Comparing the influence of temperature on the coagulation activity of blood plasma in vitro in poikilothermic and homeothermic animals

Hemostasis is a physiological process that is well-controlled and complex in the body that ensures the optimal state of blood aggregation. Deviations from the optimal temperature for the interaction between the various coagulation enzymes greatly affect the fine biochemistry of coagulation and anticoagulation processes. In vitro studies of thermal effects on the coagulation profile of animals contribute to the study of various features and pathologies of hemostasis that lead to animal diseases. The study of animal blood coagulation activity at different temperatures is crucial for human medicine, as coagulopathies are studied in animal models with body temperatures that differ from human ones. For the first time, changes in the activity of various coagulation cascade pathways (secondary hemostasis) were determined in cold-blooded (African sharptooth catfish, common carp, rainbow trout) and warm-blooded (chicken, cattle) animals under temperature conditions modulating hypo-, normal-, and hyperthermia in vitro. The aim of this study was to evaluate the differences in hemostasis parameters between animals with different thermobiological status when plasma incubation temperature changes in vitro are influenced. The study was conducted in Vologda SDFA in 2023. Healthy rainbow trout (Oncorhynchus mykiss W ., n = 15), African sharptooth catfish (Clarias gariepinus B., n = 10), and common carp (Cyprinus carpio L., n = 15) were used as poikilothermic (cold-blooded) animals. Healthy Ayrshire cows (Bos taurus L., n = 15) at different stages of lactation, 4-6 years old, and healthy hens (Gallus gallus L., n = 19) of the Rhode Island Red breed 2 years old were studied as homoiothermic (warm-blooded) animals. Blood samples were collected in IMPROVACUTER tubes (Guangzhou Improve Medical Instruments Co., Ltd, China) containing 3.8 % sodium citrate solution in a 1:9 ratio. Prior to blood collection, the fish were anesthetized by introducing clove oil into the water at a concentration of 0.033 ml/l and maintaining them in this solution for 15 minutes. Subsequently, samples were obtained through puncture of the caudal hemal canal. In birds, blood was obtained by puncture of the axillary vein, in cattle by puncture of the caudal vein. Platelet-poor plasma was obtained by centrifugation of blood in a CM-6M centrifuge (ELMI laboratory technology, Ltd, Latvia) at 3000 rpm for 20 min. The state of plasma-coagulation hemostasis was evaluated using indicators such as APTT (Activated partial thromboplastin time), PT (Prothrombin time), TT (Thrombin time) and analysis of fibrinogen activity automatically using a coagulometer Thrombostat (Behnk Elektronik GmbH & Co., Germany) at 37 °C, and manually using a medical water thermostat TW-2 (ELMI laboratory technology, Ltd, Latvia) temperatures of 46 °C, 43 °C, 40 °C, 28 °C, 24 °C and 18 °C. The anticoagulation properties of blood were assessed by assessing the activity of Antithrombin III in blood plasma at the same temperatures. The research employed reagents produced by Tekhnologiya-Standart LLC (Russia) and NPO RENAM (Russia). Statistical analysis has shown that when heated in vitro, the coagulation system of warm-blooded animals exhibits a tendency towards hypercoagulation, which can vary depending on the coagulation mechanisms involved. In the case of cattle, there is a significant activation of the coagulation process through tissue factors and a decrease in the effectiveness of anticoagulant mechanisms, namely PT (R = -0.79; p ≤ 0.01) and antithrombin activity (R = -0.8; p ≤ 0,01) are 60% reliable dependent on the temperature of the reaction medium. Birds demonstrate increased coagulation along the common pathway (R = -0.8; p ≤ 0.01) with a simultaneous decrease in fibrinogen activity (R = -0.8; p ≤ 0.01), the proportion of the influence of temperature in which are approx. 71 % and 39 %,, respectively. Fish and other poikilothermic animals reliably confirm a diverse thermally-mediated hemostasis response. Carp was characterized by hypocoagulation by reducing tissue activation of coagulation, where the PT value (R = 0.8; p ≤ 0.01) was 50 % determined by the plasma incubation temperature. Catfish showed a significant array of hypercoagulation processes, resulting from a rise in fibrinogen activity (R = -0.7; p ≤ 0.01) and a decrease in antithrombin activity (R = -0.8; p ≤ 0.01). Among all fish species studied, catfish has the plasma blood coagulation factors that are the most thermolabile or species-specific. There were no significant relationships established for trout. The thermal regime in standard humane medicine coagulological studies has been shown to affect the activation of blood coagulation in animals in vitro, but the changes are not specific to poikilotermic and homoerothermic. The data obtained can be used to develop coagulological tests adapted for biology, zoology and veterinary science.