Biological effects of short-term, high-concentration exposure to methyl isocyanate. V. Morphologic evaluation of rat and guinea pig lungs
The morphologic changes induced in the lungs of rats and guinea pigs exposed to high concentrations of MIC vapor (100, 600, and 1000 ppm in the rat and 25, 125, 225, and 675 ppm in the guinea pig) for a short time (15 min) in a static exposure chamber were evaluated at varying postexposure periods (0, 1, 2, and 4, and 16 hr). The 675 ppm-exposed guinea pigs were evaluated only immediately following removal from the chamber. Attention was primarily focused on the intrapulmonary conducting airways and the parenchyma (gas exchange region) of the lungs. The severity of morphologic changes observed by light microscopy was directly correlated with exposure concentration and time postexposure in both species. Specifically, degenerative changes were observed in the bronchial, bronchiolar, and alveolar epithelium in both species. Quantitative differences were observed; 100 ppm of MIC in the rat resulted in much less damage than did 125 ppm of MIC in the guinea pig. Morphologic evidence of sloughing of large sheets of conducting airway epithelium with fibrin buildup and increased mucus production resulted in plugging of major airways and atelectasis. These observations support the hypothesis that tissue hypoxia was a major contributing factor resulting in death.
- Research Organization:
- Union Carbide Corp., Export, PA
- OSTI ID:
- 6016029
- Journal Information:
- Environ. Health Perspect.; (United States), Vol. 72
- Country of Publication:
- United States
- Language:
- English
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ISOCYANATES
BIOLOGICAL EFFECTS
INHALATION
LUNGS
MORPHOLOGICAL CHANGES
ACUTE EXPOSURE
ADULTS
ANOXIA
EPITHELIUM
EXPOSURE CHAMBERS
FIBRIN
GUINEA PIGS
HISTOLOGY
HOMEOSTASIS
INFLAMMATION
MORTALITY
NECROSIS
PHYSIOLOGY
RATS
AGE GROUPS
ANIMAL TISSUES
ANIMALS
BODY
COAGULANTS
DRUGS
HEMATOLOGIC AGENTS
HEMOSTATICS
INTAKE
MAMMALS
ORGANIC COMPOUNDS
ORGANS
PATHOLOGICAL CHANGES
PROTEINS
RESPIRATORY SYSTEM
RODENTS
SCLEROPROTEINS
SYMPTOMS
TISSUES
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology