수핵란의 전활성화가 토끼 핵이식 수정란의 체외발달에 미치는 효과

Effect of Electrical Preactivation of Recipient Cytoplasm on In Vitro Development in Nuclear Transplant Rabbit Embryos

To examine the efficiency of nuclear transplantation the influence of electrical preactivation of recipient cytoplasm on the in vitro developmental potentyl in the nuclear transplant rabbit embryos were evaluated. The embryos of 16-cell stage were collected and synchronized to G1 phase of 32-cell stage. The recipient cytoplasms were obtained by removing the first polar body and chromosome mass by non-disruptive microsurgery procedure. The separated G1 phase blastomeres of 32-cell stage were put into the non-preactivated and/or the preactivated recipient cytoplasm by electrical stimulation. After culture until 20h post-hCG injection, the nuclear transplant oocytes were electrofused. The fused nuclear transplant embryos were co-cultured with rabbit oviduct epithelial cells and monitored every 24h to assess for developmental rate. After in vitro culture for 120h, the nuclear transplant embryos developed to blastocyst stage were stained with Hoechst 33342 and their blastomere were counted. The electrofusion rate was similar to the non-preactivated and preactivated recipient cytoplasm(81.8 and 85.7%, respectively). However, the in vitro developmental rate to blastocyst stage with the non-preactivated recipient cytoplasm (57.1%) was found significantly (P<0.05) higher, compared to the preactivated recipient cytoplasm(20.8%). The cell counts of nuclear transplant embryos developed to blastosyst stage were increased significantly (P<0.05) more in the non-preactivated recipient cytoplasm (163.7 cells), as compared with the preactivated recipient cytoplasm(85.4 cells). These results considered better that non-preactivated oocytes, MII phase oocytes, were used for recipient cytoplasms in the rabbit nuclear transplant procedure.