CARDIAC ELECTROPHYSIOLOGICAL INDICES AND PEPTIDE MOLECULAR-MASS DISTRIBUTION IN BLOOD SERUM OF RATS WITH EXPERIMENTAL MYOCARDIAL INFARCTION

Abstract

Recent studies demonstrate an increasing interest to cardio-vascular biomarkers with assessing the risk in heart ischemic disease. Along with cardiac electrophysiological indices the molecular-mass distribution of peptides appears as one of novel markers of the risk of cardiovascular complications, since they indicate the effect on developing unfavorable cardiovascular events. Fluorescent probes are also applied for diagnosis and forecasting the developing diseases, revealing the risk factors and control of the treatment efficiency. Research aim was to analyze the changes in electrophysiological indices of heart, molecular-mass distribution of peptides in blood serum and albumin loading with ligands during developing necrosis and remodeling of heart with experimental infarction in rats. Research object and methods. Experiments were performed in 30 outbred male rats of 180-250 g weight under inhalation anestheticon spontaneous breath under the regulations approved by the Bioethics Committee of the IPC&Ñ of the National Academy of Sciences of Ukraine. Myocardial necrosis was simulated by left anterior descending coronary artery ligation. Electrocardiograms (ECG) were recorded with digital ECG Poly-Spectrum 8/B system (Neorsoft, Russia). To determine the molecular weight distribution of low molecular weight fractions of peptide nature, the method of highly effective gel permeation chromatography was used. Fluorescence probes K-35 and E-176, synthesized at State Scientific Institution “Institute for Single Crystals” of the National Academy of Sciences of Ukraine (Kharkiv) was used the studies. The fluorescence spectra were recorded with a Cary Eclipse spectrometry (Varian, Australia). Microcal Origin 6.0 was used to process and visualize the spectra. Experimental studies were performed at days 1, 7, 14 and 30. The results were statistically processed with Kruskal-Wallis criterion using the STATISTICA 6.0 software (StatSoft, USA).Results. During the entire observation period, the electrocardiographic indices noted a change in the phases of the development of an experimental myocardial infarction and the processes of remodeling of the cardiac tissue of anterior-lateral parts of the heart. According to the analysis of the chromatogram of rat serum peptides, it was found that in an acute phase of myocardial infarction, the changes in molecular weight distribution in an acute phase of myocardial infarction were observed, which was reflected by a decrease of peak in the region of macromolecular peptides with m.w.> 10,000 from 61.5% to 3.3%, and the appearance of peaks in the region of low molecular weight peptides within the range of m.w. 290-527. Reducing the fluorescence intensity of probes in one day after the simulation of myocardial infarction indicates an increase in the loading of albumin by ligands. Conclusions. Characteristic peptide molecular-mass distribution in blood serum and albumin loading with ligands for each stage of myocardium necrosis development and its remodeling in experimental myocardium infarction has been shown.

Keywords

• myocardial infarction
• electrocardiography
• blood serum
• peptides
• fluorescent probes