Evaluation of the combined effect of ionizing radiation and microgravity on the development of delayed experimental myocardial infarction
Abstract
The main factors of the space environment, namely microgravity and space radiation, have a negative impact on human health, and are considered as a threat to manned interplanetary missions. Ground-based simulations may help elucidate the combined effects of space flight factors (SF) on the cardiovascular system (CVS). However, the question remains whether the influence of these factors can worsen the course of CVS diseases that occur or manifest themselves in the long term.
Aim: To study the features of the development of isoproterenol-induced myocardial infarction (MI) under the simulated conditions of delayed effects of SP on the body of experimental animals.
Methods: Two-week anti-orthostatic suspension (AOS) as a model of simulated microgravity, simulation of cosmic radiation by exposure to gamma radiation at an acute dose of 1.5 Gy, experimental MI, electrocardiography, determination of blood plasma lactate dehydrogenase (LDH) activity, laser correlation spectroscopy, histological examination.
Results: Depending on the nature of the SP factor preceding the development of MI, various changes in the variability and frequency of rhythm disturbances and in metabolic shifts of the subfractional composition of plasma and blood serum were found. In the group with delayed MI preceded by modeling the combined effect of SP factors, the earliest responses of the autonomic regulation of heart rate, the highest percentage of Q wave occurrence, a slight increase in blood LDH activity, and minimal changes in the subfractional composition of plasma and serum were observed. However, the morphological picture of isoproterenol-induced damage to myocardial tissue was similar between the experimental groups.
Conclusion: SP factors can differently modulate pathological changes in the studied body systems during the development of delayed isoproterenol-induced MI within 4 months.
