Tongxie Yaofang ameliorates chronic relapsing ulcerative colitis by regulating gut microbiota and microbial...

Tongxie Yaofang (TXYF) is a classical traditional Chinese medicine (TCM) formula described in ancient medical literature. It has been widely used for the treatment of diarrhea and has a long-standing, well-documented ethnomedicinal history. Modern studies have demonstrated its remarkable therapeutic efficacy in ulcerative colitis (UC); however, the mechanisms by which TXYF modulates intestinal microecological homeostasis remain incompletely understood. This study provides a theoretical basis for developing novel therapeutic strategies derived from traditional medicinal knowledge.

This study used a mouse model of chronic relapsing ulcerative colitis to investigate thetherapeutic effects of the TCM formula TXYF and to elucidate its regulatory mechanisms involving gut microbiota and microbiota-derived metabolites.

Ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was utilized to identify the principal chemical constituents of Tongxie Yaofang, as well as the bioactive components absorbed into systemic circulation. A chronic relapsing UC mouse model was established using dextran sulfate sodium (DSS) combined with restraint stress and intermittent fasting, followed by intervention with different doses of TXYF. Therapeutic efficacy was evaluated based on changes in body weight, disease activity index (DAI) scores, and colon length. Colonic pathological injury was evaluated using hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) staining. Inflammatory responses and intestinal barrier injury were evaluated using enzyme-linked immunosorbent assay, Western blotting, and fluorescence immunohistochemistry (FIHC). Furthermore, an antibiotic cocktail (ABX) experiment was conducted to determine whether the gut microbiota mediates the therapeutic effects of Tongxie Yaofang. Finally, 16S rRNA gene sequencing and untargeted metabolomic analyses were performed to investigate alterations in the gut microbiota and associated metabolites.

Chronic relapsing UC was characterized by body weight loss, elevated DAI scores, colon shortening, marked colonic histopathological injury, increased levels of inflammatory mediators, and impaired intestinal barrier function. TXYF significantly ameliorated these pathological manifestations in a dose-dependent manner. Depletion of the gut microbiotathrough ABX treatment markedly diminished the therapeutic efficacy of TXYF, indicating that the gut microbiota plays a critical role in mediating its therapeutic effects. Multi-omics analysis revealed pronounced microbiota-metabolite synergistic dysregulation in chronic relapsing UC, characterized by the enrichment of opportunistic pathogens, disturbances in amino acid and indole metabolism, and dysregulation of lipid-derived inflammatory mediators. TXYF restored intestinal microecological and metabolic homeostasis by suppressing proinflammatory microbial taxa and modulating the interaction network among beneficial bacteria and amino acid, indole, and lipid metabolites.

Based on a chronic relapsing UC model, this study integrated ABX-mediated gut microbiota depletion with multi-omics analyses to systematically investigate the mechanism by which TXYF ameliorates chronic relapsing UC. The findings indicate that the anti-UC effects of TXYF depend on the integrity of the gut microbiota, and that TXYF may restore intestinal microecological homeostasis by regulating the "gut microbiota-metabolites-intestinal barrier-inflammatory response" network. These results provide new experimental evidence for elucidating how traditional Chinese medicine formulas improve chronic relapsing UC through microecological modulation.