ESMOLOL PROTECTS AGAINST LPS-INDUCED CARDIAC INJURY VIA THE AMPK/mTOR/ULK1 PATHWAY IN RAT.

Aim: The purpose of this study was to investigate the effect of esmolol (ES) on LPS-induced cardiac injury and the possible mechanism.

Methods

Sepsis was induced by i.p. injection of LPS (10 mg/kg) in male Sprague-Dawley rats pretreated with ES, 3-methyladenine or rapamycin. The severity of myocardial damage was analyzed by hematoxylin-eosin staining, and myocardial damage scores were calculated. The concentration of cardiac troponin was measured by enzyme-linked immunosorbent assay. The expression of autophagy-related proteins (beclin-1, LC3-II, p-AMPK, p-ULK1, p-mTOR) in myocardial tissue was detected by Western blotting. Autophagosome formation and the ultrastructural damage of mitochondria were assessed using transmission electron microscopy.

Results

LPS induced an increase in myocardial damage score in a time-dependent manner, accompanied with an increase in autophagy at 3 h and decrease in autophagy at 6, 12, and 24 h. Pretreatment of LPS-treated rats with ES or rapamycin reduced myocardial injury (release of cardiac troponin, myocardial damage score) and increased autophagy (LC3-II, beclin-1, p-AMPK, and p-ULK1 levels and autophagosome numbers) at 12 and 24 h. In contrast, 3-methyladenine showed no effect.

Conclusion

Esmolol alleviates LPS-induced myocardial damage through activating the AMPK/mTOR/ULK1 signal pathway-regulated autophagy.