Author/Authors :
Aminizadeh، Soheil نويسنده Department of Exercise Physiology, Shahid Bahonar
University of Kerman, Kerman, IR Iran , , Marefati، Hamid نويسنده , , Najafipour، Hamid نويسنده , , Joukar، Siyavash نويسنده Physiology Research Center, Institute of
Neuropharmacology, Kerman University of Medical Sciences, Kerman, IR
Iran , , Dabiri، Shahriar نويسنده , , Shahouzehi، Beydolah نويسنده Cardiovascular Research Center, Institute of Basic and
Clinical Physiology, Kerman University of Medical Sciences, Kerman,
IR Iran ,
Abstract :
Cardiovascular diseases are among the major causes of mortality in
industrialized countries. Prevention of cardiovascular diseases and
increasing stress tolerance are two of the main goals of physical
training. This study was designed to compare the effects of two exercise
programs of different intensities on rat hearts with
isoproterenol-induced myocardial injuries. Animals were randomly divided
into four groups (n = 8 per group): control group (CTL); ISO group,
administered isoproterenol (85 mg/kg subcutaneously) for two consecutive
days; low-intensity interval training + isoproterenol group (LIIT + ISO:
5 minutes warm up at 40% VO2 max, 5 × 10 minutes at 50% - 60% VO2 max
[about 20 - 24 m/min]); and high-intensity interval training +
isoproterenol group (HIIT + ISO: 5 minutes warm-up at 40% VO2 max, 5 × 5
min at 95% - 105% VO2 max [45 - 50 m/min]). The training groups
performed high- and low-intensity interval training programs (5
days/week) on a motor-driven treadmill for 16 weeks. Seventy-two hours
after the last training session, isoproterenol (85 mg/kg) was injected
on two consecutive days. On the third day, hemodynamic parameters were
recorded, blood samples were taken, and hearts were removed for
laboratory analysis. ISO-induced heart injury raised cardiac troponin I
levels, significantly decreased + dp/dt max (P < 0.05) and -dp/dt
max (P < 0.05), and significantly increased serum CTnI and tissue
TNF α levels (P < 0.05). Exercise training had no significant
effects on HR, LVSP, and LVEDP. Impairments of + dp/dt max and -dp/dt
max were significantly improved in the HIIT + ISO and LIIT+ISO groups (P
< 0.05 for both groups versus ISO). In addition, exercise
training groups especially HIIT + ISO to some reduce exacerbated the
myocardial lesions induced by ISO (P < 0.05). These biochemical
and histopathological findings suggest there is a protective role
provided by both high- and low-intensity interval training protocols on
ischemic hearts.
