Lactobacillus helveticus LZ-R‑5 Ameliorates\nDSS-Induced Colitis in Mice by Modulating\nGut Microbiota and Enhancing Intestinal Barrier Function

Lactobacillus helveticus LZ-R-5\n(R-5), a strain with high epithelial adhesion and bioactive exopolysaccharide\nproduction, was isolated from Tibetan kefir grains. This study investigated\nits potential to alleviate intestinal inflammation using a DSS-induced\ncolitis model in BALB/c mice. We integrated microbial diversity and\nserological analyses to assess changes in gut flora and cytokines\nfollowing the R-5 treatment. Pathological assessments showed that\nR-5 reduced crypt distortion in the proximal colon and mitigated hepatic\nimmune challenges by enhancing gut barrier function. The increased\nrelative expression of TGF-β1 and the downregulation of NLRP3-related\ninflammatory factors were conducive to preventing organ damage in\nthe thymus and spleen of mice with colitis. Additionally, R-5 stimulated\nGPR43 expression and improved epithelial nutrition, promoting mucin\nproduction to prevent enterotoxin leakage. It also modulated the gut\nmicrobiota by suppressing Bacteroides and Erysipelatoclostridium,\nleading to a microbiota composition more akin to that of normal flora.