We aimed to investigate the cardioprotective effects of ethanolic Melissa officinalis L. extract (ME) in the rat model of myocardial ischemia/reperfusion (I/R) injury. Thirty-two Wistar rats were randomly divided into a CTRL non-treated control group with myocardial I/R injury and three experimental groups of rats treated with 50, 100, or 200 mg/kg of ME for 7 days per os. Afterward, hearts were isolated, and cardiodynamic function was assessed via the Langendorff model of global 20 min ischemia and 30 min reperfusion. Oxidative stress parameters were determined spectrophotometrically from the samples of coronary venous effluent (O2-, H2O2, TBARS, and NO2-,) and heart tissue homogenate (TBARS, NO2-, SOD, and CAT). H/E and Picrosirius red staining were used to examine cardiac architecture and cardiac collagen content. ME improved cardiodynamic parameters and achieved to preserve cardiac architecture after I/R injury and to decrease fibrosis, especially in the ME200 group compared to CTRL. ME200 and ME100 markedly decreased prooxidants TBARS, O2-, and H2O2 while increasing NO2-. Hereby, we confirmed the ME`s ability to save the heart from I/R induced damage, even after short-term preconditioning in terms of preserving cardiodynamic alterations, cardiac architecture, fibrosis, and suppressing oxidative stress, especially in dose of 200 mg/kg.
Keywords: Melissa officinalis L.; ethanolic extract; ischemia/reperfusion injury; oxidative stress; rat heart.