Systemic effects of nanoplastics on multi-organ at the environmentally relevant dose: The insights in physiological, histological, and oxidative damages

Nanoplastics (NPs) are ubiquitous contaminants that have adverse effects on human health. Previous research has explored the toxicity of NPs on specific organs at high doses, but this is insufficient for accurate health risk assessments. In the present study, a systematic study of NPs toxicity in the liver, kidney, and intestine was performed on mice at an equivalent dose of potential human exposure and toxic dose for four weeks. The results revealed that NPs penetrated the intestinal barrier and accumulated in various organs including liver, kidney, and intestine via the clathrin-mediated endocytosis, phagocytosis, and paracellular pathways. At the toxic dose, damage scores on physiology, morphology, and redox balance were more than twice that at the environmentally relevant dose, which was dose-depended. The jejunum experienced the most severe damage compared to the liver and kidney. In addition, a significant correlation between biomarkers was found, such as TNF-α and cholinesterase levels, indicating a close connection between the intestine and liver. Remarkably, the NPs exposed mice had an approximate double reactive oxygen species content compared to the control. This study promotes comprehensive understanding of health risks caused by NPs throughout the body and informs future policies and regulations to mitigate NPs-related health concerns.