Sensitivity of the lungs of aging fischer 344 rats to ozone: assessment by broncho-alveolar lavage. Vincent, Renaud, Duc Vu, Gary Hatch, Raymond Poon, Kevin Dreher, Jos[acute]ee Gu[acute]enette, Stephen Bjarnason, Marc Potvin, Joel Norwood, Ed McMullen. Environmental Health Directorate, Health Canada, Tunney's Pasture, Ottawa, Ontario, Canada, K1A 0L2; US Environmental Protection Agency, Research Triangle Park, North Carolina, United States, 27711
APStracts 3:0117L, 1996.
Biological effects indicators in broncho-alveolar lavage fluid were studied in Fischer 344 rats of different age after exposure to 0.4 -0.8 ppm ozone, for periods of two to six hours, on a single day or four consecutive days. The magnitude of alveolar protein transudation induced by ozone was not different between age groups, but the inter -individual variability of protein changes was higher in senescent (24 mo) rats. By comparison to juvenile (2 mo) and adult (9 mo) rats, senescent animals had higher increases of interleukin-6 (up to 10 -fold higher) and N-acetyl-[beta]-D-glucosaminidase (2-fold higher) in lung lavage after ozone. Ascorbic acid was lower in lungs of senescent rats (half of juvenile values), and acute ozone exposure brought a further decrease in lung ascorbate. While alveolar protein transudation was attenuated after ozone exposure on four days, persistent elevation of NAGA in senescent rats suggested only partial adaptation. Injection of endotoxin did not modify the patterns of effects. Incorporation of 18O-ozone into macrophages and surfactant was not different between age groups, indicating that the magnified biological responses in senescent rats were not dominated by differences in internal dose of ozone. The results indicate that senescent rats respond differently than juvenile and adult rats to lung injury. 

Received 14 March 1995; accepted in final form 8 May 1996.
APS Manuscript Number L81-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996