Morphofunctional Transformations in the Lungs of Rats Under the Long-Term Exposure to Sodium Tetraborate

Abstract

The aim of the study was to identify reactive and adaptive changes in the lungs of rats under the longterm exposure to sodium tetraborate.Material and methods. The study included male rats which were administered sodium tetraborate in dosage of 1/30 LD50, intraperitoneally, daily. The study samples (lung fragments) were selected for histological examination in 7, 14, 21 and 30 days from the beginning of the experiment.Results. Long-term exposure to sodium tetraborate resulted in a complex of destructive changes in the air-conducting and respiratory parts of the lung. Leukocyte infiltration in the connective tissue and epithelium of the bronchial and alveoli wall, focal destruction of the bronchial epithelium and alveoli, growth of the connective tissue in the organ interstitial were observed with underlying edema, stasis of blood corpuscles in capillaries, focal destruction of the capillary wall. The study revealed alveolocyte wall thickening and growth and sclerosing of the connective tissue in the interalveolar spaces; this appears to be the morphological equivalent of the increased thickness of the aero-hematic barrier and deterioration of the gas exchange in the alveoli. The increased proportion of the bronchi-associated lymphoid tissue mainly presented by the lymphoid tissue of the diffuse character and less rarely by the lymphoid follicles was registered in the wall of the medium bronchi.Conclusion. The results have proven the negative impact of sodium tetraborate on lung structures and demonstrated the adaptive capacity of the lungs, their ability to maintain the necessary structural-functional characteristics under the extreme destabilizing factors effect.