Received January 4, 2005
Revised February 1, 2005
Accepted after revision February 21, 2005
Antioxidant defences and ecto-5'-nucleotidase are not involved in the exercise-training induced protection against ischemia/reperfusion injury in the rat heart
María Morán 1*,
Isabel Blázquez 1,
Ana Saborido 1,
Alicia Megías 1
1 Complutense University
* To whom correspondence should be addressed. E-mail: alejandro.lucia{at}mrfs.cisa.uem.es.
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Abstract |
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Isolated Langendorff-perfused hearts from sedentary and prolonged (24 weeks) treadmill-trained rats were subjected to 30 min of normoxic perfusion either alone or followed by 20 min of global ischemia, or by 20 min of global ischemia and 15 min of normoxic reperfusion. Preischemic values of antioxidant enzyme activities and ecto-5'-nucleotidase activity were not different in sedentary and trained hearts but a five-fold increase of HSP72 levels was detected in trained myocardium. After ischemia-reperfusion (I/R), metabolic recovery was better in trained than in sedentary hearts as indicated by higher ATP and creatine phosphate levels. However, antioxidant enzymatic activities, glutathione reductase, and total and mitochondrial superoxide dismutase decreased in trained rats after I/R, whereas remained unchanged in the sedentary ones. Ecto-5'-nucleotidase activity was modified by I/R in sedentary as well as in trained hearts while HSP72 content did not change. Both parameters resulted increased in parallel by the 30 min-perfusion period. In conclusion, the cardioprotection induced by long-term training could be mediated by the exercise-induced increase in HSP72 levels and is not related to enhanced antioxidant systems or ecto-5'-NT activity.
Key Words:
Adenosine, Oxidation, Perfusion
