Interdisciplinary Program of Bioenergy and Biomaterials Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea.
Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju 61186, Republic of Korea.
Ecotoxicol Environ Saf. 2024 Sep 15;283:116847. doi: 10.1016/j.ecoenv.2024.116847. Epub 2024 Aug 10.
Plastics are widely used worldwide due to their convenience. However, microplastics (MPs) accumulation poses a serious threat to ecosystem health. Therefore, understanding the effects of MPs on living organisms within their native ecosystem is crucial. Previous studies have primarily focused on the impacts of MPs in aquatic environments, whereas the effects of MPs on terrestrial ecosystems have remained largely understudied. Therefore, our study assessed the impacts of MPs on soil ecosystems by characterizing their toxic effects on earthworms (Eisenia fetida). Here, we exposed earthworms to two representative plastics within soil environments: polyvinyl chloride (PVC) and low-density polyethylene (LDPE). Given the known link between MPs and oxidative stress, we next quantified oxidative stress markers and mitochondrial function to assess the effects of MPs on the redox metabolism of earthworms. Mitochondria are crucial metabolic organelles that generate reactive oxygen species via uncontrolled ATP production. Our findings demonstrated that MPs exert different effects depending on their type. Neither the PVC-exposed groups nor the LDPE-exposed groups exhibited changes in oxidative stress, as worked by the action of superoxide dismutase (SOD) and glutathione (GSH). While treatment of the two types of MP did not significantly affect the amount of reactive oxygen species/reactive nitrogen species (ROS/RNS) generated, PVC exhibited a more pronounced effect on antioxidant system compared to LDPE. However, mitochondrial function was markedly decreased in the group exposed to high LDPE concentrations, suggesting that the examined LDPE concentrations were too low to activate compensatory mechanisms. Collectively, our findings demonstrated that exposure of MPs not only influences the antioxidant defense mechanisms of earthworms but also alters their mitochondrial function depending on their types.
塑料由于其便利性而在全球范围内得到广泛应用。然而，微塑料（MPs）的积累对生态系统健康构成了严重威胁。因此，了解 MPs 对其原生生态系统中生物的影响至关重要。以前的研究主要集中在 MPs 在水生环境中的影响，而 MPs 对陆地生态系统的影响在很大程度上仍未得到充分研究。因此，我们的研究通过表征 MPs 对土壤生态系统中的蚯蚓（赤子爱胜蚓）的毒性作用来评估 MPs 对土壤生态系统的影响。在这里，我们将蚯蚓暴露在土壤环境中的两种代表性塑料中：聚氯乙烯（PVC）和低密度聚乙烯（LDPE）。鉴于已知 MPs 与氧化应激之间存在联系，我们接下来量化了氧化应激标志物和线粒体功能，以评估 MPs 对蚯蚓氧化还原代谢的影响。线粒体是产生活性氧物质的关键代谢细胞器，通过不受控制的 ATP 产生产生活性氧物质。我们的研究结果表明，MPs 根据其类型产生不同的影响。暴露于 PVC 的组和暴露于 LDPE 的组都没有表现出氧化应激的变化，这是由超氧化物歧化酶（SOD）和谷胱甘肽（GSH）的作用产生的。虽然两种类型的 MP 处理都没有显著影响生成的活性氧物质/活性氮物质（ROS/RNS）的量，但 PVC 对抗氧化系统的影响比 LDPE 更为明显。然而，暴露于高 LDPE 浓度组的线粒体功能明显降低，表明所研究的 LDPE 浓度太低，无法激活代偿机制。总的来说，我们的研究结果表明，MPs 的暴露不仅影响蚯蚓的抗氧化防御机制，而且还根据其类型改变其线粒体功能。
