Multiomics Reveals Nonphagocytosable Microplastics Induce Colon Inflammatory Injury via Bile Acid-Gut Microbiota...

Area of Science:

• Environmental Science
• Toxicology
• Gastroenterology

Background:

• Microplastics (MPs) are global pollutants with emerging concerns regarding intestinal toxicity.
• Nonphagocytosable MPs (NPMs) cause colonic inflammation, but the mechanisms are not fully understood.

Purpose of the Study:

• To investigate the mechanisms by which 10 μm polystyrene MPs (PS MPs) induce colonic inflammation and injury in a mouse model.
• To elucidate the role of the gut-liver axis and bile acid metabolism in NPM-induced toxicity.

Main Methods:

• Establishment of a BALB/c mouse model with long-term oral exposure to 10 μm PS MPs.
• Assessment of colonic redox balance, immune homeostasis (Th17/Treg ratio, cytokines), and intestinal barrier function (mucin, tight junctions).
• Multiomics analysis to explore liver function, gut microbiota, and bile acid (BA) metabolism; in vitro and in vivo validation of specific BA effects.

Main Results:

• PS MPs exposure disrupted colonic redox balance, induced oxidative stress, and altered immune homeostasis.
• Intestinal barrier function was compromised, with reduced mucin and tight junction protein expression.
• PS MPs dysregulated bile acid metabolism via the liver-gut axis, leading to increased colonic bile acids, particularly conjugated BAs like TCDCA, which induced colonic epithelial cell apoptosis.

Conclusions:

• Nonphagocytosable microplastics induce colonic inflammation and injury through oxidative stress, immune dysregulation, and barrier dysfunction.
• Microplastic toxicity is mediated via a novel "liver-BA-gut axis," involving dysregulated bile acid metabolism.
• This study provides critical insights into the cross-organ mechanisms of microplastic intestinal toxicity.