Assessment of Epidermal Growth Factor (EGF) Effects on Development of Vitrified Mouse Morulae to the Blastocyst Stage

Many investigators are interested in finding the new cultural systems that can support the in vitro development of pre-implantation embryos better. Previous studies suggested that growth factors such as epidermal growth factor (EGF) are important in pre-implantation embryo development and implantation process. On the other hand, it is very important to support post thaw development of frozen embryos. The purpose of this study was to determine if the developmental potential of mouse morulae survived after vitrification could be increased using medium containing EGF. Mouse morulae were divided into vitrified and non-vitrified groups. Vitrification procedure was carried out using a combination of 40% ethylene glycol, 30% ficoll and 0.5 M sucrose (EFS40) as cryoprotectant. The embryos were warmed rapidly using 0.5 M sucrose. The survived embryos were cultured either on T6 or T6+EGF media. Accordingly, the embryos of the non-vitrified group were also cultured. The developmental rates in all groups were daily recorded and compared statistically using Chi-square test. The results showed that after 4 days of culture, the developmental potential of non-vitrified embryos cultured on T6+EGF was significantly increased. There was no significant difference between vitrified embryos cultured on T6 and T6+EGF media. In conclusion, the developmental potential of vitrified-warmed embryos does not increase in the medium containing EGF, even though there was significant increased developmental potential of non-vitrified embryos after culture on medium containing EGF. It is needed to do more study about the changes which will probably happen on the embryo EGF receptors following vitrification