탈핵 후 동결한 MII 난자의 활성화 시기가 체세포 핵치환 이후 소 난자의 체외발달에 미치는 영향

In vitro Development of Somatic Cell Nuclear Transferred Bovine Embryos Following Activation Timing in Enucleated and Cryopreserved MII Oocytes

  • 박세필 (마리아 기초의학연구소/마리아 생명공학연구소) ;
  • 김은영 (마리아 기초의학연구소/마리아 생명공학연구소) ;
  • 김선균 (마리아 기초의학연구소/마리아 생명공학연구소) ;
  • 이영재 (마리아 기초의학연구소/마리아 생명공학연구소) ;
  • 길광수 (마리아 기초의학연구소/마리아 생명공학연구소) ;
  • 박세영 (마리아 기초의학연구소/마리아 생명공학연구소) ;
  • 윤지연 (마리아 기초의학연구소/마리아 생명공학연구소) ;
  • 이창현 (마리아 기초의학연구소/마리아 생명공학연구소) ;
  • 정길생 (건국대학교 축산대학)
  • 발행 : 2002.09.01

초록

본 연구는 체세포 핵치환에 탈핵 후 통격한 소미수정란을 사용함에 있어서, MVC 초자화 동결방법과 탈핵난자의 활성화시기가 융해 후 생존율과 핵치환 이후 체외 발달에 미치는 영향을 조사하고자 실시하였다. 체외에서 20시간 동안 체외성숙된 소 미수정란은 수핵란으로 사용하기 위하여 5$\mu\textrm{g}$/$m\ell$ hoechst 처리 후, 형광현미경하에서 핵을 제거하였다. 본 실험은 세 그룹으로 나누어 실행되었다 Group I은 동결하지 않고 핵치환을 한 대조군이며, group III와 group II는 핵이 제거된 난자를 MVC 방법으로 동결하기 전과 후에 활성화 처리 (5$\mu\textrm{m}$의 ionomycin에 의해서 5분간 처리) 한 군이다. 초자화 동결을 위해서는 group II와 group III의 탈핵란은 EG10에서 5~10분간 전처리하고 EG30에서 30초간 노출하여 액체 질소에 침지하였다. 융해는 37$^{\circ}C$에서 4단계로 이루어졌다. 실험군은 모두 소 귀세포를 이용하여 핵치환을 실시하였으며, 전핵을 유도하기 위한 활성화를 위해서는 10$\mu\textrm{g}$/$m\ell$ cycloheximide와 2.5$\mu\textrm{g}$/$m\ell$ cytochalasin D)가 첨가된 CRlaa 배양액에서 1시간, 이후 10 $\mu\textrm{g}$/$m\ell$ cycloheximide가 들어있는 CRlaa 배양액에서 4시간동안 배양하였다. 활성화 처리가 끝난 난자들은 CRlaa 배양액에서 2일간 배양하여 난할이 유도된 난자만을 선별하여 난구세포와 7일 동안 공배양하였다. 동결 융해 이후 group II와 group III의 탈핵된 소 미수정란의 체외 생존율은 81.0%와 84.9%로 유의적인 차이가 없었다. 체세포와 수핵란과의 융합율도 각각 69.0%와 70.0%로 대조군 (75.2%) 과도 유의적인 차이를 나타내지 않았다. 난할율은 53.4%와 58.4%로 group II와 group III간에 유의적인 차이를 나타내지 않았지만 group II의 분할된 세포질을 가진 이상난자의 비율이 group III보다 유의하게 높게 나타났다 (P<0.05). 또한, morula 이상으로 발달율도 group II (8.6%) 에서 group III (15.6%)보다 낮은 결과를 얻었다 하지 만 group III (15.6%)의 체외 발달율은 대조군 (24.8%)과 유의한 차이를 없었다. 따라서, MVC 동결 방법은 탈핵된 소 미수정란을 동결하기에 적합한 방법이며, 탈핵 후 activation을 유도하고 초자화 동결한 난자는 동결하지 않은 신선란과 동일하게 체세포 핵치환에 유용하게 이용될 수 있으리라 사료된다.

