title: Differential appearance of placentomes and expression of prostaglandin H synthase type 2 in placentome subtypes after betamethasone treatment of sheep late in gestation.
abstract: Inappropriate fetal exposure to maternal glucocorticoid (GC) has been proposed as a mechanism for fetal programming where the effects of GC may be mediated by the placenta. However, the consequences of maternal GC on placental morphology and enzyme expression are unclear.
  
  
  OBJECTIVE
  We used betamethasone (BET) to determine effects on placentome subtype distribution and expression of prostaglandin H synthase type 2 (PGHS-2) enzyme.
  
  
  METHODS
  Pregnant sheep carrying male fetuses were randomized to receive injections of saline (n = 30) or one (104 days of gestation, (dG); n = 6), two (104, 111 dG; n = 6) or three (104, 111, 118 dG; n = 11) doses of BET (0.5 mg/kg). Placental tissue was collected prior to (75, 84, 101 dG), during (109, 116 dG) and after BET (122, 132, 146 dG).
  
  
  RESULTS
  Total number of placentomes was not different between gestational ages. A- and B-subtypes were most affected by prenatal BET exposure; numbers of A-subtypes were increased and numbers of B-subtypes were decreased compared to controls at 116 dG. At term numbers of A-subtypes were lower after BET, but the weight range distribution was similar to controls. In controls, placental PGHS-2 protein levels increased with gestational age and PGHS-2 localized primarily to uninuclear trophoblast cells. After BET, PGHS-2 protein in C-subtypes at term was significantly increased compared to A-subtypes.
  
  
  CONCLUSIONS
  Maternal BET treatment in late gestation affects the proportions of placentome subtypes and their differential expression of PGHS-2. Our data do not support previous hypotheses that A-subtypes develop into B-, C- and D-subtypes over the course of gestation.
authors.affiliation: Department of Physiology and Obstetrics and Gynecology, University of Toronto, MSB, Rm. 3368, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada. thorsten.braun@charite.de
authors.forename: T
authors.initials: T
authors.lastname: Braun
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.forename: T J M
authors.initials: TJ
authors.lastname: Moss
authors.forename: K L
authors.initials: KL
authors.lastname: Connor
authors.forename: D A
authors.initials: DA
authors.lastname: Doherty
authors.forename: I
authors.initials: I
authors.lastname: Nitsos
authors.forename: J P
authors.initials: JP
authors.lastname: Newnham
authors.forename: J R G
authors.initials: JR
authors.lastname: Challis
authors.forename: D M
authors.initials: DM
authors.lastname: Sloboda
mesh_terms: D000818:Animals; D001623:Betamethasone; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D005260:Female; D047109:Fetal Development / Q000187:drug effects*; D005865:Gestational Age; D005938:Glucocorticoids / Q000009:adverse effects / Q000494:pharmacology; D017258:Medroxyprogesterone Acetate / Q000494:pharmacology; D010920:Placenta / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D011247:Pregnancy; D034561:Sheep, Domestic
chemical_list: D005938:Glucocorticoids; D001623:Betamethasone; D017258:Medroxyprogesterone Acetate; D051546:Cyclooxygenase 2