Cycloastragenol ameliorates experimental heart damage in rats by promoting myocardial autophagy via inhibition of AKT1-RPS6KB1 signaling

Cycloastragenol, a naturally occurring compound in Astragali Radix, has been demonstrated to possess various pharmacological actions including anti-aging, anti-inflammation, anti-fibrosis, antibacterial, liver and endothelium protection. However, whether cycloastragenol ameliorates heart failure remains unclear. Isoproterenol administration to rats triggered classic cardiac damage, as demonstrated by objective parameters of cardiac dysfunction. The treatment of cycloastragenol improved deranged cardiac parameters in the isoproterenol-induced heart damage model in a dose-dependent manner. At the same time, cycloastragenol markedly ameliorated cardiac histological changes and down-regulated serum levels of various neuroendocrine factors including norepinephrine, aldosterone, brain natriuretic peptide, endothelin 1, angiotensin II and so on. Moreover, the expressions of matrix metalloproteinase-2 (MMP-2) and MMP-9 in rat heart were also inhibited by cycloastragenol. Mechanistically, augmenting autophagy of myocardial cells via the inhibition of AKT1-RPS6KB1 signaling contributed to the improvement of isoproterenol-induced rat heart failure by cycloastragenol. These results suggest that cycloastragenol ameliorates cardiac dysfunction and remodeling through promoting autophagy in myocardial cells and suppressing MMP-2 and MMP-9 expressions, indicating that it could be a drug candidate for patients with congestive heart failure.