PURPOSE To evaluate whether mtDNA content at the blastocyst stage differs between embryos derived from fresh or vitrified sibling oocytes. MATERIAL AND METHODS A retrospective analysis was performed between March 2017 and September 2018, including 504 blastocysts from 94 couples undergoing preimplantation genetic testing for aneuploidies (PGT-A), using fresh oocytes together with previously vitrified oocytes. Trophectoderm biopsies were performed and subjected to next generation sequencing. RESULTS On average, 1.8 ± 1.0 oocyte vitrification cycles were performed per patient. Between fresh and vitrified cycles, no difference was observed between the number of fertilized oocytes (5.3 ± 4.2 versus 5.5 ± 3.0). Blastulation rate on day 5 per fertilized oocyte was significantly higher in the fresh group (62% ± 29% versus 44% ± 31%; p < 0.001). For the 504 biopsied blastocysts, 294 fresh versus 210 vitrified, no significant differences were found in the euploid rate, 40.5% versus 38.6% (p = 0.667), and mtDNA content, 30.1 (± 10.6) versus 30.0 (± 12.5) (p = 0.871), respectively. Regardless of the origin of the oocytes, aneuploid blastocysts contained significantly higher mtDNA values compared with the euploid ones (31.4 versus 28.0; p = 0.001). Furthermore, top-quality blastocysts had a significantly lower mtDNA content compared with moderate and poor-quality blastocysts (p < 0.001) and blastocysts biopsied on day 5 showed significantly lower mtDNA content compared with day 6 or day 7 blastocysts (p < 0.001). However, when analyzing the blastocyst mtDNA content according to the ploidy state, no differences were found for blastocyst quality or day of biopsy between blastocysts originating from fresh or vitrified oocytes. CONCLUSION Oocyte vitrification does not affect the mtDNA content of trophectoderm biopsies.

中文翻译：

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囊胚线粒体 DNA (mtDNA) 不受卵母细胞玻璃化冷冻的影响：一项兄弟卵母细胞研究。

目的 评估来自新鲜或玻璃化同级卵母细胞的胚胎在囊胚阶段的 mtDNA 含量是否存在差异。材料和方法 在 2017 年 3 月至 2018 年 9 月期间进行了回顾性分析，包括来自 94 对夫妇的 504 个囊胚，使用新鲜卵母细胞和先前玻璃化的卵母细胞进行植入前非整倍体基因检测 (PGT-A)。进行滋养外胚层活检并进行下一代测序。结果 每位患者平均进行 1.8 ± 1.0 次卵母细胞玻璃化冷冻周期。在新鲜周期和玻璃化冷冻周期之间，受精卵母细胞数量没有观察到差异（5.3 ± 4.2 与 5.5 ± 3.0）。新鲜组中第 5 天每个受精卵母细胞的囊胚率显着较高（62% ± 29% 对比 44% ± 31%；p < 0.001）。对于 504 个活检囊胚（294 个新鲜囊胚与 210 个玻璃化囊胚），整倍体率（40.5% 与 38.6%（p = 0.667））和 mtDNA 含量（30.1（± 10.6）与 30.0（± 12.5）（p = 0.871），分别。无论卵母细胞的来源如何，与整倍体囊胚相比，非整倍体囊胚含有明显更高的 mtDNA 值（31.4 与 28.0；p = 0.001）。此外，与中等质量和较差质量的囊胚相比，优质囊胚的 mtDNA 含量显着较低 (p < 0.001)，并且与第 6 天或第 7 天的囊胚相比，第 5 天活检的囊胚显示出显着较低的 mtDNA 含量 (p < 0.001)。然而，当根据倍性状态分析囊胚mtDNA含量时，新鲜或玻璃化卵母细胞来源的囊胚之间的囊胚质量或活检天数没有发现差异。结论 卵母细胞玻璃化冷冻不影响滋养外胚层活检的线粒体 DNA 含量。