Differential Induction of Enzymes and Genes Involved in Oxidative Stress in Gill and Liver Tissues of Mudskipper Boleophthalmus Pectinirostris Exposed to Lead

A study was carried to test the response of mudskipper for 8 days under four lead concentrations. Fish exposed to 2 mg/L Pb had the lowest glutathione peroxidase (GPX) in liver and glutathione (GSH) activities in liver and gill. Liver superoxide dismutase (SOD) in fish exposed to 1 and 2 mg/L Pb was lower than that in fish exposed to 0 and 0.5 mg/L Pb. However, the higher content of malondialdehyde (MDA) in gill and liver was found in 2 mg/L Pb group. The lower SOD, glutathione s-transferase (GST), heat shock proteins 70 (HSP-70) and HSP-90 expression in gill and liver were found in 0 mg/L Pb group. During the 8-day period, catalase(CAT), GPX and GSH activates in gill were the lowest at 8d. The lowest CAT activity in liver and the highest MDA content in gill and liver were found at day 8. The highest values of SOD and HSP-90 expression in gill were found at day 2. but the highest values of HSP-70 expression in liver were found from days 6 to 8. This study indicated that Pb-induced ROS generation is not fully counteracted by antioxidant enzymes. Functional enzyme activity was affected by mRNA expression.