Objective

To examine the cause of monopronucleated zygote (1PN) formation that includes both maternal and paternal genomes.

Design

Retrospective cohort study.

Setting

Private fertility clinic.

Patient(s)

A total of 44 1PN and 726 2-pronuclear zygotes from 702 patients were observed using 2 different time-lapse observation systems.

Intervention(s)

Previously recorded time lapse data were reviewed to examine the mechanism of 1PN formation.

Main Outcome Measure(s)

The distance between the position of the second polar body extrusion and the fertilization cone or epicenter/starting position of the cytoplasmic wave was measured, and the consequent data were analyzed. Cytoplasmic waves were confirmed using vector analysis software.

Result(s)

The cut-off value for the difference in the distance between the position of the second polar body extrusion and the fertilization cone or the epicenter/starting position of the cytoplasmic wave was 17 μm (AUC: 0.987, 95% CI: 0.976–0.999) for the Embryo Scope and 18 μm (AUC: 0.972, 95% CI: 0.955–0.988) for the iBIS time-lapse observation systems.

Conclusion(s)

In this study, it was found with a high degree of accuracy that a monopronucleus is formed when the fusion of the sperm takes place within 18 μm from the point of the second polar body extrusion. The theoretical chance of 1PN occurrence after in vitro fertilization is 2.7% when the sperm is considered to be fused anywhere in the plasma membrane of an oocyte.

中文翻译：

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当包括男性和女性基因组时，体外受精后单核受精卵的发育轨迹

客观的

检查单核合子 (1PN) 形成的原因，包括母本和父本基因组。

设计

回顾性队列研究。

环境

私人生育诊所。

耐心）

使用 2 个不同的延时观察系统观察了来自 702 名患者的总共 44 个 1PN 和 726 个 2-原核受精卵。

干预措施

审查了以前记录的延时数据以检查 1PN 形成的机制。

主要观察指标）

测量第二极体挤出位置与受精锥或胞质波震中/起始位置之间的距离，并对所得数据进行分析。使用矢量分析软件确认细胞质波。

结果）

第二极体挤出位置与受精锥或细胞质波的中心/起始位置之间的距离差的截止值为17μm（AUC：0.987，95％CI：0.976-0.999）对于胚胎范围和 18 μm (AUC: 0.972, 95% CI: 0.955–0.988) 对于 iBIS 延时观察系统。

结论

在这项研究中，高精度地发现，当精子融合发生在距第二极体挤压点 18 μm 以内时，会形成单原核。当精子被认为在卵母细胞质膜的任何地方融合时，体外受精后发生 1PN 的理论几率为 2.7%。