Ultrasound examination of rat hearts after experimental epinephrine-induced damage and the application of heart xenoextract

Abstract

Background. Determining the impact of the sympatho-adrenal system on the morpho-functional state of the heart in acute coronary syndrome is a relevant task today. On the other hand, an important objective is to study the dynamics of changes in the heart’s functional processes under the influence of biologically active substances as alternative treatments for heart muscle tissue, aiming to accelerate reparative regeneration of the myocardium after epinephrine-induced damage. Purpose – the study focuses on the dynamics of ultrasound indicators of the heart under conditions of acute experimental myocardial damage induced by high doses of adrenaline, influenced by extracts from cryopreserved heart fragments of piglets. Materials and Methods. The study was conducted on 35 outbred white rats, weighing 380–410 g and aged 15 months. Toxic myocardial damage was modeled by subcutaneously injecting epinephrine hydrotartrate in the interscapular region at a dose of 0.5 mg/100 g of body weight. Piglet heart extracts were administered intraperitoneally at a dose of 50 µg of peptides per 100 g of body weight. Sonographic examination of the heart was performed using a «Sonomed 500» ultrasound echotomoscope («Poly-Spectrum», Ukraine) in B- and M-modes with a linear transducer 7.5L38 operating at a frequency of 7.5 MHz. Results. During the period of a fully developed inflammatory process (day 7), there was a disruption of systolic myocardial function associated with volume overload, as evidenced by an increase in end-systolic volume and, consequently, a 16% decrease in ejection fraction in the control group from the norm. Daily administration of the extract had a positive inotropic and chronotropic effect, as indicated on day 7 by a 17.7 and 18.5% increase in stroke volume and cardiac output, respectively, compared to the control group. The ejection fraction, as a comprehensive indicator of the heart’s functional capacity, was 59.5% in the group receiving the extract, which was statistically significantly higher than the corresponding indicator in untreated animals. The administration of the extract facilitated a more complete recovery of volume-speed characteristics and indicators of left ventricular myocardial contractile function by day 28 after epinephrine-induced damage, during the period of the resolution of the active inflammatory process and adaptation of the heart muscle to new hemodynamic conditions. The end-systolic and end-diastolic volumes, as well as calculated indicators of left ventricular systolic function – stroke volume, cardiac output, and ejection fraction – on day 28 did not statistically differ from the corresponding indicators in intact animals. Conclusions. It was established that the administration of piglet heart extract exerts a positive inotropic and chronotropic effect on day 7 and promotes a more complete recovery of the volume-speed characteristics of the left ventricular myocardium by day 28 after epinephrine-induced damage.