In vitro culture retards spontaneous activation of cell cycle progression and cortical granule exocytosis that normally occur in in vivo unfertilized mouse eggs
In vitro culture retards spontaneous activation of cell cycle progression and cortical granule exocytosis that normally occur in in vivo unfertilized mouse eggs
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DOI：
10.1095/biolreprod59.6.1515
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发表时间：
1998-12-01
影响因子：
3.6
通讯作者：
Schultz, RM
中科院分区：
文献类型：
--
作者：
Abbott, AL;Xu, Z;Schultz, RM
我们以前已经证明，在hCG给药后，在增加的时间内从输卵管中回收的中期II停滞的卵子显示出时间依赖性的自发进入后期，以及皮质颗粒（CG）的释放和透明质膜（ZP）的相关修饰，组蛋白H1和促分裂原活化蛋白激酶活性的降低，以及母体mRNA的募集[Xu et al.，Biol Reprod 1997; 57：743-750）。这些变化与这些卵进行孤雌激活的敏感性随时间的增加有关。我们在这里报告的排卵卵，检索13或16小时后，hCG给药和体外培养不同的时间段，对上述参数的卵激活和细胞周期恢复的影响。与卵在输卵管中的长期居留相反，体外培养延缓了与完成第二次减数分裂减少相关的细胞周期事件，抑制了CG释放和相关的ZP修饰，以及母体mRNA的募集。在体外培养过程中，这些变化的延迟或抑制导致卵子对孤雌激活的敏感性低于在输卵管中停留相当时间的卵子。这些实验的结果表明，与卵在输卵管中停留时间增加的情况相比，体外卵培养（可能发生在次优条件下）抑制而不是加速进入间期样状态。这些结果还表明，对于专注于体外受精或卵子激活的研究，应尽快将排卵的卵子置于适当的体外条件下。
We have previously demonstrated that metaphase II-arrested eggs recovered from oviducts at increasing times after hCG administration display a time-dependent spontaneous entry into anaphase, as well as release of cortical granules (CGs) and the associated modifications of the zona pellucida (ZP), a decrease in histone H1 and mitogen-activated protein kinase activities, and the recruitment of maternal mRNAs [Xu et al., Biol Reprod 1997; 57:743-750). These changes are correlated with the time-dependent increase in susceptibility of these eggs to undergo parthenogenetic activation. We report here the effect of culture of ovulated eggs, retrieved 13 or 16 h post-hCG administration and cultured in vitro for various periods of time, on the aforementioned parameters of egg activation and cell cycle resumption. In contrast to extended residence of the eggs in the oviduct, culture in vitro retarded cell cycle events associated with completion of the second meiotic reduction and inhibited CG release and the associated modifications of the ZP, as well as the recruitment of maternal mRNAs. The retardation or inhibition of these changes during in vitro culture resulted in eggs that were less susceptible to parthenogenetic activation than eggs that resided in the oviduct for comparable time periods. Results of these experiments indicate that egg culture in vitro (which likely occurs under suboptimal conditions) inhibits, rather than accelerates, the progression into the interphase-like state as compared to that seen in eggs residing in the oviduct for increasing periods of time. These results also suggest that, for studies focused on in vitro fertilization or egg activation, the ovulated eggs should be placed under appropriate in vitro conditions as soon as possible.