Collagen remodeling in the guinea pig uterine cervix at term is associated with a decrease in PR and an increase in ERá expressions

RODRIGUEZ HA; KASS L; VARAYOUD J; RAMOS JG; ORTEGA HH; MUñOZ DE TORO M; LUQUE EH

Cincinatti

Congreso; 36th Annual Meeting of the Society for the Study of Reproduction; 2003

In human and guinea pig parturition, progesterone (P4) withdrawal and estrogen (E) activation are not mediated by changes in their circulating levels. Instead, these events might be promoted by changes in the responsiveness of the uterus and cervix to P4 and E via changes in their receptors. We used the guinea pig model to establish whether the high P4 levels at term are associated with a PR and ERá regionalization in the uterine horn and/or the cervix. P4 and E2 serum levels and the profile of ERá, PR and collagen remodelling in the uterus and cervix along pregnancy, parturition and postpartum were established. PR and ERá were evaluated in the epithelium, subepithelium and muscular stroma of the cervix and lower uterine horns. High levels of E2 and P4 were found at term. In the cervical subepithelium, PR expression decreased before term and remained low during parturition, while ERá expression and collagen remodelling in the cervical subepithelium, although not seen in the uterine horns. The present study indicates that regional changes in cervical PR and ER systems may be responsible for the balance between functional P4 withdrawal and E activation in guinea pig cervix at parturition, as well as the coordination between cervical dilatation and uterine contractions. Guinea pig was further validated as an animal model for human parturition studies.