PROSTAGLANDIN E(2)-INDUCED RIPENING OF THE HUMAN CERVIX INVOLVES CHANGES IN PROTEOGLYCAN METABOLISM

Objective: To elucidate how prostaglandin E2 (PGE2) induces cervical r ipening.Methods: Cervical biopsies were obtained immediately postpartu m from women successfully treated with PGE2 gel intracervically. Six s pecimens were incubated with [S-35]sulfate and five were used to chara cterize the nonlabeled proteoglycan composition. In separate experimen ts, biopsy specimens from three term pregnant women with unripe cervic es were incubated with PGE2 in organ cultures. Proteoglycans were isol ated and characterized using ion-exchange and gel chromatography and s odium dodecyl sulfate-polyacrylamide gel electrophoresis. Results: Dur ing PGE2-induced cervical ripening, the synthesis of proteoglycans, es pecially a large chondroitin/dermatan sulfate proteoglycan and biglyca n, increased three- to sixfold. This resulted in a net increase in the large proteoglycan in the PGE2-treated cervices. In organ culture, on the contrary, incubation with PGE, decreased the proteoglycan synthes is. Conclusion: Prostaglandin E2-induced cervical ripening is accompli shed by increased remodeling of the cervical connective tissue, involv ing changed proteoglycan metabolism and composition.