Programa de Pós-graduação em Biologia de Ambientes Aquáticos Continentais, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, RS 96203-900, Brazil.
Programa de Pós-graduação em Ciências Fisiológicas - Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, RS 96203-900, Brazil.
Ecotoxicol Environ Saf. 2015 Mar;113:38-44. doi: 10.1016/j.ecoenv.2014.11.023. Epub 2014 Dec 5.
Cytochrome P450 1A (CYP1A) expression in fish is used as a biomarker of exposure to organic contaminants, such PAHs, PCBs and dioxins, in the aquatic environment. South American guppy fish Jenynsia multidentata were exposed to the prototypical aryl hydrocarbon receptor (AHR) agonist beta-naphthoflavone (BNF; 1μM) and the fins were biopsied to characterize different aspects of CYP1A induction. RTq-PCR was used to quantify CYP1A mRNA levels in fish tissues. CYP1A induction in the gill, liver and anal fin (gonopodium) occurred within the first hour of waterborne exposure to BNF and persisted throughout 2, 4, 8, 24, 48 and 96h compared to controls (DMSO vehicle; p<0.05). The organ-specific temporal pattern of induction was marked by mRNA levels consistently augment as duration of exposure increases and tend to a sustained induction from 24h to 96h for gill and liver (∼15-fold and ∼50-fold over control, respectively). In gonopodium, there was a maximum CYP1A mRNA level at 4h (∼34-fold over control). Basal CYP1A mRNA levels and its induction following BNF exposure were not affected by administration of a chemical anesthetic (fish immersion in 100mgl(-1) MS-222 for 2-5min) in the gill, liver, gonopodium, dorsal or tail fin (p<0.05). In an ex vivo assay, in which small pieces of biopsied fins were exposed to BNF for 4h, high CYP1A induction was observed in the tail and gonopodium (∼49-fold and ∼69-fold, respectively) but not in the dorsal fin compared to controls. To our knowledge, this is the first study to show that a 1h waterborne exposure to an AHR agonist is sufficient to cause CYP1A induction in fish organs and fins. The present study added new information to the field regarding the use of MS-222 as an anesthetic on fish and the analysis of biopsied fins as an alternative non-lethalex vivo assay for evaluating the CYP1A biomarker in fish. This observation could be useful for planning fish toxicological bioassays and biomonitoring studies on the aquatic environments in South America.
细胞色素 P450 1A（CYP1A）在鱼类中的表达被用作水生环境中有机污染物（如多环芳烃、多氯联苯和二恶英）暴露的生物标志物。南美孔雀鱼 Jenynsia multidentata 暴露于典型的芳烃受体（AHR）激动剂β-萘黄酮（BNF；1μM）中，并对鱼鳍进行活检以表征 CYP1A 诱导的不同方面。RTq-PCR 用于定量鱼类组织中的 CYP1A mRNA 水平。在 BN 暴露于水后 1 小时内，鱼的鳃、肝和肛鳍（生殖鳍）中发生 CYP1A 诱导，并持续至 2、4、8、24、48 和 96 小时，与对照组（DMSO 载体；p<0.05）相比。诱导的器官特异性时间模式的特征是随着暴露时间的延长，mRNA 水平持续增加，并在 24 至 96 小时之间趋于持续诱导，鳃和肝中约为对照组的 15 倍和 50 倍（分别）。在生殖鳍中，CYP1A mRNA 水平在 4 小时达到最大值（约为对照组的 34 倍）。在鳃、肝、生殖鳍、背鳍或尾鳍中，BNF 暴露后，CYP1A 基础 mRNA 水平及其诱导不受化学麻醉剂（鱼浸入 100mgl(-1) MS-222 2-5min）处理的影响（p<0.05）。在离体试验中，小块活检鳍暴露于 BNF 4 小时，观察到尾鳍和生殖鳍中 CYP1A 高度诱导（分别为约 49 倍和约 69 倍），但背鳍与对照组相比无诱导。据我们所知，这是第一项表明鱼类器官和鳍在 1 小时水暴露于 AHR 激动剂后足以引起 CYP1A 诱导的研究。本研究为使用 MS-222 作为鱼类麻醉剂以及分析活检鳍作为评估鱼类 CYP1A 生物标志物的替代非致死性离体试验提供了该领域的新信息。这一观察结果可能对南美水生环境中的鱼类毒理学生物测定和生物监测研究的规划有用。
