Aquatic Contaminants Research Division, Environment and Climate Change Canada, 105 McGill street, 7th Floor, Montréal, QC H2Y 2E7, Canada.
Aquatic Contaminants Research Division, Environment and Climate Change Canada, 105 McGill street, 7th Floor, Montréal, QC H2Y 2E7, Canada.
Ecotoxicol Environ Saf. 2021 Jan 15;208:111588. doi: 10.1016/j.ecoenv.2020.111588. Epub 2020 Nov 9.
Rare earth elements (REEs) have been recently identified as emergent contaminants because of their numerous and increasing applications in technology. The impact of REEs on downstream ecosystems, notably aquatic organisms, is of particular concern, but has to date been largely overlooked. The purpose of this study was thus to evaluate the toxicity of lanthanide metals, lutetium (Lu) and dysprosium (Dy) in rainbow trout after 96 h of exposure. The lethal concentration (LC50) was determined and the expression of 14 genes involved in different pathways such as oxidative stress, xenobiotic detoxification, mitochondrial respiration, DNA repair, protein folding and turnover, inflammation, calcium binding and ammonia metabolism were quantified in surviving fish. In parallel, lipid peroxidation (LPO), DNA damage (DSB), metallothionein level (MT) and cyclooxygenase activity (COX) were examined. The acute 96 h-LC data revealed that Lu was more toxic than Dy (1.9 and 11.0 mg/L, respectively) and was able to affect all investigated pathways by changing the expression of the studied genes, to the exception of superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST). It also induced a decrease in DNA repair at concentrations 29 times below the LC. This suggests that Lu could trigger a general stress to disrupt the cell homeostasis leading to genotoxicity without promoting oxidative stress. However, Dy induced modulation in the expression of genes involved in the protection against oxidative stress, detoxification, mitochondrial respiration, immunomodulation, protein turnover and an increase in the DNA strand breaks at concentrations 170 times lower than LC. Changes in mRNA level transcripts could represent an early signal to prevent against toxicity of Dy, which exhibited inflammatory and genotoxic effects. This study thus provides useful knowledge enhancing our understanding of survival strategies developed by rainbow trout to cope with the presence of lanthanides in the environment.
稀土元素（REEs）因其在技术中的众多应用而被认为是新兴污染物。REEs 对下游生态系统的影响，特别是对水生生物的影响，引起了特别关注，但迄今为止在很大程度上被忽视了。因此，本研究旨在评估镥（Lu）和镝（Dy）在虹鳟鱼暴露 96 小时后的毒性。测定了致死浓度（LC50），并定量了 14 种参与不同途径的基因的表达，如氧化应激、外源性解毒、线粒体呼吸、DNA 修复、蛋白质折叠和周转、炎症、钙结合和氨代谢。同时，还检测了脂质过氧化（LPO）、DNA 损伤（DSB）、金属硫蛋白水平（MT）和环氧化酶活性（COX）。急性 96 小时 LC 数据表明，Lu 比 Dy 更具毒性（分别为 1.9 和 11.0mg/L），并通过改变研究基因的表达来影响所有研究的途径，除了超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽-S-转移酶（GST）。它还在 LC 以下 29 倍的浓度下诱导 DNA 修复减少。这表明 Lu 可以引发一般应激，破坏细胞内稳态，导致遗传毒性，而不会促进氧化应激。然而，Dy 在 LC 浓度低 170 倍时诱导参与抗氧化应激、解毒、线粒体呼吸、免疫调节、蛋白质周转和 DNA 链断裂增加的基因表达的调节。mRNA 水平转录物的变化可能代表一种早期信号，以防止 Dy 的毒性，Dy 表现出炎症和遗传毒性作用。因此，本研究提供了有用的知识，增强了我们对虹鳟鱼为应对环境中镧系元素而开发的生存策略的理解。
