRIP蛋白表达增加,加速GluR2受体向突触后膜的转运,可能是保护半暗带中神经元免于α-氨基羟甲基恶唑丙酸(AMPA)受体介导的兴奋性损伤的重要因素。
Objective To investigate the changes of glutamate receptor interacting protein (GRIP) expression in the penumbra of cerebral ischemia-reperfusion rats. Methods Male Sprague-Dawley rats were randomly divided into 3 groups: 1, 2, 6, 12, 24 and 72 h after reperfusion and sham operation group (6 rats in each group) 2h after cerebral ischemia. Middle cerebral artery occlusion model. The rats were sacrificed at the corresponding time point after reperfusion, and the expression and distribution of GRIP in the cortex were observed by immunohistochemistry. The expressions of GRIP positive neurons and glutamate receptor 2 ( GluR2) positive neurons. Results The number of GRIP positive neurons in the cortex of rats in sham-operation group was rare. The number of GRIP-positive neurons in penumbra cortex of rats in sham-operated group increased obviously. The dendritic positive staining in early stage and the positive cell body staining later. Immunofluorescence double-labeled results showed that GRIP and GluR2 showed co-localization in cortical neurons. Conclusions The expression of GRIP protein in the cortex of the penumbra increases after cerebral ischemia and reperfusion, and accelerates the transport of GluR2 receptor to the postsynaptic membrane. It may be that the neurons in the penumbra are protected from the α-amino hydroxymethyl oxazole propionic acid (AMPA) receptor-mediated excitatory injury.