Bifidobacterium animalis supplementation improved the intestinal microbiota in DSS-induced colitis mice

Inflammatory bowel disease (IBD) characterized by chronic and relapsed intestinal inflammation remains an extremely therapeutic challenge. Bifidobacterium genus have a potential beneficial effect on the prevention of IBD onset and relapse, while its detailed therapeutic mechanisms remain poorly understood. This study was designed to explore the protective effect of Bifidobacterium animalis on dextran sulfate sodium (DSS)-induced colitis and to elucidate its underlying potential mechanism. Here, we found that administration with B. animalis significantly decreased weight loss, DAI score, and colonic histological score in colitis mice. B. animalis alleviated DSS-induced inflammatory responses by downregulating TNF-a, IL-1b and IL-6 levels and upregulating IL-10 level in colonic tissues. Moreover, the intestinal barrier integrity was improved by reducing colonic damage, recovering mucus layer loss and enhancing tight junction expression including ZO-1 and occludin. Furthermore, 16S rRNA gene sequencing showed lower abundances of several potentially pathogenic bacteria (e.g., Bacteroides, Parabacteroides, and Helicobacter) and enrichment in specific beneficial bacteria (e.g., norank_o__Clostridia_UCG-014, Dubosiella, and Bifidobacterium) in colitis mice with B. animalis treatment. In addition, metabolomic sequencing revealed that B. animalis intervention improved the composition of intestinal phospholipid metabolism, especially increasing the production of intestinal phosphatidylethanolamine and phosphatidylcholine. Then, supplementation with PE(Phosphatidylethanolamine) or PC(Phosphatidylcholine) also relived the symptom of DSS-induced colitis in mice. Taken together, these results demonstrated that B. animalis can alleviate DSS-induced colitis by regulating inflammatory cytokines, improving intestinal barrier function, and modulating the gut microbiota and metabolomic. This study highlights the potential role and mechanisms of probiotics in the treatment IBD, which provide a scientific foundation for the future development of novel treatment strategies and clinical research.