基于扩张型心肌病大鼠模型研究内质网应激介导细胞凋亡和相关信号转导通路的时相性变化

Time-phase changes of endoplasmic reticulum stress mediated cardiomyocytes apoptosis and related signal transduction pathways in rats model of dilated cardiomyopath

目的:通过观察扩张型心肌病(DCM)大鼠病理发展过程中是否存在内质网应激现象及不同时间点内质网应激引起心肌细胞凋亡和相关信号转导通路的特点,探讨其发病机制。方法:采用呋喃唑酮水溶液诱导DCM模型。心脏彩超检测大鼠心脏功能情况,HE染色检测心肌组织病理变化,TUNEL法检测心肌细胞凋亡率,Western Blot检测内质网应激相关蛋白GRP78、ATF-6、IRE1、IP3R、SERCA2a表达。结果:超声心动图结果显示,与正常组比较,LVEF在造模4、6周差异无统计学意义,随着造模时间延长LVEF逐渐下降,且心室腔扩大,尤以造模后8周和10周显著;Western Blot显示8周开始GRP78、ATF-6、IRE1、IP3R表达显著增加(P<0.05),SERCA2a从6周开始显著降低(P<0.05);TUNEL染色表明,模型组细胞凋亡指数高于正常组,且在造模6周后差异显著(P<0.05,P<0.01)。结论:DCM大鼠病理发展过程中存在内质网应激现象,持续内质网应激可能是导致DCM发生发展的重要机制之一。

Objective:To investigate the pathogenesis of endoplasmic reticulum stress(ERS)in rats with dilated cardiomyopathy(DCM)by observing whether the ERS phenomenon existed during the pathological development,and the characteristics of apoptosis of myocardial cells and related signal transduction pathways caused by ERS at different time points.Methods:DCM model was induced by aqueous solution of furazolidone.Cardiac function was detected by heart echocardiography,myocardial pathological changes were detected by HE staining,cardiomyocyte apoptosis was detected by TUNEL method,and endoplasmic reticulum stress-related protein GRP78,ATF-6,IRE1,IP3R and SERCA2a were detected by Western Blot.Results:The results of echocardiography showed that there was no significant difference in LVEF between the normal group and the control group at the 4th and 6th week of modeling.LVEF decreased gradually with the extension of modeling time,and the ventricular cavity expanded,especially at the 8th and 10th week after modeling.Western Blot showed that the expressions of GRP78,ATF-6,IRE1 and IP3R were significantly,increased after 8 weeks(P<0.05),while SERCA2a was significantly decreased after 6 weeks(P<0.05).TUNEL staining showed that the apoptosis rate of all model groups was higher than that of the control group,and the apoptosis began to increase significantly after 6 weeks(P<0.05,P<0.01).Conclusion:ERS exists in the pathological development of DCM rats,and sustained ERS may be one of the important mechanisms leading to the development of DCM.