This study was to evaluate the in vitro survival of bovine enucleated MII (eMII) oocytes according to minimum volume cooling (MVC) freezing method and activation timing, and their in vitro development after somatic cell nuclear transfer (SONT). in vitro matured bovine oocytes for 20 h were stained with 5 $\mu\textrm{g}$/$m\ell$ Hoechst, and their 1st polar body and MII plate were removed by enucleation micropipette under UV filter. Also, eMII oocytes were subjected to activation after (group II) and before (group III) vitrification in 5 ${\mu}{\textrm}{m}$ ionomycin added CRlaa medium for 5 min. For vitrification, eMll oocytes were pretreated with EG10 for 5 min, exposed to EG30 for 30 sec and then directly plunged into L$N_2$. Thawing was taken by 4-step procedures at 37$^{\circ}C$. Survived eMII oocytes were subjected to SONT with cultured adult bovine ear cells. Reconstructed oocytes were cultured in 10 $\mu\textrm{g}$/$m\ell$ of cycloheximide and 2.5 $\mu\textrm{g}$/$m\ell$ of cytochalasin D added CRlaa medium for 1 h, and then in 10 $\mu\textrm{g}$/$m\ell$ of cycloheximide added CRlaa medium for 4 h. Subsequently, the reconstructed oocytes were incubated for 2 days and cleaved embryos were further cultured on cumulus-cell monolayer drop in CRlaa medium for 6 days. Survival rates of bovine vitrified-thawed eMII oocytes in group II (activation after vitrification and thawing) and III (activation before vitrification) were 81.0% and 84.9%, respectively. Fusion rates of cytoplasts and oocytes in group II and III were 69.0% and 70.0%, respectively, and their results were not different with non-frozen NT group (control, 75.2%). Although their cleaved rates (53.4% and 58.4%) were not different, cytoplasmic fragment rate in group II (32.8%) was significantly higher than that in group III (15.6%)(P<0.05). Also, subsequent development rate into >morula in group II (8.6%) was low than that in group III(15.6%). However, in vitro development rate in group III was not different with that in control (24.8%). This result suggested that MVC method was appropriate freezing method for the bovine eMII oocytes and vitrified eMII oocytes after pre-activation could support in vitro embryonic development after SONT as equally well as fresh oocytes.

