The effect of ozone on inflammatory cell infiltration and airway hyperresponsiveness in the guinea pig lung
Inflammatory cells may contribute to the development of exaggerated bronchoconstrictor responses since a persistent link has been noted between pulmonary inflammation and airway hyperresponsiveness. In these studies guinea pigs were exposed to 2.0 ppm ozone for 4 hours, then immediately sacrificed or allowed to breathe filtered air for up to 14 days. Following ozone exposure there was an immediate massive neutrophil infiltration into the lung. Neutrophils in lung digest dropped to control values within 3-12 hours post-ozone but remained elevated in BAL fluid for 3 days. There was probable eosinophil degranulation within the first 24 hours post-ozone. Guinea pigs were hyperresponsive to vigal stimulation through 3 days post-ozone. Although they were also hyperresponsive to ACh, responses to MCh were unchanged. Neuronal M[sub 2] receptors were dysfunctional through 3 days post-ozone. There was resolution of inflammation, airway responsiveness, and neuronal M[sub 2] receptor function by 14 days post-exposure. This investigation has (1) confirmed an immediate lung inflammation following acute ozone exposure; (2) established that cells in BAL give a distorted reflection of inflammatory events in lung digest; (3) demonstrated that ozone-induced hyperresponsiveness is at least partially due to efferent cholinergic mechanisms without functional changes of muscarinic receptors on airway smooth muscle; (4) shown that ACh may not be an appropriate agent to test ozone-induced airway hyperresponsiveness; and (5) demonstrated that inhibitory neuronal M[sub 2] receptors are dysfunctional following ozone exposure. There was close linkage between these events, suggesting that they may be causally related. This investigation proposes a specific mechanism, dysfunction of neuronal M[sub 2] receptors, by which inflammatory cells could cause airway hyperresponsiveness following acute ozone exposure.
- Research Organization:
- Johns Hopkins Univ., Baltimore, MD (United States)
- OSTI ID:
- 6280189
- 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.
ANIMAL CELLS
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY
BODY FLUIDS
EOSINOPHILS
GUINEA PIGS
INFLAMMATION
LEUKOCYTES
LUNGS
MAMMALS
MATERIALS
NERVE CELLS
NERVES
NERVOUS SYSTEM
NEUTROPHILS
ORGANS
OZONE
PATHOLOGICAL CHANGES
RESPIRATORY SYSTEM
RODENTS
SOMATIC CELLS
SYMPTOMS
VERTEBRATES