Бюллетень сибирской медицины (Apr 2017)
Influence of cooling medium on rat hemostatic system
Abstract
The purpose of the article is to study the effect of air and water-immersion cooling media on the hemostatic system in the pre-active period of cold trauma.Material and methods. The study was performed on 43 laboratory Wistar rats. Single air hypothermia was modeled by placing animals in individual cells into a cooling chamber at a temperature –25 °С. The animals were in the chamber until the rectal temperature reached 30 °C, which corresponded to a moderate degree of hypothermia in rats. Water immersion hypothermia was modeled by placing animals in individual cells into water with a temperature 5 °C and air 7 °C. The criterion for cessation of exposure was a rectal temperature of 27–30 °C, which also corresponded to a moderate degree of hypothermia. We assessed the state of vascularplatelet and plasma hemostasis, as well as the physiological state of anticoagulant and fibrinolytic systems. The study was performed by using routine techniques and an integral method - thromboelastography.Results. It was established that during water immersion cooling, experimental animals developed thrombocytosis and activated their aggregation function. Laboratory indicators characterizing the initial stages of plasma hemostasis, and external and internal ways of activation did not change at this intensity of hypothermic exposure. At the same time, at the final stage of coagulation, pronounced thrombinemia was recorded, which was confirmed by a significant increase in the concentration of soluble fibrin-monomer complexes and a decrease in the time of their self-assembly. In addition, inhibition of fibrinolytic activity of plasma associated with a decrease in the concentration of antithrombin III was observed. In this case, single air hypothermia, accompanied by the rise in a rectal temperature up to 30 ° C, also caused significant changes in the hemostatic system. Vascular-platelet hemostasis responded to a significant decrease in aggregation activity of platelets. In plasma hemostasis, the final stage of coagulation was involved the most, which was manifested in hypocoagulant shifts. Along with this, pronounced inhibition of fibrinolytic activity of blood plasma was recorded. Thus, the described hemostasiological pictures indicate a pronounced influence of the environment causing supercooling on the response of an organism with hypothermia. In case of immersion hypothermia an increase in a rectal temperature up to 30 ºС is accompanied by a pronounced activation of the coagulation processes and the thrombotic state of readiness. When supercooling with air after reaching a rectal temperature of 30 ° C, secondary hypocoagulation shifts are recorded.
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