and Galacto-Oligosaccharides Synbiotic Relieve Irritable Bowel Syndrome by Reshaping Gut Microbiota and Attenuating Mast Cell Hyperactivation.

BACKGROUND

Irritable bowel syndrome (IBS) significantly impairs the lifestyle and quality of life of the global population. However, the underlying pathophysiological mechanisms remain largely elusive. While conventional pharmacological approaches show limited therapeutic efficacy, emerging microbiota-targeted dietary interventions present promising alternatives.

OBJECTIVES

The present study aimed to elucidate the molecular mechanisms by which a synbiotic mitigates IBS and associated colonic dysfunctions in C57BL/6 mice.

METHODS

The mouse model was induced by a () infection combined with water avoidance stress (WAS). Galacto-oligosaccharides (GOS) were identified as the optimal carbon source for the growth of ZYC501 ( ZYC501), leading to the establishment of the synbiotic formulation.

RESULTS

The 32-day synbiotic intervention, consisting of ZYC501 (1 × 10 CFU/day) and GOS (10 g/L, /), significantly alleviated colonic transit dysfunction, visceral hypersensitivity, and anxiety-like behaviors in IBS mice. The synbiotic treatment significantly inhibited the expression levels of histamine, mast cell tryptase, and prostaglandin E2 (PGE2) ( < 0.05). The synbiotic also suppressed colonic inflammation by reducing the levels of lipopolysaccharide (LPS), , and ( < 0.05). Moreover, the synbiotic increased the expression of MUC2 and the production of short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate ( < 0.05). In terms of gut microbiota modulation, the synbiotic reshaped the gut microbiota composition, increasing the abundance of and while decreasing the levels of and . Correlation analysis further revealed a strong association among SCFAs, colonic inflammation, and the gut microbiota.

CONCLUSIONS

In conclusion, the synbiotic composed of ZYC501 and GOS effectively alleviates IBS and associated colonic dysfunctions by modulating the gut microbiota, reducing mast cell hyperactivity, and enhancing colonic barrier integrity. These findings provide a theoretical basis for developing gut microbiota-targeted dietary interventions for the management of IBS and improvement in gut health.