Effects of Red Rice Bran Extract on High-Fat Diet-Induced Obesity and Insulin Resistance in Mice

Abstract

Insulin resistance is a salient player in the pathogenesis of obesity and its related abnormal glucose-insulin homeostasis. Red rice bran extract (RRBE) demonstrates several bioactive phytochemicals with anti-diabetic properties. However, little is known about its molecular mechanisms. Therefore, the present study was designed to investigate the anti-insulin resistant mechanisms of RRBE in a model of high-fat diet (HFD)-induced insulin resistance. In this study, mice were randomly divided into four groups: low-fat diet with distilled water (Group L), HFD with distilled water (Group H), HFD with 0.5 g/kg RRBE, and HFD with 1 g/kg RRBE. Metabolic parameters, histological changes in the pancreas, and gene expression levels were evaluated after treating HFD-fed mice with RRBE for six weeks. Mice from Group H exhibited significantly higher blood glucose levels prior to and after an oral glucose tolerance test, fasting serum insulin levels, islet size, pancreatic insulin expression levels, and lower skeletal muscle insulin-degrading enzyme (IDE) expression levels compared to Group L. In contrast, these were all significantly restored in the RRBE-treated groups. Also, RRBE treatment was found to upregulate the expression of insulin receptor substrate (IRS) and glucose transporter (GLUT) genes in the adipose tissues and GLUT genes in the muscles and livers of HFD-fed mice. According to our results, RRBE may ameliorate abnormal glucose-insulin metabolism by modulating the expression of insulin, IDE, IRS, and GLUT genes in the major metabolic target tissues of mice after being fed with HFD.

Effects of Riceberry Rice Bran Oil Supplementation on Oxidative Stress and Cardiovascular Risk Biomarkers in Older Adults with Prehypertension

“…HRV and BP variables did not change after either form of supplementation, and no differences were found between the groups. Supplementation with rice bran and its active components, such as oryzanols, tocopherols, tocotrienols, phytosterols, and nucleotides, has been shown in animal experiments to be effective against chronic diseases such as hypertension, dyslipidemia, diabetes mellitus, metabolic syndrome, obesity, and inflammation (Ardiansyah et al, 2009;Palou et al, 2015;Wang et al, 2015;Alauddin et al, 2016;Duansak et al, 2022;Munkong et al, 2022).…”

Dietary Sinapic Acid Alleviates Adiposity and Inflammation in Diet-Induced Obese Mice

“…Previous studies have indicated a potential role of obesity-induced inflammation in the development of insulin resistance ( Uysal et al, 1997 ; Kamei et al, 2006 ; Saberi et al, 2009 ; Pierre et al, 2013 ). Prolonged ingestion of HFD (8∼16 months, 40∼60% energy from fat) in C57BL/6J mice leads to hyperglycemia, hyperinsulinemia, and impaired insulin sensitivity in addition to a significant rise in bodyweight, fat mass, and inflammation ( Do et al, 2011 ; Avtanski et al, 2019 ; Munkong et al, 2022 ). van der Heijden et al (2015) have implied that obesity-associated insulin resistance is possibly more linked to inflammation in adipose tissue rather than other tissues such as the liver.…”

Composition, Microbiota, Mechanisms, and Anti-Obesity Properties of Rice Bran

“…Similarly, RRBE supplementation improved the serum insulin level, glucose level, and expression of insulin-degrading enzyme (IDE), insulin receptor substrate (IRS), and glucose transporter (GLUT) in high-fat-diet-induced obese mice. RRBE protects the host from diet-induced damage by improving glucose–insulin homeostasis [ 98 ].…”