Shengmai Yin formula promotes ventricular remodeling in chronic heart failure rats by inhibiting excessive autophagy via activating AKT/mTOR pathway

Background:Shengmai Yin(SMY)formula,a traditional Chinese medicine,shows a definite therapeutic effect on chronic heart failure(CHF)in clinical practice,but the molecular mechanism remains largely unknown.The PI3K/Akt/mTOR pathway is a classic pathway of autophagy and plays a pivotal role in the occurrence and development of CHF.Here,we aimed to investigate whether SMY formula treat CHF rats by inhibiting excessive autophagy.Methods:Echocardiography was conducted to evaluate cardiac function.Transmission electron microscopy was used to observe the arrangement of myocardial cells.Enzyme linked immunosorbent assay analysis was performed to quantitative detecting the content of N-terminal pro-B-type natriuretic peptide,stromelysin-2,TNF-α in rat serum.Western blotting was used to detect the expression of AKT,p-AKT,mTOR,p-mTOR,light chain 3(LC3),and p62.In vitro,myocardial cells were treated with hypoxia reoxygenation and then intervened with SMY.Cell counting kit-8 method was used to measure the cell viability.The immunofluorescence expression of LC3 protein were also examined.Results:In vivo,SMY intervention assisted in the ventricular remodeling,reduced the levels of N-terminal pro-B-type natriuretic peptide,stromelysin-2,TNF-αin serum,and recovered myocardial cell structure in CHF rats.Treatment with SMY significantly promoted the ratio of p-AKT/AKT,p-mTOR/mTOR,and down-regulated the expression level of p62 and the ratio of LC3-Ⅱ/LC3-Ⅰ.In vitro,when the concentration of SMY containing serum reached 40% in the medium,the activity of myocardial cells reached the highest at 135.14%.SMY inhibited the expression of LC3 in hypoxic-reoxygenation embryonic ventricular myocytes cells.When the hypoxic reoxygenation cells treated with p-mTOR inhibitor,rapamycin,or p-AKT inhibitor,API-1,SMY could also down-regulated the LC3 expression level.Conclusions:SMY formula functions in restoring cardiac function and promoting myocardial ultrastructural recovery by reducing autophagy activity through up-regulating the ratio of p-AKT/AKT,p-mTOR/mTOR,and down-regulating the expression level of p62 and the ratio of LC3-Ⅱ/LC3-Ⅰ in CHF rats.