Pulmonary lesions induced by long-term exposure to ozone. II. Ultrastructure observations of proliferative and regresssive lesions

Journal Article · Tue Jan 01 04:00:00 EST 1974 · Arch. Environ. Health; (United States)

DOI:https://doi.org/10.1080/00039896.1974.10666588· OSTI ID:6252135

Penha, P D; Werthamer, S

Mice were exposed to 2.5 ppM O/sub 3/ for 2 hr/day for up to 120 days. Groups were killed at intervals, and the respiratory tree was examined by light and electron microscopy. Trachea showed squamous metaplasia commencing on about day 45 and accompanied by decrease in number of ciliated cells. Many cytoplasmic secretory vesicles were noted. Damage was similar to that from other agents and response was essentially nonspecific. Secretory activity may be adaptation to adverse conditions. Bronchial mucosa showed papillary hyperplasia, decrease in ciliated cells, and abnormal cilia; changes were most conspicuous after day 80. Proliferation of Clara-like cells in alveolar ducts becoming prominent after day 45 was observed. Cells are thought to be repair mechanism at bronchiole-alveoli junction. Tracheal and bronchiolar changes showed time dependence and reversibility but Clara cell hyperplasia did not, suggesting benign neoplastic proliferation. Segmental response in respiratory tree has been associated with certain carcinogens.

• OSTI ID: 6252135
• Journal Information: Arch. Environ. Health; (United States), Journal Name: Arch. Environ. Health; (United States) Vol. 29; ISSN AEHLA
• 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.
ANIMALS
BIOLOGICAL EFFECTS
CARCINOGENS
DISEASES
MAMMALS
MICE
NEOPLASMS
OZONE
PATHOLOGICAL CHANGES
RESPIRATORY SYSTEM
RODENTS
TRACHEA
VERTEBRATES