Matrix metalloproteinases and their inhibitors in the cervical mucus plug at term of pregnancy

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.