Hydroxylation of salicylate in the lungs of fischer 344 rats:
effects of aging and ozone exposure.
Liu, Ling, Prem Kumarathasan, Jos[acute]ee Gu[acute]enette, and Renaud
Vincent.
Environmental and Occupational Toxicology Division, Health
Protection Branch, Health Canada, Tunney's Pasture, Ottawa, Ontario,
Canada K1A 0L2
APStracts 3:0133L, 1996.
The formation of 2,3-dihydroxybenzoic acid (DHBA) from salicylate was
measured in the lungs and plasma in order to assay for the hydroxyl
radical in juvenile (2 months), adult (9 months) and senescent (24
months) Fischer 344 male rats exposed to clean air, 1 ppm ozone, or 2
ppm ozone for two hours. Similar rates of distribution of salicylic
acid in plasma and to the lungs were observed between air control
animals of all age groups. Levels of 2,3-DHBA were about twice as
high in the lungs of air control senescent rats by comparison to
juvenile and adult rats (p<0.05). Exposure to ozone resulted in
1.5-to-2 fold elevation of 2,3-DHBA in lungs and plasma of all age
groups (p<0.05), while levels of 2,5-DHBA were not changed
significantly. There was no effect of age on the magnitude of 2,3
-DHBA increase in the lungs or plasma following ozone exposure. The
postulated source of hydroxyl radical is chemical reduction of
hydrogen peroxide, which could be generated from increased age
-dependent endogenous oxidant production, or the age-independent
reaction of ozone or macrophage-derived oxidants with the surfactant
lining.
Received 18 July 1995; accepted in final form 26 July 1996.
APS Manuscript Number L224-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 21 August 1996