Objective: This study was undertaken to evaluate the presence of matrix metalloproteinases (MMPs) and their inhibitors in the cervical mucus plug obtained during active labor at term.
Study design: Cervical mucus plugs from 17 healthy women in normal active labor were homogenized, extracted, and analyzed by 4 different assays.
Results: Gelatin zymography revealed large amounts of MMP-2 and MMP-9, and triple-helical collagen degradation demonstrated collagenase activity (MMP-8). Reverse zymography showed that tissue inhibitor of matrix metalloproteinase 1 (TIMP-1) and TIMP-2 are detectable in the cervical mucus plug. Quantification by enzyme-linked immunosorbent assay confirmed the presence of MMP-2, MMP-8, MMP-9, and TIMP-1.
Conclusion: Our results suggest that proteolytic or nonproteolytic effects of MMP and TIMP may play a part in the function of the cervical mucus plug of pregnancy.