Great Lakes Toxicology and Ecology Division, US Environmental Protection Agency, Duluth, Minnesota, USA.
Spec-Pro Professional Services, Duluth, Minnesota, USA.
Environ Toxicol Chem. 2023 Jan;42(1):100-116. doi: 10.1002/etc.5504. Epub 2022 Nov 28.
To reduce the use of intact animals for chemical safety testing, while ensuring protection of ecosystems and human health, there is a demand for new approach methodologies (NAMs) that provide relevant scientific information at a quality equivalent to or better than traditional approaches. The present case study examined whether bioactivity and associated potency measured in an in vitro screening assay for aromatase inhibition could be used together with an adverse outcome pathway (AOP) and mechanistically based computational models to predict previously uncharacterized in vivo effects. Model simulations were used to inform designs of 60-h and 10-21-day in vivo exposures of adult fathead minnows (Pimephales promelas) to three or four test concentrations of the in vitro aromatase inhibitor imazalil ranging from 0.12 to 260 µg/L water. Consistent with an AOP linking aromatase inhibition to reproductive impairment in fish, exposure to the fungicide resulted in significant reductions in ex vivo production of 17β-estradiol (E2) by ovary tissue (≥165 µg imazalil/L), plasma E2 concentrations (≥74 µg imazalil/L), vitellogenin (Vtg) messenger RNA expression (≥165 µg imazalil/L), Vtg plasma concentrations (≥74 µg imazalil/L), uptake of Vtg into oocytes (≥260 µg imazalil/L), and overall reproductive output in terms of cumulative fecundity, number of spawning events, and eggs per spawning event (≥24 µg imazalil/L). Despite many potential sources of uncertainty in potency and efficacy estimates based on model simulations, observed magnitudes of apical effects were quite consistent with model predictions, and in vivo potency was within an order of magnitude of that predicted based on in vitro relative potency. Overall, our study suggests that NAMs and AOP-based approaches can support meaningful reduction and refinement of animal testing. Environ Toxicol Chem 2023;42:100-116. © 2022 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
为了减少完整动物在化学安全测试中的使用，同时确保生态系统和人类健康得到保护，需要新的方法学（NAMs），这些方法学能够提供与传统方法等效或更优的相关科学信息。本案例研究考察了在体外芳香酶抑制筛选试验中测量的生物活性和相关效力是否可以与不良结局途径（AOP）和基于机制的计算模型一起用于预测以前未表征的体内效应。模型模拟用于设计成年胖头鱼（Pimephales promelas）的 60 小时和 10-21 天体内暴露实验，实验中使用了三种或四种体外芳香酶抑制剂咪菌唑的测试浓度，范围从 0.12 到 260 μg/L 水。与将芳香酶抑制与鱼类生殖损伤联系起来的 AOP 一致，暴露于杀真菌剂会导致卵巢组织中 17β-雌二醇（E2）的体外产量显著降低（≥165 μg 咪菌唑/L），血浆 E2 浓度（≥74 μg 咪菌唑/L），卵黄蛋白原（Vtg）信使 RNA 表达（≥165 μg 咪菌唑/L），Vtg 血浆浓度（≥74 μg 咪菌唑/L），Vtg 进入卵母细胞的摄取（≥260 μg 咪菌唑/L），以及累积繁殖力、产卵次数和每次产卵的卵数等生殖输出的整体下降（≥24 μg 咪菌唑/L）。尽管基于模型模拟的效力和功效估计存在许多潜在的不确定性来源，但观察到的顶端效应的幅度与模型预测相当一致，体内效力与基于体外相对效力预测的效力相当。总体而言，我们的研究表明，NAMs 和基于 AOP 的方法可以支持有意义地减少和改进动物测试。环境毒理化学 2023；42：100-116。© 2022 SETAC。本文已由美国政府雇员做出贡献，其工作在美国属于公有领域。
