Cell cycle duration at the time of maternal zygotic transition for in vitro produced bovine embryos: Effect of oxygen tension and transcription inhibition
Cell cycle duration at the time of maternal zygotic transition for in vitro produced bovine embryos: Effect of oxygen tension and transcription inhibition
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DOI：
10.1095/biolreprod.103.017178
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发表时间：
2003-11-01
影响因子：
3.6
通讯作者：
Donnay, I
中科院分区：
文献类型：
--
作者：
Lequarre, AS;Marchandise, J;Donnay, I
早期胚胎卵裂主要受母体成分的调控，然后发育的控制逐渐依赖于新合成的合子产物。第一次卵裂的时间是评估胚胎质量的一种方法。本研究的目的是通过电影摄影分析评价体外生产的牛胚胎在母体-合子转变（MZT）时第四细胞周期的持续时间。我们发现，75%的胚胎显示出长的第四细胞周期（43.5 +/- 5.4小时），而其余胚胎的第四细胞周期非常短（8.9 +/- 2.9小时）。两组在卵裂节律方面没有差异，直到八细胞阶段，空化和囊胚扩张的时间是相同的。但第四细胞周期短的胚胎囊胚率高于第四细胞周期长的胚胎（59%对38%，P < 0.01）。总细胞数，内细胞质量（ICM）：总细胞的比例，和孵化率是相同的胚胎与长或短的第四细胞周期。在第二个实验中，我们表明，将氧分压从5%增加到20%，使具有短第四细胞周期的胚胎的百分比从25%降低到11%（P < 0.01），表明次优培养条件可以影响该周期的长度。最后，我们研究了转录抑制是否会影响第四细胞周期的持续时间。在授精后18小时（HPI）添加α-鹅膏蕈碱，卵裂减少（66% vs 79%），在70 HPI时，9- 16细胞率增加（50% vs 25%），同时5- 8细胞率降低（16% vs 47%）。当药物在6 HPI或42 HPI加入时观察到类似的模式，但在0 HPI时没有观察到。电影分析显示，α-鹅膏蕈碱增加了第一个细胞周期的持续时间，而第二和第三个细胞周期不受影响。使用这种药物，三分之一的胚胎可以发育到9- 16细胞阶段，它们都有一个短的第四细胞周期（11.2 +/- 3.7小时），卵裂球之间的分裂同步性良好。这些结果表明，牛胚胎的第四个细胞周期的持续时间，在MZT期间，是合子转录控制，可以受到氧化条件的影响。
Early embryonic cleavages are mostly regulated by maternal components then control of development progressively depends on newly synthesized zygotic products. The timing of the first cleavages is a way to assess embryo quality. The goal of this study was to evaluate the duration of the fourth cell cycle, at the time of maternal-to-zygotic transition (MZT) in in vitro-produced bovine embryos by means of cinematographic analysis. We found that 75% of the embryos displayed a long fourth cycle (43.5 +/- 5.4 h) whereas the remaining embryos had a very short fourth cell cycle (8.9 +/- 2.9 h). Both groups did not differ in cleavage rhythm up to the eight-cell stage and timing of cavitation and blastocyst expansion was identical. However, embryos with a short fourth cell cycle had a better blastocyst rate than embryos with a long cycle (59% versus 38%, P < 0.01). Total cell number, inner cell mass (ICM):total cell ratio, and hatching rate were identical for blastocysts produced from embryos with either a long or a short fourth cell cycle. In a second experiment, we showed that increasing the oxygen tension, from 5% to 20%, decreased the percentage of embryos with a short fourth cell cycle, from 25% to 11 % (P < 0.01), indicating that suboptimal culture conditions can influence the length of this cycle. Finally, we investigated whether fourth cell cycle duration could be influenced by transcription inhibition. With alpha-amanitin added at 18 h postinsemination (HPI), cleavage was reduced (66% versus 79%) and, at 70 HPI, the 9- to 16-cell rate increased (50% versus 25%) concomitantly with a 5- to 8-cell rate decrease (16% versus 47%). A similar pattern was observed when the drug was added at 6 HPI or 42 HPI but not at 0 HPI. Cinematographic analysis revealed that alpha-amanitin increased the first cell cycle duration whereas the second and third cell cycles were not affected. With the drug, one third of the embryos could develop up to the 9- to 16-cell stage and they all had a short fourth cell cycle (11.2 +/- 3.7 h) with a good synchrony of cleavage between blastomeres. These results suggest that duration of the fourth cell cycle of bovine embryo, during the MZT, is under a zygotic transcriptional control that can be affected by oxidative conditions.