Effects of Recipient Oocytes and Donor Cells Condition on in Vitro Development of Cloned Embryos after Interspecies Nuclear Transfer with Caprine Somatic Cell

This study was conducted to investigate the developmental ability of caprine embryos after somatic cell interspecies nuclear transfer. Donor cells were obtained from an ear-skin biopsy of a caprine, digested with 0.25% trypsin-EDTA in PBS, and primary fibroblast cultures were established in TCM-199 with 10% FBS. After maturation, expanded cumulus cells were removed by vigorous pipetting in the presence of 0.3% hyaluronidase. The matured oocytes were dipped in D-PBS plus 10% FBS＋7.5 $\mu\textrm{g}$/ml cytochalasin B and 0.05 M sucrose. The reconstructed oocytes were electrically fused with donor cells in 0.3 M mannitol fusion medium. After the electofusion, embryos were activated by electric stimulation. Interspecies nuclear transfer embryos with bovine cytoplasts were cultured in TCM-199 medium supplemented with 10% FBS including bovine oviduct epithelial cells for 7∼9 day. On the other hand, the NT embryos with porcine cytoplasts were cultured in NCSU-23 medium supplemented with 10% FBS for 6∼8 day at $39^{\circ}C, 5% CO_2$ in air. In caprine-bovine NT embryos, the cleavage(2-cell) rate was 36.8% in confluence and 43.8% in serum starvation. The developmental rate of morula- and blastocyst-stage embryos was 0.0% in confluence and 18.8% in serum starvation. In caprine-porcine NT embryos, the cleavage(2-cell) rate was 76.7% in confluence and 66.7% in serum starvation. The developmental rate of morula and blastocyst stage embryos was 3.3% in confluence and 3.0% in serum starvation, and no significant difference was observed in synchronization treatment between donor cells. In caprine-bovine NT embryos, the cleavage(2-cell) rate of cultured donor cells was 30.8% and 17.6% in 5∼9 and 10∼14 passage(P＜0.05). The developmental rate of morula and blastocyst stage embryos were significantly higher(P＜0.05) in 5∼9 passage(23.1%) than in 10∼14 passage(0.0%) of cultured donor cells. In caprine-porcine NT embryos, the cleavage rate was significantly higher(P＜0.05) in 5∼9 passage(86.7%) than in 10∼14 passage(50.0%) of cultured donor cells. The developmental rate of morula and blastocyst stage embryos were 3.3 and 0.0% in 5∼9 and 10∼14와 passage of cultured donor cells. In caprine-bovine NT embryos, the developmental rate of morula and blastocyst stage embryos were 22.6% in interspecies nuclear transfer, 33.9% in in vitro fertilization and 28.1% in parthenotes, which was no significant differed. The developmental rate of morula and blastocyst stage embryos with caprine-porcine NT embryos were lower(P＜0.05) in interspecies nuclear transfer(5.1%) than in vitro fertiltzation(26.9%) and parthenotes(37.4%).

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