General casual hypothermia as a threat of thrombosis in rats

Aim. To study the hemostasis at the pre-reactive period of cold injury occurred at the third stage of the decompensated phase of general casual hypothermia.Methods. Experiments were performed on on 23 Wistar rats. General casual hypothermia was simulated by placing the animals in individual cages in a freezer with in-temperature of -25 °C. Animals were kept in the freezer until the rectal body temperature of +30 °С. Blood samples of 10 animals, kept at 22°C during the same exposure time, were used as a control. Hemostasis parameters, including platelets and coagulation panel, as well as blood serum anticoagulant and fibrinolytic activity, were assessed in peripheral blood. Induced platelet aggregation was measured by aggregometer, with 10 μg/ml adenosine diphosphate solution as the inductor.Results. General casual hypothermia was not associates with changes in the peripheral blood. At the same time, increased platelet count by 19% (р 0.05) and reduced platelet aggregation activity by 9 times (р 0.05) was observed. The coagulation panel at the pre-reactive period of cold injury was associated with Echitox coagulation time increase by 42% (р 0.05), together with fibrinogen concentration drop by 25% (р 0.05). Increased polymerization time of circulating soluble fibrin monomer complexes by 36% (р 0.05) was suggestive of reduced I clotting factor serum concentrations. In the same animals, the serum concentration of soluble fibrin monomer complexes was increased by 96% (р 0.05), suggesting the increased clotting activity.Conclusion. Decompensated phase of general casual hypothermia was associated with significant changes of on the hemostasis. The set of observed changes was suggestive of increased clotting activity as the response to the cold trauma and predisposition to clotting in experimental animals.