Exerts Strain-Specific Effects on DSS-Induced Ulcerative Colitis in Mice.

is a commensal bacterium of the gut mucus layer. Although both and data have shown that strains exhibit strain-specific modulation of gut functions, its ability to moderate immunity to ulcerative colitis have not been verified. We selected three isolated human strains (FSDLZ39M14, FSDLZ36M5 and FSDLZ20M4) and the type strain ATCC BAA-835 to examine the effects of different strains on dextran sulfate sodium-induced colitis. All of the strains were cultured anaerobically in brain heart infusion medium supplemented with 0.25% type II mucin from porcine stomach. To create animal models, colitis was established in C57BL/6 mice which randomly divided into six groups with 10 mice in each group by adding 3% dextran sulfate sodium to drinking water for 7 days. strains were orally administered to the mice at a dose of 1 × 10 CFU. Only FSDLZ36M5 exerted significant protection against ulcerative colitis (UC) by increasing the colon length, restoring body weight, decreasing gut permeability and promoting anti-inflammatory cytokine expression. However, the other strains (FSDLZ39M14, ATCC BAA-835 and FSDLZ20M4) failed to provide these effects. Notably, FSDLZ20M4 showed a tendency to exacerbate inflammation according to several indicators. Gut microbiota sequencing showed that FSDLZ36M5 supplementation recovered the gut microbiota of mice to a similar state to that of the control group. A comparative genomic analysis demonstrated that the positive effects of FSDLZ36M5 compared with the FSDLZ20M4 strain may be associated with specific functional genes that are involved in immune defense mechanisms and protein synthesis. Our results verify the efficacy of in improving UC and provide gene targets for the efficient and rapid screening of strains with UC-alleviating effects.