Tong-Xie-Yao-Fang improves chronic intestinal fibrosis in mice with colitis through CRH-R2-mediated IL-6/STAT3 signaling pathway

Abstract

Purpose: To investigate the potential mechanism of action of Tong-Xie-Yao-Fang (TXYF) on inflammation-related intestinal fibrosis in  mice. In addition, to examine dextran sodium sulfate (DSS) induction and the stimulation of human intestinal fibroblasts (CCD-18Co) by  transforming growth factorβ1 (TGF-β1). Methods: Chronic colitis in C57BL/6 mice was induced by administering 2 % DSS and TXYF extract (11.2 g/kg per day). An intestinal fibrosis cell model was constructed by stimulating CCD-18Co cells with TGF-β1 (10 ng/mL). The status  and weight loss of colitis of the mice was assessed by Disease Activity Index (DAI) while colonic tissue injury and fibrosis were assessed  using hematoxylin-eosin (H&E)  staining and Masson’s trichrome staining. Relative expression levels of corticotrophin-releasing hormone  receptor 2 (CRH-R2) and Interleukin 6 (IL-6)/signal transducer and activator of transcription 3 (STAT3) in colon tissues and  CCD-18Co cells were determined using Western blot. A cell model of intestinal fibrosis was constructed by stimulating CCD-18Co cells with  TGF-β1 (10 ng/mL). At the same time, the cells were subjected to the intervention of TXYF drug-containing serum (TXYF-DS).   Results: TXYF significantly improve the pathological changes, weight loss, and DAI score of colon tissue in DSS induced colitis mice (p <  0.05). The expression levels of IL-6 and p-STAT3 were significantly reduced, while the expression level of CRH-R2 was upregulated in the  mouse colon tissue (p < 0.05). At the cellular level, TXYF-DS intervention significantly reduced cell mortality and mitigated the degree of  cell fibrosis (p < 0.05). Furthermore, the expression level of CRH-R2 was up-regulated while that of IL-6 and p-STAT3 were down-regulated.  Conclusion: TXYF ameliorates chronic intestinal fibrosis in colitis-afflicted mice by restricting IL6/STAT3 signaling pathway  whilst upregulating CRH-R2 expression