Quinoa bran soluble dietary fiber ameliorates dextran sodium sulfate induced ulcerative colitis in BALB/c mice by maintaining intestinal barrier function and modulating gut microbiota

To clarify the effect of quinoa bran soluble dietary fiber (QBSDF) on gut inflammation and homeostasis, ulcerative colitis (UC) mice induced by dextran sodium sulfate (DSS) were fed QBSDF for four weeks. Histological staining, immunofluorescence, western blot and 16S rRNA sequencing analysis were carried out to investigate the action mechanism of QBSDF. Results showed that QBSDF alleviated DSS-induced colitis symptoms accompanied by significant mitigation of colon shortening and colonic epithelial damage. Moreover, QBSDF supplementation downregulated the mRNA and protein expression level of TNF-α and IL-1β, while elevated the expression of tight junction proteins, and significantly reduced colonic cells apoptosis. In addition, the diversity and abundance of gut microbiota in QBSDF fed mice were significantly increased compared to that of UC mice. Moreover, QBSDF notably increased the abundance of Firmicutes at phylum level, while decreased the abundance of Bacteroidetes and pathogenic Helicobacter. Besides, the levels of short-chain fatty acids, especially acetic acid and butyric acid were significantly increased by QBSDF administration. These findings suggested the promising potential of QBSDF as a functional food ingredient to prevent ulcerative colitis through maintaining intestinal barrier function and modulating gut microbiota.