The aim of the present study was to identify whether the responses of oxidative stress in zebrafish liver are similar to those in mammalians upon low doses of Cd(2+) exposure in short durations. Fish were exposed to 1.78 μM Cd(2+) (treatment) and 0.0 μM Cd(2+) (control) for 0, 1, 3, and 6 h. The reactive oxygen species and lipid peroxidation (LPO) of hepatic tissues significantly increased after 3 and 6 h of Cd(2+) exposure, respectively. Antioxidants glutathione peroxidase (gpx1a), superoxide dismutase (sod), and catalase (cat) were up regulated after 1-3 h, and metallothionein isoforms (smtB and mt2) increased after 3-6 h of Cd(2+) exposure. The caspase-3 and p53 mRNA expressions significantly increased threefolds after 1 h of Cd(2+) exposure. Results confirmed that oxidative stress in the hepatic tissue was induced by Cd(2+) within 3 h. However, anti-oxidative functions immediately up regulated, causing cell apoptosis levels to decrease after 6 h of Cd(2+) exposure.
KEYWORDS: Apoptosis, Cadmium, Metallothionein, Oxidative stress, Zebrafish