title: Endurance training induces fiber type-specific revascularization in hindlimb skeletal muscles of rats with chronic heart failure.
abstract: OBJECTIVE
  Previous studies showed that skeletal muscle microcirculation was reduced in chronic heart failure. The aim of this study was to investigate the effects of endurance training on capillary and arteriolar density of fast and slow twitch muscles in rats with chronic heart failure.
  
  
  METHODS
  Four weeks after surgeries (left anterior descending (LAD) artery occlusion), chronic heart failure rats were divided into 3 groups: Sham (Sham, n=10); Sedentary (Sed, n=10); Exercise training (Ex, n=10). Ex group rats were subjected to endurance training in the form of treadmill running with moderate intensity for 10 weeks.
  
  
  RESULTS
  Exercise training significantly increased capillary density and capillary to fiber ratio (P<0.05) in slow twitch muscle, but didn't change fast twitch muscle capillary density and capillary to fiber ratio. Furthermore, arteriolar density in fast twitch muscle increased remarkably (P<0.05) in response to training, but slow twitch muscle arteriolar density did not change in response to exercise in chronic heart failure rats. HIF-1 increased (P<0.01) but VEGF and FGF-2 mRNA did not change in slow twitch muscle after training. In fast twitch muscle, HIF-1 mRNA increased (P<0.05), and VEGF and angiostatin decreased (P<0.01) significantly after training.
  
  
  CONCLUSIONS
  Endurance training ameliorates fast and slow twitch muscle revascularization non-uniformly in chronic heart failure rats by increasing capillary density in slow twitch muscle and arteriolar density in fast twitch muscle. The difference in revascularization at slow and fast twitch muscles may be induced by the difference in angiogenic and angiostatic gene expression response to endurance training.
authors.affiliation: Department of Physical Education and Sport Science, Bandar Abbas branch, Islamic Azad University, Bandar Abbas, Iran.
authors.forename: Kamal
authors.initials: K
authors.lastname: Ranjbar
authors.affiliation: School of Humanities, Department of Sport Science, Damghan University, Damghan, Iran.
authors.forename: Malihe
authors.initials: M
authors.lastname: Ardakanizade
authors.affiliation: Department of Sports Physiology, Faculty of Physical Education and Sports Sciences, Bu-Ali Sina University, Hamedan, Iran.
authors.forename: Farzad
authors.initials: F
authors.lastname: Nazem
keywords: Chronic heart failure; Endurance training; Fast and slow twitch muscles; Revascularization