ABSTRACT
Objective:To investigate the protective effects and related mechanisms of Astragaloside Ⅳ(ASⅣ)alleviating Angiotensin II-induced cardiomyocyte hypertrophy.Methods:H9c2 cardiomyocytes were divided into six groups: normal control group, ASⅣ group(ASⅣ 100 μmol/L), AngⅡ group(AngⅡ 1 μmol/L), and three ASⅣ dose experiments(AngⅡ 1 μmol/L + ASⅣ 25 μmol/l group, AngⅡ 1 μmol/L+ ASⅣ 50 μmol/l group, AngⅡ1 μmol/L+ ASⅣ 100 μmol/L group), and simultaneously cultured for 24 hours.Cardiomyocyte viability was assessed by CCK8 assay, and surface area of culturedcardiomyocytes in each group was assessed by immunofluorescence assay.Atrial natriuretic peptide(ANP)mRNA expression was assessed by fluorescence real-time quantitative RT-PCR.And LC3 protein expression, an autophagy related protein, was assessed by Western blotting as well as immunofluorescence.Results:(1)AngⅡ decreased cardiomyocyte H9c2 viability in a dose-dependent manner( P<0.05). ASⅣ could inhibit the decrease of cardiomyocyte H9c2 viability in response to AngⅡ in a dose-dependent manner( P<0.05). (2)H9c2 cardiomyocytes induced by AngⅡ showed a significantly larger cell area and significantly higher ANP mRNA and ANP protein expression compared with controls.Different concentrations of ASⅣ intervention could reverse the increase of cardiomyocyte H9c2 area induced by AngⅡ and also decreased the expression of ANP protein induced by AngⅡ in a dose-dependent manner(all P<0.05). (3)Compared with the control group, the autophagy level and the expression of autophagy marker LC3II/I of H9c2 cardiomyocytes induced by AngⅡ were significantly increased(all P<0.05). ASⅣ could inhibit AngⅡ-activated autophagy, and the difference was statistically significant( P<0.05). ASⅣ inhibited the expression of LC3II/I in H9c2 cardiomyocytes stimulated by AngⅡ, and the difference was statistically significant( P<0.05). Conclusions:ASⅣ inhibits AngⅡ-induced cardiac hypertrophy by inhibiting autophagy of cardiomyocytes.