The Morphological and Functional State of the Vascular Component of Hematopoiesis Organs in Different Times of Simulated Hypoxia in the Experiment

Abstract

Under conditions of hypoxia, a change in the morphological and functional state of the components of the microvasculature bed will be accompanied by a change in the adequacy and usefulness of the immune response and hematopoiesis. The purpose of the study was to determine the morphofunctional state of the vascular component of the red bone marrow and spleen at various times of simulated hypoxia and to identify the degree of influence of CD68-positive cells on this state. Chronic hypoxia was modeled on 246 outbred male rats using special chambers containing natural gas from the Astrakhan gas field (Russia) at a concentration not exceeding the maximum allowable. The experiment was continued for 120 days, inhalation was carried out five days a week for four hours a day, the removal of animals from the experiment was carried out every 30 days. The functional activity of the vascular component of the red bone marrow was determined using the method of laser Doppler flowmetry. The degree of expression of inducible (iNOS) and endothelial (eNOS) NO synthases and the distribution of CD68-positive cells in the spleen structures were determined by immunohistochemical method. The study showed that as the duration of chronic simulated hypoxia increases, there is a decrease in the microcirculation index, an increase in myogenic tone and shunting index, which, taken together, indicates a deterioration of organ perfusion and confirms the formation of a hypoxic state. An analysis of the functional activity, carried out using an immunohistochemical study of the expression of iNOS and eNOS in the structures of the spleen, showed that as the duration of the experiment increased, the level of endothelial synthase decreased and the level of inducible synthase increased. Perhaps this is due to the influence of biologically active substances secreted by macrophages activated during hypoxia. This is supported by an increase in the presence of CD68-positive cells in the red pulp and along the connective tissue trabeculae as the experimental exposure increases.