Rancidity-induced rice bran protein oxidation causes kidney injury in mice via oxidative stress and inflammatory response

Owing to the health benefits with low cost, rice bran protein (RBP) presents excellent application potential as food ingredient. However, the inevitable rice bran (RB) rancidity will induce RBP oxidation and change the nutritional value of RBP. Therefore, 12-week oral gavage of RBP with different oxidation extent and gavage dose was conducted to explore the effects of oxidized RBP on the oxidative stress, inflammatory response of the body and the underlying mechanism. The results indicated that oral gavage of oxidized RBP decreased the body weight gain and feed intake, indicating the deterioration of growth performance. Oxidized RBP induced the accumulation of oxidation products, reduced the levels of antioxidant enzymes, and caused the inflammatory response, in which the up-regulation of Keap1-Nrf2/ARE pathway and MyD88/NF-κB pathway participated. Morphological structure also indicated gavage of oxidized RBP caused kidney injury. The results presented changes in the in vivo nutritional value of oxidized RBP induced by RB rancidity, which was of great significance for better development of the food processing by-products with high nutritional value.