Institute for Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China.
State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China.
Sci Total Environ. 2024 Nov 1;949:175132. doi: 10.1016/j.scitotenv.2024.175132. Epub 2024 Jul 29.
Microplastics, recognized as emerging contaminants, are commonly observed to be charged in the environment, potentially exerting toxic effects on various organisms. However, the transgenerational reproductive toxicity and underlying mechanisms of polystyrene (PS), particularly carboxyl-modified PS (PS-COOH) and amino-modified PS (PS-NH), remain largely unexplored. In this study, the parental generation (P0) of Caenorhabditis elegans was subjected to environmental concentrations (0.1-100 μg/L) of PS, PS-COOH, and PS-NH, with subsequent generations (F1-F4) cultured under normal conditions. Exposure to PS-NH at concentrations of 10-100 μg/L exhibited more pronounced reproductive toxicity compared to PS or PS-COOH, resulting in decreased brood size, egg ejection rate, number of fertilized eggs, and cell corpses per gonad. Similarly, maternal exposure to 100 μg/L of PS-NH induced more severe transgenerational reproductive effects in C. elegans. Significant increases in H3 on lysine 4 dimethylation (H3K4me2) and H3 on lysine 9 trimethylation (H3K9me3) levels were observed in the subsequent generation, concurrent with the transgenerational upregulation of set-30 and met-2 following parental exposure to PS, PS-COOH, and PS-NH. Correlation analyses revealed significant associations between the expression of these genes with the reproductive ability. Molecular docking studies suggested that PS-NH exhibited higher affinity for SET-30 and MET-2. Further analysis demonstrated that transgenerational effects on reproduction were absent in set-30(gk315) and met-2(n4256) mutants, highlighting the pivotal role of set-30 and met-2 in mediating the transgenerational effect. This study provides novel insights into the environmental risks associated with negatively and positively charged microplastics.
微塑料被认为是新兴污染物，在环境中普遍观察到带有电荷，可能对各种生物产生毒性作用。然而，聚苯乙烯（PS），特别是羧基化改性聚苯乙烯（PS-COOH）和氨基化改性聚苯乙烯（PS-NH）的跨代生殖毒性及其潜在机制在很大程度上仍未得到探索。在这项研究中，秀丽隐杆线虫的亲代（P0）暴露于环境浓度（0.1-100μg/L）的 PS、PS-COOH 和 PS-NH 中，随后在正常条件下培养后代（F1-F4）。与 PS 或 PS-COOH 相比，PS-NH 在 10-100μg/L 浓度下表现出更明显的生殖毒性，导致产卵量、卵排出率、受精卵数量和每个生殖腺的细胞尸体减少。同样，亲代暴露于 100μg/L 的 PS-NH 诱导秀丽隐杆线虫更严重的跨代生殖效应。在随后的代中观察到组蛋白 H3 在赖氨酸 4 上二甲基化（H3K4me2）和 H3 在赖氨酸 9 上三甲基化（H3K9me3）水平显著增加，同时在亲代暴露于 PS、PS-COOH 和 PS-NH 后，set-30 和 met-2 发生跨代上调。相关性分析表明，这些基因的表达与生殖能力之间存在显著关联。分子对接研究表明 PS-NH 对 SET-30 和 MET-2 具有更高的亲和力。进一步的分析表明，在 set-30(gk315) 和 met-2(n4256) 突变体中不存在对生殖的跨代效应，这突出了 set-30 和 met-2 在介导跨代效应中的关键作用。这项研究为带负电荷和带正电荷的微塑料与环境风险之间的关系提供了新的见解。
