Expression Of PGHS-2 In Intrauterine Tissues Around Term And Preterm Parturition

OBJECTION: Prostaglandin (PG) has long been proven to stimulate contraction of smooth muscle in both pregnant and no pregnant uterus. Prostaglandin H synthase (PGHS) is a key enzyme in PG formation and has two is forms, a constitutive form (PGHS-1) and an inducible form (PGHS-2). Many studies have shown that the constructive form PGHS-1 does not change with the onset of labor. The endocrine and paracrine regulation of onset of labor may upregulate the activity of PHGS-2 to increase the production of PG in local uterus. We hypothesis that prostaglandin production by human fetal membranes (amnion and chorion) and placenta may be important in the onset and progression of labour. METHODS: We examined the cellular distribution of the PGHS-2 enzymeand PGHS-2 mRNA in term human fetal membranes, decidua and placenta 。 ; prior to and following labour, using immunohistochemistry and in situ hybridization with a cardiox labeled oligonucleotide probe. RESULT: The PGHS-2 protein was found to be mainly localized in amnion epithelial cells and syncytial trophoblast, and was at low levels in the decidual and chorion, and cells surrounding some of the blood vessels in the membranes express PGHS-2 too. No PGHS-2 protein was found in stromal cells. In situ hybridization demonstrated that PGHS-2 mRNA had a similar distribution. There was increase in the expression of PGHS-2 protein or PGHS-2 mRNA in tissues obtained prior to and following labour in chorion and decidua but significant increase was only observed in amnion epithelium and placenta epithelial cells.CONCLUSION: This studies indicate that, PGHS-2 is differently expressed in fetal tissues and placenta at term. Amnion and synthetial trophoblast cells may be the main source of PG in the onset of labor. PGHS-2 may involved into the onset of both term and preterm labor by promoting the intrauterine production of PG.