Institut national de la recherche scientifique (INRS), Centre Eau Terre Environnement, 490 de la Couronne, Québec, Québec G1K 9A9, Canada.
Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec G1V 0A6, Canada.
Aquat Toxicol. 2014 Sep;154:207-20. doi: 10.1016/j.aquatox.2014.05.024. Epub 2014 May 28.
In this experiment, we studied the transcriptional and functional (enzymatic) responses of yellow perch (Perca flavescens) to metal stress, with a focus on oxidative stress and vitamin A metabolism. Juvenile yellow perch were exposed to two environmentally relevant concentrations of waterborne cadmium (Cd) and nickel (Ni) for a period of 6 weeks. Kidney Cd and Ni bioaccumulation significantly increased with increasing metal exposure. The major retinoid metabolites analyzed in liver and muscle decreased with metal exposure except at high Cd exposure where no variation was reported in liver. A decrease in free plasma dehydroretinol was also observed with metal exposure. In the liver of Cd-exposed fish, both epidermal retinol dehydrogenase 2 transcription level and corresponding enzyme activities retinyl ester hydrolase and lecithin dehydroretinyl acyl transferase increased. In contrast, muscle epidermal retinol dehydrogenase 2 transcription level decreased with Cd exposure. Among antioxidant defences, liver transcription levels of catalase, microsomal glutathione-S-transferase-3 and glucose-6-phosphate dehydrogenase were generally enhanced in Cd-exposed fish and this up-regulation was accompanied by an increase in the activities of corresponding enzymes, except for microsomal glutathione-S-transferase. No consistent pattern in antioxidant defence responses was observed between molecular and biochemical response when fish were exposed to Ni, suggesting a non-synchronous response of antioxidant defence in fish exposed to waterborne Ni. There was a general lack of consistency between muscle transcription level and enzyme activities analyzed. The overall findings from this investigation highlight the usefulness of transcriptional and biochemical endpoints in the identification of oxidative stress and vitamin A metabolism impairment biomarkers and the potential use of multi-level biological approaches when assessing environmental risk in fish.
在这项实验中，我们研究了黄鲈（Perca flavescens）对金属胁迫的转录和功能（酶）反应，重点关注氧化应激和维生素 A 代谢。幼年黄鲈暴露于两种环境相关浓度的水基镉（Cd）和镍（Ni）中 6 周。肾脏 Cd 和 Ni 的生物积累随着金属暴露的增加而显著增加。在肝脏和肌肉中分析的主要类视黄醇代谢物随着金属暴露而减少，除了在高 Cd 暴露下肝脏中没有变化外。金属暴露也观察到游离血浆脱氢视黄醇的减少。在 Cd 暴露的鱼肝脏中，表皮视黄醇脱氢酶 2 的转录水平及其相应的酶活性视黄醇酯水解酶和卵磷脂脱氢视黄醇酰基转移酶均增加。相反，肌肉表皮视黄醇脱氢酶 2 的转录水平随着 Cd 的暴露而降低。在抗氧化防御中，肝脏中过氧化氢酶、微粒体谷胱甘肽-S-转移酶-3 和葡萄糖-6-磷酸脱氢酶的转录水平通常在 Cd 暴露的鱼中增强，并且这种上调伴随着相应酶活性的增加，除了微粒体谷胱甘肽-S-转移酶。当鱼暴露于 Ni 时，抗氧化防御反应的分子和生化反应之间没有一致的模式，这表明暴露于水基 Ni 的鱼的抗氧化防御反应不同步。肌肉转录水平和分析的酶活性之间通常缺乏一致性。这项研究的总体结果强调了转录和生化终点在鉴定氧化应激和维生素 A 代谢损伤生物标志物方面的有用性，以及在评估鱼类环境风险时使用多层次生物学方法的潜力。
