title: The inflammatory state of the rat placenta increases in late gestation and is further enhanced by glucocorticoids in the labyrinth zone.
abstract: BACKGROUND
  Inflammation plays central roles in key aspects of successful reproduction: ovulation, implantation and parturition. In this study we characterised the inflammatory profile of the rat placenta in late gestation with and without maternal glucocorticoid (dexamethasone) treatment.
  
  
  METHODS
  Placentas (n = 6/group) were collected from untreated (Con) rats at days 16 and 22 (term = day 23) and from dexamethasone-treated (Dex) rats at day 22. mRNA and protein expression was determined for enzymes of prostaglandin synthesis and metabolism (Ptgs-1, Ptgs-2, 15-Pgdh), pro-inflammatory cytokines (Tnf-α, Il-1β, Il-6), and the macrophage marker Emr-1 in the junctional (JZ) and labyrinth (LZ) zones of the placenta.
  
  
  RESULTS
  Tnf-α, Il-1β and Il-6 mRNAs all increased (2- to 4-fold) in both placental zones between days 16 and 22 (P < 0.01). Ptgs-2 mRNA (30-fold; P < 0.01) and PTGS-2 protein (2.4-fold; P < 0.05) similarly increased in LZ. In contrast, 15-Pdgh expression increased in JZ but decreased in LZ; these changes were accompanied by decreased levels of PGE2 in the JZ and a trend towards increased LZ levels. Dex treatment inhibited fetal and placental growth, but had minimal effects on expression of Ptgs-1, Ptgs-2 or 15-Pdgh. Nevertheless, Dex treatment increased LZ PGE2 levels (5-fold, P < 0.01) at the end of gestation. Dex treatment increased Tnf-α mRNA expression in LZ (40%; P < 0.05), but modestly suppressed cytokine protein expression in JZ.
  
  
  CONCLUSIONS
  These data demonstrate that the inflammatory state of the LZ increases near term coincident with the known increase in local glucocorticoid levels. This suggests the classic anti-inflammatory actions of glucocorticoids do not occur in the placental LZ.
authors: School of Anatomy, Physiology and Human Biology, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, Western Australia 6009, Australia. peter.mark@uwa.edu.au
authors: P J
authors: PJ
authors: Mark
authors: J L
authors: JL
authors: Lewis
authors: M L
authors: ML
authors: Jones
authors: J A
authors: JA
authors: Keelan
authors: B J
authors: BJ
authors: Waddell
mesh_terms: D000818:Animals; D016207:Cytokines / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D005865:Gestational Age; D005938:Glucocorticoids / Q000494:pharmacology; D007249:Inflammation / Q000503:physiopathology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects*; D011453:Prostaglandins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011956:Receptors, Cell Surface / Q000096:biosynthesis; D059467:Transcriptome / Q000187:drug effects
chemical_list: C496221:Adgre1 protein, rat; D016207:Cytokines; D005938:Glucocorticoids; D011453:Prostaglandins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D003907:Dexamethasone