Collagenase-3 (MMP-13) in fetal membranes and amniotic fluid during pregnancy.

Objective: To examine the expression, site of production and a role of collagenase-3 in human fetal membranes and amniotic fluid (AF).
Methods: Amniochorion collected at the time of elective repeat cesareans prior to labor from normal term gestation, were placed in an organ explant system for 72 hr. The AF was collected from the following groups of women: women at term; women at third trimester pregnancy; women at mid-trimester pregnancy. Women with premature rupture of the membranes (PROM) with or without pre-term labor and infection delivered by cesareans before term; women with pre-term labor and no rupture of membranes and delivered by cesareans before term. The mRNA expression of collagenase-3 was studied by reverse transcriptase-polymerase chain reaction (RT-PCR) and protein concentrations in the AF were assayed by enzyme-linked immunosorbent assay (ELISA). Site of collagenase-3 production was documented by immunohistochemistry. Statistical comparisons were made using ANOVA. All statistical hypotheses were adjusted for multiple comparisons using the Scheffe method of adjustment.
Results: Amniochorion at term expressed collagenase-3 mRNA. Immunohistochemistry localized collagenase-3 in both amnion and chorion. Collagenase-3 was seen in AF from all gestational age groups with lowest levels at mid-trimester [167.8 pg/mL] and highest during term labor (323.92 pg/mL) with no statistically significant difference between term and third trimester (310.11 pg/mL). AF levels of collagenase-3 were significantly higher in women with pre-term labor (370.02 pg/mL; P(adj) = 0.046) or pre-term labor and infection (628.73 pg/mL; P(adj) = 0.002) compared with PROM with pre-term labor and infection (87.19 pg/mL).
Conclusion: Collagenase-3 mRNA is constitutively expressed and produced in amniochorion. It is a normal physiologic constituent of AF. PROM is not associated with an increase in the AF collagenase-3.