Nandrolone Plus Moderate Exercise Increases the Susceptibility to Lethal Arrhythmias

Abstract

Background: Until now, no experimental study has directly assessed the arrhythmogenesis of chronic consumption of anabolic androgenic steroids along with moderate-intensity endurance exercise.

Objectives: We evaluated the influence of integration of anabolic androgenic steroids along with moderate-intensity endurance exercise on susceptibility to lethal ventricular arrhythmias in rat.

Materials and methods: The animal groups were as follows: control group (CTL); exercise group (EX) which were under 6 weeks of treadmill exercise; nandrolone group (Nan) which received 5 mg/kg of nandrolone decanoate twice a week; vehicle group (Arach) which received Arachis oil (solvent of nandrolone); trained vehicle group (Arach + Ex); and trained nandrolone group (Nan + Ex). One day after ending of the intervention period, arrhythmia was inducted by intravenous infusion of aconitine and ventricular arrhythmias were recorded. Then malondialdehyde (MDA) and glutathione peroxidase (GPX) of heart tissue were measured.

Results: Nandrolone, exercise, and their combination were associated with heart hypertrophy. Exercise could prevent the incremental effect of nandrolone on MDA/GPX ratio. Chronic administration of nandrolone with moderate-intensity endurance exercise had no significant effect on blood pressure, heart rate, and basal electrocardiographic parameters. Combination of nandrolone and exercise significantly increased the incidence of ventricular fibrillation (VF) and reduced the VF latency (P < 0.05).

Conclusions: The findings suggest that chronic coadministration of nandrolone with moderate-intensity endurance exercise facilitates the VF occurrence in rat. Complementary studies are needed to elucidate the involved mechanisms of this abnormality.

Keywords: Aerobic Exercise; Nandrolone Decanoate; Ventricular Fibrillation.

Figure 1.. Mean of Heart Hypertrophy Index in Different Experimental Groups at the End of 6^th Week

Values are presented as mean ± SEM. N = 7 - 9. CTL, control; Arach, animal group which received vehicle (Arachis oil); Nan, animal group which received 5 mg/kg/day of nandrolone decanoate twice a week; Ex, animal group which trained with prolonged moderate intensity exercise; Arach + Ex, animals group which received Arachis oil and exercise training; Nan + Ex, animals group which received nandrolone decanoate and exercise training;*, P < 0.05 compared with Arach group; ●, P < 0.01 compared with CTL group; ▼, P < 0.01 compared with Arach group.

Figure 2.. The Strips of Arterial Blood Pressure and Lead II of ECG That Simultaneously was Recorded From an Animal From Nan+ Ex Group in Different Condition

A, Basal normal sinus rhythm (NSR) and blood pressure of an animal from Nan+ Ex group. B, Sustained ventricular tachycardia (VT) with regular morphology and rate along with blood pressure drop in same animal six minutes after onset of aconitine injection. C, Sustained ventricular fibrillation (VF) along with severe blood pressure drops in same animal 11 minutes after onset of aconitine injection.

Figure 3.. Scores of Arrhythmia Severity in Each Experimental Group

Values are presented as mean ± SEM. N= 7 - 9. CTL, control; Arach, animal group which received vehicle (Arachis oil); Nan, animal group which received 5 mg/kg/day of nandrolone decanoate twice a week; Ex, animal group which trained with prolonged moderate intensity exercise; Arach + Ex, animals group which received Arachis oil and exercise training; Nan + Ex, animals group which received nandrolone decanoate and exercise training.

Figure 4.. The Number of Ventricular Arrhythmias in Animal Groups

Values are presented as mean ± SEM. N= 7 - 9. CTL, control; Arach, animal group which received vehicle (Arachis oil); Nan, animal group which received 5 mg/kg/day of nandrolone decanoate twice a week; Ex, animal group which trained with prolonged moderate intensity exercise; Arach + Ex, animals group which received Arachis oil and exercise training; Nan + Ex, animals group which received nandrolone decanoate and exercise training.*, P < 0.05 compared with Ex group.

Figure 5.. The Duration of Ventricular Tachycardia and Ventricular Fibrillation Arrhythmias in the Different Groups

Values are presented as mean ± SEM. N = 7 - 9. CTL, control; Arach, animal group which received vehicle (Arachis oil); Nan, animal group which received 5 mg/kg/day of nandrolone decanoate twice a week; Ex, animal group which trained with prolonged moderate intensity exercise; Arach + Ex, animals group which received Arachis oil and exercise training; Nan + Ex, animals group which received nandrolone decanoate and exercise training.

Figure 6.. The Latency Periods for Induction of Ventricular Arrhythmias

Values are presented as mean ± SEM. N= 7 - 9. CTL, control; Arach, animal group which received vehicle (Arachis oil); Nan, animal group which received 5 mg/kg/day of nandrolone decanoate twice a week; Ex, animal group which trained with prolonged moderate intensity exercise; Arach + Ex, animals group which received Arachis oil and exercise training; Nan + Ex, animals group which received nandrolone decanoate and exercise training.*, P < 0.05 compared with Ex group.