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Inhalation of ozone produces a decrease in superoxide anion radical production in mouse alveolar macrophages.
J E Ryer-Powder1, M A Amoruso, B Czerniecki
1Department of Environmental and Community Medicine, UMDNJ-Robert Wood Johnson Medical School/Rutgers University, Piscataway 08854-5635.
The American Review of Respiratory Disease
|November 1, 1988
Summary
Ozone exposure impairs pulmonary alveolar macrophages (PAMs) in mice, reducing their ability to produce superoxide anion radical (O2-), which is crucial for fighting bacterial pneumonia. This impairment occurs at common air pollution levels.
Area of Science:
- Environmental Health
- Immunotoxicology
- Pulmonary Medicine
Background:
- Ozone is a common air pollutant that can exacerbate respiratory infections.
- Pulmonary alveolar macrophages (PAMs) are critical immune cells in the lungs responsible for clearing pathogens.
- Ozone's impact on PAM function and its role in potentiating bacterial pneumonia are not fully understood.
Purpose of the Study:
- To investigate the mechanism by which ozone exposure potentiates bacterial pneumonia.
- To determine the effect of ozone on the superoxide anion radical (O2-) production by PAMs.
- To compare ozone's effect on PAMs in mice and rats, correlating with their known resistance to ozone-induced potentiation of infection.
Main Methods:
- Mice and rats were exposed to varying concentrations of ozone for 3 hours.
- PAMs were isolated, and their O2- production was measured using nitroblue tetrazolium reduction (mice) and cytochrome c reduction (rats).
- Phagocytic activity of PAMs was assessed using latex beads and sheep red blood cells. Cytochrome b558 levels were measured in rat PAMs.
Main Results:
- Ozone exposure significantly decreased O2- production in mouse PAMs, with near-complete inhibition at 1 ppm.
- Rats, which are more resistant to ozone's effects, showed less inhibition of PAM O2- production.
- Decreased O2- production in mice occurred without affecting phagocytic ability, and ozone exposure reduced cytochrome b558 levels in rat PAMs.
Conclusions:
- Ozone exposure inhibits the ability of mouse PAMs to produce O2-, a key mechanism for ozone-induced potentiation of bacterial pneumonia.
- Differences in ozone sensitivity between mice and rats correlate with their respective PAM O2- production inhibition.
- Ozone may interfere with PAM O2- production by interacting with membrane-bound electron carriers like cytochrome b558.