Aryl hydrocarbon receptor-independent toxicity of weathered crude oil during fish development.
Polycyclic aromatic hydrocarbons (PAHs), derived largely from fossil fuels and their combustion, are pervasive contaminants in rivers, lakes, and nearshore marine habitats. Studies after the Exxon Valdez oil spill demonstrated that fish embryos exposed to low levels of PAHs in weathered crude oil develop a syndrome of edema and craniofacial and body axis defects. Although mechanisms leading to these defects are poorly understood, it is widely held that PAH toxicity is linked to aryl hydrocarbon receptor (AhR) binding and cytochrome P450 1A (CYP1A) induction. Using zebrafish embryos, we show that the weathered crude oil syndrome is distinct from the well-characterized AhR-dependent effects of dioxin toxicity. Blockade of AhR pathway components with antisense morpholino oligonucleotides demonstrated that the key developmental defects induced by weathered crude oil exposure are mediated by low-molecular-weight tricyclic PAHs through AhR-independent disruption of cardiovascular function and morphogenesis. These findings have multiple implications for the assessment of PAH impacts on coastal habitats.
Incardona
John P
JP
Ecotoxicology and Environmental Fish Health Program, Environmental Conservation Division, Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration, Seattle, Washington 98112, USA. john.incardona@noaa.gov
Carls
Mark G
MG
Teraoka
Hiroki
H
Sloan
Catherine A
CA
Collier
Tracy K
TK
Scholz
Nathaniel L
NL
D000015:Abnormalities, Multiple / Q000139:chemically induced / Q000662:veterinary*; D000818:Animals; D019521:Body Patterning / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects; D004625:Embryo, Nonmammalian / Q000187:drug effects; D005393:Fish Diseases / Q000139:chemically induced* / Q000196:embryology*; D008856:Microscopy, Fluorescence / Q000662:veterinary; D009841:Oligonucleotides; D010578:Petroleum / Q000032:analysis / Q000633:toxicity*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000633:toxicity*; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish
D009841:Oligonucleotides; D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D018336:Receptors, Aryl Hydrocarbon