Different levels of Hsp72 in female rat myocardium in response to voluntary exercise and forced exercise

Abstract

Physical exercise induces hemodynamic stress. To evaluate if voluntary running and forced running induced different levels of stress protein (Hsp72) in the myocardium of female Wistar rats. Female rats were randomly assigned to the following groups: forced treadmill running group (FR; n= 6), voluntary running group (VR; n=6) and control group (C; n=6). VR group animals had free access to running wheels, and those from FR group underwent a running program on a treadmill (18 m/min, 60 min/day, 5 days/wk) for 8 weeks. Left ventricle (LV) and right ventricle (RV) fragments were collected at sacrifice, and the relative immunoblot contents of stress protein (Hsp72) were determined. VR animals ran on average 4.87 km/wk, and FR rats ran 4.88 km/wk. Animals from VR and FR groups had less body weight gain (p<0.05) than those from C group (81.67 ± 11.95g vs 81.17 ± 10.18g vs 111.50 ± 2.26g, respectively). Heart weight/body weight ratio was not significantly different (p>0.05) among VR, FR and C groups (4.54 ± 0.79 mg/g vs 4.94 ± 0.89 mg/g vs 4.34 ± 0.87 mg/g, respectively). FR group animals had levels of Hsp72 (p<0.05) higher than those from VR, both in LV (287.45 ± 35.86 % vs 135.59 ± 5.10 %, respectively) and RV (241.31 ± 25.83 % vs 137.91 ± 45.20 %, respectively). Voluntary running and forced running induced different levels of Hsp72 in the myocardium of female Wistar rats.