Effects of inhalation of 0. 12 and 0. 25 parts per million ozone on the proximal alveolar region of juvenile and adult rats

Journal Article · Sun Dec 01 04:00:00 EST 1985 · Lab. Invest.; (United States)

OSTI ID:5614229

Barry, B E; Miller, F J; Crapo, J D

The degree of lung injury caused by prolonged inhalation of low levels of ozone (O3) is of interest since urban environmental levels periodically reach 0.2 to 0.3 ppm. Since the area of the junction of the conductive and respiratory regions of the lung has been reported as the major site of injury due to O3 inhalation, techniques were devised to specifically study alveolar tissue from this region. One-day-old or 6-week-old male rats were exposed to either 0.25 ppm O3 12 hours/day or to continuous room air for 6 weeks. An additional group of 6-week-old rats were exposed to 0.12 ppm O3 for the same time period. All lungs were fixed at the end of the exposure by intratracheal installation of buffered 2% glutaraldehyde. Cylinders of tissue containing a cross-section of a terminal bronchiole were punched out of lung tissue slices using a sharpened cannula. These tissue cylinders were oriented, embedded in Epon, serial sectioned until the first alveolar duct bifurcation was reached, and then thin sectioned for electron microscopy. Qualitative examination of the tissue revealed little observable damage to the proximal alveolar tissues. However, by ultrastructure morphometric analysis, significant changes occurred in the alveolar epithelium of the proximal alveolar region of all exposed animals. In the animals exposed to 0.25 ppm O3 from 1 day of age (juvenile animals), the number of type 1 epithelial cells doubled, their mean surface area decreased 38%, and their mean thickness increased 24%. The number of alveolar type 2 epithelial cells increased, and the number of alveolar macrophages doubled. Adult animals exposed to 0.25 ppm O3 showed similar patterns of changes in the epithelium of the proximal alveolar region and in addition had a doubling of interstitial macrophages, indicating a mild inflammatory stimulus in the interstitium.

• OSTI ID: 5614229
• Journal Information: Lab. Invest.; (United States), Journal Name: Lab. Invest.; (United States) Vol. 6; ISSN LAINA
• 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.
AGE DEPENDENCE
ANIMAL TISSUES
ANIMALS
BODY
DOSE-RESPONSE RELATIONSHIPS
EPITHELIUM
INHALATION
INJURIES
INTAKE
LUNGS
MAMMALS
ORGANS
OZONE
RATS
RESPIRATORY SYSTEM
RODENTS
TISSUES
TOXICITY
VERTEBRATES