Characterization of the oxidant generation by inflammatory cells lavaged from rat lungs following acute exposure to ozone
Following exposure to 2 ppm ozone for 4 hr, two distinct effects on rat lung inflammatory cell oxidant generation were observed. TPA- and opsonized zymosan-stimulated superoxide production by the inflammatory cell population was found to be maximally inhibited 24 hr following ozone exposure. In contrast, luminol-amplified chemiluminescence increased 24 hr following ozone exposure, coinciding with an increase in the percentage of neutrophils and myeloperoxidase in the inflammatory cell population. Supporting the involvement of myeloperoxidase in the enhanced oxidant-generating status of these cells, the luminol-amplified chemiluminescence was found to be azide-, but not superoxide dismutase-inhibitable. Additionally, this cell population was found to generate taurine chloramines, a myeloperoxidase-dependent function which was absent prior to the ozone exposure and also demonstrated enhanced activation of benzo(a)pyrene-7,8-dihydrodiol to its light-emitting dioxetane intermediate. Addition of myeloperoxidase to control alveolar macrophages resulted in enhanced luminol-amplified chemiluminescence, taurine chloramine generation, and enhanced chemiluminescence from benzo(a)pyrene-7,8-dihydrodiol demonstrating that, in the presence of myeloperoxidase, alveolar macrophages are capable of supporting myeloperoxidase-dependent reactions. The possibility of such an interaction occurring in vivo is suggested by the detection of myeloperoxidase activity in the cell-free lavagates of ozone-exposed rats. These studies suggest that neutrophils recruited to ozone-exposed lungs alter the oxidant-generating capabilities in the lung which could further contribute to lung injury or to the metabolism of inhaled xenobiotics.
- Research Organization:
- Johns Hopkins Univ. School of Hygiene and Public Health, Baltimore, MD (USA)
- OSTI ID:
- 5714218
- Journal Information:
- Toxicol. Appl. Pharmacol.; (United States), Vol. 99:2
- Country of Publication:
- United States
- Language:
- English
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BENZOPYRENE
BIOLOGICAL EFFECTS
LUNGS
PATHOLOGICAL CHANGES
OZONE
TOXICITY
PHORBOL ESTERS
ZYMOSAN
ACUTE EXPOSURE
CHEMILUMINESCENCE
ENZYME ACTIVITY
EXPOSURE CHAMBERS
INFLAMMATION
MACROPHAGES
NEUTROPHILS
OXYGEN
PEROXIDASES
RATS
SUPEROXIDE DISMUTASE
ANIMAL CELLS
ANIMALS
AROMATICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY
BODY FLUIDS
CARCINOGENS
CONDENSED AROMATICS
CONNECTIVE TISSUE CELLS
ELEMENTS
ENZYMES
ESTERS
HYDROCARBONS
LEUKOCYTES
LUMINESCENCE
MAMMALS
MATERIALS
NONMETALS
ORGANIC COMPOUNDS
ORGANS
OXIDOREDUCTASES
PHAGOCYTES
RESPIRATORY SYSTEM
RODENTS
SOMATIC CELLS
SYMPTOMS
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology