State of Rat Pineal Gland Structural Components in the Conditions of Different Extracellular Dehydation Terms

Abstract

The monograph presents a theoretical generalization and a new solution for the research target to study the state of the pineal gland structural components in sexually mature rats under different terms of extracellular dehydration. The experiment was performed on 24 white sexually mature male rats aged 5-6 months. The animals of the experimental group were simulated extracellular dehydration of mild and heavy severity. Animals were kept and manipulated in compliance with national and international bioethics standards. Different degrees of extracellular dehydration severity caused negative changes in all structural components of the pineal gland in experimental animals: stromal, vascular and parenchymal, with the greatest intensity in animals with heavy severity course. Morphological rearrangements were nonspecific and polymorphic in nature. In the pineal gland of animals with a mild severity course there was a tension of adaptive processes, increased secretory activity by both indole-producing and polypeptide-producing pinealocytes (with predominance of the latter), formation of the gland’s reserve capacity. There was a moderate increase in the expression of heat shock proteins in pinealocytes, which, certainly, made these cells more resistant to apoptotic rearrangements and the subsequent action of extreme factors. With increasing duration of the experiment (severe degree), there was a significant decrease in the size of the gland, thickening and swelling of the stromal component, sharp impairment of hemodynamics in the organ. Blood viscosity increased, its rheological properties were impaired (stasis, sludge), vascular wall permeability increased, processes of accelerated apoptosis in part of pinealocytes developed. The heat shock proteins level and the proliferative activity of astrocytic glia were significantly reduced, indicating a weakening of the mechanisms of anti-apoptotic and anti-stress protection. The 90-day effect of extracellular dehydration on the experimental animals’ body caused the phenomenon of chronic stress “subcompensation”, which was expressed in the depletion of pineal indolamines reserve and their urgent evacuation into the blood to maintain general adaptive capacity of the body. However, disturbances in the morphology of the vascular wall and increased blood viscosity negatively affected the mechanisms of pineal hormones diffusion into the vascular bed, the development of compensatory-adaptive processes in the body as a whole and the course of general adaptation syndrome.

Morphometric features of rat pinealocytes in conditions of chronic ethanol intoxication

“…Information on the effect of ethanol on changes in the morphometric parameters of pinealocytes in the literature we have studied is limited [15]. However, our studies correlate with data from other researchers who studied changes in the morphology of the pineal gland in response to the influence of pathological factors of endogenous and exogenous origin [4,6,9,13].…”