The Effect of Epidermal Growth Factor on the Preimplantation Development, Implantation and Its Receptor Expression in Mouse Embryos

Cho, Yoon Kyung; Chae, Hee Dong; Cheon, Yong Pil; Kim, Chung Hoon; Kang, Byung Moon; Chang, Yoon Seok; Mok, Jung Eun

Abstract

This study was performed to investigate the influence of epidermal growth factor (EGF) on preimplantation development, implantation, and expression of epidermal growth factor receptor (EGFR) in mouse embryos. Riverse transcription-polymerase chain reaction (RT-PCR) has been used to examine the presence of transcripts. Following reverse transcription, strategically designed nested primers, optimised for specificity, were used for amplification from the cDNA equivalent of a single embryo. The products were then verified by restriction enzyme digestion and sequence analysis. Eight-cell stage mouse embryos were cultured for 48hrs with EGF at concentrations of 0.1, 1.0, 10 and 100 ng/ml. Embryos not treated with EGF were served as control. The percentages of embryos which developed to the expanded, hatched blastocyst stage and in vitro implantation at 48hrs were determined. The percentages of fully expanded murine blastocysts at 48hrs in all EGF treated group were not significantly different from the control. The percentages of hatched blastocysts were significantly higher in EGF treatment group at 0.1ng/ml (90.7%), 10 ng/ml (89.3%) compared to the control (82.1%; p < 0.05, p < 0.05). The percentages of implanted blastocyst in vitro were significantly higher following incubation with EGF at concentrations of O.lng/ml (38.1%; p < 0.05), 1.0ng/ml (33.3%; p < 0.05), 10ng/ml (22.2%; p < 0.05) compared to the control (10.7%). Embryo development and implantation in vitro were not significantly inhibited or enhanced in cultures supplemented with 100ng/ml EGF compared to the control. The mRNA concentration of EGFR in embryos treated with 0.1ng/ml of EGF were significantly higher than those of the control and other EGF treatment groups. The implantation rate and mRNA concentration of EGFR in embryos treated with 0.1ng/ml of EGF group were significantly higher than those of other treatd groups. In conclusion, EGF may have a stimulatory role in embryonic development, implantation and expression of EGFR in embryo itself with concentration-specific manner. These results suggest that EGF may act directly on the mouse embryo and favor its implantaion, irtespective of the presence ar absence of the endometrium.