Lung adaptation to low levels of ozone (O3) on long term exposure

Carroll E Cross, K. Reddy, M. Z. Hussain

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Short term exposures to O3, an important environmental oxidant, elicit well described cytopathic and biochemical changes in the lungs of experimental animals. There have been fewer studies characterizing the long term cytopathic and biochemical effects of exposure to low concentrations (0.2 to 0.8 ppm) of this oxidant. In the current studies 60 day old chronic respiratory disease free Sprague Dawley rats were exposed to 0.8 ppm O3 8 hrs/day for 90 days. Lung tissues from both exposed and control rats were examined by light microscopy and assayed for selected biochemical parameters known to accompany inflammatory and reparative responses of the lung to injury. Initial O3 induced injury is reflected by increases (7th day) in the activities of all biochemical parameters studied. By 20-50 days most biochemical correlates approximated control values. Morphological examinations showed that O3 exposed rats were indistinguishable from controls at 50-90 days. The data suggests that lungs may develop adaptation to O3 induced injury following prolonged low level exposure. The adaptation does not appear to be explained by measurable biochemical changes in whole lung homogenates.

Original languageEnglish (US)
JournalAmerican Review of Respiratory Disease
Issue number4
StatePublished - 1976

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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