Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 0C5, Canada.
Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China.
Comp Biochem Physiol C Toxicol Pharmacol. 2021 Sep;247:109056. doi: 10.1016/j.cbpc.2021.109056. Epub 2021 Apr 21.
Micro- and nanoplastics (MNPs) are ubiquitous in aquatic and terrestrial environments, and detrimental biological effects have been observed on a variety of organisms, from bacteria and alga to plants and animals. A fast-growing number of toxicological studies report diverse responses and wide species-dependent sensitivity upon MNP exposure. While studies are dominated by in vivo animal tests, our understanding of cellular toxicity and the corresponding toxicity mechanisms is still limited. This challenges the proper assessment of environmental hazards and health risks of MNPs. In this review, we gathered and analyzed the up-to-date studies on humans, animals, plants, alga, and bacteria, and identified the similarities and differences in key toxicity mechanisms of MNPs across different taxonomic groups. Particularly, human cell-based studies at the cellular level provide fundamental and valuable information on the key toxicity mechanisms, which are essential to answer the question of whether and how MNPs pose health threats. In general, toxicity mechanisms of MNPs depend on their size, surface characteristics, polymer type, as well as cell type. Plausible toxicity mechanisms mainly include membrane disruption, extracellular polymeric substance disruption, reactive oxygen species generation, DNA damage, cell pore blockage, lysosome destabilization, and mitochondrial depolarization. A deeper understanding of these key mechanisms in different taxonomic groups can also improve both in vivo and in vitro models useful for predictive impact assessments of plastic pollution on the environment and human health.
微塑料和纳米塑料（MNPs）广泛存在于水生态系统和陆地生态系统中，已观察到它们对各种生物（从细菌和藻类到植物和动物）都具有有害的生物学效应。越来越多的毒理学研究报告表明，在暴露于 MNPs 后，各种生物会产生不同的反应和广泛的物种依赖性敏感性。虽然这些研究主要以体内动物试验为主，但我们对细胞毒性及其相应毒性机制的认识仍然有限。这对 MNPs 的环境危害和健康风险的正确评估提出了挑战。在这篇综述中，我们收集和分析了关于人类、动物、植物、藻类和细菌的最新研究，确定了不同分类群中 MNPs 的关键毒性机制的相似性和差异性。特别是，基于人类细胞的细胞水平研究为关键毒性机制提供了基本而有价值的信息，这些信息对于回答 MNPs 是否以及如何构成健康威胁的问题至关重要。一般来说，MNPs 的毒性机制取决于其尺寸、表面特性、聚合物类型以及细胞类型。推测的毒性机制主要包括膜破坏、细胞外聚合物物质破坏、活性氧物质生成、DNA 损伤、细胞孔阻塞、溶酶体不稳定和线粒体去极化。深入了解不同分类群中的这些关键机制，也可以改进体内和体外模型，这些模型对于评估塑料污染对环境和人类健康的潜在影响非常有用。
