The Anti-Inflammatory Effect of Guchangzhixie-Pill by Reducing Colonic EC Cell Hyperplasia and Serotonin Availability in an Ulcerative Colitis Rat Model

Ulcerative colitis (UC) is one of the major types of inflammatory bowel diseases (IBD). Abnormal colonic enterochromaffin (EC) cell hyperplasia and serotonin availability have been described in UC. Guchangzhixie-pill (GCZX-pill), a Chinese herbal formula composed of six herbs, is modified based on a traditional formula (Jiechangyan-pill) for inflammatory and ulcerative gastrointestinal disorders. This study aims to investigate the anti-inflammatory effect and the underlying mechanisms of GCZX-pill on trinitrobenzene sulfonic acid- (TNBS-) induced UC in rats. After orally administrating a GCZX-pill to UC rats for 14 days, the results of the inflammation evaluation, such as disease activity index (DAI), macroscopic score (MS), myeloperoxidase (MPO) activity, and other methods, suggested that the GCZX-pill showed remarkable anti-inflammatory results in UC rats. In addition, the abnormal EC cell numbers, colonic tryptophan hydroxylase (TPH) expression, and serotonin (5-HT) contents in TNBS-induced UC rats were significantly reduced by the GCZX-pill. This data demonstrates that the GCZX-pill can attenuate the inflammation in UC rats and the anti-inflammatory effect of the GCZX-pill may be medicated by reducing colonic EC cell hyperplasia and 5-HT availability.