Therapeutic effects of Lacticaseibacillus paracasei PC-H1 in alleviating colitis through restoring intestinal barrier and regulating gut microbiota

Ulcerative colitis (UC), a subtype of inflammatory bowel disease (IBD), disrupts intestinal barrier integrity and microbial homeostasis. This study investigated the therapeutic potential of Lactobacillus paracasei PC-H1 in a murine UC model. L. paracasei PC-H1 administration significantly ameliorated colitis severity, as evidenced by restored body weight, colon length, and reduced disease activity index (DAI) scores and pro-inflammatory cytokine levels. Mechanistically, L. paracasei PC-H1 enhanced mucosal barrier function by upregulating tight junction proteins (ZO-1, occludin, claudin-3) and controlling colonic inflammation. Notably, high-dose inactive L. paracasei PC-H1 outperformed viable bacteria in reshaping gut microbiota composition and establishing a novel microbial homeostasis. These findings demonstrate that L. paracasei PC-H1 mitigates ulcerative colitis progression by protecting intestinal barrier integrity and restoring microbiota homeostasis. L. paracasei PC-H1 alleviates colitis by enhancing intestinal barrier, reducing inflammatory response, and regulating gut microbiota. This image is drawn by Figdraw. • L. paracasei PC-H1 restores colitis-associated mucosal architecture. • L. paracasei PC-H1 reverses colitis-induced loss of mucosal barrier function. • L. paracasei PC-H1 reshapes gut microbiota composition and establishes a novel microbial equilibrium. • Heat-killed L. paracasei PC-H1 exhibits superior efficacy to viable bacteria in ameliorating colitis.