Oxidative status and the regulation of adiponectin receptor 2 in an animal model of obesity

Abstract

We studied the role of adiponectin receptor 2 (AdipoR2) in the obesity-induced oxidative stress and inflammation in obese Zucker rats. The gene and protein expression in the kidney cortex was determined by qPCR and Western blot. The plasma and renal markers of oxidative stress were evaluated using Tothova et al. protocol. Eight-month old obese Zucker rats had significantly increased plasma adiponectin, ferric reducing ability, advanced oxidation protein products and unchanged advanced glycation end products compared to lean Zucker rats. Plasma and renal thiobarbituric acid reacting substances (marker of lipid peroxidation) were significantly decreased in obese animals. Obesity was acompanied with marked elevation of ACE/ACE2 ratio in the kidney. Renal expression of genes related to NADPH oxidase complex, inflammation and fibrosis was increased in obese rats. AdipoR2 expression was significantly increased, whereas the expression of AdipoR1 was not altered with obesity. As a result, the phosphorylation of AMPK, protein located downstream of AdipoR2, was increased. These findings confirm that increased ACE/ACE2 ratio is important in obesity-induced development of renal oxidative stress and inflammation, whereas AdipoR2 is upregulated and suggest beneficial effect of adiponectin in lipid peroxidation in this rat model of obesity.