title: [Effects of antenatal administration of dexamethasone and betamethasone on signal transduction of bone morphogenetic protein in the fetal lungs of rats].
abstract: OBJECTIVE
  To study the role of antenatal glucocorticoid (dexamethasone and betamethasone) on bone morphogenetic protein (BMP) signal transduction of the rat fetal lungs.
  
  
  METHODS
  Fifteen pregnant rats were randomly divided into five groups: the rats treated with dexamethasone for 1 day (1D-DEX) or 3 days (3D-DEX), with betamethasone for 1 day (1D-BEX) or 3 days (3D-BEX) or with normal saline (control group), followed cesarean section on the 19th day of gestation. The mRNA levels of BMP4, BMPR-II, Smad1 and ATF-2 of fetal rat lungs were ascertained by reverse transcriptase polymerase chain reaction (RT-PCR). The expression of BMP4, BMPR-II, Smad1 and ATF-2 antigen expression in fetal lungs was assessed by immune histochemical staining. The expression of BMP4 and BMPR-II was determined by Western blot.
  
  
  RESULTS
  The levels of BMP4, BMPR-II and Smad1 mRNA expression were up-regulated in the 1D-BEX, 3D-BEX and 3D-DEX groups compared with those in the control group (P<0.05). The immune histochemiscal analysis showed that the expression of BMP4, BMPR-II, Phospho-Smad1 (pSmad1) and ATF-2 in the 1D-BEX, 3D-BEX and 3D-DEX groups was significantly higher than that in the control group (P<0.01). The results of Western blot demonstrated that the expression of BMP4 and BMPR-II protein increased significantly in the 1D-BEX, 3D-BEX and 3D-DEX groups when compared with the control group (P<0.01).
  
  
  CONCLUSIONS
  Betamethasone and dexamethasone may play important roles in the regulation of BMP signal transduction in the rat fetal lungs. Up-regulation of BMP4, BMPR-II and Smad1 might be one of crucial factors for the glucocorticoid-induced maturity of fetal lungs.
authors.affiliation: Neonatal Medical Centre, Nanjing Children's Hospital, Nanjing Medical University, Nanjing 210008, China.
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Chen
authors.forename: Sheng-Hua
authors.initials: SH
authors.lastname: Wu
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Zhou
mesh_terms: D051698:Activating Transcription Factor 2 / Q000032:analysis / Q000235:genetics; D000818:Animals; D001623:Betamethasone / Q000494:pharmacology*; D055415:Bone Morphogenetic Protein 4 / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D052006:Bone Morphogenetic Protein Receptors, Type II / Q000032:analysis / Q000235:genetics; D003907:Dexamethasone / Q000494:pharmacology*; D005260:Female; D005333:Fetus / Q000187:drug effects* / Q000378:metabolism; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D051898:Smad1 Protein / Q000032:analysis / Q000235:genetics
chemical_list: D051698:Activating Transcription Factor 2; C497107:Atf2 protein, rat; C525811:Bmp4 protein, rat; D055415:Bone Morphogenetic Protein 4; D051898:Smad1 Protein; C497400:Smad1 protein, rat; D003907:Dexamethasone; D001623:Betamethasone; D052006:Bone Morphogenetic Protein Receptors, Type II