Beneficial effects of red rice bran extract on brown adipose tissue whitening, inflammation, and oxidative stress in mice with obesity induced by a high-fat diet

Red rice bran extract (RRBE) has been demonstrated to have anti-lipid accumulation, antioxidant, and anti-inflammatory effects on the livers of obese animals and/or in macrophages. However, the molecular mechanisms driving these effects have not yet been investigated in brown adipose tissue (BAT). Thus, the present study aimed to investigate the beneficial effects of RRBE on BAT in mice with obesity induced by a high-fat diet (HFD). Six weeks after induction of obesity, the obese mice were fed continuously with HFD, with or without RRBE treatment for 6 weeks. Body weight and food intake were recorded weekly. At the end of the feeding experiment, BAT was collected for determination of expressions of genes associated with liporegulation, inflammation, and oxidative stress, as well as histological examination. Compared with untreated obese mice, RRBE-treated mice had reductions in body weight, food efficiency ratio, and white-like adipocytes in BAT, accompanied by down-regulated expression of nuclear receptor subfamily 1 group H member 3 (NR1H3). Moreover, RRBE decreased the levels of nitric oxide (NO), reactive oxygen species (ROS), and malondialdehyde (MDA) in BAT, which were associated with modulated expressions of target genes for nuclear factor-kappa B and nuclear factor erythroid 2-related factor 2. RRBE produced beneficial effects against HFD-induced abnormalities in BAT by mitigating whitening, inflammation, and oxidative stress.