Arctic Fox-Derived Lactiplantibacillus plantarum J3 Alleviates Colitis in Mice in Association with Strengthening of the Intestinal Barrier and Reshaping of the Intestinal Flora

Probiotic interventions for inflammatory bowel disease (IBD) have become a hot research topic in this field. However, no previous studies have investigated whether fox-derived probiotics exert therapeutic effects against colitis. The present investigation evaluated the effects of Lactiplantibacillus plantarum (syn. Lactobacillus plantarum) J3, sourced from the intestines of healthy Arctic foxes, on colitis. In an in vitro LPS-stimulated Caco-2 cell model, strain J3 exhibited prominent anti-inflammatory and antioxidant capacities, indicating potential to preserve intestinal barrier integrity. Furthermore, in an in vivo DSS-induced colitis mouse model, oral J3 supplementation markedly alleviated body weight loss, lowered disease activity index (DAI), and ameliorated histopathological lesions in colon tissues. Mechanistic analyses revealed that the J3 group displayed significantly decreased colonic levels of TNF-α, IL-1β, IL-6, MPO, PGE2, along with downregulated COX-2 mRNA expression (p < 0.05). By contrast, the levels of IL-10, TJ protein mRNA, and MUC2 mRNA were markedly upregulated, whereas serum LPS and D-Lac concentrations were significantly reduced (p < 0.05). In an exploratory analysis of 16S rDNA and short-chain fatty acids (SCFAs) in a subset of mice, J3 treatment showed a trend toward colonic microbial remodeling, accompanied by a significant increase in short-chain fatty acid production (p < 0.05). Overall, these findings indicate that Lactiplantibacillus plantarum J3 derived from foxes may alleviate DSS-induced colitis in mice, providing a basis for future translational research.