Bifidobacterium longum subsp. infantis FJSYZ1M3 ameliorates DSS-induced colitis by maintaining the intestinal barrier, regulating inflammatory cytokines, and modifying gut microbiota.

B. longum subsp. infantis is a subspecies of Bifidobacterium longum , and very few strains are shown to have immunomodulatory effects. In the present study, the improvement of dextran sulphate sodium (DSS)-induced colitis by four B. longum subsp. infantis strains was compared. The results showed that B. longum subsp. infantis FJSYZ1M3 could significantly decrease disease activity index (DAI), inhibit weight loss and colon shortening, and attenuate colon tissue damage in DSS-induced colitis mice. And B. longum subsp. infantis FJSYZ1M3 intervention improved the integrity of intestinal tight junctions, relieved mucus layer damage and inhibited epithelial cell apoptosis, thereby maintaining the intestinal barrier. Additionally, B. longum subsp. infantis FJSYZ1M3 significantly affected the levels of inflammatory cytokines IL-6, IL-1β, and IL-10 in the colon, thus relieving inflammation in colitis mice. Furthermore, B. longum subsp. infantis FJSYZ1M3 could ameliorate gut microbiota disturbance caused by DSS exposure and increase the level of butyric acid in cecal contents. In general, these findings suggested that B. longum subsp. infantis FJSYZ1M3 alleviated DSS-induced colitis by maintaining the intestinal barrier, regulating inflammatory cytokines, and modifying the gut microbiota.