Zebra Fish as a Model for Assessing Environmental Toxicology: Expression of Antioxidant Biomarker Genes

Zebra fish is preferred as a model organism because of the ease with which zebrafish development is followed from the transparent egg stage onwards; it is possible to scrutinize the defects in different developmental stages by xenobiotic onslaughts. It has been amply recorded that most of the xenobiotics go through the three phases of detoxification covering hydroxylation, reduction and oxidation in Phase I, conjugation in Phase II and excretion in Phase III. Xenobiotics trigger differential gene expression patterns of Phases I and II affecting the rate of transcription of the biotransformation enzymes. An active Nrf2/Keap1 system also imparts a global role of zebrafish in detoxification. Majority of the antioxidant genes are expressed by different types of xenobiotics both in embryo and adult stages of zebrafish. Thus zebrafish attains the status of the most reliable model in environmental toxicology to unravel the molecular mechanisms of detoxification.