Heart Reaction to Nandrolone Decanoate plus Two Different Intensities of Endurance Exercise: Electrocardiography and Stereological Approach

Background: Regarding the negative effects of androgenic anabolic steroids (AASs) abuse, the long-term effect of nandrolone decanoate with/without two intensities of endurance exercise training was investigated on heart tissue and electrocardiogram (ECG) in rats. Methods: The experiment was conducted on 63 male Wistar rats, which were 4 months old. The rats were divide into groups of control (CTL), arachis oilasnandrolone solvent (Ar), nandrolone (Nan) (received a dose of 5 mg/kg twice/week for 8 weeks), mild swimming exercise training (mEx), severe exercise (sEx), sEx + Nan, mEx + Nan, mEx + Ar, and sEx + Ar. During the 8 weeks of swimming exercise, the animals carried dumbbells equivalent to 2% of their body weight, which was gradually increased and reached 5% and 8% in the 6th week for mild and severe exercises, respectively. Finally, ECGs recording and samplings were done. Findings: Both types of exercise, without nandrolone, significantly reduced the heart rate and increased the RR interval of ECG. Nandrolone alone and with mild (P < 0.050) and intense exercise (P < 0.010 vs. CTL) increased the left ventricular hypertrophy (LVH) index. Left ventricular volume was significantly higher in the Nan group (P < 0.050) compared to the CTL group and all exercise groups (P < 0.010) compared to the Nan, CTL, and Ar groups. Myocytes volume increased in the presence of both of mild and high-intensity exercise plus nandrolone (P < 0.050 vs. CTL and Ar groups). Hydroxyproline value of the heart was significantly higher in the nandrolone group compared to all other groups (P < 0.001). Exercise prevented the effect of nandrolone on hydroxyproline. Conclusion: Both levels of swimming exercise prevent the effect of nandrolone on the production of hydroxyproline and fibrotic cardiac remodeling.