Morphological study of the effects of ozone on rat lung. II. Long-term exposure

Journal Article · Sat Apr 01 04:00:00 EST 1989 · Exp. Mol. Pathol.; (United States)

DOI:https://doi.org/10.1016/0014-4800(89)90037-3· OSTI ID:5900822

Hiroshima, K; Kohno, T; Ohwada, H; Hayashi, Y

To evaluate the morphological changes observed in animals after prolonged ozone exposure, 56 male rats were exposed to a high ambient level of ozone (0.5 ppm) 6 hr a day, 6 days a week, for 2, 3, 5, and 12 months and examined by light and electron microscopy. Bronchitis and peribronchitis were observed throughout the exposure periods, and connective tissue around the bronchi thickened as a result of fibrosis. Some bronchiolar ciliated cells were in a degenerated condition and others in a reparative phase. Hyperplastic nodules were not found in the bronchioles, but hyperplasia of the bronchiolar epithelium was observed. Hyperplasia of lymphoid nodules around small vessels was prominent after 2 months of exposure. After 3 months of exposure, alveolar ducts were lined by type 2 cells, and after 12 months, by the bronchiolar epithelium consisting of both ciliated and nonciliated cells. Alveolar macrophages accumulated in the centriacinar alveoli. Fibrous strands were seen to be deposited in alveolar ducts after 3 months, and in bronchioles after 5 months. This fibrosis was due to an increment in collagen fibers. The degree of fibrosis increased with the length of ozone exposure.

• Research Organization: Chiba Univ. (Japan)
• OSTI ID: 5900822
• Journal Information: Exp. Mol. Pathol.; (United States), Journal Name: Exp. Mol. Pathol.; (United States) Vol. 50:2; ISSN EXMPA
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
BODY
BRONCHITIS
CONNECTIVE TISSUE CELLS
DISEASES
ELECTRON MICROSCOPY
EPITHELIUM
FIBROSIS
LUNGS
MACROPHAGES
MAMMALS
MICROSCOPY
MORPHOLOGICAL CHANGES
ORGANS
OZONE
PATHOLOGICAL CHANGES
PHAGOCYTES
RATS
RESPIRATORY SYSTEM
RESPIRATORY SYSTEM DISEASES
RODENTS
SOMATIC CELLS
TISSUES
TOXICITY
VERTEBRATES