Bushen Jianpi Qingchang Formula Ameliorates Colitis in Rats by Regulating Bile Acid Metabolism and Gut Microbiota

Traditional Chinese medicine (TCM) is widely used for the management of ulcerative colitis (UC) owing to its validated efficacy and favorable safety profile. The core pathogenesis of chronic refractory UC involves spleen and kidney deficiency accompanied by intestinal dampness-heat accumulation, and the Bushen-Jianpi-Qingchang formula (BJQF) is a clinically validated compound prescription for this condition. This study aimed to investigate the therapeutic effects of BJQF and its three decomposed sub-formulas (Bushen formula, BSF; Jianpi formula, JPF; Qingchang formula, QCF) on dextran sulfate sodium (DSS)-induced colitis in rats, and characterize their regulatory effects on fecal bile acid (BA) profiles and gut microbial communities. Fecal bacterial composition and BA concentrations in DSS-induced UC rats were quantified via 16S rRNA gene sequencing and liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the potential association between gut microbiota and BA metabolism was analyzed. BJQF significantly ameliorated colonic inflammation and ulceration in the UC model. Distinct alterations in bacterial diversity and composition were identified between colitis rats and healthy controls. The association between differential bacteria and BAs was centered on 23-deoxycholic acid (23-DCA) as a key metabolic node. Notably, taurolithocholic acid-3-sulfate (TLCA-3S) and lithocholic acid-3-sulfate (LCA-3S) may serve as potential efficacy biomarkers. The JPF sub-formula exhibited efficacy most similar to the complete BJQF. Administration of BJQF and its decomposed formulas effectively ameliorates histopathological damage, inflammation, gut microbial dysbiosis, and BA metabolic disturbance in UC rats, providing a mechanistic basis for TCM compound therapy.