TGF-beta 3 inhibits the increased gene expressions of pulmonary surfactant proteins induced by dexamethasone in fetal rat lung in vitro.
OBJECTIVE
To determine the effects of transforming growth factor-beta 3 (TGF-beta 3) on expressions of surfactant proteins (SPs).


METHODS
Northern blot hybridization and reverse transcriptase polymerase chain reaction (RT-PCR) were employed to determine the SP-A, SP-B and SP-C mRNA levels of cultured lung explants and type II cells from fetal rat lungs.


RESULTS
TGF-beta 3 alone did not affect the expressions of SPs either in explants or in type II cells. However, TGF-beta 3 did inhibit the increase of SP-B, SP-C mRNA levels caused by dexamethasone (100 nmol/L), in a dose-dependent manner. Furthermore, TGF-beta 3 had no direct inhibition on the increase of SP-B, SP-C mRNA induced by dexamethasone in type II cells, but had an indirect inhibitory effect mediated by fibroblasts.


CONCLUSIONS
TGF-beta 3 plays an important inhibitory role in the development of pulmonary surfactant proteins. The present study may provide a possible explanation for the unideal effect of glucocorticoids in the prevention of neonatal respiratory distress syndrome.
Wang
X
X
Institute of Pediatrics, Children's Hospital, Shanghai Medical University, China.
Jin
Q
Q
Xu
J
J
Shen
W
W
Wang
J
J
Post
M
M
D000818:Animals; D003907:Dexamethasone / Q000494:pharmacology; D005333:Fetus; D015870:Gene Expression; D006023:Glycoproteins / Q000096:biosynthesis*; D008168:Lung / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods; D011510:Proteolipids / Q000096:biosynthesis*; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D006023:Glycoproteins; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D003907:Dexamethasone