The interleukin-1 system in gestational tissues at term: effect of labour.
Previous studies suggest that the interleukin-1 (IL-1) system is involved in preterm labour, at least in cases associated with intrauterine infection. To investigate the effect of term labour without infection on the IL-1 system, the messenger ribonucleic acid (mRNA) expression of IL-1 beta, IL-1 receptor type I (IL-1R tI), IL-1 receptor antagonist (IL-1ra), and IL-1 beta converting enzyme (ICE) were examined by Northern blot analysis and by reverse transcriptase-polymerase chain reaction (RT-PCR) in paired samples of decidua and placenta obtained from women having spontaneous vaginal delivery (group 1) or elective caesarean section (group 2) at term. In addition, concentrations of IL-1 beta and IL-1ra proteins were measured by ELISA in paired decidual and placental cytosols. In all decidual samples, IL-1 beta mRNA was expressed strongly, and the IL-1 beta concentration was 40- to 50-fold higher than in paired placental samples, in which the signal for IL-1 beta mRNA could be detected by RT-PCR only, and the amount of IL-1 beta protein was undetectable or very low. A comparison between the study groups revealed that the decidual IL-1 beta mRNA level tended to be higher in group 1, and the median IL-1 beta concentration in decidual cytosols was significantly higher in group 1 than in group 2 (P < 0.05). The IL-1R tI mRNA transcript was stronger in decidual than in paired placental samples in both groups. The mRNAs encoding ICE and IL-1ra were detected by RT-PCR in decidual and placental samples from both groups. The IL-1ra concentration tended to be higher in decidual cytosols than in paired placental cytosols, but there was no difference between the study groups. The IL-1ra/IL-1 beta ratio was significantly lower in decidual samples in women with spontaneous labour than in women without labour (P < 0.05). The results of this study confirm that decidua is the major site of IL-1 beta production and action in term gestational tissues. Furthermore, the results show that the major change in decidual/placental IL-1 system during parturition is the increase in decidual IL-1 beta production. Whether the increased IL-1 beta production precedes or is a consequence of labour, remains still unclear.
Ammälä
M
M
Department of Obstetrics and Gynaecology, Helsinki University Central Hospital, Finland.
Nyman
T
T
Salmi
A
A
Rutanen
E M
EM
D000328:Adult; D015152:Blotting, Northern; D020170:Caspase 1; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D003600:Cytosol / Q000737:chemistry / Q000378:metabolism; D015342:DNA Probes / Q000737:chemistry; D003656:Decidua / Q000378:metabolism*; D005260:Female; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism*; D007743:Labor, Obstetric / Q000502:physiology*; D010298:Parity; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D017472:Receptors, Interleukin-1 / Q000235:genetics / Q000378:metabolism*; D053573:Receptors, Interleukin-1 Type I; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism*
D015342:DNA Probes; C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D012333:RNA, Messenger; D017472:Receptors, Interleukin-1; D053573:Receptors, Interleukin-1 Type I; D012795:Sialoglycoproteins; D003546:Cysteine Endopeptidases; D020170:Caspase 1