Abstract
As oil activity intensifies in the Arctic, marine species face mounting ecological threats. Crude oil's complex mixture of toxicants, especially polycyclic aromatic hydrocarbons (PAHs), can disrupt critical biological systems by activating receptors such as the aryl hydrocarbon receptor (AhR). In this study, we adopted alternative approaches that minimize or eliminate the use of live animals by applying ex vivo and in vitro models to investigate the molecular toxicity of crude oil components in Atlantic cod (Gadus morhua).
We employed precision-cut liver slices (PCLS) from cod as an ex vivo system to evaluate hepatic responses to water-accommodated fractions (WAFs) of crude oil. Notably, strong induction of cyp1a, a biomarker of aryl hydrocarbon receptor (AhR) activation, was observed following exposure to total WAF and the resin fraction, highlighting the biological relevance of these mixtures without requiring whole-animal exposure.
To further reduce animal use, we applied a cell-based assay using COS-7 cells transfected with cod-specific receptor genes. These engineered cells respond to crude oil compounds via a luciferase reporter system, enabling sensitive, quantifiable detection of receptor activation.
This approach reduces the need for in vivo assays and provides insights into how crude oil affects fish health at the molecular level.