Effect of Moderate and Acute Hypoxia on the Antioxidant Enzyme Complex of the Tissues of the Black Sea Mussel Mytilus galloprovincialis

The effect of moderate (2 mg O2/L) and acute (1 mg O2/L) hypoxia on the state of the antioxidant complex of the mussel Mytilus galloprovincialis (Lamarck, 1819) has been studied. The activity of superoxiddismutase (SOD), catalase, and glutathione peroxidase (GP) in the hepatopancreas and gills of the mollusk is determined. The reactions of the AO complex of mussels to oxygen deficiency depend on the degree of hypoxic exposure and had tissue specificity. Acute hypoxia has a more pronounced effect on the mussel than moderate hypoxia. An increase in the activity of all the studied enzymes is observed in the gills of the mollusk under acute hypoxia. Under these conditions, only catalase activity increases in the hepatocreas of the mussel, and SOD significantly decreases. Under moderate hypoxia conditions, the AO protection of the mollusk gills is provided by SOD and GP, and in hepatopancreas, by activation of catalase and GP. These reactions indicate the development of moderate oxidative stress in mussel tissues under both hypoxia regimes. The features of the AO response of gills and hepatopancreas reflect their tissue-specific sensitivity to the effects of oxygen deficiency.