effect of ovarian stimulation hormones, transfer media and side of transfer on implantation rate of hamster embryo: Model for human embryo transfer

ABSTRACT

Adult hamsters were superovulated with pregnant mare serum gonadotrophin on day one of the cycle followed by an injection of human chorionic gonadotrophin 76 hours later. Embryos were flushed from oviducts and uterine horns and examined for normality morphologically and biochemically [Trypan blue viability test 0.2% in Dulbeccos'phosphate buffer saline] prior to embryo transfer. They were washed twice with fresh medium and transplanted Micro-surgically under high power dissecting microscope. The effects of ovarian stimulation hormones [PMSG, HCG], transfer media and side of transfer [In a fixed design experiments] on embryo implantation rates were studied. The survival rates of hamster embryos were examined after embryo transfer, Superovulation results in significant decrease [P <.05] in implantation rate and a nine hours delay in ovulation of super ovulated ovaries compared to control group. The implantation rates of 8-cell embryos were higher in Modified Tissue Culture- 199 Medium as compared to Dulbeccos' phosphate buffer saline. Similar implantation rates were observed following surgical unilateral and bilateral transfers. Relatively higher implantations were found in mature [26 weeks] than young [14 weeks] hamsters. The implantation potentials of naturally ovulated 1-cell, 2-cell, 4-cell and 8-cell embryo following embryo transfer were similar [68%]. The results of this study revealed that hamster uterus supports the implantation of early embryos [1-cell and 2-cell embryos]. These results could be utilized as a model for the benefit of human in vitro fertilization and embryo transfer program [Test Tube Babies]