Ultrastructure of Epithelium of Terminal Bronchioles in Rabbits after Inhalation of Mineral Water Aerosol

Uhlik J., V. Konradova, L. Vajner, J. Ada‰kova: Ultrastructure of Epithelium of Terminal Bronchioles in Rabbits after Inhalation of Mineral Water Aerosol . Acta Vet. Brno 2002, 71: 283-288. Inhalation of mineral water aerosols is a widely used supplementary therapeutic method during the treatment of chronic respiratory diseases. We decided to proceed our previous experiments dealing with the effect of a short-time inhalation of this aerosol on the tracheal epithelium by the evaluation of reaction of the epithelium in distal airways ‐ terminal bronchioles. Laboratory rabbits inhaled an aerosol of special mineral water for 10 min and material for the electron microscopic examination was collected immediately after inhalation. The ultrastructure of the epithelium of terminal bronchioles was evaluated quantitatively. Computer image analysis was used in the evaluation of cytoplasm of Clara cells. As in control animals, terminal bronchioles of rabbits exposed to 10-min inhalation of the mineral water aerosol were lined with simple columnar epithelium composed of ciliated and Clara cells. On the apical surfaces of ciliated cells, formation of cytoplasmic protrusions leading sometimes to a degeneration of free cilia was recorded. In deeper layers of their cytoplasm, mild marks of the pathological alteration were observed. In secretory Clara cells, tendency to increased proliferation was recorded. This proliferation was not accompanied by elevated liberation of the secretion stored in secretory granules. Only few Clara cells revealed signs of the pathological alteration, their degeneration was not recorded. The findings of the pathological alteration of the epithelial cell cytoplasm and their increased proliferation testify that the homeostasis of the epithelium was damaged and admonish to the heedfulness in the indication even of such seemingly harmless therapeutic procedures. Airways, ciliated cells, Clara cells, electron microscopy, therapeutic method Inhalation of mineral water aerosols belongs to usual procedures in the treatment of chronic respiratory disorders. Practical physicians indicating this therapeutic method believe, that special components of selected springs play a crucial role in the treatment. As we found only one very old article dealing with the reaction of respiratory tract on the mineral water inhalation ( Vaskivskyj 1968), we started to concentrate on the evaluation of the ultrastructural and histochemical changes of the airway epithelium after the mentioned therapeutic procedure. In our previous study, we demonstrated that a single 10min inhalation of a special mineral water aerosol used in a clinical practice causes statistically significant changes of the ultrastructure of rabbits’ tracheal epithelial cells and of the chemical composition of glycoconjugates produced by tracheal goblet cells. The changes did not disappear even after 24-h recovery ( Konradova et al. 2001). We decided to extend our experiments by the study evaluating the reaction of the epithelium of terminal bronchioles to the short-time inhalation of the same aerosol. We tried to compare the effect of the mineral water inhalation on the pseudostratified columnar ciliated tracheal epithelium, where secretory elements were represented by goblet cells, with the reaction of the simple columnar epithelium of distal airways containing secretory Clara cells.