The Impact Of The GnRH Antagonist For Embryo Implantation Of Sheep

Objective:To study the influence of implantation of GnRH antagonist on sheep embryo. Methods:Fourteen Jinzhong sheep were used for this study, four of them as the donor and ten as the receptor. Embryo implantation model is built by the techniques of estrus synchronization, superovulation, artificial insemination, embryo retrieve and the surgical transplantation. Ewes which were estrus synchronization and embryo transfer were divided into two groups. The fifth day after embryo transfer injected of GnRH antagonist (Cetrorelix)0.25mg/day, continuous infusion for four days. The control group was injected with the same amount of physiological saline. Jugular vein blood collection started at the beginning of the injection day for both the experimental group and the control group and for seven consecutive days. The progesterone and estrogen concentration in blood were measured by radioimmunoassay. At the end of blood collection day, surgery sampled the uterine horn of sheep of both the experimental group and the control group. Then the samples had been protein extraction and embedded in paraffin and sliced. Immunohistochemical was used to locate the LIF factor and expression levels of LIF factor were measured by using western-blot technique.Results:Each donor sheep obtained five available embryos on average.10same breed of sheep were selected as receptor. Embryo transfer had been conducted for the6sheep which were luteal development after estrus synchronization. Blood of embryo transfer sheep had been tested by radioimmunoassay and then found that progesterone and estrogen levels of the experimental group and the control group did not show significant difference (P>0.05). No significant change (P>0.05) was detected by western-blot technique through analyzing the expression of LIF implantation factor.Conclusion:1. Using GnRH antagonist cannot have a significant impact on the secretion of progesterone and estrogen during the embryo implantation period. 2. Using GnRH antagonist cannot have a significant impact on the level of LIF factor expression during the embryo implantation period.3. GnRH antagonist contributes to a limited improvement of improving embryo pregnancy rate.