School of Biological Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom; UMR CNRS LIENSs, Littoral Environnement et Sociétés, Université de La Rochelle, La Rochelle, 17 000, France.
Institute of Biology of the Karelian Research Centre of the Russian Academy of Sciences (IB KarRC RAS), 185910, Petrozavodsk, Russia.
Mar Environ Res. 2021 Aug;170:105434. doi: 10.1016/j.marenvres.2021.105434. Epub 2021 Jul 27.
Studies that aim to characterise the susceptibility of the ecologically relevant and non-model fish polar cod (Boreogadus saida) to model carcinogens are required. Polar cod were exposed under laboratory conditions for six months to control, 0.03 μg BaP/g fish/week and 0.3 μg BaP/g fish/week dietary benzo(a)pyrene (BaP), a reference carcinogen. The concentrations of the 3-OH-BaP bile metabolite and transcriptional responses of genes involved in DNA adduct recognition (xpc), helicase activity (xpd), DNA repair (xpf, rad51) and tumour suppression (tp53) were assessed after 0, 1, 3 and 6 months of exposure, alongside body condition indexes (gonadosomatic index, hepatosomatic index and condition factor). Micronuclei and nuclear abnormalities in blood and spleen, and liver histopathological endpoints were assessed at the end of the experiment. Fish grew steadily over the whole experiment and no mortality was recorded. The concentrations of 3-OH-BaP increased significantly after 1 month of exposure to the highest BaP concentration and after 6 months of exposure to all BaP concentrations showing the biotransformation of the mother compound. Nevertheless, no significant induction of gene transcripts involved in DNA damage repair or tumour suppression were observed at the selected sampling times. These results together with the absence of chromosomal damage in blood and spleen cells, the subtle increase in nuclear abnormalities observed in spleen cells and the low occurrence of foci of cellular alteration suggested that the exposure was below the threshold of observable effects. Taken together, the results showed that polar cod was not susceptible to carcinogenesis using the BaP exposure regime employed herein.
需要研究具有生态相关性和非模式鱼类极地鳕鱼（Boreogadus saida）对模式致癌物质的敏感性。在实验室条件下，极地鳕鱼暴露于对照、每周 0.03μg BaP/g 鱼和每周 0.3μg BaP/g 鱼的饮食苯并（a）芘（BaP）中 6 个月，BaP 是一种参考致癌物质。在暴露 0、1、3 和 6 个月后，评估了胆汁代谢物 3-OH-BaP 的浓度以及参与 DNA 加合物识别（xpc）、解旋酶活性（xpd）、DNA 修复（xpf、rad51）和肿瘤抑制（tp53）的基因的转录反应，以及身体状况指数（性腺体指数、肝体指数和条件因子）。在实验结束时，评估了血液和脾脏中的微核和核异常以及肝脏组织病理学终点。在整个实验过程中，鱼体稳步增长，未记录到死亡率。在暴露于最高 BaP 浓度 1 个月后和所有 BaP 浓度暴露 6 个月后，3-OH-BaP 的浓度显著增加，表明母体化合物的生物转化。然而，在所选择的采样时间，未观察到涉及 DNA 损伤修复或肿瘤抑制的基因转录物的显著诱导。这些结果连同血液和脾脏细胞中无染色体损伤、脾脏细胞中观察到的核异常略有增加以及细胞改变灶的低发生率一起表明，暴露低于可观察到的效应阈值。总的来说，结果表明，使用本文中所采用的 BaP 暴露方案，极地鳕鱼不易发生致癌作用。
