AJP - Lung Cellular and Molecular Physiology, Vol 262, Issue 4 489-L494, Copyright © 1992 by American Physiological Society
Surfactant protein A expression is delayed in fetuses of streptozotocin-treated rats
S. H. Guttentag, D. S. Phelps, W. Stenzel, J. B. Warshaw and J. Floros
Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115.
The content and distribution of the 26-to 38-kDa surfactant protein (SP-A)
and its mRNA were determined in fetuses of control and streptozotocin
(STZ)-treated Sprague-Dawley rats using immunohistochemistry, RNA blotting,
and in situ hybridization. Female rats were treated with 50 mg/kg STZ
before mating, and the fetuses were killed at fetal days 18-21 or on
neonatal days 1 and 2 (day of birth = end of day 22). SP-A was barely
detectable on fetal day 18 in controls and easily detected by fetal day 21.
In the STZ group, SP-A was decreased compared with controls at fetal days
18-21. However, by neonatal days 1-2, there were no significant differences
in SP-A levels between groups. SP-A mRNA was detectable at fetal day 18 in
controls, but it was decreased in the STZ group at day 18-21 (P less than
0.02) and differences were no longer detected by neonatal days 1-2. SP-A
and SP-A mRNA accumulated with advancing gestational age in both groups
until neonatal days 1-2. The differences in SP-A and SP-A mRNA levels in
the two groups diminished with advancing age but remained significant at
fetal day 21. These data suggest that STZ-induced diabetes interferes with
normal expression of SP-A in the developing fetal lung.
