Objective: This study was designed to observe the in vivo status of chorion-decidua gene expression for some major metalloproteinases, an inhibitor (tissue inhibitor of metalloproteinase-1), and an activator (tissue plasminogen activator) and the hormone relaxin at accessible time points in the peripartal period.
Study design: Chorion-decidua from patients at cesarean section with and without labor and after spontaneous labor and delivery was used for preparation of poly (A)+ ribonucleic acid and quantitative Northern analyses with a series of oligo and complementary deoxyribonucleic acid probes.
Results: In the period designated as the period before parturition, relaxin and matrix metalloproteinase-1 (interstitial collagenase) gene expression were relatively high, reflecting the controlled loss of amniotic collagen necessary for fetal membrane expansion without rupture as the uterine volume increases. When active labor has begun, but before delivery, matrix metalloproteinase-3 (stromelysin) and matrix metalloproteinase-9 (type V collagenase) gene levels significantly increased. After normal spontaneous labor and delivery, tissue plasminogen activator and tissue inhibitor of metalloproteinase-1 messenger ribonucleic acids significantly increased, together with a marginally increased expression of the genes for matrix metalloproteinase-1, matrix metalloproteinase-2 (type IV collagenase), and relaxin.
Conclusion: The expression of the genes for some major collagenolytic enzymes, an inhibitor, activator, and relaxin in the chorion-decidua, is different at the different stages of parturition.