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Differentiated bronchiolar epithelium in alveolar ducts of rats exposed to ozone for 20 months.

Authors
Pinkerton-KE; Dodge-DE; Cederdahl-Demmler-J; Wong-VJ; Peake-J; Haselton-CJ; Mellick-PW; Singh-G; Plopper-CG
Source
Am J Pathol 1993 Mar; 142(3):947-956
NIOSHTIC No.
20033329
Abstract
The effects of exposure to 1.0 ppm of ozone for twenty months were studied in male Fischer 344 rats. Light microscopic, morphometric, and immunohistological approaches were used to determine the distribution and degree of differentiation of ciliated and nonciliated bronchiolar epithelial (Clara) cells lining alveolar ducts of the central acinus, a primary target of ozone-induced lung injury. Alveolar duct pathways extending beyond the level of the most proximal alveolar outpocketing of terminal bronchioles were isolated in longitudinal profile. The distance that ciliated and nonciliated bronchiolar epithelial (Clara) cells projected down each alveolar duct pathway was determined by placing concentric arcs radiating outward from a single reference point at the level of the first alveolar outpocketing. A high degree of heterogeneity in the magnitude of bronchiolar epithelial cell extension into alveolar ducts was noted for each isolation and animal. Age-matched control animals also demonstrated variation in the degree of bronchiolar epithelial cell extension down alveolar ducts. In animals exposed to ozone, a striking similarity was noted by scanning electron microscopy in the surface characteristics of cells lining both terminal bronchioles and alveolar ducts. The presence of Clara cell secretory protein in cells of bronchioles and alveolar ducts was also detected immunohistochemically and visualized using confocal laser scanning microscopy in the reflectance mode. Well-differentiated ciliated and nonciliated bronchiolar epithelial cells were found lining alveolar septal tips and alveoli up to a depth of 1,000 mu into the pulmonary acinus after 20 months of exposure to ozone. No evidence of inflammation was present in alveolar ducts, suggesting that epithelial cell transformations in alveolar ducts is a natural consequence of lifetime exposures to oxidant gases.
Keywords
Exposure-levels; Exposure-limits; Respiratory-gases; Respiratory-hypersensitivity; Respiratory-irritants; Respiratory-system-disorders; Alveolar-cells; Animal-studies; Animals; Microscopic-analysis; Morphology; Immunodiagnosis; Lung; Lung-burden; Lung-cells; Lung-disorders; Lung-function; Lung-irritants; Lung-tissue; Pulmonary-disorders; Pulmonary-function; Pulmonary-function-tests; Pulmonary-system; Pulmonary-system-disorders
Contact
K. E. Pinkerton, Department of Veterinary Anatomy and Cell Biology, School of Veterinary Medicine, University of California, Davis 95616
CODEN
AJPAA4
CAS No.
10028-15-6
Publication Date
19930301
Document Type
Journal Article
Funding Amount
1055222
Funding Type
Cooperative Agreement
Fiscal Year
1993
NTIS Accession No.
NTIS Price
Identifying No.
Cooperative-Agreement-Number-U07-CCU-906162
Issue of Publication
3
ISSN
0002-9440
Source Name
American Journal of Pathology
State
CA; PA; WA
Performing Organization
University of California - Davis
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