Morphogenesis of Adaptation and Compensatory Reactions in Mouse Adrenals during Restitution after Thermal Exposure

Abstract

Single hyperthermia session causes an appreciable decrease in adrenocorticocyte count in the adrenal cortex in mice on day 3 of postthermal restitution. Morphological changes in the adrenals under conditions of developing stress reaction manifested in increased structural and functional heterogeneity of adrenocorticocytes in all cortical layers, exhaustion of lipid incorporations in the zona fasciculata cells, pronounced shrinkage of zona reticularis, developing against the background of hemodynamic disorders. Recovery of the total count of adrenocorticocyte population was associated with the appearance of small accumulations of immature cells in the subcapsular area of zona glomerulosa. Despite the absence of pronounced changes in the architectonics of all adrenocortical zones during postthermal restitution, recovery of zona reticularis was incomplete, which manifested in its shrinkage and persistence of degenerative changes in adrenocorticocytes.

Stress-induced changes in the aged-rat adrenal cortex. Histological and histomorphometric study

“…Areas of vacuolated cells at the junctional zone between ZR and medulla existed in this group. Stress induces pronounced changes at the interphase between ZR and medulla where connective tissue cords loosened, cell count decreased and cell-to-cell spaces extended [18]. These vacuolated areas might denote an early stage of cystic degeneration [21].…”

“…The senile stressed group (group II-b) exhibited marked disruption of the normal architecture of three adrenocortical zones which may be related to the effect of elevated corticosterone level [8]. This disturbance was associated with different vascular changes in the form of patches of exudate in ZF, congestion of the capillaries in ZR and marked [18]. Immunoreactivity to Ki67 was detected only in the stressed groups (groups I-b, II-b) as the cellular turnover in the adrenal cortex occurs only to accommodate the physiological needs or in response to experimental manipulations [23].…”

Ultrastructural reorganization of rat adrenal cortex after whole body hyperthermia

“…Single whole body hyperthermia caused no appreciable shifts in body weight and adrenal weight of mice over the entire period of post-thermal restitution [4]. According to morphometry data, the width of the adrenal cortex increased significantly (by 17.4% vs. control: from 0.46±0.03 to 0.54±0.01 mm) by day 3, but on day 7 of post-thermal restitution it decreased (by 15.2%, to 0.39±0.01 mm); on day 14 this parameter virtually did not differ from the control.…”

“…It is assumed that these changes are caused by the development of nonspecific stress reaction (common adaptation syndrome) and tissue hypoxia and endotoxication, processes specific for whole body hyperthermia [4,6,8]. The development of general adaptation syndrome is realized through the pituitary-adrenal interactions and is paralleled by elevation of blood glucocorticoids and catecholamines.…”

“…These criteria were also used for evaluating the stress effects of hyperthermia [4,5,9]. Evaluation of the compensatory adaptive reserve of the adrenals, specifically, of the type of intracellular reorganization in adrenocorticocytes (ACC), is an interesting approach to evaluation of the adaptive potential of the organism.…”