Testosterone improves cardiac function and alters angiotensin II receptors in isoproterenol-induced heart failure

Background. - The renin-angiotensin-aldosterone system is known to play an important role in the pathophysiology and development of heart failure. Several studies have reported the benefits of testosterone in heart failure. However, the mechanisms of testosterone-induced effects on heart failure require further study. Aims. - To determine the effects of castration and testosterone administration on cardiac function and angiotensin II receptor function in rats with isoproterenol-induced heart failure. Methods. - Wistar rats were divided randomly into control and heart failure groups. The heart failure groups were further divided into the following groups: castration; castration + testosterone replacement; and sham castration. Echocardiography and haemodynamic measurements were used to evaluate cardiac function. Cardiocyte apoptosis and fibrosis were determined using terminal deoxyribonucleotide transferase-mediated dUTP nick-end labelling (TUNEL) staining and Masson's Trichrome staining, respectively. Angiotensin II receptor (AT1 and AT2) messenger ribonucleic acid (mRNA) expression levels were assayed using real-time reverse transcriptase-polymerase chain reactions, while Western immunoblotting was used to estimate Bcl-2 protein expression levels. Results. - Castration significantly increased cardiomyocyte apoptosis and fibrosis that was normally induced by isoproterenol (P < 0.05). AT2 receptor mRNA expression in the castration group was increased and Bcl-2 protein expression was decreased compared with the castration + testosterone replacement group (P < 0.05). Conclusion. - These data suggest that androgen therapy could play an important role in pathophysiological changes in heart failure and have beneficial effects for its treatment. (C) 2012 Elsevier Masson SAS. All rights reserved.