Short-term effects of Poly(I:C) on gut permeability

Area of Science:

• Gastroenterology
• Immunology
• Epithelial Biology

Background:

• Intestinal barrier function is crucial for pathogen defense.
• Toll-like receptor 3 (TLR-3) recognizes viral double-stranded RNA.
• The effect of luminal TLR-3 agonists on gut barrier integrity is largely unknown.

Purpose of the Study:

• To investigate the short-term effects of Poly(I:C) on rat ileal and colonic permeability ex vivo.
• To assess the acute impact of intrarectal Poly(I:C) administration on colonic barrier function.

Main Methods:

• Ex vivo incubation of rat ileum and colon with Poly(I:C).
• Measurement of transepithelial electrical resistance (TEER).
• Assessment of macromolecule (dextran) transit across the mucosa.
• In vivo intrarectal administration of Poly(I:C) followed by ex vivo gut sac assays.

Main Results:

• Ileum tissues showed decreased TEER after Poly(I:C) exposure, indicating increased permeability to small molecules.
• Colon tissues exhibited reduced thinning of the mucosal layer and decreased macromolecule transit after Poly(I:C) stimulation.
• In vivo administration of Poly(I:C) led to decreased colonic permeability to macromolecules.

Conclusions:

• Acute Poly(I:C) exposure differentially affects intestinal barrier function, reducing colon permeability while increasing ileum permeability.
• This study is the first to report a direct effect of a TLR-3 ligand on intestinal barrier function.
• Findings suggest region-specific interactions between gut mucosa and microbiota influenced by TLR-3 activation.