Mechanisms for the generation of gas-exchange surface area in rat
lung.
Blanco, Luciano N.
Pulmonary Research Center (R-120), Departments of Medicine and
Pediatrics, University of Miami School of Medicine, P.O. Box 016960,
Miami, FL 33101, U.S.A., * Present Address: Institute for Theoretical
Research, PO Box 248514, Coral Gables, FL 33124-8514, U.S.A.
APStracts 2:0098L, 1995.
During development, rat lung seems to make use of the mechanisms of:
a) expansion, b) replication, and c) subdivision to increase its gas
-exchange surface area. To quantitate the contribution of each one of
these mechanisms from birth to adulthood, four models of lung
development have been mathematically evaluated: (1) Existing saccules
at birth septate (subdivide) during the first two postnatal weeks
creating smaller alveoli that undergo a continuous expansion up to
adulthood; (2) same as the previous model except that new alveoli are
also formed by means other than septation after the second postnatal
week; (3) same as the previous model except that the alveoli formed
by means other than septation start forming immediately after birth;
and 4) saccules continue to be formed up to adulthood and
subsequently septate forming alveoli. Evaluating these models
mathematically, it was found that expansion followed by replication
are the most important mechanisms for the generation of gas-exchange
surface area in all four models in the maturing lung. Although the
contribution of septation is important during early postnatal life,
its importance decreases with age.
Received 4 March 1994; accepted in final form 22 May 1995.
APS Manuscript Number L76-4.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.