Department of Statistics and Medical InformaticsMedical University of Bialystok, Bialystok, Poland.
Department of EmbryologyFaculty of Biology, University of Warsaw, Warsaw, Poland.
Reproduction. 2018 Jan;155(1):1-14. doi: 10.1530/REP-17-0230. Epub 2017 Oct 9.
fertilization has become increasingly popular as an infertility treatment. In order to improve efficiency of this procedure, there is a strong need for a refinement of existing embryo assessment methods and development of novel, robust and non-invasive selection protocols. Studies conducted on animal models can be extremely helpful here, as they allow for more extensive research on the potential biomarkers of embryo quality. In the present paper, we subjected mouse embryos to non-invasive time-lapse imaging and combined the Particle Image Velocimetry analysis of cytoplasmic dynamics in freshly fertilized oocytes with the morphokinetic analysis of recordings covering 5 days of preimplantation development. Our results indicate that parameters describing cytoplasmic dynamics and cleavage divisions independently correspond to mouse embryo's capacity to form a high-quality blastocyst. We also showed for the first time that these parameters are associated with the percentage of abnormal embryonic cells with fragmented nuclei and with embryo's ability to form primitive endoderm, one of the cell lineages differentiated during preimplantation development. Finally, we present a model that links selected cytoplasmic and morphokinetic parameters reflecting frequency of fertilization-induced Ca-oscillations and timing of 4-cell stage and compaction with viability of the embryo assessed as the total number of cells at the end of its preimplantation development. Our results indicate that a combined analysis of cytoplasmic dynamics and morphokinetics may facilitate the assessment of embryo's ability to form high-quality blastocysts.
受精已成为一种越来越受欢迎的不孕治疗方法。为了提高这一程序的效率，强烈需要改进现有的胚胎评估方法，并开发新的、稳健的和非侵入性的选择方案。在动物模型上进行的研究在这里可以非常有帮助，因为它们可以更广泛地研究胚胎质量的潜在生物标志物。在本文中，我们对小鼠胚胎进行了非侵入性的延时成像，并将细胞质动力学的粒子图像测速分析与覆盖着床前发育 5 天的记录的形态动力学分析相结合。我们的结果表明，描述细胞质动力学和卵裂分裂的参数独立于胚胎形成高质量囊胚的能力。我们还首次表明，这些参数与具有核碎片的异常胚胎细胞的百分比以及胚胎形成原始内胚层（着床前发育过程中分化的细胞谱系之一）的能力相关。最后，我们提出了一个模型，该模型将反映受精诱导 Ca 震荡的频率和 4 细胞阶段及致密化时间的选定细胞质和形态动力学参数与胚胎的活力联系起来，活力评估为其着床前发育结束时的细胞总数。我们的结果表明，细胞质动力学和形态动力学的综合分析可能有助于评估胚胎形成高质量囊胚的能力。
