Objective: To investigate the role of matrix metalloproteinase-2,9 (MMP-2, MMP-9) and tissue inhibitor of matrix metalloproteinases-2,1 (TIMP-2, TIMP-1) in human amniochorionic membrane.
Methods: Amniochorionic membranes were collected from the following groups of women: (1) women with spontaneous premature rupture of membrane (PROM) before onset of labor (PROM group, n = 8), (2) Women with term labor after vaginal delivery (vaginal delivery group, n = 8), (3) Women undergoing elective cesarean section (C-section group, n = 8). Messenger ribonucleic acid expression for MMP-2, MMP-9, and their specific inhibitors TIMP-2 and TIMP-1 were studied with reverse transcriptase polymerase chain reaction.
Results: (1) MMP-2 level in PROM group was 0.849 +/- 0.037; in vaginal delivery group 0.327 +/- 0.023; in C-section group 0.307 +/- 0.028. Expression in PROM group was highest, with significant difference compared with the other groups (P < 0.05). Its expression in vaginal delivery group and C-section group had no significant difference (P > 0.05). (2) MMP-9 level in PROM group was 0.026 +/- 0.004; in vaginal delivery group 0.008 +/- 0.001, with significant difference between the two groups (P < 0.05), while the expression was absent in C-section group. (3) TIMP-2 level in PROM group was 0.420 +/- 0.122; in vaginal delivery group 0.730 +/- 0.148; in C-section group 0.885 +/- 0.065. The expression in PROM group was significantly lower than in vaginal delivery group and C-section group (P < 0.05). And it was significantly lower in vaginal delivery group than in C-section group (P < 0.05). (4)TIMP-1 level in PROM group was 0.442 +/- 0.020; in vaginal delivery group 0.431 +/- 0.016; in C-section group 0.427 +/- 0.011. The expression in three groups had no significant difference (P > 0.05).
Conclusions: In PROM group, the expression of MMP-2, MMP-9 and their inhibitors TIMP-2, TIMP-1 is imbalanced, leading to increased extracellular matrix degradation, and weakening of the fetal membranes, and eventually premature rupture of the membranes.