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Oxidative Medicine and Cellular Longevity
Volume 2017, Article ID 7921363, 11 pages
https://doi.org/10.1155/2017/7921363
Research Article

High-Intensity Exercise Reduces Cardiac Fibrosis and Hypertrophy but Does Not Restore the Nitroso-Redox Imbalance in Diabetic Cardiomyopathy

1Department of Basic Biomedical Sciences, Faculty of Health Sciences, Universidad de Talca, Talca, Chile
2Institute for Chemistry of Natural Resources, Universidad de Talca, Talca, Chile
3Department of Human Movement Sciences, Faculty of Health Sciences, Universidad de Talca, Talca, Chile

Correspondence should be addressed to Daniel R. Gonzalez; lc.aclatu@zelaznogad

Received 10 February 2017; Revised 18 April 2017; Accepted 27 April 2017; Published 18 June 2017

Academic Editor: Patricia C. Brum

Copyright © 2017 Ulises Novoa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Diabetic cardiomyopathy refers to the manifestations in the heart as a result of altered glucose homeostasis, reflected as fibrosis, cellular hypertrophy, increased oxidative stress, and apoptosis, leading to ventricular dysfunction. Since physical exercise has been indicated as cardioprotective, we tested the hypothesis that high-intensity exercise training could reverse the cardiac maladaptations produced by diabetes. For this, diabetes was induced in rats by a single dose of alloxan. Diabetic rats were randomly assigned to a sedentary group or submitted to a program of exercise on a treadmill for 4 weeks at 80% of maximal performance. Another group of normoglycemic rats was used as control. Diabetic rat hearts presented cardiomyocyte hypertrophy and interstitial fibrosis. Chronic exercise reduced both parameters but increased apoptosis. Diabetes increased the myocardial levels of the mRNA and proteins of NADPH oxidases NOX2 and NOX4. These altered levels were not reduced by exercise. Diabetes also increased the level of uncoupled endothelial nitric oxide synthase (eNOS) that was not reversed by exercise. Finally, diabetic rats showed a lower degree of phosphorylated phospholamban and reduced levels of SERCA2 that were not restored by high-intensity exercise. These results suggest that high-intensity chronic exercise was able to reverse remodeling in the diabetic heart but was unable to restore the nitroso-redox imbalance imposed by diabetes.