| Abstract
| - Since in the aged heart an increased basal production of reactive oxygen species (ROS) has beendemonstrated, and the resistance to ROS attack could be ameliorated by antioxidant supplementation,we verified the protective effect of selenium, as sodium selenite (SS) or seleno methionine (SM), incultured rat cardiomyocytes aged in vitro. In normoxia, glutathione peroxidase (GPx) activity andtotal antioxidant activity were higher in old than in young cardiomyocytes, suggesting the existenceof a compensatory increase of antioxidant defenses. When aged cells were submitted to hypoxia/reoxygenation, GPx activity was not modified; while total antioxidant activity decreased, conjugateddiene level increased. Selenium supplementation, particularly as SM, was able to increase GPx, andconsequently total antioxidant activity, and to decrease conjugated diene production. The observedability of selenium supplementation to protect aged cardiomyocytes from hypoxia/reoxygenationdamage underlines the importance of an optimal selenium dietary intake, particularly in the elderly. Keywords: Selenium; aging; hypoxia/reoxygenation; cardiomyocytes; glutathione peroxidase
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