Laboratorio de Toxicología Ambiental, Escuela Nacional de Ciencias Biológicas, IPN. Av. Wilfrido Massieu s/n, Unidad Profesional Zacatenco, CP 07839, México D.F., Mexico.
Fish Physiol Biochem. 2013 Dec;39(6):1603-17. doi: 10.1007/s10695-013-9812-8. Epub 2013 Jun 5.
In mammals, it has been shown that halomethanes (HM) are bioactivated by enzymes such as CYP 2E1 and the theta isoform of GST to produce reactive metabolites. However, in fish, little information is available, although HM can form autochthonously in aquatic environments. This study assessed the effect of HM in dusky splitfin (Goodea gracilis) from three lakes of the Valley of Mexico by analysing specific HM biomarkers as well as a broad range of biomarkers. The concentration of HM was a function of its half-life (higher in deep waters), while its precursors and solar radiation are secondary factors that determine its concentration. The kidney showed higher basal metabolism than the liver, probably because of its function as a haematopoietic and filtration organ. Using integrated biological response version 2 (IBRv2), it was found that the hepatic and renal O₂· content is a pro-oxidant force capable of inducing oxidative stress (ROOH, TBARS and RC=O). Early damage was found to be dependent on low concentrations of HM in Major Lake, whereas late damage was observed in fish exposed to higher concentrations of HM in Zumpango Lake and Ancient Lake. The activities of enzymes involved in antioxidant defence seemed to be inefficient. The quantitative assessment of biomarkers (ANOVA) and the estimate of parameter A obtained from IBRv2 provided different information. However, the data support the greater predictive power of IBRv2, but it requires a series of interrelated biomarkers to infer these possibilities. G. gracilis presents marked patterns of adaptation, which are dependant on the HM concentrations in environmental mixtures, although the response is complex and many toxicants could induce similar responses.
在哺乳动物中，已经表明卤代甲烷（HM）可以被酶如 CYP2E1 和 GST 的θ同工酶生物转化为活性代谢物。然而，在鱼类中，虽然 HM 可以在水生环境中自主形成，但相关信息却很少。本研究通过分析特定的 HM 生物标志物以及广泛的生物标志物，评估了墨西哥谷三个湖泊中的暗鳍半线脂鲤（Goodea gracilis）中的 HM 的影响。HM 的浓度与其半衰期呈函数关系（在深水中更高），而其前体和太阳辐射是决定其浓度的次要因素。肾脏的基础代谢率高于肝脏，可能是因为其作为造血和过滤器官的功能。使用综合生物反应版本 2（IBRv2），发现肝和肾的 O₂·含量是一种能够诱导氧化应激的促氧化剂（ROOH、TBARS 和 RC=O）。在主要湖中，早期损伤依赖于低浓度的 HM，而在祖马潘戈湖和古代湖中，暴露于高浓度 HM 的鱼类则观察到晚期损伤。参与抗氧化防御的酶的活性似乎效率低下。生物标志物的定量评估（ANOVA）和从 IBRv2 获得的参数 A 的估计提供了不同的信息。然而，这些数据支持了 IBRv2 具有更大的预测能力，但它需要一系列相互关联的生物标志物来推断这些可能性。G. gracilis 表现出明显的适应模式，这些模式取决于环境混合物中 HM 的浓度，尽管反应很复杂，许多有毒物质可能会引起类似的反应。
