基于PI3K/PKB通路研究EGCG对CVB3感染致病毒性心肌炎小鼠细胞凋亡的影响

Effect of EGCG on Apoptosis in Mice with CVB3 Infection-induced Viral Myocarditis Based on the PI3K/PKB Pathway

细胞凋亡是造成病毒性心肌炎(VMC)发病过程中心肌损伤的重要因素;表没食子儿茶素没食子酸酯(EGCG)对缺血再灌注引起的细胞凋亡具有抑制作用,但是否抑制VMC发病过程中的心肌细胞凋亡尚不明确。因此,本研究将分析EGCG对VMC小鼠细胞凋亡的影响及分子机制。BALB/c小鼠随机分为对照组、VMC组(腹腔注射CVB3悬液造模)、VMC+EGCG组(腹腔注射CVB3悬液造模后腹腔注射EGCG)、VMC+EGCG+LY组(腹腔注射CVB3悬液造模后腹腔注射EGCG及PI3K抑制剂LY294002)。检测血清心肌损伤标志物肌钙蛋白I(cTnI)及乳酸脱氢酶(LDH),心肌中CVB3滴度及RNA表达、HE染色、凋亡基因及p-PI3K、p-PKB表达。结果显示,与对照组比较,VMC组血清cTnI、LDH含量、心肌中CVB3滴度及RNA表达、细胞凋亡率、cleaved caspase-3表达升高,心肌中Survivin、p-PI3K、p-PKB表达降低(P<0.05);与VMC组比较,VMC+EGCG组血清cTnI、LDH含量及心肌中细胞凋亡率、cleaved caspase-3表达降低,心肌中Survivin、p-PI3K、p-PKB表达升高(P<0.05),心肌中CVB3滴度及RNA表达无明显变化(P>0.05);与VMC+EGCG组比较,VMC+EGCG+LY组血清cTnI、LDH含量、心肌中细胞凋亡率、cleaved caspase-3表达升高,心肌中Survivin、p-PI3K、p-PKB表达降低(P<0.05),心肌中CVB3滴度及RNA表达无明显变化(P>0.05)。以上结果表明EGCG对VMC小鼠心肌细胞凋亡具有抑制作用且该作用与激活PI3K/PKB通路有关。

Apoptosis is an important factor in viral myocarditis(VMC).Epigallocatechin gallate(EGCG)can inhibit the apoptosis induced by ischemia–reperfusion,but it is not clear whether it can inhibit apoptosis in VMC.Therefore,we analyzed the effect of EGCG on apoptosis in mice suffering from VMC and its molecular mechanism.BALB/c mice were divided randomly into the control group,VMC group(intraperitoneal injection of coxsackievirus B3(CVB3)suspension for modeling),VMC+EGCG group(intraperitoneal injection of EGCG after intraperitoneal injection of CVB3 suspension for modeling),VMC+EGCG+LY group(intraperitoneal injection of EGCG and the PI3 K inhibitor LY294002 after intraperitoneal injection of CVB3 suspension for modeling).We measured:serum levels of cardiac-injury markers(cardiac troponin I(cTnI)and lactate dehydrogenase(LDH));CVB3 titer;RNA expression;hematoxylin and eosin(H&E)staining;expression of apoptosis-related genes,p-PI3 K,and p-PKB.Compared with the control group,the serum level of cTnI and LDH,CVB3 titer,RNA expression,apoptosis rate,and expression of cleaved caspase-3 increased,and expression of survivin,p-PI3 K and p-PKB decreased in the VMC group(P<0.05).Compared with the VMC group,the serum level of cTnI and LDH,apoptosis rate,and expression of cleaved caspase-3 decreased,and expression of survivin,p-PI3 K,and p-PKB increased(P<0.05),but the CVB3 titer and RNA expression did not change significantly,in the VMC+EGCG group(P>0.05).Compared with the VMC+EGCG group,the serum level of cTnI and LDH,apoptosis rate,and expression of cleaved caspase-3 increased,and expression of survivin,p-PI3 K and p-PKB decreased(P<0.05),but the CVB3 titer and RNA expression showed no significant change,in the VMC+EGCG+LY group(P>0.05).These results suggest that that EGCG has an inhibitory effect on cardiomyocyte apoptosis in VMC mice,which is related to the activation of the PI3 K/PKB pathway.