Morphological, hemodynamical and hemorheological changes of mature artificial saphenous arterio-venous shunts in the rat model.

Artificial femoral arterio-venous (AV) shunts are widely used in rodent models for studying shunt maturation and to optimize various surgical techniques. However, little is known about complex circulatory, microcirculatory, and hemorheological effects of end-to-side saphenous AV shunts. We aimed to study these parameters in mature AV shunts. Studying these questions in CD rats, end-to-side anastomoses were made between the left saphenous artery and vein. On the right-side the nonoperated saphenous vessels served as own control. Furthermore healthy control animals were also investigated. On the 8th to 12th postoperative week microcirculatory and blood flow measurements were performed and blood samples were taken both from the shunt's arterial and venous limbs and from the nonoperated side vessels. Hematological parameters, erythrocyte aggregation, and deformability were determined. The entire shunt and the control vessels were removed for histological examinations. The skin microcirculation on shunt side slightly increased on thigh and decreased on paws versus the nonoperated side. Blood flow measurements made directly on the vessels showed that arterial to venous blood flow rate ratio was 1.59 ± 0.29 on nonoperated side and 1.2 ± 0.13 on the shunt side, and 1.49 ± 0.05 in control animals. Erythrocyte aggregation and deformability worsened on the shunt side. Histologically increased number of smooth muscle elements and connective tissue were found in venous limb of the shunts. The artificial AV shunt between the saphenous artery and vein seems to be a suitable model for further functional-morphological and hemorheological examinations of hemodialysis in various states and diseases.

Application of leukocyte antisedimentation rate calculation in investigation of spleen salvaging experimental surgical techniques.

Clinical studied showed leukocyte antisedimentation rate (LAR) changes in various conditions that modulate the immune system. There is a lack of LAR data in animal experiments concerning splenic function after splenectomy or spleen preserving operations, thus we aimed to include LAR in our ongoing inbred canine study on following-up spleen salvaging surgical techniques. Blood samples of healthy beagle dogs served as normal control. The experimental groups were: "SH"-sham operated, "SE"-splenectomy, "R1/3" and "R2/3"-one-third/two-third of the spleen resected, "AU-5" and "AU-10"-autotransplantation with 5/10 spleen chips using Furka's techniques. On the 12th postoperative month Rabigen-Mono+Vanguard-Plus-5 vaccines were given to the animals, which provoked immune response. Blood samples were taken before and one week after the vaccination. LAR was calculated by Bogar's method. In normal control group LAR was 3.11, leukocyte count was 12.04 G/l. In the experimental groups LAR varied between 2.4-7.3 before vaccination. After vaccination LAR increased in all groups. Although "SE" group expressed the largest changes (LAR = 16.56; 135%), the leukocyte count increased only by 12%. In "AU" groups the increase was smaller, while "R" groups showed slight changes only. LAR can be applicable in animal experiments and may serve as a supplementary parameter in hemorheological investigations of hyposplenic-asplenic states.

Changes of local and systemic hemorheological properties in intestinal ischemia-reperfusion injury in the rat model.

The aim of this study was to investigate intestinal ischemia-reperfusion and its local and systemic hemorheological relations in the rat. Ten anaesthetized female CD outbred rats were equally divided into 2 experimental groups. (1) Ischemia-reperfusion (I/R): the superior mesenterial artery was clipped for 30 minutes. After removing the clip, 60 minutes of the reperfusion was observed before extermination. Blood samples were taken from the caudal caval vein and from the portal vein before ischemia, 1 minute before and after clip removal, and at the 15th, 30th, and 60th minutes of the reperfusion. (2) Sham operation: median laparotomy and blood sampling were done according to the timing as in I/R group. Hematological parameters, red blood cell aggregation, and deformability were determined. Leukocyte count and mean volume of erythrocytes increased slightly but continuously in portal venous samples during the reperfusion period. Red blood cell aggregation values were higher in portal blood by the end of ischemia, and then became elevated further comparing to the caval venous blood. Both in caval and portal venous samples of I/R group red blood cell deformability significantly worsened during the experimental period compared to its base and Sham group. In portal blood red blood cell deformability was impaired more than in caval vein samples. Histology showed denuded villi, dilated capillaries, and the inflammatory cells were increased after a 30 minutes ischemia. In conclusion, intestinal ischemia-reperfusion causes changes in erythrocyte deformability and aggregation, showing local versus systemic differences in venous blood during the first hour of reperfusion.