Ameliorating Effects of Intermittent Fasting on Cardiac Dysfunctions in Experimentally Induced thyrotoxicosis in Adult Rats. Role of Ghrelin Hormone

Abstract

Abstract Background Cardiovascular complications of hyperthyroidism have high morbidity and mortality rates. The cardioprotective effect of intermittent fasting (IF) in addition to the concomitant rise of blood ghrelin hormone level during IF have gained attention, but their effects on thyrotoxic hearts are still unclear. Therefore, we aimed to investigate the impacts of IF on hearts of rats subjected to induced thyrotoxicosis (TH) elucidating the role of ghrelin hormone in the assumed cardio protection. Methods Forty-five adult male Wistar Albino rats in 3 groups: control group, thyrotoxic group, injected IP with L-thyroxine100 μg/kg/day, 5 days/week for 4 weeks and intermittent fasting-treated thyrotoxic group, subjected to alternative day fasting regimen for 4 weeks. cardiac functions were assessed by in-vivo studies (ECG recording and arterial blood pressure evaluation) and in-vitro studies (responses to isoproterenol infusion using Langendorff’s preparation). Results Compared to the TH rats, intermittent fasting showed significant body weight loss, decreased left ventricular and whole heart absolute weights, with significant decrease of heart rate (HR) and prolongation of P-R interval in ECG. The baseline values of PT/LV, HRT and MFR/LV as well as their maximal responses and their delta changes in response to isoproterenol infusion were increased and were positively correlated to ghrelin hormone. Ghrelin hormone was increased in IF rats reaching the control group value and showed positive correlation with GPx and BCL-2. Conclusions IF conferred partial cardioprotective effects against thyrotoxicosis. These effects were attributed – at least partially- to normalization of ghrelin hormone which has anti-inflammatory, antioxidant as well as anti-apoptotic effects.