ORAL ABSTRACT SESSION: Mechanisms of exercise in heart failure: news from translational research: Friday, 2 May 2008, 9:00–10:30 Location: Room 352

Abstract

Previous exercise training is associated with lower local levels of apoptosis and inflammatory markers after myocardial infarction in rats M Santos; ECA Veiga; EL Antonio; DS Bocalini; AA Santos; SA Palomino; PJF Tucci; ML Higuchi; RC Maranhao INCOR-HCFMUSP Pathology, Sao Paulo, Brazil; EPM-UNIFESP Cardiac Physiology Lab, Sao Paulo, Brazil; InCor-HC FMUSP Pathology Lab, Sao Paulo, Brazil Apoptosis, and inflammatory modulators, such as NF-kB and TNF-alpha participate in cardiovascular remodeling after myocardial infarction (MI) and are associated with heart failure. Physical exercise reduces cardiovascular morbidity and mortality. The cardioprotective effects of exercise training include higher myocardial tolerance to ischemiareperfusion, improved cardiac performance and higher cell defense capacity against stress. Here we evaluated the effects of previous exercise training on myocardial levels of apoptosis, NF-kB and TNF-alpha 4 weeks after MI. Methods: 20 Wistar rats were randomly distributed in groups: Sedentary (S); Exercise (E); Sedentary plus MI (SI); Exercise plus MI (EI). Exercise training consisted in 8 wks of swimming; 1h/day, 5d/wk. MI was performed through surgical ligation of the left coronary artery. 4 wks after MI animals were submitted to echocardiographic study and sacrificed and the heart was excised and prepared for histological studies. Apoptosis was detected by TUNEL. Rabbit polyclonal antibody antiNFkB p65 and anti-TNF alpha were used for immunohistochemistry. Quantification of % positive area for each antigen was performed through an Automatic Color Detector Analysis System. Results: The number of apoptotic cells/20x field was higher in SI comparing to EI, in both infarcted myocardium and infarct border zone (3.97±0.27 vs 1.9±0.81, P=0.04 and 3.67±0.33 vs1.56±0.48, P=0.007, respectively). Comparing to EI, SI group had higher % positive area for NF-kB and TNF-alpha antigen at myocardium infarcted area (0.53±0.12 vs 0.26±0.06, P=0.08 and 1.72±0.24 vs 0.62±0.18, P=0.01). Conclusion:MI in previously trained animals was associated with lower levels of apoptosis, TNF-alpha and NF-kB. Physical exercise training promotes a better immune response against myocardial infarction that can lead to better functional outcomes. These results reinforce the need to develop cardiovascular prevention programs with exercise.