Physiological and histological alterations in the bronchial mucociliary clearance system of rabbits following intermittent oral or nasal inhalation of sulfuric acid mist

Journal Article · · J. Toxicol. Environ. Health; (United States)

DOI:https://doi.org/10.1080/15287398309530440· OSTI ID:6846734

Schlesinger, R B; Naumann, B D; Chen, L C

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), Journal Name: J. Toxicol. Environ. Health; (United States) Vol. 12:2-3; ISSN JTEHD
• Country of Publication: United States
• Language: English

Related Subjects

560305* -- Chemicals Metabolism & Toxicology-- Vertebrates-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AEROSOLS
ANIMALS
BIOLOGICAL EFFECTS
CLEARANCE
COLLOIDS
DISPERSIONS
HISTOLOGY
HYDROGEN COMPOUNDS
INHALATION
INORGANIC ACIDS
INTAKE
MAMMALS
MEMBRANES
MUCOUS MEMBRANES
PARTICLE SIZE
PATHOLOGICAL CHANGES
PHYSIOLOGY
RABBITS
RESPIRATORY SYSTEM
SIZE
SOLS
SULFURIC ACID
VERTEBRATES