脑缺血再灌注大鼠半暗带皮质谷氨酸受体相互作用蛋白表达的增加

Increase of glutamate receptor interacting protein in the penumbra cortex of rats after transient ischemia and reperfusion

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 explore the expression of glutamate receptor interacting protein （GRIP） after isehemiareperfusion in the rat brain. Methods Seventy-two male Sprague Dawley rats were randomly divided into 6 isehemia- reperfusion groups and sham groups with 6 rats per group. Middle cerebral artery occlusion （MCAO） was achieved with the use of an intraluminal filament to occlude the left middle eerebral artery, and reperfused 2 hours later. At the 1st, 3rd, 6th, 12th, 24th and 72th hour after reperfusion or sham operation, the rats from each group were decapitated. Immunohistochemistry and double immunofluoreseenee were used to observe the distribution of GRIP in the cortex and also its relationship with glutamate receptor 2 （GluR2）. Results Compared with the sham-operated group which showed few positive neurons, GRIP positive neurons increased obviously from 3 hours after isehemia-reperfusion in the ischemic penumbra cortex, mainly on the dendrites at the early stage and moved to the cell body lately. Double immunohistochemical staining showed that the GRIP positive cells were co-stained with GluR2 neurons. Conclusion GRIP increased and accelerated to transfer GluR2 to the membrane after isehemia-reperfusion which may protect the neurons in the penumbra zone from the AMPA receptor mediated exeitotoxie injury.