Embryonic cardiotoxicity of weak aryl hydrocarbon receptor agonists and CYP1A inhibitor fluoranthene in the Atlantic killifish (Fundulus heteroclitus)

作者：Brown D R^*; Clark B W; Garner L V T; Di Giulio R T

来源：Comparative Biochemistry and Physiology C-Toxicology & Pharmacology, 2016, 188: 45-51.

DOI：10.1016/j.cbpc.2016.05.005

• Aryl hydrocarbon receptor agonists
• Cardiotoxicity
• Fundulus heteroclitus
• Development
• Cytochrome P450
• Morpholino

High affinity aryl hydrocarbon receptor (AHR) ligands, such as certain polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), cause severe cardiac teratogenesis in fish embryos. Moderately strong AHR agonists, for example benzo[a]pyrene and beta-naphthoflavone, are capable of causing similar cardiotoxic effects, particularly when coupled with cytochrome P450 IA (CYP1A) inhibitors (e.g., fluoranthene (FL). Additionally, some weaker AHR agonists (carbaryl, 2-methylindole, 3-methylindole, and phenanthrene) are known to also cause cardiotoxicity in zebrafish (Danio rerio) embryos when coupled with FL; however, the cardiotoxic effects were not mediated specifically by AHR stimulation. This study was performed to determine if binary exposure to weak AHR agonists and FL were also capable of causing cardiotoxicity in Atlantic killifish Fundulus heteroclitus embryos. Binary exposures were performed in both naive and PAH-adapted killifish embryos to examine resistance to weak agonists and FL binary exposures. Weak agonists used in this study included the following: carbaryl, phenanthrene, 2-methylindole, 3-methylindole, indigo, and indirubin. Carbaryl, indigo, and indirubin induced the highest CYP1 activity levels in naive killifish embryos, but no significant CYP1 induction was observed in the PAH-adapted killifish.
Embryos were coexposed to subteratogenic levels of each agonist and 500 mu g/L FL to assess if binary administration could cause cardiotoxicity. Indigo and indirubin coupled with FL caused cardiac teratogenesis in naive killifish, but coexposures did not produce cardiac chamber abnormalities in the PAH-adapted population. Knockdown of AHR2 in naive killifish embryos did not prevent cardiac teratogenesis. The data suggest a unique mechanism of cardiotoxicity that is not driven by AHR2 activation.

• 出版日期2016-10