自噬在雌激素保护大鼠脑缺血再灌注损伤中的作用研究

Effects of autophagy on the estrogen protection in cerebral ischemia-reperfusion injury in rats

目的:探讨自噬在雌激素保护脑缺血再灌注损伤(CIRI)中的作用。方法:雌性SD大鼠去势后建立CIRI模型,按随机数字表法分为A组(不进行CIRI模型建立,等量生理盐水干预)、B组(进行CIRI假手术,等量生理盐水干预)、C组(CIRI模型大鼠,等量生理盐水干预)和D组(CIRI模型大鼠,腹腔注射100μg/kg雌激素);ELASA法测定各组大鼠血清中雌激素、白细胞介素-6(IL-6)和细胞间黏附分子-1(ICAM-1)的含量;Shohami法对各组大鼠进行神经功能评分;TTC染色测定各组大鼠测定脑梗死体积;透射电镜法观察大脑皮层细胞的超微结构及其自噬小体数目的变化;Western blotting检测缺血侧脑组织自噬相关蛋白Beclin1、LC3Ⅱ、P62的表达。结果:与A组相比,C组和D组的雌激素水平均显著降低(P<0.05),IL-6和ICAM-1含量以及神经缺损功能评分均显著升高(均P<0.05),而B组与A组相比,差异均无统计学意义(均P>0.05)。与B组相比,C组和D组大鼠的雌激素水平均显著降低,IL-6和ICAM-1含量、脑梗死体积、神经缺损功能评分、自噬小体数目、自噬相关蛋白Beclin1、LC3Ⅱ和P62表达显著增加(均P<0.05)。与C组相比,D组的雌激素水平显著升高,IL-6和ICAM-1含量、脑梗死体积、神经缺损功能评分、自噬小体数目、自噬相关蛋白Beclin1、LC3Ⅱ和P62表达显著降低(均P<0.05)。结论:雌激素能够通过促进细胞自噬从而发挥其对CIRI的保护作用。

Objective:To explore the effect of autophagy in the protective effect of estrogen on cerebral ischemia-reperfusion injury(CIRI).Methods:Female SD rats were ovariectomized to establish CIRI model,and were randomly divided into group A(no CIRI model,equal volume of saline intervention),group B(sham CIRI operation,equal volume of saline intervention),group C(CIRI model rats,equal volume of saline intervention)and group D(CIRI model rats,intraperitoneally injected with 100μg/kg estrogen).The contents of estrogen,interleukin-6(IL-6)and intercellular adhesion molecule-1(ICAM-1)in serum of rats in each group were measured by ELASA.The neurological function of rats in each group was scored by Shohami method.The volume of cerebral infarction was measured by TTC staining.The ultrastructure of cerebral cortical cells and the number of autophagosomes were observed by transmission electron microscope.Western blotting was used to detect the expression of autophagy-related proteins Beclin1,LC3Ⅱand P62 in ischemic brain tissue.Results:Compared with group A,the levels of estrogen in group C and group D were significantly lower(P<0.05),the contents of IL-6 and ICAM-1 and the score of neurological deficit function were significantly higher in group C and group D than those in group A(P<0.05),but there was no significant difference between group B and group A(P>0.05).Compared with group B,the level of estrogen in group C and group D decreased significantly,while the content of IL-6 and ICAM-1,the volume of cerebral infarction,the score of neurological deficit function,the number of autophagosomes,the expression of autophagy-related proteins Beclin1,LC3II and P62 increased significantly(P<0.05).Compared with group C,the level of estrogen in group D was significantly higher,while the content of IL-6 and ICAM-1,the volume of cerebral infarction,the score of neurological deficit function,the number of autophagosomes,the expression of autophagy-related proteins Beclin1,LC3II and P62 were significantly decreased(P<0.05).Conclusion:Estrogen can protect CIRI by promoting autophagy.