Maintenance of the inner cell mass in human blastocysts from fragmented embryos
Maintenance of the inner cell mass in human blastocysts from fragmented embryos
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DOI：
10.1095/biolreprod.102.010090
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发表时间：
2003-04-01
影响因子：
3.6
通讯作者：
Winston, RML
中科院分区：
文献类型：
--
作者：
Hardy, K;Stark, J;Winston, RML
在人类体外受精治疗中，卵裂早期的碎裂程度被普遍用作衡量胚胎质量的指标。广泛的碎裂与胚泡形成和着床的减少有关。我们研究了人类胚泡早期分裂和随后将细胞分配到滋养外胚层和内细胞团之间的关系。我们回顾分析了363个第2天出现不同程度碎裂的单精子人胚胎的数据。从第2天到第6天，胚胎在含有1 mM葡萄糖和人血清白蛋白的Earle平衡盐液中培养。测定胚胎发育率和囊胚形成率。用多核苷酸特异性荧光染料进行差异标记后，评估滋养外胚层和内细胞团中的细胞数量和细胞凋亡率。随着碎片化程度的增加，囊胚形成减少，囊泡细胞数减少。对于最小和中等程度的碎裂，细胞数量的减少主要限于滋养外胚层，内细胞团细胞的数量保持稳定。然而，随着超过25%的广泛碎裂，在少数形成胚泡的胚胎中，两个谱系中的细胞数量都减少了。凋亡核存在于滋养外胚层和内细胞团中，在由微小碎裂(5-10%)的胚胎发育而来的囊胚中，凋亡核的发生率最低。矛盾的是，在形态良好的胚胎中发现了更高水平的凋亡，这表明可能在细胞数量的调节中发挥了作用。
The degree of fragmentation during early cleavage is universally used as an indicator of embryo quality during human in vitro fertilization treatment. Extensive fragmentation has been associated with reduced blastocyst formation and implantation. We examined the relationship between early fragmentation and subsequent allocation of cells to the trophectoderm and inner cell mass in the human blastocyst. We retrospectively analyzed data from 363 monospermic human embryos that exhibited varying degrees of fragmentation on Day 2. Embryos were cultured from Day 2 to Day 6 in Earle balanced salt solution with 1 mM glucose and human serum albumin. Rates of development and blastocyst formation were measured. The number of cells in the trophectoderm and inner cell mass and the incidence of apoptosis were assessed following differential labeling with polynucleotide-specific fluorochromes. Increasing fragmentation resulted in reduced blastocyst formation and lower blastocyst cell numbers. For minimal and moderate levels of fragmentation, the reduction in cell numbers was confined largely to the trophectoderm and a steady number of inner cell mass cells was maintained. However, with extensive fragmentation of more than 25%, cell numbers in both lineages were reduced in the few embryos that formed blastocysts. Apoptotic nuclei were present in both the trophectoderm and inner cell mass, with the lowest incidence in blastocysts that had developed from embryos with minor (5-10%) fragmentation. Paradoxically, higher levels of apoptosis were seen in embryos of excellent morphology, suggesting a possible role in regulation of cell number.