HTD4010可减轻脓毒症心肌病小鼠的心肌损伤:基于促进AMPK/mTOR信号通路介导的自噬

HTD4010 attenuates myocardial injury in mice with septic cardiomyopathy by promoting autophagy via the AMPK/mTOR signaling pathway

目的探究HTD4010对脂多糖(LPS)所致脓毒症心肌病(SCM)小鼠的作用及潜在机制。方法将45只雄性ICR小鼠随机分为3组:对照组、LPS组(10 mg/kg)和LPS+HTD4010组(LPS注射后的1 h和6 h分别皮下注射2.5 mg/kg HTD4010),15只/组。采用超声评价小鼠心功能,HE染色观察心肌组织病理变化,酶联免疫吸附试验检测小鼠血清和心肌组织中炎症因子IL-6和TNF-α的含量,TUNEL染色检测心肌细胞凋亡水平,蛋白免疫印迹法检测小鼠心肌组织中凋亡相关蛋白、自噬相关蛋白及AMPK/mTOR信号通路相关蛋白的表达水平,透射电镜观察心肌线粒体超微结构。结果与对照组相比,LPS组心肌病理损伤严重,有不同程度心肌纤维断裂及排列结构的紊乱、炎性细胞的浸润和线粒体损伤,心脏LVEF、FS值显著降低(P<0.01),血清和心肌组织中IL-6和TNF-α显著升高(P<0.01),心脏组织细胞凋亡率显著升高(P<0.01),Bax、p-62、p-mTOR蛋白表达升高(P<0.05),Bcl-2、LC3Ⅱ/Ⅰ、Beclin-1、p-AMPK蛋白表达降低(P<0.05或P<0.01)。与LPS组相比,LPS+HTD4010组心肌病理损伤明显减轻,心脏LVEF、FS值显著升高(P<0.01),血清和心肌组织中IL-6和TNF-α显著降低(P<0.01),心肌组织细胞凋亡率显著减少(P<0.01),Bax、p-62、p-mTOR蛋白表达降低(P<0.01,P<0.05),Bcl-2、LC3Ⅱ/Ⅰ、Beclin-1、p-AMPK蛋白表达升高(P<0.05或P<0.01)。结论HTD4010能够减轻SCM小鼠的心肌损伤,其机制可能与通过AMPK/mTOR信号通路促进自噬有关。

Objective To investigate the protective effects of HTD4010 against lipopolysaccharide(LPS)-induced septic cardiomyopathy(SCM)in mice and explore the mechanisms mediating its effect.Methods Forty-five male ICR mice were randomized equally into control group,LPS(10 mg/kg)group,and LPS+HTD4010 group(in which 2.5 mg/kg HTD4010 was injected subcutaneously at 1 h and 6 h after LPS injection).Cardiac function of the mice was evaluated by ultrasound,and pathological changes in the myocardial tissues were observed with HE staining.The levels of IL-6 and TNF-αin serum and myocardial tissues were detected using ELISA,and apoptosis of the cardiomyocytes was detected with TUNEL staining.The expression levels of the key proteins associated with apoptosis,autophagy and the AMPK/mTOR pathway in the myocardial tissues were detected using Western blotting.The ultrastructural changes of cardiac myocardial mitochondria was observed with transmission electron microscopy.Results LPS exposure caused severe myocardial damage in mice,characterized by myocardial fiber rupture,structural disorder,inflammatory cell infiltration,and mitochondrial damage.The LPS-treated mice exhibited significantly decreased cardiac LVEF and FS values,elevated IL-6 and TNF-αlevels in serum and myocardial tissue,and an increased myocardial cell apoptosis rate with enhanced expressions of Bax,p-62 and p-mTOR and lowered expressions of Bcl-2,LC3 II/I,Beclin-1 and p-AMPK(P<0.05 or 0.01).Treatment of the septic mice with HTD4010 significantly alleviated myocardial damage,increased LVEF and FS values,reduced IL-6 and TNF-αlevels in serum and myocardial tissue,decreased cardiomyocyte apoptosis,lowered myocardial expressions of Bax,p-62 and p-mTOR,and increased Bcl-2,LC3 II/I,Beclin-1 and p-AMPK expressions(P<0.05 or 0.01).Conclusion HTD4010 can attenuate myocardial injury in SCM mice possibly by promoting autophagy via modulating the AMPK/mTOR signaling pathway.