title: Prolonged labour associated with lower expression of syndecan 3 and connexin 43 in human uterine tissue.
abstract: BACKGROUND
  Prolonged labour is associated with greater morbidity and mortality for mother and child. Connexin 43 is a major myometrial gap junction protein found in human myometrium. Syndecan 3 seems to prevail in the human uterus among heparan sulphate proteoglycans, showing the most significant increase during labour. The aims of the present study were to investigate syndecan 3 and connexin 43 mRNA expressions and protein distributions in human uterine tissue during normal and prolonged labour.
  
  
  METHODS
  Uterine isthmic biopsies were collected from non-pregnant (n = 7), term pregnant women not in labour (n = 14), in normal labour (n = 7) and in prolonged labour (n = 7). mRNA levels of syndecan 3 and connexin 43 were determined by real time RT-PCR. The localization and expression were demonstrated by immunohistochemistry and confocal microscopy.
  
  
  RESULTS
  In women with prolonged labour, the mRNA expressions of syndecan 3 and Connexin 43 were considerably lower than the expression level at normal labour (p < 0.05). In term-pregnant tissue, the expression of syndecan 3 and connexin 43 did not differ significantly compared to non-pregnant and normal labour. The immunoreactivity of syndecan 3 was strong at normal labour, in contrast to prolonged labour, where both a weaker expression and an irregular distribution were detected. The immunoreactivity of connexin 43 increased until term and further stronger staining occurred at normal labour. At prolonged labour, the immunoreactivity was weaker and more unevenly distributed. At labour, a co-localization of syndecan 3 and connexin 43 could be demonstrated in the smooth muscle by confocal microscopy.
  
  
  CONCLUSIONS
  The high expression of syndecan 3 and connexin 43 and their co-localization to the smooth muscle bundles during normal labour, together with the significant reduction in prolonged labour, may indicate a role for these proteins in the co-ordination of myometrial contractility.
authors: Department of Woman and Child Health, Division for Obstetrics and Gynaecology, Karolinska University Hospital Solna, S-171 76 Stockholm, Sweden. ann.hjelm@home.se
authors: Ann Hjelm
authors: AH
authors: Cluff
authors: Birgitta
authors: B
authors: Byström
authors: Aurelija
authors: A
authors: Klimaviciute
authors: Camilla
authors: C
authors: Dahlqvist
authors: Gvido
authors: G
authors: Cebers
authors: Anders
authors: A
authors: Malmström
authors: Gunvor
authors: G
authors: Ekman-Ordeberg