Polystyrene microplastics induce potential toxicity through the gut-mammary axis.

Area of Science:

• Environmental Health
• Toxicology
• Microbiome Research

Background:

• Microplastics (MPs) are emerging pollutants with limited research on toxicity beyond the intestine.
• The link between MPs, intestinal microbiota, and organ toxicity is not well understood.

Purpose of the Study:

• To investigate the toxicity of polystyrene microplastics (PS-MPs) on the gut and mammary glands during lactation in mice.
• To explore the role of the gut microbiota in MP-induced toxicity via the gut-mammary axis.

Main Methods:

• Exposure of mice to PS-MPs (~1 μm) during lactation.
• Analysis of intestinal barrier function, colonic inflammation, and gut microbiota composition.
• Assessment of MP accumulation and inflammatory damage in mammary tissue.
• Transcriptome analysis for mammary gland disorders and ferroptosis.
• Fecal microbial transplant (FMT) to confirm the role of gut microbiota.

Main Results:

• PS-MPs disrupted the intestinal barrier, induced colonic inflammation, and caused gut microbiota dysbiosis.
• MPs accumulated in mammary tissue, leading to inflammatory damage, lipid metabolism disorders, and ferroptosis.
• Fecal microbial transplant (FMT) reproduced blood-milk barrier leakage and mammary gland inflammation.
• The gut-mammary axis plays a critical role in mediating MP-induced inflammation and damage.

Conclusions:

• PS-MPs can translocate to organs beyond the intestine, such as the mammary gland.
• Gut microbiota dysbiosis induced by MPs exacerbates inflammation and toxicity in the mammary gland.
• MPs pose potential foodborne risks, impacting maternal health and possibly infant exposure through milk.