Microplastic Release from Paper Cups Causes Metabolic and Reproductive Toxicity in Mice

The health implications of microplastics (MPs), especially those originating from disposable paper cups (DPCs), are increasingly alarming. We investigated the accumulation and metabolic and reproductive toxicological effects of MPs from DPCs in various tissues in a pregnant mouse model. Simulating human intake of 0.3, 3.3, and 33.3 cups daily, we found MPs exposure-induced dose-responsive harmful effects on fetal development and maternal physiology. MPs were detected in all 13 examined tissues, with the highest accumulation in the cecal contents, followed by significant depositions in the fetus, placenta, kidney, spleen, lung, and heart. A higher proportion of smaller MPs (90.35% being <10 µm) was identified in brain tissues. Dose-responsive changes in functional microbiome and gene pathways were observed in maternal blood, placenta, and mammary glands. Moderate MPs intake of 3.3 cups daily significantly altered cecal microbiome composition and metabolic functions. The transcriptomic functional variations in maternal blood, placenta, and mammary gland underscore the significant impacts of realistic MPs exposure on metabolic and immune health and posing neurodegenerative and miscarriage risks. Our results shed light on the tissue-specific deposition and metabolic and reproductive toxicity of MPs at realistic consumption levels.