Lactobacillus gasseri JM1 Isolated from Infant Feces Alleviates Colitis in Mice via Protecting the Intestinal Barrier

Ulcerative colitis (UC) is a chronic and recurrent inflammatory bowel disease, and the intestinal barrier is an important line of defense against intestinal disease. Herein, we investigated the effect of Lactobacillus gasseri JM1 at different doses (1 × 10(6), 1 × 10(7), 1 × 10(8) CFU/day) on colitis mice and explored the possible mechanism. The results showed that L. gasseri JM1 alleviated DSS-induced colitis in mice, with reductions in disease activity index (DAI), histological scores and myeloperoxidase activity as well as alleviation of colonic shortening. Furthermore, L. gasseri JM1 regulated the levels of inflammatory cytokines TNF-α, IL-6, IL-1β, and IL-10; restored the expression of Claudin-3, Occludin, ZO-1, and MUC2; and increased the number of goblet cells and acidic mucin. The 16S rDNA sequencing results indicated that intervention with L. gasseri JM1 balanced the gut microbiota structure by elevating the abundance of beneficial bacteria (Oscillospira, Clostridium and Ruminococcus) and decreasing that of harmful bacteria (Shigella and Turicibacter). Meanwhile, the contents of short-chain fatty acids (SCFAs) increased. In conclusion, L. gasseri JM1 could alleviate intestinal barrier damage in colitis mice by modulating the tight junction structures, intestinal mucus layer, inflammatory cytokines, gut microbiota, and SCFAs. It can be considered a potential preventive strategy to alleviate colitis injury.