Morpho functional changes in the adrenal glands of rats under the conditions of an experimental model of immobilization stress

The adrenal gland, referring to the hypothalamic pituitary adrenal system, not only participates in the implementation of stress limiting reactions, but also is the object of structural changes. Against the background of isolated immobilization stress for 3 hours for 5 days, modeled on 176 white Wistar male rats, changes were detected in all structural components of both the cortical and medullar substances. To analyze the morphological state of the adrenal glands, histological sections were stained with hematoxylin and eosin, according to Van Gieson for connective tissue, by Sudan for lipid content, by carmine for glycogen content, and according to Brachet for the state of synthetic function. When stained with hematoxylin and eosin, a pronounced dilatation of the walls of the vessels was revealed, which was manifested by hyperemia in all the studied structures of the adrenal gland. Impregnation with silver nitrate according to Foote showed a dissociation and violation of the structure of the stromal framework - the capsule and intraorgan partitions. Analysis of the state of the zones of cortical substance demonstrated changes in all areas. So, relative to the total volume of cortical substance after 5 days of experimental exposure, there was a decrease in glomerular and a sharp increase in the bundle zones, the mesh zone did not show any changes, while signs of cytoplasm vacuolization, intracellular hydration and depletion of glycogen stores were detected in the cells of all zones. When analyzing the adrenal medulla, a change in the components of the microvasculature was noted, similar to changes in the cortical substance, with pronounced vascular congestion. The high functional activity of cellular elements, manifested by euchromatization of nuclei and a change in the nuclear cytoplasmic ratio, was determined. A biochemical analysis of the concentration of cortisol in the blood showed a sharp increase compared with the control group, and by the end of the 5th day of the experiment the increase reached ten times the size. Thus, immobilization stress causes a stereotypic change in both the structural components of the adrenal glands and its synthetic function, and the degree of detected changes indicates significant adaptive resources of the organ under study.