OBJECTIVE: To elucidate how prostaglandin E2 (PGE2) induces cervical ripening.METHODS: Cervical biopsies were obtained immediately postpartum from women successfully treated with PGE2 gel intracervically. Six specimens were incubated with [35S]sulfate and five were used to characterize the nonlabeled proteoglycan composition. In separate experiments, biopsy specimens from three term pregnant women with unripe cervices were incubated with PGE2 in organ cultures. Proteoglycans were isolated and characterized using ion-exchange and gel chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis.RESULTS: During PGE2-induced cervical ripening, the synthesis of proteoglycans, especially a large chondroitin/dermatan sulfate proteoglycan and biglycan, 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 PGE2 decreased the proteoglycan synthesis.CONCLUSION: Prostaglandin E2-induced cervical ripening is accomplished by increased remodeling of the cervical connective tissue, involving changed proteoglycan metabolism and composition.
Adult Cervix Uteri