Mouse strain differences in ozone dosimetry and body temperature
changes.
Slade, R., Watkinson, W. P. and Hatch, G. E.
Pulmonary Toxicology Branch, Experimental Toxicology Division, U.S.
Environmental Protection Agency, Research Triangle Park, NC 27711
APStracts 3:0148L, 1996.
Strain differences in susceptibility to inhaled ozone (O3) have been
observed in mice with C57BL/6J (B6) mice reported to be more
sensitive than C3H/HEJ (C3) mice when exposed to equal concentrations
of O3. To determine whether differences in the delivered dose of O3
to the lung could help explain these differences, C3 and B6 mice were
exposed to 18O-labeled ozone (18O3), and the resulting 18O
concentrations in pulmonary tissues were monitored as an indicator of
O3 delivered dose. Body core temperatures (TCO) of similarly treated
mice were measured during O3 exposures (using surgically implanted
temperature probes) in an effort to correlate lung O3 dose to changes
in basal metabolism. Immediately following exposure to 18O3, C3 mice
had 47% less 18O (per mg dry weight) in lungs and 61% less in
tracheas than B6 mice. Nasal 18O tended to be lower in the C3 mice,
but these differences were not significant. Although both strains
responded to the O3 exposure with significant decreases in TCO, C3
mice had an 80% greater mean temperature x time product decrease
during the exposure than B6 mice. These results suggest that the
strain differences in O3 susceptibility may in turn be due to
differences in O3 dose to the lung, which may be related to
differences in the ability of the mice to lower their TCO in response
to O3 exposure.
Received 18 January 1996; accepted in final form 27 August 1996.
APS Manuscript Number L23-6.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996