Gamma-oryzanol reduces renal inflammation and oxidative stress by modulating AGEs/RAGE axis in animals submitted to high sugar-fat diet

Abstract

Introduction: The receptor for AGEs (RAGE) is a multiligand member of the immunoglobulin superfamily of cell surface receptors expressed in many organs, among them, the kidneys. When activated, RAGE leads to a sequence of signaling that results in inflammation and oxidative stress, both involved in kidney disease pathogenesis. Gamma-oryzanol (γOz) comprises a mixture of ferulic acid (FA) esters and phytosterols (sterols and triterpene alcohols) mainly found in rice, with antioxidant and anti-inflammatory activities. Aim: To evaluate the effect of γOz to reduce renal inflammation and oxidative stress by modulating AGEs/ RAGE axis in animals submitted to a high sugar-fat diet. Methods: Male Wistar rats (±187g) were randomly divided into two experimental groups: control (n = 7 animals) and high sugar-fat diet (HSF, n = 14 animals) for 20 weeks. After this period, when the presence of renal disease risk factors was detected in the HSF group (insulin resistance, dyslipidemia, increased systolic blood pressure and obesity), the HSF animals were divided to begin the treatment with γOz or continue receiving only HSF for 10 more weeks. Results: No effect of γOz on obesity and metabolic parameters was observed. However, kidney inflammation and oxidative stress decreased as soon as RAGE levels were reduced in HSF + γOz. Conclusion: It is possible to conclude that the gamma- oryzanol was effective in reducing inflammation and oxidative stress in the kidney by modulating the AGEs/RAGE axis.