Inhibitory Effect and Mechanism of Tirzepatide on Angiotensin Ⅱ-Induced Cardiomyocyte Hypertrophy
Objective To investigate the effect and mechanism of tirzepatide(TZP)in angiotensin Ⅱ(Ang Ⅱ)-induced neonatal rat cardiomyocyte hypertrophy.Methods Neonatal rat cardiomyocytes were isolated and cultured in vitro,Ang Ⅱ(1 μmol/L)was used to stimulate cardiomyocytes for 24 h to establish a cardiomyocyte hypertrophy model,and neonatal rat cardiomyocytes were co-incubated using TZP(100 nmol/L)and Ang Ⅱ(1 μmol/L)for 24 h.The experiment will be randomly divided into four groups:control group,TZP group,Ang Ⅱ group,and Ang Ⅱ+TZP group.Phalloidin staining was used to assess the degree of hypertrophy of individual cardiomyocytes;TUNEL staining was used to detect cardiomyocyte apoptosis;CCK-8 was used to detect cardiomyocyte activity;DCFH-DA fluorescent probe was used to detect the level of reactive oxygen species(ROS);and reverse transcription-polymerase chain reaction was used to detect the mRNA levels of atrial natriuretic peptide,brain natriuretic peptide,and β-myosin heavy chain(β-MHC),B-cell lymphoma-2 associated X protein(Bax),B-cell lymphoma-2(Bcl-2),reduced nicotinamide adenine dinucleotide phosphate oxidase(Nox)2,Nox4,reduced nicotinamide adenine dinucleotide phosphate oxidase activator 2(NOXA2),superoxide dismutase 2(SOD2),NADPH quinone oxidoreductase 1(NQO1)and glutathione peroxidase(GSH-Px).The expression levels of brain natriuretic peptide,Bax,Bcl-2,SOD2,NQO1 and GSH-Px proteins were detected by Western blot in neonatal rat cardiomyocyte.In addition,reverse transcription-polymerase chain reaction and Western blot were performed to detect the mRNA and protein expression levels of Beclin-1 and p62 in cardiomyocytes of each group.Results TZP can significantly reduce the increase in protein and mRNA expression levels of cardiomyocyte hypertrophy markers and apoptosis markers induced by Ang Ⅱ,down-regulate the mRNA expression levels of pro-oxidant factors Nox2,Nox4 and NOXA2,and promote the antioxidant factors SOD2,NQO1 and GSH-Px mRNA expression levels.Compared with the control group,the above effects were statistically significant(P＜0.05).Meanwhile,Western blot and autophagosome assay confirmed that TZP antagonized Ang Ⅱ-induced cardiomyocyte hypertrophy mainly by inhibiting intracellular autophagy pathway.Conclusion TZP can alleviate Ang Ⅱ-induced cardiomyocyte hypertrophy and improve the effect of Ang Ⅱ-induced cardiomyocyte hypertrophy by inhibiting autophagy.
万方数据
