Objective   To study the differential expressions of labour-associated genes

including interleukin-8 (IL-8)

oxytocin receptor (OTR) and prostaglandin H synthase type-2 (PGHS-2)) between preterm labour and term labour myometrium and their clinical significance.    Methods   Seventeen cases of preterm labour (PTL) and 31 cases of preterm no labour (PTNL) of pregnant women were selected as study group

while 6 cases of term labour (TL) and 6 cases term no labour (TNL) of pregnant women were chosen as control. Lower myometrial tissue biopsies were collected to detect the expressions of IL-8

OTR and PGHS-2 by real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) as well as Western blot analysis. The expression data were then statistically analyzed in combination with clinical data.    Results   In the lower myometrial tissues

the mRNA levels of IL-8 and PGHS-2 were significantly lower in PTL group than in TL samples (P0.01 for IL-8 and P0.05 for PGHS-2). IL-8 mRNA levels in PTL group and TL group were significantly up-regulated compared to those of PTNL and TNL groups respectively (P0.05 and P0.01 respectively). There was no significant difference of PGHS-2 mRNA levels between PTL and PTNL groups (P0.05)

but the PGHS-2 mRNA level was significantly higher in TL group than in TNL group (P0.05). The protein level of PGHS-2 was higher in TL group than in TNL group (P0.05)

but there was no difference of PGHS-2 protein among TL

PTL and PTNL groups (P0.05). Correlation analysis suggested that the mRNA level of IL-8 was significantly correlated with gestational age in PTNL group (r=0.294

P=0.042). Multiple linear regression analysis showed a mutual control effect of the expressions of IL-8

OTR and PGHS-2 in preterm but not in term labour group.    Conclusion   Our results show that there are significant differences of the expression of labour-associated genes in lower myometrum between preterm labour and term labour

which might becorrelated with the progression of preterm labour. 