Respiratory toxicology following inhalation of NO/sub x/

Technical Report · Sun Aug 01 04:00:00 EDT 1982

OSTI ID:6489681

Pickrell, J A; Gregory, R E; Johnson, W K; Hahn, F F; Bice, D E; Henderson, R F; Hobbs, C H

Pulmonary responses observed in rats, hamsters and dogs after acute or subacute exposure to various concentrations of nitrogen dioxide (NO/sub 2/) are reported. Acute exposure of rats and hamsters to moderate levels of NO/sub 2/ (5 to 30 ppM) produced alveolar type II cell hyperplasia indicative of type I cell death, pulmonary alveolar macrophage proliferation and increased membrane lipid production in isolated type II cells. Also observed were pulmonary inflammation and edema, increased humoral and cellular immune response after instillation of antigen and elevated biochemical indicators of lung epithelial cell injury or death and adaptation or recovery. In contrast to the response in exposed rodents, dogs exposed acutely to high levels of NO/sub 2/ (approx. 70 ppM) showed no type I cell death or type II cell hyperplasia, but bronchiolar and type II cell degeneration. Since the dog and human lung are similar anatomically, the dog may represent a better model for human NO/sub 2/ exposure. Rats exposed chronically for up to 2 months to a moderate level (approx. 20 ppM) of NO/sub 2/ extensive pulmonary injury initially (peak response at 0.5 to 1 week of exposure), identical to that observed in the acute exposures. However, after 2 months of exposure, the rats had recovered from the initial injury except for increases in tissue collagen and mean intercepts that persisted for up to 10 months after exposure. These changes may be indicators of developing chronic lung injury. Rats exposed to low level NO/sub 2/ (1 to 5 ppM) for 2.5 months showed a very mild and delayed (peak response at 2 to 4 weeks of exposure) pulmonary injury. After 2.5 months of exposure all biochemical indicators of injury had resolved. However, areas of minimal focal hyperinflation and macrophage accumulation persisted.

• Research Organization: Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (USA). Inhalation Toxicology Research Inst.
• DOE Contract Number: AC04-76EV01013
• OSTI ID: 6489681
• Report Number(s): LMF-101; ON: DE83007110
• Country of Publication: United States
• Language: English

Related Subjects

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560305* -- Chemicals Metabolism & Toxicology-- Vertebrates-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BODY
CHALCOGENIDES
HAMSTERS
INHALATION
INTAKE
LUNGS
MAMMALS
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
ORGANS
OXIDES
OXYGEN COMPOUNDS
PATHOLOGICAL CHANGES
RATS
RESPIRATORY SYSTEM
RODENTS
TOXICITY
VERTEBRATES