Endometrial secretory proteins enhance early embryo development.

Abstract

To evaluate the role of endometrial stromal cells and their secretory proteins in early embryo development, two-celled CB6F1 mouse embryos were cultured alone or cocultured with human endometrial stromal cells in various culture conditions. The percentage of embryo blastocyst formation, hatching, and outgrowth was significantly greater in (1) coculture with endometrial stromal cells than in a cell-free control when both coculture and control were carried out in protein-free medium or in RPMI 1640 plus 10% fetal calf serum; (2) coculture with hormone (i.e., progesterone plus relaxin)-treated cells than in coculture with hormone-nontreated cells; and (3) media supplemented with isolated endometrial secretory proteins than in media supplemented with BSA (0.35%). Embryo development was not found to be significantly different in coculture and in media supplemented with endometrial secretory protein. Our data provides credence to the theory that endometrial stromal cells enhance embryo development by secreting specific proteins that are beneficial to embryo growth in vitro.