脑室内注射胰岛素对全脑缺血后大鼠海马CA1区Bcl-xL蛋白表达及神经元凋亡的影响

The effect of intraventricular administration of insulin on expression of Bcl-xL protein and apoptosis of neuron in rat hippocampal CA1 region

目的 :探讨胰岛素对全脑缺血后海马 CA1区 Bcl x L 蛋白表达及神经元凋亡的影响。方法 :利用四血管闭塞法制作全脑缺血大鼠模型。造成脑缺血 15分钟后行再灌注 ,于再灌注后即刻经脑室注入 1U胰岛素 ,利用免疫组织化学及原位标记法分别于全脑缺血后 1、3日观察海马 CA 1区 Bcl x L蛋白表达及神经元凋亡的情况。结果 :全脑缺血后 1日 ,缺血组及胰岛素治疗组鼠海马 CA1区未见原位标记阳性细胞。治疗组鼠海马 CA1区可见呈阳性表达的 Bcl x L 蛋白 ,而缺血组鼠海马 CA1区 Bcl x L 蛋白的表达则呈阴性。全脑缺血后 3日 ,缺血组鼠海马 CA1区 Bcl x L 蛋白的表达仍呈阴性 ,海马 CA1区原位标记阳性细胞计数为 ( 14 3 .5±11.6)个。治疗组鼠海马 CA1区 Bcl x L 蛋白呈阳性表达 ,海马 CA1区原位标记阳性细胞计数为 ( 75 .6± 6.7)个。结论 :全脑缺血后脑室内注入胰岛素具有促进海马 CA1区 Bcl x L 蛋白表达及减少神经元凋亡的中枢直接保护作用。

Objective:To investigate the effect of insulin administration on the expression of BclxL protein and the apoptosis of neuron in rat hippocampal CA1 region following global brain ischemia.Methods:Fourvessel occlusion was used to establish the rat global brain ischemic model.After 15 minutes brain ischemia,1 U insulin was injected into the brain ventricular immediately after reperfusion.The expression of BclxL protein and the apoptosis of neuron in hippocampal CA1 region were detected by immunocytochemistry and in situ endlabeling (ISEL) method,respectively.Results:There were no positive ISEL labeled cells detected in either ischemic group or treatment group.The expression of BclxL protein was negative in ischemic group,and it was positive in treatment group,on day one post brain ischemia.On day three post brain ischemia,the expression of BclxL protein was still negative in ischemic group and the count of positive cells labeled by ISEL method was 143.5±11.6,while the expression of BclxL protein was positive in treatment group and the count of positive cells labeled by ISEL method was 75.6±6.7.Conclusions:Intraventricular administration of insulin can improve the expression of BclxL protein and reduce the apoptosis of neuron in rat hippocampal CA1 region following global brain ischemia.