Effects of Clostridium butyricum and chitooligosaccharides (COS), singly and in synbiotic combination, were evaluated in a C57BL/6 mouse model of dextran sulfate (DSS)-induced acute ulcerative colitis (UC). Treatment with C. butyricum and/or COS ameliorated UC symptoms in vivo, and the strongest effects were observed for the combination in terms of reduced mortality rates and disease activity indices, increased body weight and colon length, and improved histological features. The C. butyricum and COS combination achieved the following: (i) regulated levels of inflammation-related cytokines (tumor necrosis factor alpha [TNF-α], interleukin-1β [IL-1β], IL-6, IL-10) and had a stronger anti-inflammatory effect than either component alone, based on inhibition of Toll-like receptor 4 (TLR-4)/NF-κB/MAPK signaling pathway activation; (ii) enhanced intestinal barrier function by restoring levels of tight junction proteins (occludin, claudin-1, ZO-1) and MUC2; (iii) increased abundance and diversity of beneficial bacteria (gut microbiota) and reduced levels of pathogenic bacteria; and (iv) enhanced production of short-chain fatty acids. Our findings indicate that the synbiotic C. butyricum and COS combination has strong potential as a therapeutic adjuvant for UC. IMPORTANCE Ulcerative colitis (UC), an idiopathic intestinal disease characterized by continuous remission/relapse inflammatory cycles in the colonic mucosal layer, has strong adverse effects on patients' quality of life and considerable costs for health care systems. Probiotics, prebiotics, and synbiotics are regarded as potential therapeutic agents for UC, in terms of safety and efficacy. In this study, we present detailed evaluation of effects in a DSS-induced UC mouse model of a synbiotic composed of Clostridium butyricum and COS (molecular weight [MW], 2,500 Da). We found that synergistic (synbiotic) action of the C. butyricum and COS combination is more effective than either factor alone for prevention and/or therapy of UC by regulating gut microbiota and intestinal barrier function. Our findings indicate that C. butyricum and COS in combination has strong potential for development as anti-UC therapeutic drugs or adjuvant agents in pharmaceutical, food, and livestock industries. Highlights include the following. (i) The C. butyricum and COS combination ameliorated clinical UC symptoms and improved colonic morphology. (ii) The C. butyricum and COS combination displayed strong anti-inflammatory and antioxidant effects. (iii) The C. butyricum and COS combination enhanced expression of tight junction proteins. (iv) The C. butyricum and COS combination inhibited the TRL-4/NF-κB/MAPK signaling pathway. (v) The C. butyricum and COS combination modulated gut microbiota abundance and composition.
Keywords: Clostridium butyricum; chitooligosaccharides; cytokines; gut microbiota; synbiotic; ulcerative colitis.