In Vitro Maturation and Parthenogenetic Activation of Bovine and Porcine Oocytes

卵母细胞的孤雌激活是当前哺乳动物克隆方案的关键组成部分。本研究旨在研究不同激活刺激条件下不同日龄牛、猪卵母细胞的细胞变化。在实验1和实验2中，牛卵母细胞体外成熟后22、30和40h分别用电脉冲(100V mm，50μs)，钙离子载体，并结合放线菌胺或6-二甲氨基嘌呤进行激活。这表明，年龄较大的牛卵母细胞更容易被激活，而且与年龄相关的表面超微结构变化与卵母细胞的年龄相关。牛卵母细胞的表面特性在孤雌激活的联合作用下发生了更为深刻的变化，其超微结构效应是可逆的。在实验3和实验4中，猪卵母细胞在体外成熟，以检查卵母细胞…过程中卵丘-卵母细胞联合的形态动力学更加成熟。结果表明，在MI期和MII期之间，由于卵丘的扩张，卵丘-卵母细胞的跨带投射发生了脱节。然而，在这些阶段，积云-积云的通信仍然完好无损。在实验5和实验6中，对电激活和化学激活的猪卵母细胞的激活率、发育方式、微管和微丝组装的变化与卵母细胞老化的关系进行了评价。结果表明，两次电脉冲处理后猪卵母细胞的激活率高于钙离子载体和乙醇处理后的激活率，老年卵母细胞中微管的解体和微丝分布的改变可能分别导致二倍体孤雌体率和碎裂率的增加。研究还表明，电脉冲和Cd联合处理后，胚泡发育加快可能是由于Cd处理产生了更高的二倍体单倍体。较少

Parthenogenetic activation of oocytes is a key component of the current mammalian cloning regimen. This study was designed to examine the cellular alterations of the bovine and porcine oocytes at different ages following different activation stimulations. In Experiments 1 and 2, bovine oocytes of 22,30 and 40 h after in vitro maturation was activated by an electrical pulse (100Vmm, 50μsec), Ca ionophore, and combined with cycloheximide or 6-dimethylaminopurine. It is suggested that older bovine oocytes are more readily activated and that the age-dependent surface ultrastructural alterations correlate very well with the age dependent activation of oocytes. It was also shown that surface characteristics of the bovine oocyte were more profoundly changed by a combination of parthenogenetic stimulation, and that the ultrastructural effects were reversible. In Experiments 3 and 4, porcine oocytes were matured in vitro to examine morphodynamics of the cumulus-oocyte association during oocyte … More maturation. It was concluded that the cumulus-oocyte transzonal projections became disconnected between MI and MII stage as a result of cumulus expansion. However, the cumulus-cumulus communications remained intact at these stages. In Experiments 5 and 6, the activation rate, developmental pattern and changes in microtubule and microfilament assembly of the porcine oocytes activated electrically or chemically were evaluated in relation to the oocyte aging. The present results suggest that a higher activation rate was obtained in the porcine oocytes after two electrical pulses that in those after Ca ionophore or ethanol treatments and that the disorganization of microtubule and the alteration of microfilament distribution observed in the aged oocyte may result in higher incidences of diploid parthenotes and fragmentation, respectively. It is also suggested that increased development to blastocysts after the combined treatment of electrical pulses and CD may due to higher incidence of diploid parthenotes derived from CD treatment. Less