YINDARA-4 relieves visceral hypersensitivity in irritable bowel syndrome rats via regulation of gut microbiota and serotonin levels

Objective: The present study aims to evaluate the in vivo efficacy of YINDARA-4 in improving the symptoms of irritable bowel syndrome (IBS) in a rat model and investigate the impact of YINDARA-4 on potential targets of IBS management, such as the serotonin level in intestinal tissues and the structure and composition of the gut microbiota. Methods: We developed an IBS rat model by combining stress from maternal separation, acetic acid administration, and restraint. We administered YINDARA-4 water extract to the IBS rat model for 10 consecutive days. The fecal water content, visceral sensitivity, gut microbiota, and serotonin levels in the colonic tissue were then analyzed and compared between the control group, IBS model group, and YINDARA-4–treated groups. Results: Treatment with YINDARA-4 reversed visceral hypersensitivity in a dose-dependent manner in the experimental rat model of IBS. The relief of visceral hypersensitivity upon treatment with YINDARA-4 involved regulation of the gut microbiota structure and composition, and normalization of elevated serotonin levels in the colon. The decrease in colonic serotonin levels with YINDARA-4 treatment might be associated with a reduction in the abundance of Helicobacter and enrichment of Butyricimonas. Conclusions: Treatment with YINDARA-4 was beneficial against visceral hypersensitivity in a rat model of IBS. The improved symptoms exhibited in IBS rats were associated with favorably altered gut microbiota and normalization of serotonin levels in the colon.