Protective effects of Lacticaseibacillus rhamnosus Hao9 on dextran sulphate sodium-induced ulcerative colitis in mice

Some probiotics used as food additives or food supplements had an anti-inflammatory effect. We tested the potential protective effects of probiotic Lacticaseibacillus rhamnosus Hao9 (Hao9) in mice with dextran sulphate sodium (DSS)-induced ulcerative colitis (UC) and determined whether these effects were related to the modulation of gut microbiota and amelioration of inflammation.Ulcerative colitis mouse model was established by feeding mice with 2.5% (w/v) DSS in drinking water for 7 days. We analysed the disease activity index (DAI), colon length and histological changes in the colon. In addition, we investigated the effects of Hao9 (1 × 109 colony forming unit/day) and curcumin (CUR) (200 mg/kg/day) on gut microbiota and serum inflammatory cytokines. In this study, CUR was used as a positive control. The results showed that both Hao9 and CUR effectively reduced body mass loss and DAI, restored colon length, alleviated colonic pathological variations and reduced histological scores compared with the UC group. Hao9 reduced the serum concentrations of proinflammatory cytokines (tumour necrosis factor alpha, interleukin [IL]-6 and IL-1β) and increased the concentration of the anti-inflammatory cytokine IL-10. In addition, Hao9 promoted the growth of Faecalibaculum and Romboutsia in the gut and helped to maintain intestinal homeostasis.Hao9 had a protective effect against DSS-induced colitis, and the mechanisms underlying Hao9 may involve controlling inflammation and maintaining host micro-ecological balance. This study provided experimental evidence for the application of Hao9 in the treatment of ulcerative colitis and suggested that Hao9 may be a promising candidate as a dietary supplement against colitis.The comparison of probiotics and prebiotics in terms of therapeutic efficacy in UC helps us to understand their different patterns of regulation of intestinal microbiota.