Evaluation of the gill filament-based EROD assay in African sharptooth catfish (Clarias gariepinus) as a monitoring tool for waterborne PAH-type contaminants
Department of Veterinary Medicine and Public Health, Faculty of Veterinary Medicine, Sokoine University of Agriculture, P.O. Box 3021, Morogoro, Tanzania; Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa; Veterinary Faculty, University of Eduardo Mondlane, P.O. Box 257, Maputo, Mozambique; Department of Pharmacology, Microbiology and Food Hygiene, Norwegian School of Veterinary Science, Dep., 0033, P.O. Box 8156, Oslo, Norway; Department of Veterinary Public Health and Preventive Medicine, Faculty of Veterinary Medicine, Makerere University, P.O. Box 7062, Kampala, Uganda; Norwegian Veterinary Institute, Dep., 0033, P.O. Box 8146, Oslo, Norway
The ability of African sharptooth catfish (Clarias gariepinus) in inducing cytochrome P-450 class 1A (CYP1A) and glutathione S-transferase (GST) biomarkers was determined in liver and gill filaments after 4 days of waterborne exposure to the polycyclic aromatic hydrocarbon, benzo[a]pyrene (B[a]P). Male (n = 6) and female (n = 6) fish were exposed to B[a]P added to the water (30 μg/l) corresponding to 5 mg/kg total body weight. Five female and six male fish, exposed to acetone alone added to the water served as controls. The 7-ethoxyresurufin-O-deethylase (EROD) activity was measured in hepatic microsomes and gill filaments. In addition, GST activity was determined in the hepatic cytosolic fraction and fluorescent aromatic compounds (FACs) in bile and biliverdin. Benzo[a]pyrene strongly induced EROD activities in gill filaments of both sex. Levels of FACs per ml of bile were 17-fold higher in exposed fish compared to the controls. Correlations between induction of EROD activities in gill filaments and liver and between induction of EROD activities in gill filaments and levels of biliary FACs metabolites were strong. GST activities in the hepatic cytosolic fraction were similar amongst the treated and control groups. This is the first report on studies determining EROD activities in gill filaments and hepatic tissue, FACs in bile and GST in hepatic tissues of C. gariepinus after waterborne exposure to B[a]P. The findings suggest that the gill filament-based EROD assay in C. gariepinus can be used to monitor the pollution of AhR agonists in aquatic ecosystems in eastern and southern African countries. © 2005 Springer Science + Business Media, Inc.
acetone; benzo[a]pyrene; biliverdin; biological marker; cytochrome P450 1A; ethoxyresorufin; ethoxyresorufin deethylase; glutathione transferase; liver enzyme; polycyclic aromatic hydrocarbon; resorufin; aquatic ecosystem; biomarker; biomonitoring; fish; PAH; Africa; animal experiment; animal tissue; aquatic environment; article; bile; catfish; controlled study; cytosol; environmental exposure; environmental monitoring; enzyme activity; enzyme assay; enzyme induction; evaluation; female; fluorescence; gill; liver; liver microsome; male; metabolite; nonhuman; priority journal; water pollution; Animals; Bile; Biological Assay; Biological Markers; Catfishes; Cytochrome P-450 CYP1A1; Environmental Monitoring; Female; Gills; Glutathione Transferase; Liver; Male; Polycyclic Hydrocarbons, Aromatic; Water Pollutants, Chemical; Animalia; Clarias gariepinus