Partial hepatic portal vein ligation: morphological assessment of prehepatic portal hypertension modelling

Portal hypertension is an increase in pressure in the hepatic portal vein system. The most common animal model of prehepatic portal hypertension in use today is partial ligation of the hepatic portal vein in rats but existing studies focus on determining the short-term effects of partial ligation of the hepatic portal vein. Purpose - to evaluate the model of prehepatic portal hypertension by means of a histological study of partial portal vein ligation influence on liver tissue. Materials and methods. Male Wistar rats (n=45), aged 6 weeks and weighing 150±15 grams, were included in the study. The animals were divided into 3 groups: the Group 1 - partial ligation of the portal vein of the liver was performed (formation of stenosis; n=15), the Group 2 - ligation of the portal vein of the liver without its obstruction was performed (pseudo-operated; n=15), the Group 3 - a control group (intact animals, n=15). The rats were withdrawn from the experiment six months after the operation. For histological examination, liver fragments were taken, after standard preparation of the preparations, photographed with an OLYMPUS BX51 light microscope and examined with a PEM-125k electron microscope. The obtained microphotographs were processed and analyzed using the biomedical image processing software ImageJ v.1.50 (National Institutes of Health, USA). Digital data were analyzed in Graphpad Prizm v. 8.3 (Graphpad, USA) statistical package. Results. In rats of the Group 1 the presence of large droplet and total fatty dystrophy of hepatocytes in the center of the lobules was established. The development of connective tissue with the formation of centro-central and porto-central septa was observed. The prolonged effect of partial ligation of the portal vein most closely corresponded to the picture of zonal fatty parenchymal dystrophy of the liver and balloon degeneration of hepatocytes with subsequent fibrosis development. In animals of the Group 1, the distribution of the specific number of hepatocyte nuclei differed from the normal one (p=0.0124), the presence of differences in this indicator between the animals of the three groups was established (p