THE ROLE OF ENDOCRINE STRUCTURES OF THE RESPIRATORY ZONE OF THE LUNGS IN ONTOGENESIS AND THE PATHOGENESIS OF EXPERIMENTAL PNEUMONIA

Abstract

Inflammatory lung diseases, including pneumonia, remain a major medical and social problem, requiring detailed study of their morphological mechanisms. The respiratory zone of the lungs functions not only as a site of gas exchange but also as a regulatory and immune component. Endocrine structures within this zone, part of the diffuse neuroendocrine system (DNES), play a significant role in local and systemic regulation, yet their involvement in lung ontogenesis and inflammatory processes is not fully understood. This study aimed to investigate the morphofunctional characteristics of the respiratory zone and its endocrine elements during postnatal development and under experimental pneumonia. Morphological analysis revealed sequential differentiation of alveolar epithelium, formation of the air-blood barrier, and maturation of microcirculation, accompanied by quantitative and functional development of endocrine structures. Experimental pneumonia induced alveolar epithelial damage, thickening of the air-blood barrier, microcirculatory disturbances, and inflammatory infiltration. Reactive changes in endocrine elements, including neuroendocrine cell hyperplasia and increased secretory activity, were observed, indicating their participation in reparative processes. These findings suggest that endocrine structures of the respiratory zone are integral to lung tissue adaptation and may provide a morphological basis for the development of pathogenetically justified therapeutic strategies for inflammatory lung diseases.