Collagen remodelling in the guinea-pig uterine cervix at term is associated with a decrease in PR expression

RODRIGUEZ HA; KASS L; VARAYOUD JG; RAMOS JG; ORTEGA HH; DURANDO M; MUÑOZ DE TORO MM; LUQUE EH

MOLECULAR HUMAN REPRODUCTION.

Año: 2003 vol. 9 p. 807 - 813

1360-9947

In human and guinea-pig parturition, progesterone (P4) withdrawal and estrogen (E) action 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. Herein, the guinea-pig model was used to investigate whether high levels of P4 and E at term are associated with regional changes in PR and ERα levels in uterus and cervix. PR and ERa profiles were established in both subepithelium and muscular layer of the cervix and the lower uterine horns along pregnancy, parturition and postpartum; while collagen remodelling was measured in the subepithelium. Our data showed that collagen remodelling involved in cervical ripening is temporarily and spatially associated to a decrease in PR while high expression of ERa is observed. This association was found in the subepithelium of the cervical tissue but not in the same region of the uterus. Muscular region of the cervix and uterus also present a transient decreased expression of PR while ERa levels are kept high. Thus, the present results indicate that, before parturition, diminished responsiveness of the cervix to P4 might be caused by a decrease in PR levels  and this may be the mechanism of functional P4 withdrawal. Guinea-pig was further validated as an animal model for human parturition studies.