Rice Protein Peptides Alleviate Dextran Sulfate Sodium-Induced Colitis via the Keap1–Nrf2 Signaling Pathway and Regulating Gut Microbiota

Inflammatory bowel disease (IBD), with increasing incidence, causes a range of gastrointestinal symptoms and brings distress and impact on the health and lives of patients. The aim of this study was to explore the protective effects of industrially produced rice protein peptides (RPP) on dextran sulfate sodium (DSS)-induced acute colitis in mice and the potential mechanisms. The results showed that RPP treatment alleviated the symptoms of colitis in mice, including weight loss, colon shortening, and injury, decreased the level of disease activity index (DAI), regulated the balance of inflammatory factors and oxidation, activated Kelch-like ECH-associating protein 1 (Keap1)-nuclear factor E2-related factor 2 (Nrf2) signaling pathway, regulated the expression of related antioxidant proteases, and promoted the expression of intestinal tight junction proteins. In addition, RPP maintained intestinal mucosal barrier function and alleviated acute colitis caused by DSS treatment in mice by increasing the value of F/B, increasing the relative abundance of beneficial bacteria such as Akkermansia, and regulating the level of short-chain fatty acids. In conclusion, RPP alleviated colitis symptoms through the Keap1–Nrf2 signaling pathway and regulating gut microbiota, which had the potential as dietary supplements or functional foods.