Changes in the Expression of Cyclooxygenase-2 after Labor in Myometrium and Fetal Membrane of Term Pregnancy

Objective : Cyclooxygenase-2 (Cox-2) is a rate-limiting enzyme in the production of prostaglandins. The purpose of this study was to investigate the expression of Cox-2 in various human conceptional tissues obtained from term pregnant women in labor and those not in labor. Methods : Myometrium, chorion, and amnion were collected during cesarean section from women in labor and women not in labor. The expression of Cox-2 in each tissue was measured by Western blot analysis and the localization of Cox-2 in these tissues was confirmed by immunohistochemical staining. Results : Western blot analysis showed significantly higher levels of Cox-2 in the tissue from women in labor than that from women not in labor. Immunohistochemical detection showed stronger cytoplasmic staining in the smooth muscle cells and amnion obtained from women in labor than that from women not in labor, but no change was found in chorion. Conclusion : In term pregnancy, the expression of Cox-2 increases in the smooth muscle cells and amnion, placenta, but not in chorion after labor.