Teerawongsuwan Sasipat, Wiangwised Kodchakorn, Ngampiyakul Nattapavee, Wanikorn Nitid, Boonnithipaisit Panida, Khiuhok Panyada, Aekudompong Phanthitra, Narkwichean Amarin, Pongmayteegul Sirinun, Rungsiwiwut Ruttachuk
Reprod Fertil. 2025 Apr 29;6(2). doi: 10.1530/RAF-25-0001. Print 2025 Apr 1.
Mitochondrial DNA (mtDNA) from embryonic cells is released into the spent culture medium (SCM) during cellular processes, providing a potential biomarker of embryo health. Analysing mtDNA levels in SCM enables a non-invasive evaluation of embryo quality and potential developmental abnormalities. In this retrospective study, we aimed to investigate the relationship between relative mtDNA copy number in embryo SCM and key factors, including embryo fragmentation, morphological quality and chromosomal abnormalities. Fertilised embryos produced through intracytoplasmic sperm injection were cultured to the blastocyst stage in an incubator. Embryo fragmentation was assessed on day 3 using the Istanbul criteria, while morphological grading was evaluated on day 5 using the Gardner criteria. On day 5, trophectoderm (TE) biopsies were performed for preimplantation genetic testing for aneuploidy, followed by embryo cryopreservation and collection of embryo SCM. The mtDNA was quantified using quantitative PCR. Statistical analyses using the Mann-Whitney U and Kruskal-Wallis tests (significance at P < 0.05) showed that relative mtDNA copy number did not significantly differ among embryos with fragmentation levels <10%, 10-25% and >25% (P > 0.05). For blastocyst grading, which evaluates the inner cell mass (ICM) and TE, no significant difference was observed in relative mtDNA copy number between grades B and C for ICM (P = 0.190) and TE (P = 0.289). Furthermore, a trend towards higher relative mtDNA levels was observed in aneuploid than in euploid embryos, although the difference was not statistically significant. Thus, relative mtDNA copy number in SCM may not accurately reflect embryo characteristics, such as fragmentation, morphological grading or chromosomal abnormalities.
This study examined whether the amount of mitochondrial DNA (mtDNA) in the fluid used to culture embryos in the laboratory could indicate embryo quality. We assessed various factors, including the appearance of the embryos, the presence of fragmented cells and the occurrence of chromosomal abnormalities. Fertilized eggs were cultured until they developed into blastocysts, and the amount of mtDNA in the culture fluid was measured using a machine that detects genetic material. The results revealed no clear association between mtDNA levels and embryo appearance or fragmentation. Although embryos with chromosomal abnormalities had slightly more mtDNA, the difference was not statistically significant. These findings suggest that mtDNA in the culture fluid may not be a reliable marker for assessing embryo quality or chromosomal status.
胚胎细胞中的线粒体DNA（mtDNA）在细胞过程中会释放到用过的培养基（SCM）中，这为胚胎健康提供了一个潜在的生物标志物。分析SCM中的mtDNA水平能够对胚胎质量和潜在的发育异常进行非侵入性评估。在这项回顾性研究中，我们旨在探究胚胎SCM中相对mtDNA拷贝数与关键因素之间的关系，这些关键因素包括胚胎碎片化、形态质量和染色体异常。通过胞浆内单精子注射产生的受精卵在培养箱中培养至囊胚阶段。在第3天使用伊斯坦布尔标准评估胚胎碎片化情况，而在第5天使用加德纳标准评估形态分级。在第5天，对滋养外胚层（TE）进行活检以进行非整倍体的植入前基因检测，随后进行胚胎冷冻保存并收集胚胎SCM。使用定量PCR对mtDNA进行定量。使用曼-惠特尼U检验和克鲁斯卡尔-沃利斯检验进行统计分析（P < 0.05时有统计学意义），结果显示，碎片化水平<10%、10 - 25%和>25%的胚胎之间，相对mtDNA拷贝数没有显著差异（P > 0.05）。对于评估内细胞团（ICM）和TE的囊胚分级，ICM的B级和C级之间（P = 0.190）以及TE的B级和C级之间（P = 0.289），相对mtDNA拷贝数没有观察到显著差异。此外，虽然非整倍体胚胎中的相对mtDNA水平有高于整倍体胚胎的趋势，但差异没有统计学意义。因此，SCM中的相对mtDNA拷贝数可能无法准确反映胚胎特征，如碎片化、形态分级或染色体异常。
本研究考察了实验室用于培养胚胎的液体中线粒体DNA（mtDNA）的量是否能够表明胚胎质量。我们评估了各种因素，包括胚胎的外观、破碎细胞的存在以及染色体异常的发生情况。受精卵被培养至发育成囊胚，使用检测遗传物质的仪器测量培养液中的mtDNA量。结果显示，mtDNA水平与胚胎外观或碎片化之间没有明显关联。虽然染色体异常的胚胎mtDNA略多，但差异没有统计学意义。这些发现表明，培养液中的mtDNA可能不是评估胚胎质量或染色体状态的可靠标志物。
