Oxidative stress and genotoxicity biomarker responses in grey mullet (Mugil cephalus) from a polluted environment in Saronikos Gulf, Greece.

Abstract

This study aimed to assess oxidative stress and genotoxicity biomarkers in grey mullet Mugil cephalus from a site receiving discharges from industrial and harbor activities and a reference site in Saronikos Gulf, Greece. Cellular antioxidant defenses, i.e., antioxidant enzyme activities (catalase, selenium [Se]-dependent glutathione peroxidase, glutathione-S-transferase) and oxidative damage, i.e., lipid peroxidation (measured as thiobarbituric acid reactive substances) were used as biomarkers of oxidative stress. The micronucleus test was used for evaluation of chromosome damage, and the frequency of cells with double nuclei was used as an indication of damage to cell divisions. Antioxidant enzyme activities were lower in fish from the polluted site compared with fish from the reference site, suggesting deficiency of the antioxidant system to compensate for oxidative stress. This is further supported by the higher lipid peroxidation levels in fish from the polluted site, which represent oxidative damage. Micronuclei and double-nuclei frequencies were higher in fish from the polluted site compared with fish from the reference site, indicating genotoxic effects. Correlations between biomarkers suggest that observed effects were due to contaminants exhibiting oxidative stress potential that can also induce genotoxicity. Results suggest that the selected biomarkers in M. cephalus are useful for the assessment of pollution impacts in coastal environments influenced by multiple pollution sources.