Effect of increased dietary selenium intake on blood and cardiac selenium status during aging in rats

Oral selenium supplementation has been described as cardioprotective against pathophysiological situations involving oxidative stress in young adults rats. However no data are available concerning the effects of selenium supplementation on selenium status and glutathione peroxidase (GPX) activity in senescent rats. In the present study young adult and senescent rats were fed a diet containing selenium either 0.05 mg/kg (control) or 1.5 mg/kg (selenium) for 10 weeks. Selenium content in both diets was adjusted by sodium selenite addition. At the end of the supplementation period although plasma selenium level was lower in the two groups of aged rats than in the corresponding adults (p < 0.05), cardiac GPX activity, measured in both cytosolic and mitochondrial extracts appeared to be similarly increased in both categories of age. These data are the first to indicate that oral Se-supplementation is able to increase the plasma selenium concentration and cardiac GPX activity in senescent rats as well as in young adults. (C) 2003 Elsevier Science Inc. All rights reserved.