REMODELING PECULIARITIES OF ILEUM HEMOMICROCIRCULATORY BED VESSELS AT RESECTIONS OF DIFFERENT LIVER SIZE

Abstract

Liver resection is widely used in modern surgical departments. Removal of large liver sizes leads to postresection portal hypertension, which is complicated by bleeding from varicose veins of the esophagus, stomach, rectum, ascites, splenomegaly, secondary hyperpselinism, parenchymal jaundice and portosystemic encephalopathy. The widespread prevalence of this pathology, high mortality from its complications indicates that it is an important medical and social problem.

The aim of the study – quantitative morphological study of the blood vessels remodeling features of the hemo-microcirculatory bed of the ileum at resection of different sizes of the liver.

Materials and Methods. The studies were conducted on 43 sexually mature male rats, which were divided into 4 groups. The group 1 consisted of 12 intact virtually animals, 2–11 rats after resection of the left lateral part – 31.5% of the parenchyma of the liver, 3 – 12 animals after resection of the left lateral and internal parts – 42.0% hepar, 4 – 8 rats after resection of the right and left lateral portions of the liver (58.1 %). Euthanasia of experimental animals was carried out by bloodletting in conditions of thiopental anesthesia 1 month after the beginning of the experiment. The hemo-microcirculatory bed of the ileum was studied by injection of its vessels into the carcass-gelatinous mixture, which was injected through the abdominal aorta. On a freezing microtome, sections of 30–40 microns thickness were made, which were dehydrated in ethyl alcohol of increasing concentration, clarified in methylene ether of salicylic acid and placed in polystyrol. From the observations of the filled-in vessels with carcass-gelatinous mixture, histological micropreparations painted with hematoxylin-eosin were made. Morphometrically we determined the diameters of arterioles, precapillary arterioles, hemocapillaries, postcapillary venules, venules, vessel density of the hemo-microcirculatory bed at 1 mml of the ileum of experimental animals. Quantitative indicators were processed statistically.

Results and Discussion. All-round analysis of the obtained data revealed that resection of 1/3 of the liver parenchyma resulted in the expressive remodeling of the blood vessels of the hemo-micocirculatory bed of the ileum, which was characterized by pronounced narrowing of the lumen (arterioles, precapillary arterioles), exchange (hemocapillaries) of micro-hemocirculatory bed and expansion of the post-capillary venules and venules, venous plethora, hypoxia, dystrophy, necrobiosis of cells and tissues. The severity of the structural reconstruction of the vessels of the micro-hemocirculatory bed of the ileum depends on the volume of the removed liver parenchyma. The most pronounced degree of remodeling of blood vessels of the hemo-microcirculatory bed of the ileum was after resection of 58.1 % of liver parenchyma. The diameter of arterioles with this statistically significant (p<0.001) decreased by 31.5 %, precapillary arterioles – by 35.4 %, hemocapillaries – by 24.6 %. Post-capillary venules of ileum after resection of 58.1 % of liver parenchyma increased by 38.9 %, venules – by 31.7 %, density of microvessels decreased by 28.2 %.

Conclusions. Resection of 42 % and more of liver parenchyma leads to a marked structural reconstruction of the vessels of the micro-hemocirculatory bed of the ileum, which was characterized by pronounced narrowing of the arterioles, precapillary arterioles, hemocapillaries of micro-hemocirculatory bed and expansion of the postcapillary venules and venules, venous plethora, hypoxia, dystrophy, necrobiosis of cells and tissues. The severity of the structural reconstruction of the vessels of the micro-hemocirculatory bed of the ileum depends on the volume of the removed liver parenchyma.