Nanoplastics induces oxidative stress and triggers lysosome-associated immune-defensive cell death in the earthworm Eisenia fetida. (April 2023)

• Record Type: Journal Article
• Authors: Zhou, Yanfei; He, Gang; Jiang, Hao; Pan, Ke; Liu, Wenzhi
• Is Part Of: Environment international. Volume 174(2023)
• Publication Date: 2023-04
• Subjects: Ecological effects -- Nanoparticles -- Soil fauna -- Bioaccumulation -- Nanotoxicology; Environmental protection -- Periodicals; Environmental health -- Periodicals; Environmental monitoring -- Periodicals; Environmental Monitoring -- Periodicals; Environnement -- Protection -- Périodiques; Hygiène du milieu -- Périodiques; Environnement -- Surveillance -- Périodiques; Environmental health; Environmental monitoring; Environmental protection; Periodicals; 333.705
• DOI: 10.1016/j.envint.2023.107899
• Languages: English
• ISSNs: 0160-4120

Abstract

Graphical abstract: Highlights: The accumulation of nanoplastics lead to adverse effects on soil fauna. Positively charged and ecologically relevant nanoplastics exerted significant toxicity. Immune defense was provoked to counteract the challenge of nanoplastics. Aggregations of nanoplastics in lysosomes induced coelomocyte death. Abstract: Nanoplastics (NPs) are increasingly perceived as an emerging threat to terrestrial environments, but the adverse impacts of NPs on soil fauna and the mechanisms behind these negative outcomes remain elusive. Here, a risk assessment of NPs was conducted on model organism (earthworm) from tissue to cell. Using palladium-doped polystyrene NPs, we quantitatively measured nanoplastic accumulation in earthworm and investigated its toxic effects by combining physiological assessment with RNA-Seq transcriptomic analyses. After a 42-day exposure, earthworm accumulated up to 15.9 and 143.3 mg kg −1 of NPs for the low (0.3 mg kg −1 ) and high (3 mg kg −1 ) dose groups, respectively. NPs retention led to the decrease of antioxidant enzyme activity and the accumulation of reactive oxygen species (O2 − and H2 O2 ), which reduced growth rate by 21.3 %–50.8 % and caused pathological abnormalities. These adverse effects were enhanced by the positively charged NPs. Furthermore, we observed that irrespective of surface charge, after 2 h of exposure, NPs were gradually internalized by earthworm coelomocytes (∼0.12 μg per cell) and mainly amassed at lysosomes. Those agglomerations stimulated lysosomal membranes to lose stability and even rupture, resulting in impeded autophagy process and cellular clearance, and eventually coelomocyte death. In comparison with negatively charged nanoplastics, the positively charged NPs exerted 83 % higher cytotoxicity. Our findings provide a better understanding of how NPs posed harmful effects on soil fauna and have important implications for evaluating the ecological risk of NPs.