Improved cardiac performance after ischemia in aged rats supplemented with vitamin E and α-lipoic acid

Abstract

The purpose of these experiments was to examine the effects of dietary antioxidant supplementation with vitamin E (VE) and α-lipoic acid (α-LA) on biochemical and physiological responses to in vivo myocardial ischemia-reperfusion (I-R) in aged rats. Male Fischer-334 rats (18 mo old) were assigned to either 1) a control diet (CON) or 2) a VE and α-LA supplemented diet (ANTIOX). After a 14-wk feeding period, animals in each group underwent an in vivo I-R protocol (25 min of myocardial ischemia and 15 min of reperfusion). During reperfusion, peak arterial pressure was significantly higher ( P < 0.05) in ANTIOX animals compared with CON diet animals. I-R resulted in a significant increase ( P < 0.05) in myocardial lipid peroxidation in CON diet animals but not in ANTIOX animals. Compared with ANTIOX animals, heart homogenates from CON animals experienced significantly less ( P < 0.05) oxidative damage when exposed to five different in vitro radical producing systems. These data indicate that dietary supplementation with VE and α-LA protects the aged rat heart from I-R-induced lipid peroxidation by scavenging numerous reactive oxygen species. Importantly, this protection is associated with improved cardiac performance during reperfusion.