QUANTITATIVE MORPHOLOGICAL ASSESSMENT OF FEATURES OF REMODELING OF THE MUSCULAR LAYER OF JEJUNUM AT THE RESECTION OF DIFFERENT VOLUMES OF LIVER PARENCHYMA

Abstract

Liver resection is widely used in modern surgical departments. Resections of large volumes of liver parenchyma are complicated by postresection portal hypertension, which leads to structural and functional changes in the organs of the basin portal hepatic vein. The features of the structural reconstruction of jejunum muscle at postresection portal hypertension have not been adequately investigated. The aim – using the morphometrical methods to study the features of remodeling of the structures of muscular layer of jejunum at resection of different volumes of liver parenchyma.

Materials and Methods. The complex of morphological methods examined the jejunum of 45 sexuale mature white male rats, which were divided into 3 groups. The group 1 consisted of 15 intact animals, group 2 – 15 rats, in which 31.5 % of the liver parenchyma was removed, group 3 – 15 animals after resection of 58.1 % of liver parenchyma. Euthanasia of rats was carried out by bloodletting in conditions of thiopental anesthesia 1 month from the beginning of the experiment. Histological preparations were made from the jejunum. The thickness of the circular and longitudinal muscular layers, the diameters of smooth myocytes and their nuclei, the nuclear-cytoplasmic relations in these cells, the stromal-myocytal relations, and the relative volumes of damaged myocytes were measured. Quantitative indicators were processed statistically.

Results and Discussion. It was established that one month after resection of 31.5 % of liver parenchyma, morphometric indices were slightly changed. Removal of 58.1 % of liver parenchyma leads to the development of postresection portal hypertension. The morphometric parameters of the structures of the circular and longitudinal muscular layers of the jejunum were manifested by altered ones. The thickness of the circular muscular layer a month after the resection of 58.1 % of the liver parenchyma statistically significantly decreased by 4.1 %, the diameter of myocytes – by 6.1 %, the nuclear-cytoplasmic relation of them increased by 35.4 %, stromally – myocytal relation – by 14.3 %, relative the number of damaged myocytes – by 14.4 times. Quantitative morphological indices of the structures of the longitudinal muscular layer of the jejunum a month after the resection of 58.1 % of the liver parenchyma changed in a similar manner, but the degree of their expression was smaller compared with the structures of the circular muscular layer. Thus, the diameter of myocytes in the given experimental conditions was reduced by only 1.6 %, the diameter of the nuclei increased by 4.6 % (p<0.01), nuclear-cytoplasmic relations – by 15.2 % (p<0.001), stromally-miocytal relations – by 14.1 %, relative volume of damaged myocytes – by 8.1 times.

Conclusions. Removal of large volumes of liver parenchyma leads to postresection portal hypertension and pronounced remodeling of the structures of the circular and longitudinal muscular layers of the jejunum, characterized by disproportional uneven changes in the morphometric parameters of smooth myocytes, their nuclei, violations of nuclear-cytoplazmatic relations in these cells, atrophy, growth of stromal structures and relative volumes of damaged myocytes in the muscular layer, which may be complicated by the dysfunction of the organ.