MATURATION OF MOUSE OOCYTE IN VITRO .I. SEQUENCE AND TIMING OF NUCLEAR PROGRESSION
MATURATION OF MOUSE OOCYTE IN VITRO .I. SEQUENCE AND TIMING OF NUCLEAR PROGRESSION
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DOI：
10.1002/jez.1401690210
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发表时间：
1968-01-01
影响因子：
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通讯作者：
DONAHUE, RP
中科院分区：
文献类型：
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作者：
DONAHUE, RP
将小鼠卵泡卵母细胞释放到含有丙酮酸的化学定义的克雷布斯-林格盐溶液中，随后恢复减数分裂并完成第一次成熟分裂。通过光镜检查固定的整个载体制剂显示，90-95%的生发囊泡破裂并至少持续到中期I，其中约5%停滞；其余的进入中期II。从胚泡期（生发囊泡）开始可以看到染色质凝聚的三个阶段，首先是丝缩短形成染色质晶格，然后是核和核仁周围的凝聚，最后是离散二价体的出现。在纺锤出现之前，二价体呈圆形排列并达到最大长度。纺锤体形成后依次为前期I、中期I、后期I、末期I（第一个极体形成）、染色质质量阶段（染色质呈半月形）、前期II和最终中期II（卵母细胞在体外和体内停滞的阶段）。每隔1 - 2小时检查一次，发现第一次减数分裂纺锤体形成开始于培养3小时后，中期I首次出现在4 -一个半小时。培养9小时后，大多数卵母细胞处于中期I期，此时首次出现后期I期。在这个分裂过程中似乎有6个小时的不同步，一些生发囊泡需要6个小时才能分解，中期II期在11到17个小时的培养中积累。
Liberation of mouse follicular oocytes into a chemically defined Krebs‐Ringer salt solution with pyruvate is followed by resumption of meiosis and completion of the first maturation division. Examination of fixed whole mount preparations by light microscopy reveals that 90–95% of the germinal vesicles breakdown and proceed at least as far as metaphase I where about 5% arrest; the remainder go on to metaphase II.Three stages of chromatin condensation from the dictyate (germinal vesicle) stage are seen, first with filament shortening forming a chromatin lattice‐work followed by condensation about the nuclear and nucleolar periphery and finally the appearance of discrete bivalents. Just prior to appearance of the spindle, the bivalents are circularly arranged and reach their maximum shortness. Spindle formation is followed by prometaphase I, metaphase I, anaphase I, telophase I with first polar body formation, the chromatin mass stage in which the chromatin assumes a half‐moon shape, prometaphase II and finally metaphase II, the stage at which oocytes arrest bothin vitroandin vivo.Examination at one‐two hour intervals reveals first meiotic spindle formation beginning after three hours of culture and metaphase I first appearing at 4 and one‐half hours. After nine hours of culture the majority of the oocytes are in metaphase I and anaphase I first appears at this time. There appears to be a six hour asynchrony in this division, some germinal vesicles requiring six hours to breakdown and the metaphase II stage accumulating between 11 and 17 hours of culture.