The aim of ecotoxicology is to study toxic effects on constituents of ecosystems, with the protection goal being populations and communities rather than individual organisms. In this ecosystem perspective, the use of in vitro methodologies measuring cellular and subcellular endpoints at a first glance appears to be odd. Nevertheless, more recently in vitro approaches gained momentum in ecotoxicology. In this article, we will discuss important application domains of in vitro methods in ecotoxicology. One area is the use of in vitro assays to replace, reduce, and refine (3R) in vivo tests. Research in this field has focused mainly on the use of in vitro cytotoxicity assays with fish cells as non-animal alternative to the in vivo lethality test with fish and on in vitro biotransformation assays as part of an alternative testing strategy for bioaccumulation testing with fish. Lessons learned from this research include the importance of a critical evaluation of the sensitivity, specificity and exposure conditions of in vitro assays, as well as the availability of appropriate in vitro-in vivo extrapolation models. In addition to this classical 3R application, other application domains of in vitro assays in ecotoxicology include the screening and prioritization of chemical hazards, the categorization of chemicals according to their modes of action and the provision of mechanistic information for the pathway-based prediction of adverse outcomes. The applications discussed in this essay may highlight the potential of in vitro technologies to enhance the environmental hazard assessment of single chemicals and complex mixtures at a reduced need of animal testing.

中文翻译：

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体外还是不体外：经历漫长历史的短暂旅程。

生态毒理学的目的是研究对生态系统组成部分的毒性作用，其保护目标是人口和社区，而不是单个生物。从这个生态系统的角度来看，乍一看使用体外方法测量细胞和亚细胞终点的方法似乎很奇怪。然而，最近的体外方法在生态毒理学中获得了动力。在本文中，我们将讨论体外方法在生态毒理学中的重要应用领域。一个领域是使用体外测定法替代，减少和完善（3R）体内试验。该领域的研究主要集中在使用鱼类细胞的体外细胞毒性测定法作为鱼类体内杀伤力测试的非动物替代方法，以及将体外生物转化测定法作为鱼类生物蓄积性测试方法的一部分。从这项研究中吸取的教训包括，对体外试验的敏感性，特异性和暴露条件进行严格评估的重要性，以及适当的体外-体内外推模型的可用性。除了这种经典的3R应用之外，生态毒理学中体外分析的其他应用领域还包括化学危害的筛选和优先级，根据化学品的作用方式对化学品进行分类，并为基于路径的不良后果预测提供机械信息。本文讨论的应用程序可能会强调体外技术在减少动物测试需求的情况下增强单一化学品和复杂混合物的环境危害评估的潜力。