Treadmill exercise training prevents myocardial mechanical dysfunction induced by androgenic-anabolic steroid treatment in rats

• Published in: PloS one Vol. 9; no. 2; p. e87106
• Main Authors: Bocalini, Danilo S, Beutel, Abram, Bergamaschi, Cássia T, Tucci, Paulo J, Campos, Ruy R
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 12-02-2014; Public Library of Science (PLoS)
• Subjects: Anabolic Agents - pharmacology; Anabolic steroids; Analogs; Androgens; Animals; Biology; Blood Pressure; Calcium; Cardiac Output; Cardiovascular system; Exercise; Exercise Test - methods; Fitness equipment; Fitness training programs; Heart; Heart - drug effects; Heart diseases; Heart failure; Heart Rate - drug effects; Heart Ventricles - drug effects; Hematocrit; Hemodynamics; Hemodynamics - drug effects; Male; Medicine; Muscle contraction; Muscles; Myocardial Contraction - drug effects; Myocardium - pathology; Organ Size - drug effects; Physical Conditioning, Animal; Physical training; Physiology; Rats; Rats, Wistar; Rodents; Stanozolol; Stanozolol - pharmacology; Steroids - pharmacology; Tension; Testosterone; Treadmills; Ventricle
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0087106

Elevated concentrations of testosterone and its synthetic analogs may induce changes in cardiovascular function. However, the effects of the combination of anabolic/androgenic steroid (AAS) treatment and exercise training on systolic and diastolic cardiac function are poorly understood. In the present study, we aimed to investigate the effects of low-dose steroid treatment (stanozolol) on cardiac contractile parameters when this steroid treatment was combined with exercise training in rats and the effects of chronic steroid treatment on the Frank-Starling (length-tension curves) relationship. Male Wistar rats were randomly assigned to one of four groups: U (untrained), US (untrained and treated with stanozolol 5 mg/kg/week), T (trained, 16 m/min/1 h) and TS (trained and treated with stanozolol 5 mg/kg/week). Continuous exercise training was conducted 5 days/week for 8 consecutive weeks. The speed of the treadmill was gradually increased to a final setting of 16 m/min/1 h. Experiments were divided into two independent series: 1) central hemodynamic analysis for mean arterial blood pressure (MAP) and cardiac output (CO) measurements and 2) isolated papillary muscle preparation in Krebs solution. Stanozolol treatment significantly increased the MAP and the heart size in untrained and trained rats (U 113±2; T 106±2; US 138±8 and TS 130±7 mmHg). Furthermore, stanozolol significantly decreased developed tension and dT/dt (maximal and minimal) in U rats. However, the developed tension was completely restored by training. The Frank/Starling relationship was impaired in rats treated with stanozolol; however, again, training completely restored diastolic function. Taken together, the present data suggest that AAS treatment is able to decrease cardiac performance (systolic and diastolic functions). The combination of stanozolol and physical training improved cardiac performance, including diastolic and systolic functions, independent of changes in central hemodynamic parameters. Therefore, changes in ventricular myocyte calcium transients may play a cardioprotective role.