Physiological and histological alterations in the bronchial mucociliary clearance system of rabbits following intermittent oral or nasal inhalation of sulfuric acid mist
Rabbits were exposed to submicrometer sulfuric acid mist (H/sub 2/SO/sub 4/) for 1 h/d, 5 d/w for 4 wk, during which time mucociliary clearance was monitored by external in vivo measurements of tagged tracer aerosol retention. One group was exposed orally to 250 ..mu..g/m/sup 3/, another to the same concentration via the nose, and a third to 500 ..mu..g/m/sup 3/ also via nasal breathing. Clearance was accelerated on specific individual days during the course of the acid exposures, especially at 500 ..mu..g/m/sup 3/. In all series, clearance was significantly faster, compared to preexposure controls, during a 2-wk follow-up period after acid exposures had ceased. At the end of this period, the rabbits were sacrificed, and histological sections were obtained from the tracheobronchial tree. Significantly increased epithelial thickness of small conducting airways, compared to sham exposure controls, occurred in rabbits exposed orally at 250 ..mu..g/m/sup 3/ or nasally at 500 ..mu.., and additionally the lumen of the smallest airways of the former group was narrower than control. The number of airways containing epithelial secretory cells was also significantly greater in these acid exposure groups compared to sham controls. The only change in the rabbits exposed nasally at 250 ..mu..g/m/sup 3/ was a significant increase in the number of airways with epithelial secretory cells in the smallest airway classfication. Differences in site and degree of histological response and degree of physiological change between the two groups exposed to identical acid concentrations appear to have been due to differences in exposure mode, with resultant effects on breathing pattern, aerosol size distribution, and concentration penetrating beyond the upper respiratory tract to specific lung sites.
- Research Organization:
- Inst. of Environmental Medicine, New York, NY
- OSTI ID:
- 6846734
- Journal Information:
- J. Toxicol. Environ. Health; (United States), Vol. 12:2-3
- Country of Publication:
- United States
- Language:
- English
Similar Records
Long-term intermittent exposure to sulfuric acid aerosol, ozone, and their combination: alterations in tracheobronchial mucociliary clearance and epithelial secretory cells
Dose-dependent effects of submicrometer sulfuric acid aerosol on particle clearance from ciliated human lung airways
Related Subjects
AEROSOLS
BIOLOGICAL EFFECTS
PARTICLE SIZE
RESPIRATORY SYSTEM
PATHOLOGICAL CHANGES
SULFURIC ACID
INHALATION
CLEARANCE
HISTOLOGY
MUCOUS MEMBRANES
PHYSIOLOGY
RABBITS
ANIMALS
COLLOIDS
DISPERSIONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INTAKE
MAMMALS
MEMBRANES
SIZE
SOLS
VERTEBRATES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)