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

Technical Report · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5242625

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

One-day-old or 6-week-old male rats were exposed to either 0.25 ppm O/sub 3/ 12 hr/day or to continuous room air for 6 weeks. An additional group of 6-week-old rats was exposed to 0.12 ppm of O/sub 3/ for the same time period. In the animals exposed to 0.25 ppm O/sub 3/ from 1 day of age (juvenile animals), the number of type I epithelial cells doubled, their mean surface area decreased 38%, and their mean thickness increased 24%. The number of alveolar macrophages doubled. Adult animals exposed to 0.25 and 0.12 ppm O/sub 3/ showed similar patterns of changes in the epithelium of the proximal alveolar region. Compared to the juvenile animals, the adult 0.25 ppm O/sub 3/ exposed animals showed more reaction in the interstitium with a doubling of interstitial macrophages, suggesting a mild inflammatory stimulus in the interstitium. Animals exposed to 0.12 ppm O/sub 3/ showed smaller, but statistically significant changes in the alveolar type I epithelium, suggesting a relatively linear concentration response relationship. These results suggest that low concentrations of O/sub 3/ cause a chronic epithelial injury in the proximal alveolar region of both juvenile and adult rats and that the extent of these changes occurs in a concentration-dependent manner, even at concentrations at low as 0.12 ppm.

• Research Organization: Environmental Protection Agency, Research Triangle Park, NC (USA). Health Effects Research Lab.
• OSTI ID: 5242625
• Report Number(s): PB-86-217874/XAB; EPA/600/J-85/430
• Country of Publication: United States
• Language: English

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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOASSAY
BIOLOGICAL EFFECTS
BODY
DISEASES
INHALATION
INTAKE
LABORATORY ANIMALS
LUNGS
MAMMALS
ORGANS
OZONE
RATS
RESPIRATORY SYSTEM
RESPIRATORY SYSTEM DISEASES
RODENTS
VERTEBRATES