Verbueken Evy, Alsop Derek, Saad Moayad A, Pype Casper, Van Peer Els M, Casteleyn Christophe R, Van Ginneken Chris J, Wilson Joanna, Van Cruchten Steven J
Applied Veterinary Morphology, Department of Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Antwerp, Belgium.
Wilson Tox Lab, Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.
Int J Mol Sci. 2017 Jan 22;18(1):217. doi: 10.3390/ijms18010217.
At present, the zebrafish embryo is increasingly used as an alternative animal model to screen for developmental toxicity after exposure to xenobiotics. Since zebrafish embryos depend on their own drug-metabolizing capacity, knowledge of their intrinsic biotransformation is pivotal in order to correctly interpret the outcome of teratogenicity assays. Therefore, the aim of this in vitro study was to assess the activity of cytochrome P450 (CYP)-a group of drug-metabolizing enzymes-in microsomes from whole zebrafish embryos (ZEM) of 5, 24, 48, 72, 96 and 120 h post-fertilization (hpf) by means of a mammalian CYP substrate, i.e., benzyloxy-methyl-resorufin (BOMR). The same CYP activity assays were performed in adult zebrafish liver microsomes (ZLM) to serve as a reference for the embryos. In addition, activity assays with the human CYP3A4-specific Luciferin isopropyl acetal (Luciferin-IPA) as well as inhibition studies with ketoconazole and CYP3cide were carried out to identify CYP activity in ZLM. In the present study, biotransformation of BOMR was detected at 72 and 96 hpf; however, metabolite formation was low compared with ZLM. Furthermore, Luciferin-IPA was not metabolized by the zebrafish. In conclusion, the capacity of intrinsic biotransformation in zebrafish embryos appears to be lacking during a major part of organogenesis.
目前，斑马鱼胚胎越来越多地被用作一种替代动物模型，用于筛选接触外源性物质后的发育毒性。由于斑马鱼胚胎依赖自身的药物代谢能力，了解其内在生物转化对于正确解释致畸性试验结果至关重要。因此，本体外研究的目的是通过一种哺乳动物CYP底物，即苄氧基甲基试卤灵（BOMR），评估受精后5、24、48、72、96和120小时（hpf）的全斑马鱼胚胎（ZEM）微粒体中细胞色素P450（CYP）（一组药物代谢酶）的活性。在成年斑马鱼肝脏微粒体（ZLM）中进行相同的CYP活性测定，以作为胚胎的参考。此外，还进行了用人CYP3A4特异性荧光素异丙醇缩醛（荧光素-IPA）的活性测定以及酮康唑和CYP3cide的抑制研究，以鉴定ZLM中的CYP活性。在本研究中，在72和96 hpf时检测到BOMR的生物转化；然而，与ZLM相比，代谢物形成较低。此外，荧光素-IPA未被斑马鱼代谢。总之，在器官发生的大部分时间里，斑马鱼胚胎似乎缺乏内在生物转化能力。
