Sustained ameliorative effect of Lactobacillus acidophilus LA85 on dextran sulfate sodium‐induced colitis in mice

Ulcerative colitis (UC) is a type of inflammatory bowel disease associated with immune system dysfunction caused by gut dysbiosis. This study aimed to investigate the alleviating effect of Lactobacillus acidophilus LA85 on colitis and its underlying mechanism using mouse models of dextran sulfate sodium (DSS)-induced UC. The UC mouse models were established by treating C57BL/6J male mice with 2.5% (w/v) DSS in drinking water for 7 days. These mice received supplementation with either L. acidophilus LA85 (1 × 109 colony-forming units/day) or 200 µL of sterile water once daily (LA85-treated and UC model mice, respectively). The disease activity index (DAI), colon length, and histological changes in the colons of mice were then analyzed at Day 21, and the effects of L. acidophilus LA85 on the gut microbiota and serum inflammatory cytokines were also investigated. Compared with the UC model mice, L. acidophilus LA85-treated UC mice showed significant reductions in a variety of colitis symptoms, including weight loss, the DAI score, colon shortening, and colon tissue damage. Lactobacillus acidophilus LA85 supplementation also significantly decreased the serum concentrations of tumor necrosis factor α and interleukin-6 while increasing the serum concentration of IL-10. Furthermore, LA85 supplementation improved the diversity and composition of the gut microbiota, both of which had been decreased by DSS. In particular, L. acidophilus LA85-treated UC mice showed higher relative abundances of Akkermansia and Romboutsia than the UC model mice. These results demonstrate that L. acidophilus LA85 can alleviate inflammatory diseases of the intestine, such as inflammatory bowel disease, by regulating immune responses and restoring the gut microbiota. PRACTICAL APPLICATION: Ulcerative colitis is a type of inflammatory bowel disease caused by imbalance of gut microbiota. This study showed that L. acidophilus LA85 can alleviate DSS-induced colitis in mice through regulation of inflammatory cytokines, protection of intestinal barrier, and regulation of specific gut microbiota. L. acidophilus LA85 is a promising probiotic candidate for the treatment of UC.