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

Journal Article · Mon Mar 01 04:00:00 EST 1993 · American Journal of Pathology; (United States)

OSTI ID:6878146

Pinkerton, K E; Dodge, D E; Cederdahl-Demmler, J; Wong, V J; Peake, J; Haselton, C J; Mellick, P W; Singh, G; Plopper, C G ^[1]

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1. Univ. of California, Davis (United States)

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.

• OSTI ID: 6878146
• Journal Information: American Journal of Pathology; (United States), Journal Name: American Journal of Pathology; (United States) Vol. 142:3; ISSN AJPAA4; ISSN 0002-9440
• Country of Publication: United States
• Language: English

Related Subjects

550300 -- Cytology
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL TISSUES
ANIMALS
BIOLOGICAL EFFECTS
BODY
BRONCHI
CELL DIFFERENTIATION
CELL TRANSFORMATIONS
CHRONIC EXPOSURE
ELECTRON MICROSCOPY
EPITHELIUM
INFLAMMATION
LUNGS
MAMMALS
MICROSCOPY
ORGANS
OZONE
PATHOLOGICAL CHANGES
RATS
RESPIRATORY SYSTEM
RODENTS
SCANNING ELECTRON MICROSCOPY
SYMPTOMS
TISSUES
VERTEBRATES