Effect of LH treated ovine oviductal epithelial cell co-culture system on murine pre-embryo development

Background: This study was designed to develop a new co-culture system, assess the effect of luteinizing hormone (LH) using sequential media to promote development and increase the quality of 2-cell murine embryos through the 8-16 cell stage to morula and blastocyst stages. Materials and Methods: Monolayers for co-culture were prepared from ovine oviduct epithelial cells (OOEC) in DMEM/F12 medium and in-vivo-fertilized 2-cell embryos were collected by flushing from superovulated mice. Co-culture media was treated with 10ng/ml LH. For the control groups, embryos were cultured solely in G1/G2™Ver.5 drops and containing LH; and on OOEC monolayers in G1/G2™Ver.5 drops alone and containing LH as the experimental groups. Development and quality rates were determined for all embryos daily and statistically compared. At the end of the cultivation period, differentially stained trophectoderm (TE) and inner cell mass (ICM) of expanded blastocysts from each group were examined microscopically. Results: The embryos cultured on an OOEC monolayer in G1/G2™Ver.5 drops treated with LH had a significantly higher developmental rate than those of the group without LH and the control groups (p≤0.05). The blastocysts from the LH treated co-culture, in comparison with the group without LH and the control groups, also had a significantly higher mean cell number (p≤0.05). Conclusion: These findings suggest that elevated periovulatory LH levels may promote preimplantation embryo development. These results have important implications for assisted reproductive technologies in which co-cultures are used to improve pregnancy rates. OOEC cell co-culture system treated by LH could improve in vitro preimplantation embryo development both in terms of quality (increasing blastocyst cellularity) and developmental rate.