Electroacupuncture-Regulated Bile Acid Metabolism and Farnesoid X Receptor Expression in Constipation-Predominant Irritable Bowel Syndrome Rat: A Preclinical Study

INTRODUCTION: The efficacy of electroacupuncture (EA) treatment in alleviating visceral hypersensitivity with irritable bowel syndrome (IBS) has been established. Abnormal bile acid metabolism and farnesoid X receptor (FXR) expression are recognized as potential contributors to visceral hypersensitivity in IBS. This study as a preclinical study of IBS visceral hypersensitivity explored the potential of EA to reduce visceral hypersensitivity in rats with IBS by improving bile acid metabolism and FXR expression. METHODS: Heterotypic intermittent stress (HIS) for 9 days was used to induce visceral hypersensitivity in constipation-predominant irritable bowel syndrome (IBS-C). EA/sham EA bilateral ST36 and LR3 acupoints began on the 5th day of HIS. Electromyography of the abdominal external oblique muscle and calcitonin gene-related peptide were used to assess colonic hypersensitivity. Colonoscopy and histopathological examination were used to evaluate pathological changes in the colon. Bile acid composition was analyzed using high-performance liquid chromatography-mass spectrometry, while FXR expression in colon tissue was quantified through immunofluorescence and Western blot. RESULTS: HIS induced visceral hypersensitivity in IBS-C rats. EA not only regulated bile acid levels in the feces of IBS-C rats, but also had a downregulatory effect on the overexpression of FXR in the colon tissue of rats with IBS-C. The therapeutic effects were better than those of the sham EA. EA treatment alleviated visceral hypersensitivity in the colon of IBS-C rats. CONCLUSION: Our data suggested that EA normalized colonic bile acid signaling and FXR protein expression in an IBS-C rat model, offering a mechanistic hypothesis for future clinical evaluation.