키워드

참고문헌

  1. Aman, R. R. and Parks, J. E. 1994. Effects of cooling and rewarming on the meiotic spindle and chromosomes of in vitro matured bovine oocytes. Biol. Reprod., 50:103-110 https://doi.org/10.1095/biolreprod50.1.103
  2. Baguisi, A., Behboodi, E., Melican, D. T., Pollock, J. S., Destrempes, M. M., Cammuso, C., Williams, J. L., Nims, S. D., Porter, C. A., Midura, P., Palacios, M. L., Ayres, S. L., Denniston, R. S., Hayes, M. L., Ziomek, C. A., Meade, H. M., Godke, R. A., Gavin, W. G., Overstrom, E. W. and Echelard Y. 1999. Production of goats by somatic cell nuclear transfer. Nat. Biotechnol., 17:456-461 https://doi.org/10.1038/8632
  3. Colman, A. 2000. Somatic cell nuclear transfer in mammals: Progress and applications. Cloning, 1:185-2002
  4. Dinnyes, A., Dai, Y., Jiang, S. and Yang, X. 2000. High development rates of vitrified bovine oocytes following parthenogenetic acti-vation, in vitro fertilization, and somatic cell nuclear transfer. Biol. Reprod., 63:513-518 https://doi.org/10.1095/biolreprod63.2.513
  5. Dorbrinsky, J. R., Long, C. R. and Johnson, L. A. 1997. Stability of microfilaments during swine embryos cryopreservation. Theriogenology, 47:343
  6. Dorbrinsky, J. R., Pursel, V. G., Long, C. R. and Johnson, L. A. 1998. Birth of normal piglets after cytoskeletal stabilization of embryos and cryopreservation by vitrification. Theriogenology, 49:166
  7. Ito, K., Hirabayashi, M., Ueda, M., Nagao, Y., Kimura, K., Hanada, A. and Hochi, S. 1999. Effects of timing of oocyte cryopreservation on in vitro development of nuclear-transferred bovine zygotes. Mol. Reprod. Dev., 54:81-85
  8. Kato, Y., Tani, T., Sotomaru, Y., Kurokawa, K., Kato, J., Doguchi, H., Yasue, H. and Tsunoda, Y. 1998. Eight calves cloned from somatic cells of a single adult. Science, 282: 2095-2098
  9. Kim, E. Y., Kim, D. I., Rhee, M. G., Weon, Y. S., Nam, H. K., Lee, K. S., Park, S. Y., Park, E. M., Yoon, J. Y., Heo, Y. T., Cho, H. J., Park, S. P., Chung, K. S. and Lim, J. H. 2001. Establishment of bovine ovum bank : I. Full term development of vitrified in vitro matured Hanwoo (Korean cattle) oocytes by minimum volume cooling (MVC) method. Korean J. Animal. Reprod., 25(1):1-7
  10. Kubota, C., Yang, X., Dinnyes, A, Todoroka, J., Yamakuchi, H., Mizoshita, K., Inohae, S. and Tabara, N. 1998. In vitro and in vivo survival of frozen thawed bovine oocytes after IVF, nuclear transfer, and parthenogenic activation. Mol. Reprod. Dev., 51:281-286 https://doi.org/10.1002/(SICI)1098-2795(199811)51:3<281::AID-MRD7>3.0.CO;2-L
  11. Lim, J. M., Fukui, Y. and Ono, H. 1991. The post-thaw developmental capacity of frozen bovine oocytes following in vitro maturation and fertilization. Theriogenology, 35:1225-1235
  12. Liu, L., Ju, J. C. and Yang X. 1998. Parthenogenetic development and protein patterns of newly matured bovine oocytes after chemical activation. Mol. Reprod. Dev., 49:298-307 https://doi.org/10.1002/(SICI)1098-2795(199803)49:3<298::AID-MRD10>3.0.CO;2-T
  13. Martino, A., Songsasen, N. and Leibo, S. P. 1996. Development into blastocysts of bovine oocytes cryopreserved by ultra-rapid cooling. Biol. Reprod., 54:1059-1069 https://doi.org/10.1095/biolreprod54.5.1059
  14. Onishi, A., Iwamoto, M., Akita, T., Mikawa, S, Takeda, K., Awata, T., Hanada, H. and Perry, A. C. 2000. Pig cloning by microinjection of fetal fibroblast nuclei. Science, 289:1188-1190 https://doi.org/10.1126/science.289.5482.1188
  15. Papis, K., Shimizu, M. and Izaike, M. 1999. The effect of gentle pre-equilibration on survival and development rates of bovine in vitro matured oocytes vitrified in droplets. Theriogenology, 51:173 (abstract)
  16. Parrish, J. J., Susko-Parrish, J., Winer, M. A. and First, N. L. 1998. Capacitation of bovine sperm by heparin. Biol. Reprod., 38:1171-1180
  17. Polejaeva, I. A., Chen, S. H., Vaught, T. D. Page, R. L., Mullins, J., Ball, S., Dai, Y., Boone, J., Walker, S., Ayares, D. L., Colman, A. and Campbell, K. H. 2000. Cloned pigs produced by nuclear transfer from adult somatic cells. Nature, 407:505-509
  18. Rosenkrans, C. F. and Zeng, G. Q., McNamara, G. T., Schoff, P. K. and First, N. L. Development of bovine embryos in vitro as affected by energy substrartes. Biol. Reprod., 49:459-462
  19. Vajta, G., Holm, P., Kuwayama, M., Booth, P. J., Jacobsen, H., Greve, T. and Callesen, H. 1998. Open pulled straw (OPS) vitrification: a new way to reduce cryoinjuries of bovine ova and embryos. Mol. Reprod. Dev., 51:53-38
  20. Wakayama, T, Perry, A C. F., Zuccotti, M., Johnson, K. R. and Yanagimachi, R. 1998. Full-term development of mice from enucleated oocytes injected with cumulus cell nuclei. Nature, 394:369-374 https://doi.org/10.1038/28615
  21. Wakayama, T. and Yanagimachi, R. 1999. Cloning of male mice from adult tail-tip cells. Nat. Genet., 22:127-128 https://doi.org/10.1038/9632
  22. Wells, D. N., Misica, P. M. and Tervit, H. R. 1999. Production of cloned calves following nuclear transfer with cultured adult mural granulosa cells. Biol. Reprod., 60:996-1005 https://doi.org/10.1095/biolreprod60.4.996
  23. Wilmut, I., Schnieke, A. E., McWhir, J., Kind, A. J. and Campbell, K. H. S. 1997. Viable offspring derived from fetal and adult mammalian cells. Nature, 385:810-813 https://doi.org/10.1038/385810a0
  24. Yang, B. S. and Leibo, S. P. 1999. Viability of in vitro-derived bovine zygotes cryopreserved in microdrops. Theriogenology, 51:178 (abstract)