Changes in the microvasculature and hemostatic system in rats after insonation

Abstract

Ultrasound, one of the most physically impactful factors of the modern human living environment, can cause hemodynamic changes in the microvasculature and the hemostatic system. Such shifts can be considered as possible predictors of cardiovascular diseases and their complications. This study aimed to examine the effect of 7-day in-air insonation on the microvasculature and hemostatic system of rats. The study included 28 male Wistar rats. A group of study animals was insonated over 7 days at a frequency of 25 kHz. The emitters were installed in a vertical position at a distance of 10 cm from both the sidewalls of a coarse wire cage. The sound pressure was 89.0 dB and power flux density was 7.73 ± 0.03 W/cm2. The microvasculature values of the study rats obtained by laser Doppler flowmetry were compared to those of control animals. To evaluate the hemostatic system, an integral research method, thromboelastography, was used. In the study rats, in response to 7-day insonation, statistically significant decreases in the active and passive factors of blood circulation modulation were observed compared to the control animals: microcirculation, flux, amplitude of endothelial and vasomotor vibrations, and amplitude of respiratory and pulse waves. According to the thromboelastography data, prolonged coagulation time at the initial stage and inhibited fibrinolytic activity were recorded. Thus, the study animals showed signs of a stress reaction based on changes in their microcirculatory parameters confirmed by increased serum concentrations of adrenocorticotropic hormone and cortisol and analysis of behavioral reactions in the open-field test.