Does chondroitin sulfate defend the human uterine cervix against ripening in threatened premature labor?

Abstract

Glycosaminoglycans and collagen are the main noncellular components of uterine cervical connective tissue.1 These extracellular matrix components are thought to change qualitatively and quantitatively during labor under the influence of cytokine regulation and to play an important role during cervical ripening.2-8 The most remarkable change in glycosaminoglycans during labor is the increase in the hyaluronic acid content.7, 8 Low-molecular-weight hyaluronic acid, which is produced by hyaluronidase, acts as an inflammatory mediator to induce cervical ripening.9-13 Uterine cervical tissue mainly contains hyaluronic acid, chondroitin sulfate, and heparan sulfate.2, 7 Heparan sulfate is located in vessel walls, and its concentration increases during pregnancy because of increased vascularization.2, 8 However, neither the change in chondroitin sulfate level in the cervix nor the physiologic role of glycosaminoglycans in the process of uterine cervical ripening has yet been clarified. Furthermore, there have been no reports on the changes of chondroitin sulfate levels in preterm cervical ripening such as occur in threatened premature labor. We therefore investigated changes in 3 isomers of chondroitin sulfate (Fig 1) in cervical mucus, which has been reported to reflect the biochemical changes in cervical tissue.14 In addition, the effects of exogenous chondroitin sulfate on hyaluronidase activity in cervical mucus were evaluated to test the hypothesis that chondroitin sulfate modulates the formation of low-molecular-weight hyaluronic acid, a factor that promotes cervical ripening.