Detection of water toxicity using cytochrome P450 transgenic zebrafish as live biosensor: for polychlorinated biphenyls toxicity.

ABSTRACT

Cytochrome P450 (CYPs) is significant in degradation of endogenous substrates and detoxification of carcinogens, therefore it is a biomarker for assessment of polycyclic aromatic hydrocarbons (PAHs) level in aquatic environment. In the present study, a transgenic line of zebrafish had been generated using a CYP-green fluorescence protein (CYP-GFP) construct, driven by CYP1A1 promoter. Polychlorinated biphenyls (PCBs) were used as toxicant, in concentrations of 0.02 µg/ml, 0.04 µg/ml, 0.08 µg/ml, 0.4 µg/ml, and 0.8 µg/ml. The transgenic control fish showed low intensity of fluorescence in the liver. After exposed to PCBs, zebrafish had morphological changes such as expansion of yolk, contortion of tails and inflation of pericardial area. Green fluorescence signals were found to express according to concentrations and time. The green fluorescence signal was most intense after treatment with 0.08 µg/ml PCBs. However, the maximum area of green fluorescent signal was found at 0.04 µg/ml PCBs. GFP started to express at 3h exposure to PCBs, increasing its intensity until 6 h exposure, and then level off. Since the GFP expression is fast responding and is sensitive to low PAHs concentrations, transgenic fish is a good tool for live imaging and monitoring of aquatic contamination.