Aryl Hydrocarbon Receptor-Independent Toxicity of Weathered Crude Oil during Fish Development

• Published in: Environmental health perspectives Vol. 113; no. 12; pp. 1755 - 1762
• Main Authors: Incardona, John P., Carls, Mark G., Teraoka, Hiroki, Sloan, Catherine A., Collier, Tracy K., Scholz, Nathaniel L.
• Format: Journal Article
• Language: English
• Published: United States National Institute of Environmental Health Sciences. National Institutes of Health. Department of Health, Education and Welfare 01.12.2005; National Institute of Environmental Health Sciences
• Subjects: Abnormalities, Multiple - chemically induced; Abnormalities, Multiple - veterinary; Animals; Body Patterning - drug effects; Cardiovascular System - drug effects; Chemical hazards; Chrysenes; Crude oil; Danio rerio; Embryo, Nonmammalian - drug effects; Embryos; Fish Diseases - chemically induced; Fish Diseases - embryology; Fluorescent antibody techniques; Larvae; Marine fishes; Microscopy, Fluorescence - veterinary; Oligonucleotides; Petroleum - analysis; Petroleum - toxicity; Petroleum mining; Phenanthrenes; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - analysis; Polycyclic Aromatic Hydrocarbons - toxicity; Receptors, Aryl Hydrocarbon - genetics; Receptors, Aryl Hydrocarbon - metabolism; Weathering processes; Zebrafish
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.8230

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.