Remodeling of the Blood-Air Barrier Components in the Landscape of the Far North

Abstract

The aim of the study was to evaluate the structural and functional changes in the components of the respiratory department of the lungs during the stay of experimental animals in the conditions of the Far North.Material and methods. The experiments were carried out on white outbred male rats 140–160 g by mass on the 7-, 15- and 30th days of stay in the conditions of northern latitudes – in Kogalym (62° 26′ N and 74° 48′ E). The structural components of the blood-air barrier were studied using light microscopy, transmission and scanning electron microscopy. The thickness of cytoplasmic processes of type I pneumocytes, cytoplasmic processes of endotheliocytes of capillaries and basement membranes was determined.Results. During all periods of stay of animals in the conditions of the Far North, thickening of the cytoplasmic processes of type I pneumocytes was noted, while the thickness of the cytoplasmic processes of endotheliocytes was significantly increased on the 7th day (p<0,032) and reached control values by the 15th day. During these periods, interstitial edema of the walls and transudate exudation in the lumen of the alveoli, multivesicular and osmophilic lamellar bodies in the cytoplasm  of  type  II  pneumocytes  were  observed,  followed  by  surfactant  release  into  the  lumen  of  the   alveoli  according to the merocrine type. Later, in the conditions of the Far North, there was a tendency to decrease the main indicators of the blood-air barrier. There were single blood cells in the lumen of the alveoli, Kohn pores between the alveoli, and the merocrine type of surfactant release into the lumen of the alveoli was preserved in type II pneumocytes.Conclusion. As a result of the research, it was established that in the early periods of the animals' stay in the conditions of the Far North, there is an increase in the main components of blood-air barrier (cytoplasmic  processes  of  type  I  pneumocytes,  basal  membranes  and  capillary  endotheliocytes).  In  the  early stages of animal adaptation, the phenomena of interstitial edema of the walls with transudation into their lumen are noted in individual alveoli. By the 30th day, there is a tendency to decrease the main indicators of the blood-air barrier compared to previous terms, but they do not reach the control values; the surfactant yield in the apical part of type II pneumocytes by the merocrine type is preserved.