[目的]为了给牛体细胞克隆和转基因克隆工作提供基础性材料.[方法]在显微镜下,从卵液中捡出卵丘-卵母细胞复合体,置入成熟培养液中进行成熟培养,处理培养不同时期的卵母细胞,所得的去掉卵丘的卵母细胞固定在载玻片上,染色、冲洗、晾干,在显微镜下观察.[结果]表明:成熟培养0 h到4 h大多数卵母细胞处于GV期(97.5%～87.8%),培养6 h以后GVBD发生了卵母细胞数量明显增多(51.6%),成熟培养8 h～12 h处于Pre-MI的卵母细胞逐渐减少(76.7%～43.2%),MI期卵母细胞逐渐增多(13.3%～50.0%).成熟培养16 h有17.8%的卵母细胞处于MII期,大部分细胞仍处于MI期(40.0%)和AI/TI期(42.2%).从16 h～24 h,MII期卵逐渐增多,培养24 h后大多数卵母细胞排出第一极体到达MII期(86.5%).[结论]在减数分裂过程中,染色体也发生了显著的形态变化.第一次减数分裂中期时的染色体清晰可数,进入后期时,分开的两团染色体各自凝集成染色质团,并且一直持续到末期,到达第二次减数分裂中期时又成为清晰可数的染色体状态.%To investigate the meiotic progression and the chromosomal morphological changes of the bovine oocytes matured in vitro, oocytes were collected form from ooctye liquid under microscope. The majority of the oocytes maintained at GV stage (97.5%～87.8%) during the first 4 h after culture. Six hours later, around 51.6% of the oocytes occurred GVBD. When the oocytes were matured for 8h to 12h, the number of the oocytes in pre-metaphase stage gradually decreased (from 76.7% to 43.2%) and the oocytes in metaphase I (MI) rapidly increased (from 13.3% to 50.0%). Approximately 17.8% of the oocytes reached metaphase II (MII) at 16 h, and reached the highest (86.5%) after the oocytes matured for 24 h. Simultaneously, the morphology and configuration of the chromosomes occurred obviously changed during in vitro maturation. The chromosomes were accountable at MI, and gradually became condensed into mass of chromatin when the oocytes developed to anaphase and telophase. The chromosomes then became countable when the oocytes developed to next metaphase stage.
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