Beclin-1、LC3-Ⅱ在缺血后处理大鼠再灌注中的表达及意义

Expression and significance of BECLIN1 and LC3-Ⅱ in cerebral ischemia reperfusion injury after ischemic postconditioning in rats

目的研究自噬相关蛋白Beclin-1、LC3-Ⅱ在缺血后处理大鼠脑缺血再灌注海马中的表达及意义。方法根据Zea-Longa线栓法制作大脑中动脉缺血再灌注损伤模型,将实验动物随机分为3组:假手术组、缺血再灌注组、缺血后处理组,缺血后处理组再按不同缺血后处理时间分为15 s、30 s、1 min 3个亚组。缺血2 h再灌注24h后用免疫组织化学法检测自噬相关蛋白Beclin-1、LC3-Ⅱ的表达情况,透射电镜观察神经细胞中自噬和溶酶体的激活以及细胞超微结构的变化。结果与缺血再灌注组相比,缺血后处理组神经行为学评分明显降低(P<0.05),脑梗死体积明显减小(P<0.01),Beclin-1、LC3-Ⅱ蛋白表达细胞数明显增加(P<0.01),自噬体形成和溶酶体激活量增加;缺血30 s亚组相比较15 s和1 min亚组上述指标(神经行为学评分除外)(P>0.05),差异亦有显著性(P<0.01)。结论脑缺血后处理的抗缺血再灌注损伤作用可能与上调自噬相关蛋白Beclin-1、LC3-Ⅱ的表达有关。

Objective To study the expression and significance of autophagy-associated protein BECLIN1 and LC3- II in the hippocampus with cerebral ischemia reperfusion injury after ischemic postconditioning in rats. Methods The mid- dle cerebral artery ischemia and reperfusion model was produced by Zea-Longa filamene method, the rats were randomly divided into the following three groups：sham operated group,ischemia reperfusion group and ischemic postconditioning group, the rats in ischemic postconditioning group were subdivided into 15 s subgroup,30 s subgroup and 1 rain subgroup. After ischemia for 2 hours and reperfusion for 24 hours, the samples of each group underwent immunohistochemistry staining to observe the expressions of autophagy-associated protein BECLIN1 and LC3-II, the autophagosomes and lysosomes in neuron cells were observed with transmission electron microscope. Results In ischemic postconditioning group,the neurobehavioral scores and cerebral infarct volume reduced significantly（P 〈 0.05 ,P 〈 0.01 ） ,the cells expression of BECLIN1 and LC3-II protein increased clearly（P 〈 0.01 ）, meanwhile the formation of autophagosome and the activation of lysosome were more obvious, compared with ischemia reperfusion group, the effects of 30 s subgroup except neurobehavioral scores （ P 〉 0. 05 ） were superior to that 15 s subgroup and 1 min subgroup（ P 〈 0.01 ）. Conclusion The effects of ischemic postconditioning against ischemia reperfusion injury may be associated with significant up-regulation of the expression of autophagy-associated protein BECLIN 1 and LC3-II.