Microscopic changes of the pancreas vessels in the dynamics after experimental thermal injury
Authors: Zykova N. P. 
Published: October 2021

The problem of burns is relevant in the world and in Ukraine. Thermal injury is not limited to local tissue changes, but causes significant morphofunctional disorders in the organs and systems of the affected organism, the result of this factor is a violation of blood supply to organs, including the pancreas. The aim of this work was to establish the histological condition of the vessels of the pancreas after experimental thermal injury. The experiments were performed on 40 adult white rats. Burns were applied under thiopental-sodium anesthesia with copper plates at a temperature of 96-97℃ on the epilated surface of the skin of the back of animals for 15 seconds (the lesion area was 18-20 % of the body surface). Decapitation of animals was performed on 1, 7, 14 and 21 days of the experiment. Pieces of the pancreas were taken for histological examination and processed according to generally accepted methods. Histological sections 5-6 μm thick were stained with hematoxylin-eosin, impregnated with silver by the Gordon-Sweets method, as well as staining by the tricolor method of MSB (ORB). Histological specimens were examined and documented using an SEO SCAN light microscope and a Vision CCD Camera. In the early stages of the experiment revealed a violation of the blood supply to the body. The lumens of most arteries were found to be dilated, and the wall thickness increased due to hypertrophy of the smooth muscle cells of the media. Leukocyte infiltration was determined in the perivascular spaces. The lumens of the small and middle veins were dilated and filled with blood, with parietal thrombi in some of them. Capillaries are characterized by a moderate expansion of their lumens, stasis. There was swelling of the paravasal spaces. Significant destructive-degenerative, inflammatory and sclerotic changes were observed in the later stages of the experiment. The walls of the vessels were moderately swollen. Smooth myocytes of the arterial media were hypertrophied, the cytoplasm was vacuolated, and contained pyknotically altered nuclei. Adventitia of vessels, especially veins, was swollen and fibrous. Occasionally there were violations of the wall of the components of the microcirculatory tract, which was accompanied by hemorrhage. There are single thrombosed vessels, spasmed arterioles, hemocapillaries with dilated lumens. The greatest changes, especially on the 21st day, were the adventitial membrane with the growth of collagen and reticular fibers. The blood supply to the vessels was moderate. Vessels of small diameter and hemomicrocirculatory tract were also significantly altered, their wall is deformed, thin, homogeneous. The lumens are dilated, with the formation of blood clots. Thus, in the early stages of the experiment there are adaptive-compensatory processes and initial destructive changes in the walls of the vessels of the organ, manifested by stasis, thrombosis, edema, deformation, infiltration of the wall and perivascular space. In the late period, significant destructive-degenerative changes in the structure of the walls of the vessels of the pancreas, accompanied by hemorrhage, inflammation, sclerosis of the wall and edema of the adventitia. These changes lead to a deterioration of blood supply and, consequently, a decrease in the functional activity of the body.