The morphological changes dynamics at the early stages after irradiation in organs with different radioresistance

It is important to examine structural changes in topographically close organs with varying degrees of resistance because the standard method of treating malignant neoplasms uses radiation and combined therapy. The aim of the work is morphological characteristics and analysis of reactive changes in the small intestinal mucosa, structures of the renal cortex and respiratory part of the lung in the early stages after exposure to X-rays on the 1st, 3rd and 5th days. The object of the study is sexually mature outbred white male mice weighing 18-22 g (n=72). Acute radiation sickness was modeled by exposure to X-rays with an absorbed dose of 7 Gray. The standard method for electron transmission microscopy was applied to histological material before examining it through light microscopy after toluidine blue staining. During the first day after the exposure, lumen expansions and deformations were noted in the capillaries of the renal corpuscles, in the capillaries of the respiratory section of the lung and in the stroma of the villi of the small intestine. The basal part of microvillous epithelial cells in the epithelial lining of the small intestine is highly vacuolarized on the 3rd day, causing disruption of cell contacts. The number of mucosal intestinal cells decreases, compared with the indices in intact mice. Deformation and smoothing of the folding of the mucous membrane continues on the 5th day. On the 5th day, the number of macrophages in the respiratory section of the lung sharply increases against the background of reactive changes in the vessels of the microcirculatory bed. In the nephrons of the kidney, vascular changes were noted first in the capillary network of the renal corpuscle, and then in the capillaries located between the proximal tubules of the nephron. The conducted comprehensive study of organs confirms the general idea of the primacy of dystrophic changes in the vessels of the microcirculatory bed of organs with different radiosensitivity (lung, kidney, small intestine) in the early stages of experimental radiation sickness, along with more specific manifestations of the effects of radiation in the epithelium.