Qingjie Fuzheng Granules treat ulcerative colitis via regulating Th17/Treg cell balance

Abstract

Abstract Objective: To investigate the anti-inflammatory properties of Qingjie Fuzheng Granules (QFG)in vivo experiments using a DSS-induced ulcerative colitis (UC) model, and to elucidate the mechanism by which QFG alleviates UC by examining the Th17/Treg cell balance. Methods: The DSS-induced UC mouse model was established, and the mice were administrated with QFG (1 g/kg) or saline by gavage. The general growth of the mice, including body weight, fecal occult blood, and disease activity index (DAI), was observed, and the length of the colon was recorded. HE staining was utilized to examine the pathological injury of the colon tissue. The expression levels of TGF-β, IFN-γ, IDO1, IL-1β, TNF-α, IL-6, IL-17, IL-21, IL-22, IL-25, IL-10 in serum were detected by ELISA or Bio-Plex. The relative mRNA expressions in spleen and colon tissues were detected by RT-qPCR. The protein expressions of RORγt, Foxp3 or IDO1 in spleen and colon were detected by Western Blot or Immunohistochemical. Results: QFG demonstrated potential for improving the overall pathological conditions of UC mice induced by DSS, as evidenced by its significant inhibition of colon length shortening and improvement of colon tissue pathology. Additionally, QFG exhibited the ability to decrease the expression of pro-inflammatory cytokines IL-1β, TNF-α, IFN-γ and IL-6, as well as IDO1 expression. Moreover, QFG significantly reduced the expression of Th17-related cytokines (IL-17, IL-21, IL-22, IL-25) and concurrently increased the expression of Treg-related cytokines (IL-10, TGF-β). The expression of transcription factor RORγt was observed to decrease while the transcription factor Foxp3 was observed to increase in colon and spleen. Conclusion: QFG has demonstrated the ability to suppress inflammation in mice with DSS-induced UC. This effect is achieved through the inhibition of Th17 cell differentiation, the promotion of Treg cell differentiation, and the maintenance of Th17/Treg cell balance. These actions are mediated by the regulation of transcription factors RORγt and Foxp3. This mechanism may contribute significantly to the observed inhibition of colon inflammation in mice treated with QFG.