Meta-analytical analysis on oxidative stress caused by micro- and nanoplastics in different life stages of Danio...

Microplastics, known for being persistent and widespread, are environmental small particles that have the potential to be considered as pollutants with different aspects of stress in the environment. This review is a meta-analysis based on 50 articles (2016-2023) with 403 estimations examining the relationship between exposure to micro- and nanoplastic particles (MP/NP) and oxidative stress in Danio rerio (zebrafish) in both larval and adult life stages. Results indicate that exposure to MP/NP may induce changes in markers of oxidative stress. Notably, a general decline in Glutathione Peroxidase (GPx) activity as well as an elevation in Reactive Oxygen Species (ROS) was identified. While GPx activity was diminished in adults and larvae, CAT activity was decreased only in adults and was unaltered in larvae. Glutathione S-transferase (GST) activity increased in adults but decreased in larvae. MDA content remained unchanged in adults but decreased significantly in larvae. ROS levels consistently demonstrated an increasing pattern in both life stages, and no significant alterations were detected in Superoxide Dismutase (SOD) activity and GSH levels. Tissue-specific analyses in adult D. rerio demonstrated diverse results, with reduced CAT in the brain and GPx in the gills, and increased GST in gills and liver, and enhanced ROS production in brain, gills, and liver. It seemed that different types of plastic (polystyrene and polypropylene) could induce different enzymatic profiles. Although these findings may provide indications of potential trends and serve as a reference for biomarker selection and risk assessment, the identified considerable heterogeneity and publication bias imply that the associated effect sizes should be interpreted with caution, highlighting the need for further, context-dependent studies.