[Regulation of epidermal growth factor, thyrotropin releasing hormone and dexamethasone on the expression of fetal lung SP mRNAs in rabbits].
OBJECTIVE
To compare the effect of epidermal growth factor (EGF), thyrotropin releasing hormone (TRH) and dexamethasone (Dex) on the expression of surfactant protein (SP)-A, SP-B and SP-C mRNA in fetal rabbit lungs.


METHODS
Sixty-four Japanese white pregnant rabbits, put into four different groups (16 rabbits each), were given EGF (EGF group), TRH (TRH group), Dex (Dex group) or normal saline (control group) intravenously from gestational day 22(nd) (5 rabbits in each group) or 24(th) (11 rabbits in each group) for three days before killing. The levels of SP-A, SP-B and SP-C mRNAs in the fetal rabbit lungs were detected by reverse transcription polymerase chain reaction (RT-PCR) and Southern blotting.


RESULTS
In the 27(th) gestational day, SP-B mRNA levels in the fetal rabbit lungs in all treated groups were found significantly higher than those in the control group (P < 0.05). In the 25(th) day, there had a higher expression of SP-A and SP-C mRNAs in the fetal lungs in all groups, but SP-B mRNA could be tested only in the Dex group. SP-B mRNA level was lower than that of SP-A mRNA and SP-C mRNA in the same fetal lungs in the 27(th) gestationed day.


CONCLUSIONS
The time of detectable SP-B mRNA in rabbit fetal lungs appeared later than that of the SP-A and SP-C mRNAs. The expression of SP-B mRNA is lower in comparison with those of SP-A mRNA and SP-C mRNA in the same samples. Prenatal maternal treatment with intravenously Dex, EGF and TRH could increase the expression of SP-B mRNA in fetal rabbit lungs, and the effect of Dex may be more significant at earlier stage of gestation.
Wang
Feng-ying
FY
Department of Obstetrics and Gynecology, Southwestern Hospital, Third Military Medical University, Chongqing 400038, China.
Wang
Yu-mei
YM
Cao
Hong-wei
HW
Zhang
Chan-yu
CY
Zhang
Ning
N
Shi
Chang-xu
CX
D000818:Animals; D003907:Dexamethasone / Q000494:pharmacology*; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005260:Female; D005325:Fetal Organ Maturity; D005333:Fetus / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D008168:Lung / Q000196:embryology; D011247:Pregnancy; D037662:Pulmonary Surfactant-Associated Protein A / Q000235:genetics*; D037701:Pulmonary Surfactant-Associated Protein B / Q000235:genetics*; D037721:Pulmonary Surfactant-Associated Protein C / Q000235:genetics*; D011663:Pulmonary Surfactants; D012333:RNA, Messenger / Q000032:analysis; D011817:Rabbits; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*
D037662:Pulmonary Surfactant-Associated Protein A; D037701:Pulmonary Surfactant-Associated Protein B; D037721:Pulmonary Surfactant-Associated Protein C; D011663:Pulmonary Surfactants; D012333:RNA, Messenger; D013973:Thyrotropin-Releasing Hormone; D004815:Epidermal Growth Factor; D003907:Dexamethasone