PET Microplastics Persist 14 Days in Mouse Lungs and Alter Allergen-Induced Inflammation, Study Finds

Inhaled PET microplastic particles remained detectable in the lungs of mice for at least 14 days after a single administration, according to researchers at the Medical University of Vienna. The particles also induced dose-dependent airway inflammation accompanied by increased lymphocytes and eosinophils.

The study, published in the Journal of Hazardous Materials Advances, stated that PET microplastics remained detectable in the lung for 14 days and induced airway inflammation with lymphocyte and eosinophil recruitment.

When combined with ragweed pollen, the microplastics exacerbated inflammation and altered the body’s defensive response against the allergen. ” The researchers reported that PET microplastics are biologically active particles that alter airway inflammation and immune responses in a dose- and context-dependent manner.

They also concluded that PET microplastics persist in the lung, induce airway inflammation, and modulate immune responses in a dose, timing, and context-dependent manner.

Reported airborne levels of PET have reached about 135-158 nanograms per cubic metre of air in cities. Researchers calculated that an adult inhaling 10–20 cubic metres of air daily may take in about 1–3 micrograms of microplastics. The study noted that the results were obtained in mouse models and may not be directly extrapolated to humans.

Researchers added that the findings support the inclusion of immune endpoints while emphasising the need for cautious extrapolation to real-world exposure scenarios. Microplastic particles are under 5mm in size. PET is one of the most widely used plastics worldwide.