Leukemia inhibitory factor enhanced the developmental and implantation compatibility of mouse embryos in co-culture with human endometrial epithelial cells

Objective: Among the various in vitro embryo culture systems, co-culture has demonstrated remarkable effects in pre-implantation embryo development owing to the production of embryo-nourishing factors. Nevertheless, little is known about the secretion of these factors. Therefore, in this study, the effect of leukemia inhibitory factor (LIF), one of the most important nourishing factors in the early development of mouse embryos, in human endometrial epithelial cells (hEECs) was evaluated. Methods: Two-cell stage embryos were collected from the oviducts of hyper-stimulated and mated mice and cultivated in a co-culture with an hEEC monolayer with or without LIF. The quality and developmental and attachment potential rates of cultured embryos were evaluated by determining the levels of octamer-binding transcription factor 4 (Oct4) and caudal type homeobox 2 (Cdx2) transcripts. Results: LIF significantly increased the developmental rate (82.67% vs. 61.04%, respectively) and attachment rate (64% vs. 45.45%, respectively) of mouse embryos co-cultured with hEECs compared to those in untreated embryos. The expression levels of Oct4 and Cdx2 in blastocysts cultured in the presence of LIF were higher than those in blastocysts cultured without LIF. Conclusions: Despite the secretion of LIF by hEECs during co-culture with embryos, the amount of this factor was insufficient, and its addition to the culture media could increase the developmental potential of embryos.