IN-VITRO TREATMENT OF EMBRYOS WITH EPIDERMAL GROWTH-FACTOR IMPROVES VIABILITY AND INCREASES THE IMPLANTATION RATE OF BLASTOCYSTS TRANSFERRED TO RECIPIENT MICE

OBJECTIVE: Our purpose was to study, by means of a mouse embryo donation model, the possible role of epidermal growth factor in the development of preimplantation embryos. STUDY DESIGN: Seven blastocysts developed either in vivo or in vitro, with or without treatment with epidermal growth factor, were transferred to a uterine horn of pseudopregnant recipient mice on day 3 (the presence of a vaginal plug indicated day 1 of pseudopregnancy). Recipients were killed on day 8 of pseudopregnancy, and the number of implantation sites was counted. RESULTS: The implantation rate in recipient mice of in vitro-cultured blastocysts was significantly lower than that of embryos grown in vivo (i.e., 57.1% vs 84.2%) (p < 0.001). Treatment of embryos in vitro with epidermal growth factor, 10 ng/ml, effectively prevented a decrease in implantation rate (77.9%). CONCLUSION: Epidermal growth factor may play a stimulatory role in the development of the preimplantation mouse embryo.