AJP - Lung Cellular and Molecular Physiology, Vol 267, Issue 1 46-L51, Copyright © 1994 by American Physiological Society
Ontogeny and effects of exogenous surfactant treatment on SP-A, SP-B, and SP-C mRNA expression in rabbit lungs
T. Ohashi, D. Polk, M. Ikegami, T. Ueda and A. Jobe
Department of Pediatrics, Harbor-University of California, Los Angeles Medical Center, Torrance 90509.
The aims of the present study were to first characterize the ontogeny of
mRNAs encoding the principal surfactant proteins SP-A, SP-B, and SP-C in
rabbit lung tissues, followed by an evaluation of the effect of exogenous
surfactant administration on endogenous expression of mRNA levels. Lung
tissues were collected from New Zealand White rabbits on days 19, 21, 24,
26, 28, 30 of gestation, 1 day and 10 days after birth, and as adults.
SP-A, SP-B, and SP-C mRNAs were first detected on gestational days 26, 24,
and 19, respectively. The specific levels of these mRNAs generally
increased to gestational day 28 and decreased transiently on 1 day of life.
Adult values remained lower than those noted at 30 days gestation. For the
second study, 29-day-gestation preterm rabbits were given either one or two
treatment doses of natural surfactant or an organic solvent extract of
natural surfactant, and mRNA levels were measured 10 or 24 h later. No
effect of surfactant treatments, type of surfactant, or dosage (1 or 2
treatments) was noted on SP-A, SP-B, or SP-C mRNA expression. These data
indicate that the mRNA expression for the three major surfactant proteins
was highest late in gestation in developing rabbits and that exogenous
surfactant treatment was not associated with significant changes in SP-A,
SP-B, or SP-C mRNA levels.
