Anti-oxidative Responses on Hepatic Tissue of Zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) in a Short Duration of Sub-lethal Concentrations of Cadmium Exposure

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 Cd²⁺ exposure in short durations. Fish were exposed to 1.78 μM Cd²⁺ (treatment) and 0.0 μM Cd²⁺ (control) for 0, 1, 3, and 6 h. The reactive oxygen species (ROS) and lipid peroxidation (LPO) of hepatic tissues significantly increased after 3 and 6 h of Cd²⁺ 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 Cd²⁺ exposure. The caspase-3 and p53 mRNA expressions significantly increased threefolds after 1 h of Cd²⁺ exposure. Results confirmed that oxidative stress in the hepatic tissue was induced by Cd²⁺ within 3 h. However, anti-oxidative functions immediately up regulated, causing cell apoptosis levels to decrease after 6 h of Cd²⁺ exposure.