Lipid peroxidation and level of antioxidant compounds (GSH, vitamin E) in the digestive glands of mussels of three different age groups exposed to anaerobic and aerobic conditions

The effects of anaerobiosis and subsequent re-oxygenation on lipid peroxidation and on the levels of the two major antioxidant compounds (GSH and vitamin E) were evaluated in the digestive gland of mussels (Mytilus edulis L.) of three different age groups (I = 2-4 years; II = 6-8 years; III = > 10 years). The lipid peroxidation level, as evaluated by malondialdehyde (MDA) concentration is significantly higher in the digestive gland of the > 10 year old mussels with respect to the younger animals. This fact appears to be related to the lower levels of GSH and vitamin E found in the tissue of the aged mussels. A decrease both in the MDA concentration and in the level of GSH and vitamin E was observed in mussels of the three age groups exposed for 24 h to anaerobic conditions. After re-immersion in aerated seawater the MDA level greatly increased only in the > 10 year old mussels. The results demonstrate that, during anaerobiosis, a reduction of the cellular antioxidant compounds occurs in the digestive gland of mussels. In the > 10 year old animals, such a decrease in the cellular defence systems would result in a major oxidative stress, as evidenced by the high MDA level observed in the older mussels after re-oxygenation.