柚皮素对心肌缺血/再灌注损伤大鼠PI3K/AKT信号通路和内质网应激及其相关凋亡通路的影响

Effects of naringenin on PI3K/AKT signaling pathway and endoplasmic reticulum stress and its related apoptotic pathways in rats with myocar⁃dial ischemia/reperfusion injury

目的:观察柚皮素对缺血/再灌注(I/R)大鼠心脏损伤的影响,并探讨柚皮素的作用是否涉及PI3K/AKT信号通路和内质网应激及其相关凋亡通路。方法:48只SD大鼠按随机数字表法分成假手术组(sham组)、模型组(I/R组)、柚皮素处理组(NAR组)和柚皮素处理+LY294002组(NL组)。结扎大鼠冠状动脉左前降支30 min再灌注120 min制备心肌I/R模型。ELISA法检测血清中心肌肌钙蛋白I(cTnI)的含量;HE染色、TTC染色及TUNEL染色分别检测心肌组织病理学变化、心肌梗死面积和心肌细胞凋亡率;RT-qPCR法检测内质网应激相关指标葡萄糖调节蛋白78(GRP78)、C/EBP同源蛋白(CHOP)和caspase-12的mRNA表达;Western blot法检测cleaved caspase-3、GRP78、CHOP、caspase-12、p-PI3K和p-AKT的蛋白水平。结果:与I/R组比,NAR组大鼠血清cTnI的含量显著下降(P<0.05),心肌病理损伤减轻,心肌梗死面积和细胞凋亡率显著减少(P<0.05),cleaved caspase-3、GRP78、CHOP和caspase-12表达降低(P<0.05),p-PI3K和p-AKT蛋白水平升高(P<0.05);LY294002能在一定程度上削弱柚皮素的保护效应。结论:柚皮素能减轻大鼠心肌I/R损伤,其机制可能是通过激活PI3K/AKT信号通路进而调控内质网应激及其相关凋亡通路。

AIM:To observe the effect of naringenin on cardiac injury in ischemia/reperfusion(I/R)rats,and to explore whether the role of naringenin is involved in PI3K/AKT signaling pathway and endoplasmic reticulum stress and its related apoptotic pathways.METHODS:SD rats(n=48)were randomly divided into sham operation(sham)group,model(I/R)group,naringenin treatment(NAR)group and naringenin+LY294002(NL)group.Myocardial I/R injury model was prepared by ligation of left anterior descending coronary artery of rats for 30 min followed by reperfusion for 120 min.After reperfusion,the serum levels of cardiac troponin I(cTnI)was measured by ELISA.HE staining,TTC staining and TUNEL staining were used to detect the myocardial histopathological changes,myocardial infarction area and myocardial cell apoptotic rate.The mRNA levels of endoplasmic reticulum stress-related indicators glucose-regulated protein 78(GRP78),C/EBP homologous protein(CHOP)and caspase-12 were detected by RT-qPCR.The protein levels of cleaved caspase-3,GRP78,CHOP,caspase-12,p-PI3K and p-AKT were determined by Western blot.RESULTS:Compared with I/R group,the serum content of cTnI,myocardial pathological damage,myocardial infarction area and myocardial cell apoptotic rate were significantly reduced(P<0.05),the protein levels of cleaved caspase-3,GRP78,CHOP and caspase-12 were decreased(P<0.05),and the protein levels of p-PI3K and p-AKT were increased in NAR group(P<0.05).LY294002 attenuated the protective effect of naringenin to some extent.CONCLUSION:Naringenin reduces myocardial I/R injury in rats possibly by activating PI3K/AKT signaling pathway and subsequently regulating endoplasmic reticulum stress and its related apoptotic pathways.