Aim: 

Antarctic marine environment is characterised by increased oxygen partial pressure (pO2), correlated to low temperature of waters (-1.9°C). In these conditions, reactive oxygen specie (ROS) formation is favoured. Among pro-oxydants, factors which may favour the ROS production, there are heavy metals, expecially those whit redox properties (such as Fe and Cu) which catalyse Fenton and Haber-Weiss reactions. In the present study we have verified the effect of simultaneous presence of increased pO2 and Cu on induction of the antioxidant enzyme selenium glutathione peroxidise (Se-GPX).

Methods: 

With this aim, the Antarctic teleost Trematomus eulepidtus, sampled in the Ross Sea (Terra Nova Bay), was examined. Fifty specimens of each species were separated into two groups of ten and maintained at –1.9°C. One group was exposed to Cu (100 mg/l). The other group, untreated, was used as controls. After ten days the animals were sacrificed to analyse Cu accumulation by atomic absorption spectrophotometry. The expression of Se-GPX was evaluated in in gills, liver and skeletal muscle, both at mRNA and active protein levels.

Results: 

Increase of mRNA is evident in gills and liver, indicating that Se-GPX may play an important role in elimination of H2O2 produced in these tessues.

Conclusion: 

The induction of this antioxidant enzyme probably is related to a Cu-mediated oxidative stress condition. (PNRA and MIUR grants)