Anabolic steroid- and exercise-induced cardiac stress protein (HSP72) in the rat

The present study investigated the effects of exercise and anabolic-androgenic steroids on cardiac HSP72 expression. Male Wistar rats were divided into experimental groups: nandrolone exercise (NE, N = 6), control exercise (CE, N = 6), nandrolone sedentary (NS, N = 6), and control sedentary (CS, N = 6). Animals in the NE and NS groups received a weekly intramuscular injection (6.5 mg/kg of body weight) of nandrolone decanoate, while those in the CS and CE groups received mineral oil as vehicle. Animals in the NE and CE groups were submitted to a progressive running program on a treadmill, for 8 weeks. Fragments of the left ventricle were collected at sacrifice and the relative immunoblot contents of HSP72 were determined. Heart weight to body weight ratio was higher in exercised than in sedentary animals (P < 0.05, 4.65 +/- 0.38 vs 4.20 +/- 0.47 mg/g, respectively), independently of nandrolone, and in nandrolone-treated than untreated animals (P < 0.05, 4.68 +/- 0.47 vs 4.18 +/- 0.32 mg/g, respectively), independently of exercise. Cardiac HSP72 accumulation was higher in exercised than in sedentary animals (P < 0.05, 677.16 +/- 129.14 vs 246.24 +/- 46.30 relative unit, respectively), independently of nandrolone, but not different between nandrolone-treated and untreated animals (P > 0.05, 560.88 +/- 127.53 vs 362.52 +/- 95.97 relative unit, respectively) independently of exercise. Exercise-induced HSP72 expression was not affected by nandrolone. These levels of HSP72 expression in response to nandrolone administration suggest either a low intracellular stress or a possible less protection to the myocardium.