OBJECTIVE: To explore the protective and therapeutic effects of Faecalibacterium prausnitzii (Fp) supernatant on ulcerative colitis (UC) in mice induced by dextran sulfate sodium (DSS) and the underlying mechanisms.
 METHODS: Forty male mice were randomly divided into a control group, a model group, a treatment group and a prevention group (n=10 in each group). The colorectal histopathologic damage score (HDS) were calculated; the proportion of helper T cell (Th17) in mononuclear cells (MNC) in spleen, the levels of IL-17A and IL-6 in plasma were detected; the mRNA levels of transcription factor retinoic acid-related orphan receptor-γt (ROR-γt), interleukin (IL)-17A and IL-6 in colon mucosa tissues were also determined.
 RESULTS: Compared with the model group, the colon HDS in the treatment group and the prevention group were significantly decreased (both P<0.05), but there was no significant difference in the treatment group and the prevention group (P>0.05). The proportion of Th17 cells in spleen in the treatment group and the prevention group was also remarkably lower than that in the model group (both P<0.01). The levels of IL-17A and IL-6 in plasma in the treatment group were significantly lower than those in the model group (both P<0.05). The mRNA expression of ROR-γt, IL-17A and IL-6 in the colon mucosa tissues in the treatment group were remarkably lower than those in the model group (all P<0.05). But there was no statistic difference in the level of IL-6 in the plasma and the colon mucosa tissues between the prevention group and the model group (P>0.05).
 CONCLUSION Fp supernatant has protective and therapeutic effects on ulcerative colitis in mice induced by DSS, which might be mediated by decrease of Th17 and IL-17A levels in the plasma and the colon mucosa tissues. Fp supernatant also can decrease mice colitis by reducing IL-6 levels.
Animals ; Clostridiales ; Colitis, Ulcerative ; chemically induced ; immunology ; Culture Media, Conditioned ; pharmacology ; Dextran Sulfate ; adverse effects ; Interleukin-17 ; blood ; immunology ; Interleukin-6 ; blood ; immunology ; Intestinal Mucosa ; immunology ; Male ; Mice ; Nuclear Receptor Subfamily 1, Group F, Member 3 ; metabolism ; Random Allocation ; Th17 Cells ; drug effects ; immunology