<i>Bifidobacterium bifidum</i> Ameliorates DSS-Induced Colitis in Mice by Regulating Microbial Metabolome and Targeting Gut Microbiota

Abstract

Inflammatory bowel disease (IBD) is a recurrent inflammatory condition affecting the gastrointestinal tract, and its clinical treatment remains suboptimal. Probiotics have shown effectiveness in alleviating dextran sulfate sodium salt (DSS)-induced colitis, exhibiting strain-specific anti-inflammatory properties. In this study, we compared the therapeutic effects of five strains of <i>Bifidobacterium bifidum</i> isolated from healthy adult feces on DSS-induced colitis in mice. Additionally, we investigated the underlying mechanisms by examining gut microbiota composition and microbial metabolome. Our findings highlighted the superior efficacy of <i>B. bifidum</i> M1-3 compared to other strains. It significantly improved colitis symptoms, mitigated gut barrier disruption, and reduced colonic inflammation in DSS-treated mice. Moreover, gut microbiota composition analysis revealed that <i>B. bifidum</i> M1-3 treatment increased the abundance and diversity of gut microbiota. Specifically, it significantly increased the abundance of <i>Muribaculaceae</i>, <i>Lactobacillus</i>, <i>Bacteroides</i>, and <i>Enterorhabdus</i>, while decreasing the abundance of <i>Escherichia-Shigella</i>. Furthermore, our nontargeted metabolomics analysis illustrated that <i>B. bifidum</i> M1-3 treatment had a regulatory effect on various metabolic pathways, including tyrosine metabolism, lysine degradation, and tryptophan metabolism. Importantly, we confirmed that the therapeutic efficiency of <i>B. bifidum</i> M1-3 was dependent on the gut microbiota. These results are conducive to the development of probiotic products for alleviating colitis.