Laboratoire d'Ecologie Systématique et Evolution, Université Paris-Sud, AgroParisTech, CNRS, Paris Saclay, 91405 Orsay, France; Toxicology Area, Faculty of Veterinary, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, 30100 Murcia, Spain.
Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, 30100 Murcia, Spain.
Environ Pollut. 2018 Feb;233:156-167. doi: 10.1016/j.envpol.2017.10.046. Epub 2017 Oct 23.
Due to their longevity and extensive migration areas, marine turtles are able to accumulate diverse contaminants over many years and as a consequence they represent an interesting bioindicator species for marine ecosystem pollution. Metals provoke toxicological effects in many aquatic animal species, but marine turtles have been under-investigated in this area. Thus, we have determined the presence of certain inorganic elements (As, Cd, Cu, Ni, Pb, Se and Zn) in olive ridley turtles (Lepidochelys olivacea) and related them to metallothionein (MT), superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) transcription and/or enzymatic activities. Gene expression of sod, cat and gr was found to be higher in blood than liver or kidney but most of the significant relationships were found in liver, not only for gene expression but also for enzyme activities. This must be related to the role the liver has as the first filter organ. Several positive relationships of sod, cat and gr gene expression in the different tissues were found in this population, as well as very high Cd concentrations. This could mean that these turtles are adapting to the metals-production of ROS and damage through a high transcription of these antioxidants. Multiple positive relationships with GR seem to be part of its compensatory effect due to the decrease of SOD production against the high and chronic exposure to certain xenobiotics. CAT, on the other hand, seems not to be used much, and glutathione detoxification of HO may be more important in this species. Finally, despite the very high Cd concentrations found in this population, no significant relationship was found in any tissue with metallothionein gene expression. These results, along with very high Cd concentrations and a negative relationship with Cu, lead us to consider some kind of disruption in mt gene expression in these turtles.
由于海龟寿命长，活动范围广，因此能够在多年时间里积累各种污染物，从而成为海洋生态系统污染的一个有趣的生物指标物种。金属会对许多水生动物物种产生毒理学影响，但在这一领域，海龟受到的研究关注较少。因此，我们测定了榄蠵龟（Lepidochelys olivacea）体内某些无机元素（砷、镉、铜、镍、铅、硒和锌）的含量，并将其与金属硫蛋白（MT）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽还原酶（GR）的转录和/或酶活性相关联。结果发现，SOD、CAT 和 GR 的基因表达在血液中高于肝脏或肾脏，但大多数显著的相关性存在于肝脏中，不仅在基因表达方面，在酶活性方面也是如此。这一定与肝脏作为第一道过滤器官的作用有关。在该种群中，我们在不同组织中发现 sod、cat 和 gr 的基因表达存在多种正相关关系，同时还发现镉浓度非常高。这可能意味着这些海龟通过这些抗氧化剂的高转录来适应金属产生的 ROS 和损伤。GR 与多种物质呈正相关，似乎是其补偿效应的一部分，因为 SOD 产量的下降可能是由于其对某些外源性物质的高慢性暴露所致。另一方面，CAT 的作用似乎不大，谷胱甘肽对 HO 的解毒可能在该物种中更为重要。最后，尽管在该种群中发现了非常高的镉浓度，但在任何组织中均未发现 MT 基因表达与镉浓度之间存在显著相关性。这些结果，加上非常高的镉浓度以及与铜之间的负相关关系，使我们认为在这些海龟中存在 MT 基因表达的某种紊乱。
