Short-term effects of electrically induced tachycardia on antioxidant defenses in the normal and hypertrophied rat left ventricle

The effect of resveratrol on angiotensin II levels and the rate of transcription of its receptors in the rat cardiac hypertrophy model

This study investigated the effect of resveratrol on serum and cardiac levels of angiotensin II and transcription of its main receptors following pressure overload induced-hypertrophy. Rats were divided into untreated (Hyp) and resveratrol treated hypertrophied groups (H + R). Intact animals served as the control (Ctl). Cardiac hypertrophy was induced by abdominal aortic banding. Blood pressure (BP) was recorded via left carotid artery cannula. Fibrosis was confirmed by Masson trichrome staining. Angiotensin II level was measured using an ELIZA test. Gene expression was assessed by a real time PCR (RT-PCR) technique. We observed that in the H + R group BP and heart weight/body weight were decreased significantly (p < 0.001, p < 0.05, respectively vs Hyp). The cardiac levels of angiotensin II and AT1a mRNA were increased in the Hyp group (p < 0.01 vs Ctl). In the H + R group the AT1a mRNA level was decreased significantly (p < 0.05 vs Hyp). It could be concluded that resveratrol protects the heart against hypertrophy progression in part by affecting cardiac AT1a transcription.

High-dose testosterone propionate treatment reverses the effects of endurance training on myocardial antioxidant defenses in adolescent male rats

This study was aimed at evaluation of changes in activities of selected antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase) and contents of key nonenzymatic antioxidants (glutathione, protein thiol groups, and α- and γ-tocopherols) in the left heart ventricle of young male Wistar rats subjected to endurance training (treadmill running, 1 h daily, 5 days a week, for 6 weeks) or/and testosterone propionate treatment (8 or 80 mg/kg body weight, intramuscularly, once a week, for 6 weeks) during adolescence. The training alone increased the activities of key antioxidant enzymes, but lowered the pool of nonenzymatic antioxidants and enhanced myocardial oxidative stress as evidenced by elevation of the lipid peroxidation biomarker malondialdehyde. The lower-dose testosterone treatment showed mixed effects on the individual components of the antioxidant defense system, but markedly enhanced lipid peroxidation. The higher-dose testosterone treatment decreased the activities of the antioxidant enzymes, lowered the contents of the nonenzymatic antioxidants, except for that of γ-tocopherol, reversed the effect of endurance training on the antioxidant enzymes activities, and enhanced lipid peroxidation more than the lower-dose treatment. These data demonstrate the potential risk to cardiac health from exogenous androgen use, either alone or in combination with endurance training, in adolescents.