Influence of Insulin Resistance and Obesity on the Autonomic Regulation of Rat Heart Rate under Conditions of Adequate and Limited Iodine Supply

Abstract

Cardiovascular diseases remain a major medical problems in most countries around the world, causing significant economic disbenefit. An important pathogenetic mechanism of the influence of insulin resistance and hypothyroidism on the cardiovascular system is the alteration in the autonomic regulation of heart rhythm.
 Objective. The aim of the study was to evaluate the dynamics of heart rate variability (HRV) in rats with insulin resistance and obesity under the conditions of adequate and limited iodine supply.
 Materials and Methods. Studies were performed on 90 nonlinear rats pandomized by random sampling. The response of the autonomic nervous system (ANS) was studied using a computer program to analyze HRV “Poly-Spectrum.NET” with the additional module “Poly-Spectrum.NET/Veterinary”.
 Results. It was determined that the co-directed dynamics of geometric and statistical analysis of HRV and balance shift in the direction of the low-frequency component in spectrum analysis of the heart rate regarding control data were revealed in rats with isolated insulin resistance, obesity and combined endocrinopathy (insulin resistance and obesity under the conditions of limited iodine supply). 
 Conclusion. The prevalence of sympathetic ANS activity under the conditions of insulin resistance and obesity can contribute to cardiac arrhythmias, the development of diabetic autonomic neuropathy and with a high probability to cause some cases of life-threatening arrhythmias (supraventricular and ventricular). Iodine deficiency contributes to the depletion of regulatory effects of ANS and limits the range of adaptive capabilities and resources of the organism.