Role of COX-2 for Successful Embryo Implantation Process: A Mini-review

Abstract

The endometrium undergoes a dynamic proliferation of cells and vascular tissue under the influence of ovarian steroid hormones. Implantation is an essential process in the development of pregnancy, where there is close contact between embryo and uterus, including supposition, adhesion, and invasion. The changes occur in the human endometrium, including endometrial secretion changes, blood vessels, and immune response, leading to the uterine receptivity period. Cyclooxygenase (COX) is an enzyme that plays a role in the metabolic conversion of arachidonic acid to prostaglandins (PG). It is known that Cyclooxygenase-2 (COX-2) plays a key role in the endometrium. COX-2 is essential for blastocyst implantation and decidualization. The deficiency of COX-2, but not COX-1, results in multiple female reproductive failures (including implantation defects). We reviewed the literature on COX-2 and embryonal implantation in the endometrium and its potential mechanisms that lead to physiological implantation. This review aims to identify the essential roles of COX-2 in the successful implantation process, especially in decidualization, implantation, and embryo growth. The regulation of COX-2 expression in endometrial cells is controlled by ovarian steroid hormones (progesterone and estrogen) through the ENaC pathway to regulate the phosphorylation CREB transcription factor. The presentation of COX-2 varies throughout the stage of embryo development.