Total Glycosides of Peony Protects Against Inflammatory Bowel Disease by Regulating IL-23/IL-17 Axis and Th17/Treg Balance.

Inflammatory bowel disease (IBD) is a group of autoimmune diseases, including ulcerative colitis and Crohn's disease, characterized by nonspecific inflammation in the gut. Total glycoside of peony (TGP) has been widely used for treatment of autoimmune diseases because of its pharmacological effects. However, it is lack of depth in whether TGP regulate T helper 17 cell (Th17) / T regulatory cell (Treg) immune balance or interleukin 23 (IL-23) / IL-17 axis to achieve the goal of treating IBD. Hence, the aim of this study was to investigate the effects of TGP on experimental colitis mice and the related mechanisms. In the present study, we demonstrated that administration of TGP effectively attenuates colonic inflammation of TNBS-induced colitis mice, mainly reflected in significantly improved clinical parameters, reduced inflammatory response and myeloperoxidase (MPO) activity, even stronger systemic immune ability and effective improvement of Th17/Treg immune disorders. In addition, there was a stronger immunosuppressive ability in a positive cluster of differentiation 4 (CD4 + ) T-lymphocytes from the TGP treated mouse colon, characterized by the inhibition of high levels of inflammatory factors and increased regulatory T cells. Importantly, high-dose TGP has similar therapeutic effects as salicylazosulfapyridine (SASP) on IBD treatment. The potential mechanisms might be, at least in part, related to the adjustment of imbalance of Th17/Treg cells and the inhibition of IL-23/IL17 inflammatory signal axis.