Objective: In order to address the global public health concern of colitis, this study was conducted to investigate the beneficial effect of Lactobacillus plantarum LR002 (LR) on the remission of ulcerative colitis (UC) in mice and to explore the possible underlying mechanisms.

Methods: The effect of LR on UC was analyzed by using dextran sodium sulfate (DSS)-induced UC model in mice (n = 9). To assess the therapeutic effect of LR on UC in mice, the disease activity index (DAI) of mice, histopathological alterations, intestinal epithelial barrier integrity, and intestinal microflora were determined.

Results: The results demonstrated a reduction in the DSS-induced DAI in UC mice. Additionally, it mitigated colon shortening, minimized intestinal tissue damage, and preserved intestinal tight junction proteins (Claudin-3, Occludin, and ZO-1). LR reduced the levels of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and oxidative mediators (MPO, SOD and MDA) in the colon of UC mice, which could also alleviate the imbalance of intestinal flora in UC mice, increase the abundance of Prevotellaceae, and Ligilactobacillus, and decrease the abundance of Bacteroidaceae and Eubacteriumrum. LR can also increase the levels of PPARγ in the nucleus and inhibit the MAPK/NF-ĸB signaling pathway in UC mice. Besides, the reduction of the content of short-chain fatty acid (SCFAs) in the colon of UC mice was relieved.

Conclusions: The above results forge a scientific basis for LR as natural anti-inflammatory food to improve the imbalance of inflammatory intestinal flora and promote intestinal health.