Effects of Freezing and Thawing on the Development of Enucleated Bovine Oocytes Following Nuclear Transfer

除核後凍結保存したウシ未受精卵が核移植のためのレシピエント卵子として使用可能か否かを検討した.体外受精由来8～20細胞期胚の単一割球を除核未受精卵細胞質に電気的に融合し,体外での発生能を調べた.実験1では,活性化刺激前あるいは活性化刺激後のどちらかの時期に凍結するのが良いかを検討した.活性化刺激前に凍結した卵子をレシピエント卵子とした場合の2および8細胞期への発生率(60および24%)は,活性化刺激後に凍結した卵子を使用した場合(50および13%)よりも高い傾向にあった.実験2では,核移植卵の発生能に及ぼすレシピエント卵子の卵齢の影響を検討した.若齢凍結卵子をレシピエント卵子とした場合の8細胞期への発生率(15%)は,過齢卵子を使用した場合(26%)よりも低い傾向にあった.しかしながら,若齢卵子を用いた場合にのみ,低率(2%)ではあるが胚盤胞への発生が観察された.以上の結果から,あらかじめ染色体を除去した未受精卵を凍結保存後,レシピエント卵細胞質としてウシ胚の核移植に使用すると,核移植卵はきわめて低率ではあるが胚盤胞へ発生することが明らかとなった.

[1]  N. Songsasen,et al.  Development into blastocysts of bovine oocytes cryopreserved by ultra-rapid cooling. , 1996, Biology of reproduction.

[2]  B. Downey,et al.  Ultrastructural changes in bovine oocytes cryopreserved by vitrification. , 1995, Cryobiology.

[3]  G. Brem,et al.  Effects of different cryoprotectants and carbohydrates on freezing of matured and unmatured bovine oocytes. , 1994, Theriogenology.

[4]  S. Stice,et al.  Bovine nuclear transfer embryos: Oocyte activation prior to blastomere fusion , 1994, Molecular reproduction and development.

[5]  R. Foote,et al.  Synergistic effect of ethanol and cycloheximide on activation of freshly matured bovine oocytes. , 1994, Theriogenology.

[6]  K. Koyama,et al.  Production of Offspring by Nuclear Transferred Bovine Embryos Produced In Vitro. , 1994 .

[7]  J. Parks,et al.  Effects of cooling and rewarming on the meiotic spindle and chromosomes of in vitro-matured bovine oocytes. , 1994, Biology of reproduction.

[8]  Y. Sotomaru,et al.  Effect of ooplast activation on the development of oocytes following nucleus transfer in cattle. , 1994, Theriogenology.

[9]  T. Otoi,et al.  Developmental capacity of bovine oocytes frozen in different cryoprotectants. , 1993, Theriogenology.

[10]  K. Koyama,et al.  Effect of aging of recipient oocytes on the development of bovine nuclear transfer embryos in vitro. , 1993, Theriogenology.

[11]  M. Westhusin,et al.  Embryo cloning in cattle: the use of in vitro matured oocytes. , 1993, Journal of reproduction and fertility.

[12]  P. Collas,et al.  Electrically induced calcium elevation, activation, and parthenogenetic development of bovine oocytes , 1993, Molecular reproduction and development.

[13]  S. Hamano,et al.  Full-term development of in vitro-matured, vitrified and fertilized bovine oocytes. , 1992, Theriogenology.

[14]  T. Otoi,et al.  Developmental capacity of bovine oocytes cryopreserved after maturation in vitro and of frozen-thawed bovine embryos derived from frozen mature oocytes. , 1992, Theriogenology.

[15]  G. J. Marcus,et al.  In vitro fertilization and development of frozen-thawed bovine oocytes. , 1992, Cryobiology.

[16]  H. Ono,et al.  Developmental competence of bovine oocytes frozen at various maturation stages followed by in vitro maturation and fertilization , 1992 .

[17]  B. A. Wolfe,et al.  Methods in bovine nuclear transfer , 1992 .

[18]  H. Ono,et al.  The post-thaw developmental capacity of frozen bovine oocytes following in vitro maturation and fertilization , 1991 .

[19]  C. Matthews,et al.  Freeze-thaw-induced changes of the zona pellucida explains decreased rates of fertilization in frozen-thawed mouse oocytes. , 1990, Journal of reproduction and fertility.

[20]  T. Tokunaga,et al.  Beneficial effect of agar for the frozen storage of bisected embryos. , 1987, Theriogenology.

[21]  P. Glenister,et al.  Incidence of chromosome anomalies in first-cleavage mouse embryos obtained from frozen-thawed oocytes fertilized in vitro. , 1987, Gamete research.

[22]  D. Whittingham.  Fertilization in vitro and development to term of unfertilized mouse oocytes previously stored at --196 degrees C. , 1977, Journal of reproduction and fertility.

[23]  D. Whittingham,et al.  Survival of Mouse Embryos after Freezing and Thawing , 1971, Nature.

[24]  R. Dulbecco,et al.  PLAQUE FORMATION AND ISOLATION OF PURE LINES WITH POLIOMYELITIS VIRUSES , 1954, The Journal of experimental medicine.