Dietary selenium intake affects cardiac susceptibility to ischaemia/reperfusion in male senescent rats.
BACKGROUND
cardiovascular ageing is associated with an increase in cardiac susceptibility to ischaemia and reperfusion. This has been suggested to be partly related to an increased sensitivity of the myocardium to the reactive oxygen species that are produced during post-ischaemic reperfusion. The aim of the present study was therefore to determine whether increasing cardiac glutathione peroxidase activity by a selenium-enriched diet could afford some protection against ischaemia and reperfusion to senescent rat hearts.


METHODS
22 months old male Wistar rats received either a high-selenium (1.5 mg Se/kg diet) or a low-selenium (0.05 mg Se/kg diet) diet for 10 weeks. At the end of the diet, hearts were submitted to ischaemia and reperfusion ex vivo and either fixed for semi-quantitative analysis of ultrastructural damage by electron microscopy or used for glutathione peroxidase activity assessment.


RESULTS
high-selenium supply increased cardiac total, mitochondrial and cytosolic glutathione peroxidase activities. Moreover, this diet induced a significant improvement of cardiac post-ischaemic functional recovery. Finally, this preservation of cardiac function was associated with a significant limitation of ultrastructural alterations of sarcomeres and mitochondria.


CONCLUSIONS
our high-selenium diet considerably limits the sensitivity of senescent rat hearts to ischaemia and reperfusion. This finding suggests that peroxides might play a key role in the increase in cardiac sensitivity to ischaemia and reperfusion during ageing. Together with the observation that selenium status decreases with age in humans, our results indicate that reinforcing selenium supply could improve the prognosis of cardiovascular diseases in old patients.
Tanguy
Stéphane
S
Laboratoire Stress Cardiovasculaires et Pathologies Associées, Université Joseph Fourier, Grenoble, France.
Toufektsian
Marie-Claire
MC
Besse
Sophie
S
Ducros
Véronique
V
De Leiris
Joël
J
Boucher
François
F
D000375:Aging / Q000502:physiology*; D000818:Animals; D004912:Erythrocytes / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D008297:Male; D017202:Myocardial Ischemia / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D012643:Selenium / Q000008:administration & dosage* / Q000097:blood
D017382:Reactive Oxygen Species; D005979:Glutathione Peroxidase; D012643:Selenium