Effect of Mechanical Enucleation Methods on Development of Bovine Nuclear Transfer Embryos

The aim of this study was to examine the effect of mechanical enucleation methods, aspiration and squeezing, on the developmental ability of nuclear transfer bovine embryos. Enucleated oocytes made by both enucleation methods were fused to adult ear skin cells. After 7 days of culture, developmental ability up to blastocyst stage was similar in both squeezing($33.6{\pm}15.7%$) and aspiration enucleation methods($31.9{\pm}13.4%$). The proportion of blastocysts at Day 8 of culture was also similar between the aspiration($37.8{\pm}10.4%$) and squeezing enucleatign s($35.3{\pm}15.1%$). The mean cell number in Day 7 blastocysts was also similar between the both groups(aspiration: $110.3{\pm}39.2$ vs. squeezing: $103.7{\pm}42.8$). The ratio of apoptotic cells was also found to be not significant different between the both groups(aspiration: $2.8{\pm}2.6%$ vs. squeezing: $4.3{\pm}4.4%$). These results suggest that aspiration and squeezing methods, as mechanical enucleation technique, are both useful for the production of bovine somatic cell nuclear transfer embryos.

물리적 탈핵 방법이 소 복제수정란의 발달 능력에 미치는 영향

본 연구는 물리적 탈핵 방법인 aspiration 방법과 squeezing 방법을 사용해 핵이식된 소 체세포 복제란의 발달능을 조사하였다. 두 방법에 의해 탈핵된 수핵란에 한우 귀피부 세포를 융합하여 체외에서 $7{\sim}8$일간 배양하여 발육능을 검사하였다. 배양 7일째 배반포 발달율은 aspiration 방법($31.9{\pm}13.4%$)과 squeezing 방법($33.6{\pm}15.7%$) 간에 차이가 없었다. 또한 배양 8일째 배반포 발달율도 squeezing 방법($35.3{\pm}15.1%$)과 aspiration 방법($37.8{\pm}10.4%$) 간에 차이가 없는 것으로 나타났다. 배양 7일째 배반포의 평균 세포수에 있어 각 처리 간에 차이가 없는 것으로 조사되었으며(aspiration: $110.3{\pm}39.2$, squeezing $103.7{\pm}42.8$), 세포자연사의 비율에 있어서도 역시 유의적인 차이가 없는 것으로 조사되었다(aspiration: $2.8{\pm}2.6%$, squeezing: $4.3{\pm}4.4%$). 본 연구의 결과는 물리적 탈핵 방법인 aspiration 방법과 squeezing 방법 모두 소 체세포 복제수정란의 생산을 위한 유용한 방법임을 보여준다.