Post-Graduation Program in Environmental Sciences, Federal University of Goiás, Goiânia, GO, Brazil.
Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute, Urutaí, GO, Brazil.
J Hazard Mater. 2022 Jun 15;432:128691. doi: 10.1016/j.jhazmat.2022.128691. Epub 2022 Mar 14.
Despite the toxicity of microplastics (MPs) in freshwater fish has been demonstrated in previous studies, their effects when mixed with other pollutants (organic and inorganic) are poorly understood. Thus, we aimed to test the hypothesis that the association of polyethylene MPs (PE-MPs) to a mix of emerging pollutants induces more adverse genotoxic, mutagenic, and redox unbalance effects in adult zebrafish (Danio rerio), after 15 days of exposure. Although the accumulation of MPs in animals was greater in animals exposed to PE-MPs alone, erythrocyte DNA damage (comet assay) and the frequency of erythrocytic nuclear abnormalities (ENAs) evidenced in zebrafish exposed to PE-MPs alone were as pronounced as those observed in animals exposed to the mix of pollutant (alone or in combination with MPs), which constitutes the big picture of the current study. Moreover, we noticed that such effects were associated with an imbalance between pro-and antioxidant metabolism in animals, whose activity of superoxide dismutase (SOD) and catalase (CAT) was assessed in different organs which were not sufficient to counterbalance the production of reactive oxygen species [hydrogen peroxide (HO)] and nitrogen [nitric oxide (NO)] evaluated. The principal component analysis (PCA) also revealed that while the antioxidant activity was more pronounced in the brain and liver of animals, the highest production of HO was perceived in the gills and muscles, suggesting that the biochemical response of the animals was organ-dependent. Thus, the present study did not demonstrate antagonistic, synergistic, or additive effects on animals exposed to the combination between PE-MPs and a mix of pollutants in the zebrafish, which reinforces the theory that interactions between pollutants in aquatic ecosystems may be as complex as their effects on freshwater ichthyofauna.
尽管先前的研究已经证明了微塑料（MPs）在淡水鱼中的毒性，但当它们与其他污染物（有机和无机）混合时的影响仍知之甚少。因此，我们旨在检验以下假设，即聚乙烯 MPs（PE-MPs）与新兴污染物混合物的结合会在 15 天的暴露后，在成年斑马鱼（Danio rerio）中引起更严重的遗传毒性、致突变性和氧化还原失衡效应。尽管单独暴露于 PE-MPs 的动物体内 MPs 的积累量更大，但单独暴露于 PE-MPs 的斑马鱼的红细胞 DNA 损伤（彗星试验）和红细胞核异常（ENAs）频率与单独暴露于污染物混合物（单独或与 MPs 结合）的动物一样明显，这构成了当前研究的全貌。此外，我们注意到，这些影响与动物体内抗氧化和促氧化剂代谢之间的失衡有关，我们评估了不同器官中超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的活性，以评估其活性，但其活性不足以抵消活性氧（H2O2）和氮（NO）的产生。主成分分析（PCA）还表明，虽然抗氧化活性在动物的大脑和肝脏中更为明显，但在鳃和肌肉中检测到最高的 H2O2 产生，这表明动物的生化反应依赖于器官。因此，本研究并未证明单独暴露于 PE-MPs 和污染物混合物的斑马鱼之间存在拮抗、协同或相加效应，这进一步证实了污染物在水生生态系统中的相互作用可能与其对淡水鱼类的影响一样复杂的理论。
