Regulatory Ecotoxicology Chemicals.
Experimental Toxicology and Ecology, BASF SE, 67056 Ludwigshafen, Germany.
Toxicol Sci. 2017 Sep 1;159(1):86-93. doi: 10.1093/toxsci/kfx116.
Early life stages of zebrafish (Danio rerio, zf) are gaining attention as an alternative invivo test system for drug discovery, early developmental toxicity screenings and chemical testing in ecotoxicological and toxicological testing strategies. Previous studies have demonstrated transcriptional evidence for xenobiotic metabolizing enzymes (XME) during early zf development. However, elaborate experiments on XME activities during development are incomplete. In this work, the intrinsic activities of representative phase I and II XME were monitored by transformation of putative zf model substrates analyzed using photometry and high pressure liquid chromatography techniques. Six different defined stages of zf development (between 2.5 h postfertilization (hpf) to 120 hpf) were investigated by preparing a subcellular fraction from whole organism homogenates. We demonstrated that zf embryos as early as 2.5 hpf possess intrinsic metabolic activities for esterase, Aldh, Gst, and Cyp1a above the methodological detection limit. The activities of the enzymes Cyp3a and Nat were measurable during later stages in development. Activities represent dynamic patterns during development. The role of XME activities revealed in this work is relevant for the assessing toxicity in this test system and therefore contributes to a valuable characterization of zf embryos as an alternative testing organism in toxicology.
斑马鱼（Danio rerio，zf）的早期生命阶段作为一种替代体内药物发现、早期发育毒性筛选和化学测试的测试系统，在毒理学和生态毒理学测试策略中受到关注。先前的研究已经证明了在 zf 早期发育过程中外源生物代谢酶（XME）的转录证据。然而，关于 XME 活性在发育过程中的详细实验尚未完成。在这项工作中，通过使用分光光度法和高压液相色谱技术分析潜在的 zf 模型底物的转化，监测了代表性的 I 期和 II 期 XME 的固有活性。通过从整个生物体匀浆中制备亚细胞级分，研究了 zf 发育的六个不同定义阶段（从受精后 2.5 小时（hpf）到 120 hpf）。我们证明，早在 2.5 hpf 的 zf 胚胎就具有酯酶、Aldh、Gst 和 Cyp1a 的内在代谢活性，超过了方法检测限。在发育后期可以测量 Cyp3a 和 Nat 酶的活性。活性在发育过程中呈现出动态模式。这项工作中揭示的 XME 活性的作用对于评估该测试系统中的毒性至关重要，因此有助于将 zf 胚胎作为毒理学替代测试生物进行有价值的表征。
