Lung cytokinetics following exposure to hypobaria and/or hypoxia,
and undernutrition in growing rats.
Sekhon, Harmanjatinder S., and William. M. Thurlbeck.
Department of Pathology and Laboratory Medicine, University of
British Columbia, and the Department of Laboratory Medicine, British
Columbia's Children's Hospital, Vancouver, B.C., Canada.
APStracts 2:0251A, 1995.
Lung cellular dynamics were examined in growing rats from 4 to 7 weeks
of age following exposure to: (1) room air (general controls), (2)
hypobaric normoxia, (3) normobaric hypoxia, (4) hypobaric hypoxia,
and (5) room air and restricted food intake (weight-matched
controls). Tritiated thymidine (3H-TdR) incorporation diminished in
weight-matched controls. In both hypoxic groups, maximum 3H-TdR
incorporation occurred in day 3 in all cells of peripheral alveoli,
capillary endothelium of central alveoli, airway walls and
epithelium, and arterial wall and endothelium, but maximum 3H-TdR
labelling of interstitial and unidentifiable cells of central alveoli
occurred on day 5. The percentage labelling with 3H-TdR was higher in
cells of peripheral alveolar walls than those in central alveolar
walls. Labelling of the interstitium was higher in hypobaric hypoxic
than normobaric hypoxic rats. In hypobaric normoxia, DNA synthetic
activity increased in alveolar wall cells, except for capillary
endothelium. In hypobaric hypoxia, DNA synthesis occurred primarily
because of low oxygen, but low pressure may also affect cytokinetics.
3H-TdR incorporation in the alveoli of the peripheral part of the
lung is greater and earlier than central alveoli, and the cellular
response of the various cells types is not synchronous.
Received 13 February 1995; accepted in final form 25 May 1995.
APS Manuscript Number A178-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.