Qingchang Huashi Formula attenuates DSS-induced colitis in mice by restoring gut microbiota-metabolism homeostasis and goblet cell function

Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disease of the gastrointestinal tract, consisting of ulcerative colitis (UC) and Crohn's disease (CD). Gut microbiota and their metabolites may play a role in the pathogen of IBD, especially of the UC. Qingchang Huashi Formula (QHF), a traditional Chinese medicine formula, has shown therapeutic effect on treating UC based on the clinical practice without clear pharmacological mechanism. The aim of this study was to clearly define the effect of QHF and its components, Baitouweng (PBR) and Baizhi (ADR) on treating UC. Pharmacodynamic effects of QHF and single herb were evaluated in dextran sulfate sodium (DSS) induced acute or chronic colitis mice. Body weight loss, disease activity index (DAI) and colon length were estimated. Histological changes were observed by H&E staining. The number and abundance of gut microbiota were measured with 16S rRNA sequencing. LC-MS and GC-MS were used to detect the concentration of metabolites (e.g., bile acids (BAs) and short chain fatty acids (SCFAs)). The goblet cell was observed by Alcian blue/periodic acid-Schiff (AB/PAS) straining and the crypt stem cell was estimated by immunohistochemical analyses. The colorectal tissues were used to detect levels of IL-1β, IL-6 and TNF-α by ELISA or qRT-PCR. The expression of NLRP3, Caspase 1 and IL-1β were examined by western blotting. QHF significantly inhibited colitis, protected mice from the loss of body weight and colon shorten. Comparatively, ADR and PBR showed strong efficacy in inhibiting DSS-induced colitis. We verified that while ADR was responsible for QHF's effect on maintaining gut microbiota homeostasis and metabolism, PBR was more prominent in keeping crypt stem cells proliferation and colonic goblet cells function. Moreover, we demonstrated that the alleviation of colitis by QHF was associated with the restoration of gut microbiota-metabolism homeostasis, protection of intestinal epithelial barrier and regulation of NLRP3/IL-1β pathway. The finding of the present study suggested that QHF is curative in DSS-induced colitis by restoring gut microbiota-metabolism homeostasis and goblet cells function. An optimized QHF was constituted by ADR and PBR, which showed comparable efficacy on colitis to that of QHF. Our work probed out the active constitutes as well as the relevant pharmacological mechanisms of QHF, shedding light on potential new drug combination for the treatment of IBD.