Oxidized Wheat Germ Protein Induces Oxidative Stress and Inflammation by Altering Gut Microbiota in Mice

This study aimed to elucidate the effects of wheat germ protein (WGP) with varying oxidation levels on the composition of the gut microbiota and inflammatory response in mice, focused on their body weight, organ indices, tissue morphology, tight junction proteins, oxidative stress biomarkers, inflammatory cytokine levels, and gut microbiota composition. The results indicated that the highly oxidized wheat germ protein (HP) treatment significantly suppressed body weight gain in mice, reduced their feed intake, and caused liver atrophy, kidney enlargement, and cardiac dysfunction. Histological analysis revealed intestinal villus damage in the ileum and colon, increased lymphocytic infiltration, and exacerbated fibrosis in the liver and kidneys in the HP group. The HP group markedly elevated oxidative stress markers (ROS, carbonyls, MDA), then downregulated tight junction proteins (ZO-1, Occludin, Claudin-1). Concurrently, gut microbiota analysis revealed a decrease in Firmicutes and Lactobacillus and an increase in Desulfobacterota and potentially pathogenic bacteria in mice treated with HP. These further significantly elevated pro-inflammatory cytokines (TNF-α, IL-6, IL-1β). Those findings suggest that oxidized WGP exacerbates systemic inflammation by inducing oxidative stress, disrupting intestinal integrity, and altering the composition of the gut microbiota, thereby providing a theoretical basis for the high-value utilization of wheat processing byproducts.