Protective Effects of Clostridium Butyricum in a Murine Model of Dextran Sodium Sulfate-Induced Colitis That Involve Inhibition of the TLR2 Signaling Pathway and T Helper 17 Cells

Abstract

This study aimed to investigate the role of Clostridium butyricum (C. butyricum) in conjunction with the Toll-like receptor2 (TLR2) signaling pathway and T helper 17 (Th17) cells in dextran sodium sulfate (DSS)-induced colitis in mice. Forty 8-week-old BALB/c mice were randomly divided into 5 groups of 8 mice for 7 days: control, DSS (5% DSS), DSS+C. butyricum (1×109 CFU), DSS+C. butyricum (1×108 CFU) and DSS+C. butyricum (1×107 CFU) groups. We assessed the disease activity index (DAI) and histological damage scores. The expression levels of TLR2, myeloid differentiation factor 88 (MyD88), nuclear factor kappa-B p65 (NF-κBp65), interleukin (IL) 17 (IL17), IL23 and retineic acid receptor related orphan nuclear receptor gamma t (RORγt) were determined through immunohistochemical staining, western blot and quantitative real-time PCR (qRT-PCR). The expression levels of CD3+CD4+IL17+ cells in peripheral blood were measured by flow cytometry. C. butyricum dose-dependently decreased DAI and histological damage scores in DSS mice and down-regulated the mRNA and protein levels of TLR2, MyD88 and NF-κBp65 in mouse colon tissue (all P < 0.05). In addition, C. butyricum dose-dependently decreased the levels of CD3+CD4+IL17+ cells in peripheral blood and down-regulated the mRNA and protein levels of IL17, IL23 and RORγt in mouse colon tissue (all P < 0.05). Moreover, the effect of C. butyricum on TLR2 was positively correlated with IL17, IL23 and RORγt. C. butyricum exerts a dose-dependently protective effect on acute intestinal inflammation induced by DSS in mice, by inhibiting the TLR2 signaling pathway, down-regulating the expression of IL23 and RORγt, and inhibiting the secretion of IL17.