Effect of hypoosmotic and thermal stress on gene expression anthe activity of antioxidant enzymes in the cinnamon clownfish, Amphiprion melanopus

Abstract

We studied oxidative stress in cinnamon clownfish exposed to hypoosmotic (35 psu {combining right arrow above} 17.5 psu and 17.5 psu with prolactin (PRL)) and low temperature (28°C {combining right arrow above} 24°C and 20°C) conditions by measuring the expression and activity of Cu/Zn-superoxide dismutase (Cu/Zn-SOD), catalase (CAT), and glutathione peroxidase (GPX). The expression and activity of the antioxidant enzymes were significantly higher after the fish were exposed to 24°C, 20°C, and 17.5 psu, and expression was repressed by PRL treatment. Furthermore, we measured H 2O 2 and lipid peroxidation levels and found that they were significantly higher after exposure to the hypoosmotic and low-temperature environments. Additionally, we investigated changes in plasma AST and ALT levels after exposure to low temperature and hypoosmotic stress. These levels increased upon exposure of the clownfish to 24°C, 20°C, and 17.5 psu, but the levels of these parameters decreased in the 17.5 psu with PRL treatment during a salinity change. The results indicate that hypoosmotic and low-temperature conditions induce oxidative stress in cinnamon clownfish and that the parameters tested in this study may be indices of oxidative stress in the cinnamon clownfish. © 2011 Korean Society for Integrative Biology.