Rice bran water extract prevents cardiac lipid accumulation and oxidative damage in rats fed a high-fat diet

Rice bran water extract (RBE) has been reported to have cardiovascular protective effects including lipid-lowering and antioxidant effects. The present study aims to investigate the effects of RBE and its possible protective mechanisms against lipid accumulation and oxidative damage to the heart of male Sprague-Dawley rats induced by a high-fat diet (HFD). After four weeks of exclusive HFD feeding, elevated triglyceride, total cholesterol and malondialdehyde contents in the cardiac tissue were examined. The HFD group showed elevated serum levels of free fatty acid, triglyceride and total cholesterol. By contrast, these elevations decreased after four weeks of oral RBE treatment (2,205 mg/kg/day). RBE treatment also increased cardiac free radical-scavenging activity. Mechanistically, expression levels of peroxisome proliferator-activated receptor alpha, AMP-activated protein kinase alpha, glucose transporter 4 and heme oxygenase-1 were up-regulated in the heart of the RBE-treated rats. However, down-regulated expression levels of cluster of differentiation 36, sterol regulatory element binding protein-1 and nuclear factor-kappa B p65 were detected in the RBE-treated group as compared with the HFD group. However, cardiomyocyte size and cardiac marker levels were unchanged between the groups. RBE intake may prevent HFD-induced lipid overaccumulation and oxidative damage in the cardiac tissue, resulting in cardioprotective effects.