Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure

TLDR

Microplastics are ubiquitous in oceans, rivers, soils, and even table salt, yet their toxicity in mammals remains poorly understood. The study aimed to assess the tissue distribution, accumulation, and potential health risks of microplastics in mice. Fluorescent and pristine polystyrene microplastics of 5 µm and 20 µm were administered to mice to map their distribution and accumulation. Microplastics accumulated in liver, kidney, and gut with size‑dependent kinetics, disrupting energy and lipid metabolism, inducing oxidative stress, and altering neurotoxic blood biomarkers, thereby revealing significant adverse effects.

Abstract

Abstract Microplastics (MPs) are a significant environmental health issue and increasingly greater source of concern. MPs have been detected in oceans, rivers, sediments, sewages, soil and even table salts. MPs exposure on marine organisms and humans has been documented, but information about the toxicity of MPs in mammal is limited. Here we used fluorescent and pristine polystyrene microplastics (PS-MPs) particles with two diameters (5 μm and 20 μm) to investigate the tissue distribution, accumulation, and tissue-specific health risk of MPs in mice. Results indicated that MPs accumulated in liver, kidney and gut, with a tissue-accumulation kinetics and distribution pattern that was strongly depended on the MPs particle size. In addition, analyses of multiple biochemical biomarkers and metabolomic profiles suggested that MPs exposure induced disturbance of energy and lipid metabolism as well as oxidative stress. Interestingly, blood biomarkers of neurotoxicity were also altered. Our results uncovered the distribution and accumulation of MPs across mice tissues and revealed significant alteration in several biomarkers that indicate potential toxicity from MPs exposure. Collectively, our data provided new evidence for the adverse consequences of MPs.