title: Cardioprotection afforded by exercise training prior to myocardial infarction is associated with autonomic function improvement.
abstract: BACKGROUND
  It has been suggested that exercise training (ET) protects against the pathological remodeling and ventricular dysfunction induced by myocardial infarction (MI). However, it remains unclear whether the positive adjustments on baroreflex and cardiac autonomic modulations promoted by ET may afford a cardioprotective mechanism. The aim of this study was to evaluate the effects of aerobic ET, prior to MI, on cardiac remodeling and function, as well as on baroreflex sensitivity and autonomic modulation in rats.
  
  
  METHODS
  Male Wistar rats were divided into 4 groups: sedentary rats submitted to Sham surgery (C); trained rats submitted to Sham surgery (TC); sedentary rats submitted to MI (I), trained rats submitted to MI (TI). Sham and MI were performed after ET period. After surgeries, echocardiographic, hemodynamic and autonomic (baroreflex sensitivity, cardiovascular autonomic modulation) evaluations were conducted.
  
  
  RESULTS
  Prior ET prevented an additional decline in exercise capacity in TI group in comparison with I. MI area was not modified by previous ET. ET was able to increase the survival and prevent additional left ventricle dysfunction in TI rats. Although changes in hemodynamic evaluations were not observed, ET prevented the decrease of baroreflex sensitivity, and autonomic dysfunction in TI animals when compared with I animals. Importantly, cardiac improvement was associated with the prevention of cardiac autonomic impairment in studied groups.
  
  
  CONCLUSIONS
  Prior ET was effective in changing aerobic capacity, left ventricular morphology and function in rats undergoing MI. Furthermore, these cardioprotective effects were associated with attenuated cardiac autonomic dysfunction observed in trained rats. Although these cause-effect relationships can only be inferred, rather than confirmed, our study suggests that positive adaptations of autonomic function by ET can play a vital role in preventing changes associated with cardiovascular disease, particularly in relation to MI.
authors.forename: Fernando
authors.initials: F
authors.lastname: Rodrigues
authors.forename: Daniele Jardim
authors.initials: DJ
authors.lastname: Feriani
authors.forename: Catarina Andrade
authors.initials: CA
authors.lastname: Barboza
authors.forename: Marcos Elias Vergilino
authors.initials: ME
authors.lastname: Abssamra
authors.forename: Leandro Yanase
authors.initials: LY
authors.lastname: Rocha
authors.forename: Nicolle Martins
authors.initials: NM
authors.lastname: Carrozi
authors.forename: Cristiano
authors.initials: C
authors.lastname: Mostarda
authors.forename: Diego
authors.initials: D
authors.lastname: Figueroa
authors.forename: Gabriel Inacio Honorato
authors.initials: GI
authors.lastname: Souza
authors.forename: Kátia
authors.initials: K
authors.lastname: De Angelis
authors.forename: Maria Cláudia
authors.initials: MC
authors.lastname: Irigoyen
authors.affiliation: Human Movement Laboratory, Sao Judas Tadeu University (USJT), São Paulo, SP, Brazil. prof.brodrigues@gmail.com.
authors.forename: Bruno
authors.initials: B
authors.lastname: Rodrigues
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001341:Autonomic Nervous System / Q000503:physiopathology*; D017704:Baroreflex; D004195:Disease Models, Animal; D005081:Exercise Therapy; D017079:Exercise Tolerance; D006439:Hemodynamics; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D017208:Rats, Wistar; D057185:Sedentary Behavior; D013997:Time Factors; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000517:prevention & control*; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling