Prior exercise training does not prevent acute cardiac alterations after myocardial infarction in female rats

Abstract

OBJECTIVE:This study aimed to investigate whether previous exercise training could prevent or attenuate acute cardiac alterations after myocardial infarction.METHODS:Female rats were submitted to swim training (1 h/day; 5 days/week) or allowed to remain sedentary for 8 weeks. Afterwards, they were randomly assigned to left coronary artery occlusion or sham surgery. After this procedure, the rats remained sedentary for one week until euthanasia. Cardiac structural and functional analyses were performed using Doppler echocardiography. The rats that had a moderate or large infarct size were included in the evaluations. The data (mean ± SEM) were analyzed using a two-way ANOVA model followed by Tukey's post-hoc test.RESULTS:After the surgery, no significant difference between the exercise and sedentary groups was observed in the left ventricular infarct sizes (34.58±3.04 vs. 37.59±3.07). In another group of rats evaluated with Evans blue 1 h after myocardial infarction, no siginificant difference in the area at risk was observed between the exercised and sedentary rats (49.73±1.52 vs. 45.48±3.49). The changes in the left ventricular fractional areas for the exercised and sedentary myocardial infarction groups (36±2% and 39±3%, respectively) were smaller than those for the exercise sham surgery (ES, 67±1%) and sedentary sham surgery (SS, 69±2%) groups. The E/A was higher in the sedentary myocardial infarction (4.4±0.3) and exercised myocardial infarction (5.5±0.3) rats than in the SS (2.4±0.1) and ES (2.2±0.1) rats.CONCLUSION:Previous swim training of female rats does not attenuate systolic and diastolic function alterations after myocardial infarction induced by left coronary artery occlusion, suggesting that cardioprotection cannot be provided by exercise training in this experimental model.

Cardiology in Brazilian scientific journals: an overview

“…They conclude that there is variability regarding baroreflex sensitivity among Wistar Kyoto rats from the same laboratory. Veiga et al [53] investigated whether previous exercise training could prevent or attenuate acute cardiac alterations after myocardial infarction in female rats submitted to swim training or allowed to remain sedentary for 8 weeks. They were randomly assigned to left coronary artery occlusion or sham surgery and found that previous swim training does not attenuate systolic and diastolic function alterations after myocardial infarction induced by left coronary artery occlusion, suggesting that cardioprotection cannot be provided by exercise training in this experimental model.…”

Repercussões cardíacas após infarto do miocárdio em ratas submetidas previamente a exercício físico

“…Recently, it was demonstrated in a study carried out in our laboratory 18 that exercise performed prior to MI showed no reduction in infarction size or attenuation of the myocardial remodeling process in animals studied seven days after coronary occlusion. To the best of our knowledge, there are no studies that evaluated the influence of exercise on late ventricular remodeling.…”

[ARTIGO RETRATADO] Exercício e suas interações com vários aspectos da vida do homem e dos animais

“…They conclude that the effect of chronic exercise training in decreasing infarct size seems to occur, at least in part, through the opioid receptor stimulus and not by increasing myocardial perfusion. A contrasting result is described by Veiga et al 10 who investigated whether previous exercise training could prevent or attenuate acute cardiac alterations after myocardial infarction in female Wistar rats submitted to swim training or allowed to remain sedentary. Their results indicate that previous swim training does not attenuate systolic and diastolic function alterations after myocardial infarction induced by left coronary artery occlusion, suggesting that cardioprotection cannot be provided by exercise training in this experimental model.…”