Ultrastructure of the tracheal epithelium after inhalation of solid heavy metal aerosol. V. Early phase of regeneration of the tracheal epithelium
Konrádová, V.; Bencko, V.
Folia Morphologica 24(3): 209-216
1976
ISSN/ISBN: 0015-5640 PMID: 964786 Document Number: 107361
The early phase of regeneration of the tracheal epithelium was studied over a period of 26 h after the inhalation of needle-structured pyrite dust . After discontinuing inhalation, progressive repair of the lesions produced in the epithelium does not start immediately. The maximum ultrastructural changes are found 2 h after stopping inhalation. Thr ciliary border is largely disorganized by a quantity of cytoplasmic processes and by the destruction of a large number of kinocilia. Most of the epithelial cells undergo degeneration. A source of further injury to the epithelium, after completing experimental inhalation, are the goblet cells, which in this phase release large amount of secretory material containing pyrite particles. Not until 26 h does this process show signs of stopping. All that remains of the emptied goblet cells in the epithelium are the rims of degenerated cytoplasm. The pyrite particles expelled from the goblet cells from thin layers on the apical cell membranes. A large number of ciliated cells pervaded by pyrite particles does not change within 26 h after discontinuing inhalation. Towards the end of this period they begin to display degenerative changes. The only way in which the pyrite dust captured in the cells can be removed is for the whole of the particle-containing cell to be segregated. Twenty-six hours after discontinuing inhalation, this process is only just beginning. Twenty-six hours after terminating the inhalation of pyrite dust, there is still a large amount of inhaled dust in the area of the tracheal epithelium and the actual repair of ultrastructural changes is only in the initial stages. The above model experiment on the inhalation of dust draws attention to the significance of the structure of the inhaled particles and to the danger of their prolonged action on the epithelial cells.