Background Ulcerative colitis (UC) is a chronic immune-mediated disorder primarily characterized by gastrointestinal tract inflammation. Probiotics are an adjunct to traditional drug therapy for UC. In this study, Bifidobacterium adolescentis AF91-08b2A was isolated and screened, and the beneficial effect of B. adolescentis AF91-08b2A on mice colitis induced by sodium dextran sulfate (DSS) was evaluated. Our data show that B. adolescentis AF91-08b2A alleviates IBD symptoms by protecting against intestinal barrier damage and modulating the immune response.

Methods Metagenome-wide association studies (MWAS) have implicated gut dysbiosis in the pathogenesis of IBD. The research analyzed the abundance of B. adolescentis in IBD patients and healthy cohorts, revealing a decreased presence in IBD groups. Genomic characterization of strain AF91-08b2A identified key genes associated with probiotic properties, including antibiotic resistance, virulence factors, and stress resistance, indicative of its potential as a safe and effective probiotic candidate. The study also highlighted the strain’s metabolic capabilities, particularly in pathways related to energy production and carbohydrate metabolism, which may contribute to its therapeutic effects. The beneficial effects of B. adolescentis AF91-08b2A on inflammation were assessed through measurements of inflammation, cytokine levels, and tight junction protein expression in colitis mice.

Results Results demonstrated that B. adolescentis AF91-08b2A treatment significantly improved disease activity index (DAI) scores, reduced weight loss, and mitigated colon tissue damage in DSS-induced colitis mice. Furthermore, B. adolescentis AF91-08b2A increased the number of goblet cells and modulated cytokine expression, decreasing pro-inflammatory factors such as IL-6, IL-1β, IL-17a, IFN-γand TNF-α while promoting anti-inflammatory IL-4, IL-10, and TGF-β1. The restoration of tight junction proteins ZO-1, occludin, and claudin-2 by AF91-08b2A suggested a protective role in maintaining intestinal epithelial barrier integrity.

Conclusions This study demonstrates that B. adolescentis AF91-08b2A exhibits promise as a next-generation probiotic supplement for the management of IBD. Its ability to reduce inflammation and protect the intestinal epithelial barrier positions it as a potential therapeutic agent for alleviating IBD symptoms.