Center for Nanotechnology and Nanotoxicology, Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA.
MicRoN Core Facility, Department of Microbiology, Harvard Medical School, Boston, MA, 02115, USA.
Food Chem Toxicol. 2021 Dec;158:112609. doi: 10.1016/j.fct.2021.112609. Epub 2021 Oct 18.
Despite mounting evidence of increasing micro- and nanoplastics (MNPs) in natural environments, food, and drinking water, little is known of the potential health hazards of MNPs ingestion. We assessed toxicity and uptake of environmentally relevant MNPs in an in vitro small intestinal epithelium (SIE). Test MNPs included 25 and 1000 nm polystyrene (PS) microspheres (PS25 and PS1K); 25, 100, and 1000 nm carboxyl modified PS spheres (PS25C, PS100C, and PS1KC), and secondary MNPs from incinerated polyethylene (PEI). MNPs were subjected to 3-phase digestion to mimic transformations in the gastrointestinal tract (GIT) and digestas applied to the SIE. Carboxylated MNPs significantly reduced viability and increased permeability to 3 kD dextran. Uptake of carboxyl PS materials was size dependent, with significantly greater uptake of PS25C. Fluorescence confocal imaging showed some PS25C agglomerates entering cells independent of endosomes (suggesting diffusion), others within actin shells (suggesting phagocytosis), and many free within the epithelial cells, including agglomerates within nuclei. Pre-treatment with the dynamin inhibitor Dyngo partially reduced PS25 translocation, suggesting a potential role for endocytosis. These findings suggest that ingestion exposures to MNPs could have serious health consequences and underscore the urgent need for additional detailed studies of the potential hazards of ingested MNPs.
尽管越来越多的证据表明微塑料和纳米塑料（MNPs）在自然环境、食品和饮用水中存在，但人们对 MNPs 摄入的潜在健康危害知之甚少。我们评估了环境相关 MNPs 在体外小肠上皮（SIE）中的毒性和摄取。测试的 MNPs 包括 25nm 和 1000nm 聚苯乙烯（PS）微球（PS25 和 PS1K）；25nm、100nm 和 1000nm 羧基修饰 PS 球（PS25C、PS100C 和 PS1KC），以及来自焚烧聚乙烯（PEI）的次生 MNPs。MNPs 经历了 3 相消化以模拟胃肠道（GIT）中的转化，并将消化物应用于 SIE。羧基化 MNPs 显著降低了细胞活力并增加了对 3kD 葡聚糖的通透性。羧基 PS 材料的摄取与尺寸有关，PS25C 的摄取显著增加。荧光共焦成像显示一些 PS25C 聚集体独立于内体（暗示扩散）进入细胞，另一些则位于肌动蛋白壳内（暗示吞噬作用），许多聚集体在肠上皮细胞内自由存在，包括核内的聚集体。用动力蛋白抑制剂 Dyngo 预处理可部分减少 PS25 的转运，这表明内吞作用可能起作用。这些发现表明，摄入 MNPs 可能会对健康造成严重后果，并强调迫切需要对摄入 MNPs 的潜在危害进行更多详细的研究。
