Search for optimal methods of blood sampling from laboratory rats under conditions of chronic experiment

Purpose: to identify the optimal ways of taking blood from rats in the framework of a chronic experiment.Materials and methods. Two series of studies were conducted, in the first of which a comparative assessment of the diameter of the venipuncture needle was carried out. In the second series, the volume of blood received with and without anticoagulant was determined. The experiment was carried out on male Wistar rats, using butterfly needles with a flexible catheter of various sizes - 23G, 24G and 25G, a 2 ml syringe and heparin diluted with saline in a ratio of 1:10 (500 IU/ml).Results. In a scientific experiment, it was found that the optimal size of the butterfly needle for blood sampling in laboratory rats is G-24 (needle diameter 0.55 mm). Needles with a smaller diameter are not suitable for blood sampling, as a blood clot forms in their lumen, which significantly reduces the volume of blood taken. Butterfly catheters with a large needle diameter (needle diameter 0.6 mm) create the effect of vessel tamponade. The results of the second series of experiments indicate a significant increase in the volume of blood received with the use of an anticoagulant than without it. This is confirmed in the intergroup comparison of the amount of blood obtained in rats of the first group (with the use of anticoagulant) by 46.5 % higher than in the second group (without the use of anticoagulant) (P<0.05).Conclusion. The conducted studies indicate that when taking blood from the tail vein of rats, the optimal size of the butterfly needle was 24G. Also, the use of a heparin solution at a concentration of 500 U / ml made it possible to obtain a blood volume from rats that was 46.5 % higher than without the use of an anticoagulant. The use of this method in practice (a syringe and a G-24 butterfly catheter together with an anticoagulant) actualizes multiple blood sampling in a chronic experiment, reduces the laboriousness of the blood sampling process and minimizes trauma to laboratory animals.