Acta Medica Leopoliensia (Feb 2020)
Immunohistochemical investigation of rat cardiac muscle in experimental ischemia
Abstract
Ischemic heart disease is currently the most common cause of heart failure development. Nevertheless, morphological and immunohistochemical changes in myocardium in early stages of ischemic heart disease require further studies. The aim was to study redistribution of immunohistochemical markers in structural components of myocardium in early stages of ischemia development. Material and methods. The study was carried out on 20 adult male Wistar rats weighing 180-220 g (5 control and 15 experimental animals). Myocardial ischemia was induced by subcutaneous administration of a 0.1% solution of adrenaline (epinephrine hydrotartrate) at a dose of 0.2 ml per 100 g of body weight. Forty-eight hours after the adrenaline injection, the rats were euthanized by ethyl ether overdose. Samples of the heart muscle excised from the atria and the ventricles were fixed in 4% neutral formalin and embedded in paraffin. Immunohistochemical studies were performed using primary monoclonal antibodies to Ki-67, VEGF, CD34, and polyclonal Casp3. The reaction products were visualized using 3,3'-diaminobenzidine tetrahydrochloride as chromogen. Results and discussion. Acute ischemia induced apoptotic processes in the cardiomyocytes accompanied by destruction of myofibrils with the accumulation of damaged myofibrillary proteins in the form of cytoplasmatic granularity; these changes apparently led to impaired cardiomyocyte contractility. The above changes were combined with increased immunoreactivity of vascular bed endothelium, and emergence of VEGF-positive macrophages in perivascular spaces. The mast cells in both groups of rats showed Casp3/Кі-67-reactivity. Conclusion. The rat heart myocardium, subjected to experimental adrenalin-induced ischemia, demonstrated significant changes in microcirculatory bed endothelial cells immunoreactivity, which was accompanied by fine-grained dystrophy of contractile cardiomyocytes myofibrillary content, both signs including impairments of these cells functional activities.
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