Thyroid hormones effects on oxidative stress and cardiac remodeling in the right ventricle of infarcted rats

Abstract Right ventricle (RV) dysfunction post-myocardial infarction (MI) was associated with a worsened prognosis. In this scenario, reactive oxygen species (ROS) are related with the progression from MI to heart failure. Previous work showed that thyroid hormones (TH) are cardioprotective after MI. Aims This study aims to investigate the effect of T3 and T4 administration on oxidative stress and angiogenesis parameters in the RV after MI. Main methods Wistar rats were allocated into four groups: Sham-operated (SHAM), infarcted (AMI), sham-operated + TH (SHAMT), and infarcted + TH (AMIT). The treated groups received T3 (2 μg/100 g/day) and T4 (8 μg/100 g/day) by gavage for 26 days. After this, echocardiographic analysis was performed and the RV was collected to western blot and biochemical analysis. Key findings Infarcted treated rats showed RV hypertrophy compared with AMI and SHAMT. Hydrogen peroxide levels were decrease and SOD activity and expression were increased in the infarcted treated rats. Besides that, the hormonal administration increased eNOS expression and prevented the reduction of VEGF levels in AMIT rats. Significance In conclusion, TH seems to improve oxidative stress parameters, to promote physiological hypertrophy and to increase the expression of proteins involved with angiogenesis in the right heart.