Abdominal massage alleviates IBS-D by modulating the gut microbiota and suppressing the LPS/TLR4/NF-κB/MLCK pathway

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common functional gastrointestinal disorder with complex and incompletely understood pathophysiology. This study aimed to investigate the therapeutic effects and underlying mechanisms of abdominal massage on diarrhea-predominant IBS-D using a rat model.

IBS-D was induced in Sprague-Dawley rats through a combination of maternal separation and chronic stress. The experimental interventions consisted of abdominal massage and fecal microbiota transplantation (FMT) using donor microbiota obtained from IBS-D + abdominal massage rats. Assessments included fecal moisture content (FMC), Bristol stool scores, visceral hypersensitivity, intestinal motility, open field test, gut microbiota, short-chain fatty acids (SCFAs), inflammatory markers (LPS, TLR4/MyD88/NF-κB pathway), and intestinal barrier integrity (TEM, tight junction proteins, FITC-dextran permeability).

Abdominal massage significantly improved diarrheal symptoms, visceral hypersensitivity, gastrointestinal motility, and anxiety-like behaviors in IBS-D rats. It restored gut microbiota diversity, reduced SCFA levels, and suppressed the TLR4/MyD88/NF-κB pathway, leading to decreased pro-inflammatory cytokines and LPS levels. FMT replicated these effects, suggesting the role of gut microbiota modulation. Moreover, abdominal massage also ameliorated barrier dysfunction in IBS-D rats by restoring ultrastructure, modulating MLCK and junctional proteins, and reducing macromolecular permeability.

Abdominal massage alleviates IBS-D symptoms by modulating gut microbiota, inhibiting the TLR4/MyD88/NF-κB/MLCK signaling pathway, reducing inflammation, and restoring intestinal barrier function. These findings support its potential as a non-invasive therapeutic strategy for IBS-D.