背景:缺血再灌注(IR)导致心肌功能受损,自噬激活可改善心肌IR损伤。已发现异甘草素(ISO)通过AMPK保护心肌组织,通过自噬激活发挥抗肿瘤作用。本研究旨在探讨ISO通过AMPK/mTOR/ULK1信号介导的自噬激活减轻心肌IR的能力。
方法:观察SD大鼠和H9c2细胞对ISO的影响。通过结扎左冠状动脉前降支(LAD)和缺氧/复氧来建立IR大鼠和IR诱导的H9c2细胞模型,分别,其次是低,ISO干预的中等和高剂量(大鼠:10、20和40mg/kg;H9c2细胞:1、10和100μmol/L)。用心肌功能相关指标评估大鼠心肌组织损伤,HE染色,Masson三色染色,TTC染色,和ELISA。透射电镜(TEM)和免疫荧光法检测H9c2细胞的自噬。Westernblot检测自噬相关蛋白和AMPK/mTOR/ULK1通路相关蛋白的表达。
结果:ISO治疗导致心肌功能改善,和抑制心肌炎性浸润,纤维化,梗死面积,氧化应激,CK-MB,cTnI,和cTnT在IR大鼠中的表达。在IR建模的H9c2细胞中,ISO处理降低了细胞凋亡率,激活了自噬和LC3荧光表达。体内和体外,ISO干预表现出增强的Beclin1,LC3II/LC3I,和p-AMPK/AMPK水平,而抑制P62,p-mTOR/mTOR和p-ULK1(S757)/ULK1蛋白表达,激活自噬,保护心肌组织免受IR损伤。
结论:ISO治疗可能通过调节AMPK/mTOR/ULK1信号,从而改善心肌IR损伤,作为治疗心肌IR损伤的潜在候选者。
BACKGROUND: Ischemia reperfusion (IR) causes impaired myocardial function, and autophagy activation ameliorates myocardial IR injury. Isoliquiritigenin (ISO) has been found to protect myocardial tissues via AMPK, with exerting anti-tumor property through autophagy activation. This study aims to investigate ISO capacity to attenuate myocardial IR through autophagy activation mediated by AMPK/mTOR/ULK1 signaling.
METHODS: ISO effects were explored by SD rats and H9c2 cells. IR rats and IR-induced H9c2 cell models were established by ligating left anterior descending (LAD) coronary artery and hypoxia/re-oxygenation, respectively, followed by low, medium and high dosages of ISO intervention (Rats: 10, 20, and 40 mg/kg; H9c2 cells: 1, 10, and 100 μmol/L). Myocardial tissue injury in rats was assessed by myocardial function-related index, HE staining, Masson trichrome staining, TTC staining, and ELISA. Autophagy of H9c2 cells was detected by transmission electron microscopy (TEM) and immunofluorescence. Autophagy-related and AMPK/mTOR/ULK1 pathway-related protein expressions were detected with western blot.
RESULTS: ISO treatment caused myocardial function improvement, and inhibition of myocardial inflammatory infiltration, fibrosis, infarct area, oxidative stress, CK-MB, cTnI, and cTnT expression in IR rats. In IR-modeled H9c2 cells, ISO treatment lowered apoptosis rate and activated autophagy and LC3 fluorescence expression. In vivo and in vitro, ISO intervention exhibited enhanced Beclin1, LC3II/LC3I, and p-AMPK/AMPK levels, whereas inhibited P62, p-mTOR/mTOR and p-ULK1(S757)/ULK1 protein expression, activating autophagy and protecting myocardial tissues from IR injury.
CONCLUSIONS: ISO treatment may induce autophagy by regulating AMPK/mTOR/ULK1 signaling, thereby improving myocardial IR injury, as a potential candidate for treatment of myocardial IR injury.