Synergistic protective effects of β-glucan and Lactobacillus johnsonii NSP009 in ulcerative colitis.

The combination of probiotics and prebiotics has emerged as a promising strategy for managing ulcerative colitis (UC). Among these, β-glucan (BG) and Lactobacillus johnsonii have individually shown potential in alleviating colitis, with BG notably enriching L. johnsonii populations, suggesting a synergistic therapeutic potential when combined. This study investigates the protective effects of a novel synbiotic formulation, BG and L. johnsonii NSP009 (LJ), termed BGLJ, in a dextran sulfate sodium (DSS)-induced colitis mouse model. Our results reveal that BGLJ significantly mitigated DSS-induced weight loss, reduced the disease activity index, and alleviated intestinal inflammation and barrier dysfunction. Notably, BGLJ markedly increased L. johnsonii abundance in mouse feces, with LJ producing substantial levels of indole-3-lactic acid (ILA), an aryl hydrocarbon receptor (AhR) agonist. BGLJ treatment robustly elevated ILA levels in the gut, activating AhR and upregulating IL-22 production. Collectively, our findings highlight the therapeutic potential of the BGLJ-based synbiotic in maintaining intestinal homeostasis and underscore its promise as a novel intervention for UC management.