Effect of inhaled endotoxin on intraepithelial mucosubstances in F344 rat nasal and tracheobronchial airways.
Am J Respir Cell Mol Biol 1994 Feb; 10(2):177-183
The effects of repeated exposure to airborne endotoxins on the production of intraepithelial mucosubstances in the respiratory tract were assessed in rats. F344-rats were exposed via aerosol to occupationally relevant concentrations of endotoxin for 3 hours per day for 3 days; rats were killed 24 hours after the last exposure for histochemical analysis of the nasal and tracheobronchial airways. Exposure to endotoxin was associated with a rapid and dose dependent increase in the volume density of stored intraepithelial mucosubstances (Vs) in the intrapulmonary airways. The quantity of Vs in the intrapulmonary airways was significantly increased in rats exposed to as little endotoxin as 0.3 micrograms/cubic meter; in the trachea, in contrast, significant effects were observed only after exposure to more than 3 micrograms/cubic meter. No significant endotoxin related changes were observed in the nasal airways. The authors conclude that inhaled endotoxin contaminated dusts may play a role in the increased sputum production and chronic bronchitis reported in occupationally exposed workers. The regimen used in this study may provide a useful in-vivo model for examining the cellular signals involved in the induction of mucin glycoprotein production and secretion by intrapulmonary airway mucous goblet cells.
NIOSH-Publication; NIOSH-Grant; Laboratory-animals; Pulmonary-system; Toxins; Lung-cells; Respiratory-irritants; Inhalation-studies; Mucous-membranes
Terry Gordon, Ph.D., Department of Environmental Medicine, NYU Medical Center, AJ Lanza Laboratory, Long Meadow Rd., Tuxedo, NY 10987
American Journal of Respiratory Cell and Molecular Biology
New York University, New York, New York