鱼类(胚胎)毒性测试指南主要基于水生暴露。然而,在某些情况下,其他暴露途径可能更实用和相关。微量注射到鱼胚的蛋黄中可以为施用疏水性化合物提供特别的优势,如许多内分泌干扰物。在化合物积累和生物反应方面,将单剂量微量注射与连续水生暴露进行了比较。17α-乙炔雌二醇(EE2)用作模型化合物。首先,优化了最佳溶剂和液滴尺寸,并评估针头变异。接下来,评估生物学终点.在两种暴露情况下,EE2的累积内部剂量随时间减少。雌激素受体激活是浓度/注射剂量依赖性的,每天增加,与esr2b转录有关。卵黄蛋白原1(vtg1)和脑芳香化酶(cyp19a1b)的转录在两种情况下都被诱导,但是cyp19a1b的转录模式在不同的路径之间是不同的。从受精后48小时(hpf)开始,注射导致cyp19a1b转录本增加,而水生暴露后,主要增加发生在96至120hpf之间。有些畸形只在注射后出现,而其他人则出现在这两种情况下。我们得出的结论是,暴露途径之间的反应可能不同,因此微注射不能直接替代,但可以补充水生暴露。然而,vtg1和cyp19a1b转录和雌激素受体激活是两种情况下内分泌干扰物筛选的合适生物标志物。环境毒物化学2019;38:533-547。©2018SETAC。
Fish (embryo) toxicity test guidelines are mostly based on aquatic exposures. However, in some cases, other exposure routes can be more practical and relevant. Micro-injection into the yolk of fish embryos could offer a particular advantage for administering hydrophobic compounds, such as many endocrine disruptors. Single-dose micro-injection was compared with continuous aquatic exposure in terms of compound accumulation and biological responses. 17α-Ethinyl estradiol (EE2) was used as a model compound. First, the optimal solvent and droplet size were optimized, and needle variation was assessed. Next, biological endpoints were evaluated. The accumulated internal dose of EE2 decreased over time in both exposure scenarios. Estrogen receptor activation was concentration/injected dose dependent, increased daily, and was related to esr2b transcription. Transcription of vitellogenin 1 (vtg1) and brain aromatase (cyp19a1b) was induced in both scenarios, but the cyp19a1b transcription pattern differed between routes. Injection caused an increase in cyp19a1b transcripts from 48 hours post fertilization (hpf) onward, whereas after aquatic exposure the main increase occurred between 96 and 120 hpf. Some malformations only occurred after injection, whereas others were present for both scenarios. We conclude that responses can differ between exposure routes and therefore micro-injection is not a direct substitute for, but can be complementary to aquatic exposure. Nevertheless, vtg1and cyp19a1b transcription and estrogen receptor activation are suitable biomarkers for endocrine disruptor screening in both scenarios. Environ Toxicol Chem 2019;38:533-547. © 2018 SETAC.