한우 미성숙 난자의 vitrification 동결시 발생단계별 생존성과 체외발생율을 알아보고자 난자를 0, 10, 14 및 20시간 성숙배양시킨 후 vitrification 동결 융해 후의 체외발생율을 조사하였다 본 연구에서 나타난 결과를 요약하면 다음과 같다. 1. 0, 10, 14 및 20시간 성숙배양시킨 난자를 vitrification 동결보존 후 MR 단계로의 발생율은 각각 33.3%, 55.0%, 68.3% 73.3%였으며, diploid로의 발생율은 26.7%, 21.7%, 6.7%, 1.7%로서 대조군의 M II 단계의 78.2%에 비해 낮게 나타났으나 diploid단계의 3.6%에 비해서는 높게 나타났다. 2. 미성숙 난자를 0, 10, 14 및 20시간 성숙배양 시킨 후 vitrification 동결 응해 후의 생존율은 각각 38.0%, 30.0%, 20.0% 및 12.0%로서 비동결 대조군의 48.0%에 비해 낮은 생존율을 나타냈다. 3. 미성숙 난자를 0, 10, 14 및 20시간 성숙배양 시킨 다음 vitrification동결 응해 후 수정하였 때 체외수정율은 64.6%, 61.6%, 54.8%, 32.3% 였으며, 배 반포로의 체 외 발생 율은 각각 32.3%, 21.7%, 14.5%, 4.6%로서 대조춘의 80.0%와 55.0%에 비해 낮은 체외수정율과 체외발생율을 나타냈다.
This study was carried out to study the viability of oocytes when vitrified at various maturation stages. Bovine cumulus-oocyte complexes were recovered from ovaries at a slaughter and then divided into five groups: control group(unvitrified oocytes), 0 hr. group(composed of oocytes vitrified before the onset of maturation) and 10, 14, and 20 hrs groups(vitrified at 10, 14 and 20 hrs after the onset of maturation, respectively). The oocytes remained vitrified for 24 hrs, and then were thawed in 3$0^{circ}C$. Survival and cleavage rates were investigated by results of in vitro culture and aceto-orcein staining or FDA test. No difference in the incidence of diploid oocytes was observed among the control, non-vitrified group(3.6%) and oocytes vitrified at 14 hrs(6.7%) or 20 hrs(1.7%). However, more diploid oocytes were detected after vitrification at 0 hr.(26.7%) and 10 hrs(21.7%) post maturation. The survival rate of all vitrified immature oocytes(12.0~38.0%) was low, 48.0% of unvitrified oocytes and oocytes vitrified before maturation or 0~ 10 hrs after the onset of maturation were higher than that of other groups. The overall fertilization and cleavage rates of vitrified immature oocytes (32.3 ~ 64.6% and 4.6 ~ 32.3%) were low, and 55.0% of unvitrified oocytes and the rate of immature oocytes were very higher than that of mature oocytes.
