EROD activities in a primary cell culture of grass carp ( Ctenopharyngodon idellus) hepatocytes exposed to polychlorinated aromatic hydrocarbonas

Abstract

Aryl hydrocarbon (Ah) receptor (Ah-agonist) effects of environmental samples containing polychlorinated aromatic hydrocarbons were evaluated using a 7-ethoxyresorufin- O-deethylase (EROD) assay of a primary hepatocyte culture from grass carp ( Ctenopharyngodon idellus). The results were compared with those obtained from the assay using the rat hepatoma cell line H4IIE and chemical analysis using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). A dose–response relationship was observed between the EROD activities, either from primary hepatocyte culture assay or from H4IIE assay, and concentrations of 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD). The results showed that the assay based on the H4IIE cell line (EC 50=0.83 pg/mL) is more sensitive to TCDD than the assay based on primary hepatocyte culture (EC 50=9.7 pg/mL). In tests of environmental samples, the results from the assay using primary hepatocyte culture were comparable to those from the assay using the H4IIE cell line and chemical analysis of concentrations of mixtures of polychlorinated dibenzo- p-dioxin and dibenzofuran (PCDD/PCDF). The lack of a change in the activities of glutathione- S-transferase (GST) and lactate dehydrogenase (LDH) in cell culture upon exposure to TCDD indirectly indicates that the compound is persistent to biodegradation in the cell culture system.