Suppression of Oxidative Stress and Apoptosis in Electrically Stimulated Neonatal Rat Cardiomyocytes by Resveratrol and Underlying Mechanisms

Purpose: We explored the effects of resveratrol on oxidative stress in cardiomyocytes subjected to rapid electrical stimulation (RES) and also investigated the underlying mechanisms. Methods: Cultured ventricular myocytes of neonatal rat were subjected to RES at 4.0 Hz, with or without resveratrol, an NADPH oxidase inhibitor apocyanin (APO) or a Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor autocamtide-2-inhibitory peptide (AIP). Cell counts, to optimize resveratrol concentration, and angiotensin II content were evaluated. Reactive oxygen species (ROS), intracellular Ca2+ in cardiomyocytes, and cardiomyocyte apoptosis were also assessed. Levels of methionine sulfoxide reductase A (MsrA), Nox, oxidative CaMKII (OX-CaMKII), and cleaved caspase-3 in cardiomyocytes were examined. Results: Resveratrol treatment, as compared with APO and AIP, significantly decreased ROS levels, improved Ca2+ amplitudes, and intracellular Ca2+ transient decay rates, and inhibited cardiomyocyte apoptosis. Resveratrol also increased MsrA protein levels. In cardiomyocytes subjected to RES, after pretreatment with resveratrol or APO, protein levels of Nox4, Nox2, OX-CaMKII, and cleaved caspase-3 were decreased. In comparison, with AIP pretreatment, only Nox2, OX-CaMKII, and cleaved caspase-3 were decreased. However, in the presence of dimethyl sulfoxide, a competitive inhibitor of MsrA function, a decrease in cleaved caspase-3 did not occur. Conclusions: Resveratrol decreased ROS, partially through the inhibition of NADPH oxidase activity and upregulation of MsrA expression.