Validating a sexual development test using the 3-spined stickleback for addressing the 3Rs in fish toxicity testing

使用三刺刺鱼验证性发育测试，以解决鱼类毒性测试中的 3R

• 批准号: G0800733/1
• 负责人: Ioanna Katsiadaki
• 金额: $ 50.8万
• 依托单位: Centre for Environment, Fisheries and Aquaculture Science
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=G0800733%2F1
• 关键词: Validating; sexual; development; test; using

A wide range of man-made chemicals has the ability to interfere with the endocrine system that controls amongst other functions, sexual development. These are called endocrine disruptors (EDs). Steroidal oestrogens are often implicated in the causation of the widely observed sexual disruption in fish and are of both natural and synthetic origin (e.g. ethinyl-oestradiol, which is the active ingredient of the human contraceptive pill). As well as posing potential risks to humans (there are several studies that attempt to link exposure to EDs with the decline of sperm counts, the increased incidence of testicular and prostate cancers, male congenital reproductive abnormalities and infertility rates), EDs are of particular concern for fish as the aquatic environment is often the most important sink for man-made chemicals and sewage waste. There is clearly a need to develop tools for the detection of such chemicals and fish have been recognised as providing the ideal biological system for this purpose, leading to the development of a number of tests by the OECD, including the fish sexual development test (FSDT) The species that have entered a validation phase for the FSDT to date are the zebrafish and the fathead minnow, both of which are routinely used in aquatic ecotoxicological studies. However, we argue that they are not the ideal test subjects for the FSDT. The main disadvantage of these fish species is the lack of a genetic sex marker, which could unequivocally assign sex, leading to an enormous wastage of experimental fish. This is because the main endpoint employed by the FSDT is sex ratio, which in the case of the stickleback can be assigned genetically using a simple test. In the case of alternative models, sex is assigned by means of gonadal histology, a strategy that presents many drawbacks. Firstly, if the stickleback is used, an acceptable sex ratio for the control groups does not need to be defined waiving the risk of test failure. Secondly, the mode of action of a chemical can be better defined as an oestrogen or an androgen for example because any differences between genetic and histological sex can be attributed to the chemical exposure. Thirdly, but most importantly the ability to assign genetic sex increases the power of the test and can dramatically reduce the number of animals used in scientific procedures for both research and regulatory purposes.

许多人造化学物质都有能力干扰内分泌系统，而内分泌系统除其他功能外，还控制性发育。这些物质被称为内分泌干扰物(EDs)。类固醇雌激素通常与广泛观察到的鱼类性功能障碍的原因有关，既有自然来源，也有合成来源(例如，人类避孕药的有效成分--乙炔雌二醇)。除了对人类构成潜在风险(有几项研究试图将暴露在EDs中与精子数量下降、睾丸和前列腺癌发病率增加、男性先天性生殖异常和不育率联系起来)，EDs对鱼类特别令人担忧，因为水环境往往是人造化学品和污水废物最重要的汇。显然有必要开发检测这类化学物质的工具，鱼类已被公认为为此目的提供了理想的生物系统，导致经合组织制定了一系列测试，包括鱼类性别发育测试(FSDT)迄今已进入FSDT验证阶段的物种是斑马鱼和愚头鱼，这两种鱼都经常用于水生生态毒理学研究。然而，我们认为它们不是FSDT的理想测试对象。这些鱼类的主要缺点是缺乏基因性别标记，这种标记可以明确地指定性别，导致实验鱼类的大量浪费。这是因为FSDT采用的主要终点是性别比例，在刺鱼的情况下，可以使用简单的测试来遗传分配性别比例。在另一种模型的情况下，性别是通过性腺组织学来分配的，这一策略存在许多缺点。首先，如果使用刺鱼，则不需要为对照组定义可接受的性别比例，从而放弃测试失败的风险。其次，化学物质的作用方式可以更好地定义为雌激素或雄激素，因为遗传和组织性别之间的任何差异都可以归因于化学物质的暴露。第三，但最重要的是，指定基因性别的能力增加了测试的力量，并可以显著减少用于研究和监管目的的科学程序中的动物数量。