Ochota Małgorzata, Niżański Wojciech
Department of Reproduction and Clinic of Farm Animals, Wroclaw University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Wrocław, Poland.
Department of Reproduction and Clinic of Farm Animals, Wroclaw University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Wrocław, Poland.
Theriogenology. 2017 Feb;89:26-31. doi: 10.1016/j.theriogenology.2016.10.002. Epub 2016 Oct 11.
The study compared developmental competence of embryos, based on the timing of the first cleavage and morula formation, with their subsequent ability to reach the blastocyst stage and the resulting blastocyst morphology and quality. Cleaved embryos were separated at 18 hours post insemination (hpi), 24 hpi, and 30 hpi and then cultured in droplets to follow the individual embryo development. The significantly higher percentage of the blastocyst formation was noted in the group I of embryos cleaving within less than 18 hpi (12.7%) compared with the group II cleaving within 18 to 24 hpi (10.7%), None of the late-cleaving embryos (group III >24-30 hpi) reached blastocyst stage in our experiment. Interestingly, the hatching ability was similar regardless the time of the first cleavage (I: <18 hpi; 6.4% and II: 18-24 hpi; 5.4%). The ability to hatch was correlated with the time of morula formation; only embryos that reached morula on Day 4 or Day 5 were able to develop into hatching blastocyst (8.4% and 3.3%, respectively). The differential cell staining revealed significantly more blastomeres in blastocysts obtained from embryos cleaving within 18 to 24 hpi than the blastocysts obtained from embryos cleaving less than 18 hpi (188.6 ± 21.9 vs. 129.3 ± 16). Embryos cleaving within 18 to 24 hpi also demonstrated the higher number and percentage of embryoblast cells (97.2 ± 12.6, 51.6 ± 2.9 vs. 46.6 ± 9, 36.3 ± 6.6). The presented results confirmed the association among the onset of the first cleavage, time reaching morula, and subsequent blastocyst formation and quality.
该研究根据首次卵裂和桑葚胚形成的时间，将胚胎的发育能力与其随后发育至囊胚阶段的能力以及所形成囊胚的形态和质量进行了比较。在授精后18小时（hpi）、24 hpi和30 hpi分离已卵裂的胚胎，然后在液滴中培养以跟踪单个胚胎的发育。与在18至24 hpi内发生卵裂的II组胚胎（10.7%）相比，在授精后不到18 hpi内发生卵裂的I组胚胎中，囊胚形成的百分比显著更高（12.7%）。在我们的实验中，晚期卵裂胚胎（III组>24 - 30 hpi）均未发育至囊胚阶段。有趣的是，无论首次卵裂时间如何（I组：<18 hpi；6.4%，II组：18 - 24 hpi；5.4%），孵化能力相似。孵化能力与桑葚胚形成时间相关；只有在第4天或第5天达到桑葚胚的胚胎才能发育成孵化囊胚（分别为8.4%和3.3%）。差异细胞染色显示，与授精后不到18 hpi内发生卵裂的胚胎所形成的囊胚相比，在18至24 hpi内发生卵裂的胚胎所形成的囊胚中的卵裂球显著更多（188.6 ± 21.9对129.3 ± 16）。在18至24 hpi内发生卵裂的胚胎中，内细胞团细胞的数量和百分比也更高（97.2 ± 12.6，51.6 ± 2.9对46.6 ± 9，36.3 ± 6.6）。所呈现的结果证实了首次卵裂开始时间、达到桑葚胚的时间以及随后囊胚形成和质量之间的关联。
