Department of Biology, University of Southern Denmark, Syddansk Universitet, Odense, Denmark.
John W Green Ecostatistical Consulting LLC, 372 Chickory Way, Newark, DE 19711, USA.
Aquat Toxicol. 2022 Mar;244:106094. doi: 10.1016/j.aquatox.2022.106094. Epub 2022 Jan 29.
Several chemicals have been identified as thyroid hormone axis disrupting chemicals (THADCs) able to interfere with the thyroid hormone system during fetal life and early life stages, thereby impairing neurodevelopment in mammals and inducing development and growth disorders in fish and amphibians. However, identification of THADCs is particularly challenging, and thyroid modalities are currently only assessed in vivo by mammalian and amphibian tests. The aquatic African clawed frog (Xenopus laevis/tropicalis) is the model species of the amphibian test guidelines developed by the OECD and the United States Environmental Protection Agency, but as most European amphibians are semi-aquatic, concern has been raised whether the sensitivity of native European species is comparable to Xenopus. A shortened version of the OEDC test guideline 241 (Larval Amphibian Growth and Development Assay, LAGDA) was used to investigate the effects of two model THADCs on the metamorphosis and thyroid histopathology in the European common frog (Rana temporaria). R. temporaria eggs were collected on the field and exposed till metamorphic climax to sodium perchlorate (11.9-426.5 μg/L perchlorate concentrations) and 6-propylthiouracil (PTU: 1.23-47.7 mg/L). PTU severely delayed metamorphosis and affected several thyroid gland histopathological endpoints at slightly lower concentrations compared to Xenopus. As opposed to what was described in similar Xenopus studies, we observed no effect of perchlorate on the investigated endpoints. Interspecies differences may be linked to mechanisms of action.
已经鉴定出几种化学物质为甲状腺激素轴干扰化学物质（THADCs），它们能够在胎儿期和生命早期干扰甲状腺激素系统，从而损害哺乳动物的神经发育，并在鱼类和两栖动物中诱导发育和生长障碍。然而，THADCs 的鉴定特别具有挑战性，目前仅通过哺乳动物和两栖动物试验来评估甲状腺模式。水生非洲爪蟾（Xenopus laevis/tropicalis）是经合组织和美国环境保护署制定的两栖动物试验指南的模式物种，但由于大多数欧洲两栖动物为半水生动物，人们担心本地欧洲物种的敏感性是否与非洲爪蟾相当。OEDC 试验指南 241（幼虫两栖动物生长和发育测定法，LAGDA）的缩短版用于研究两种模型 THADCs 对欧洲普通蛙（Rana temporaria）变态和甲状腺组织病理学的影响。R. temporaria 卵在野外收集，并暴露于过氯酸纳（11.9-426.5 μg/L 过氯酸浓度）和丙硫氧嘧啶（PTU：1.23-47.7 mg/L）直至变态高峰。与 Xenopus 相比，PTU 严重延迟了变态，并在略低的浓度下影响了几个甲状腺组织病理学终点。与类似 Xenopus 研究中描述的情况相反，我们未观察到过氯酸对所研究终点的影响。种间差异可能与作用机制有关。
