SummaryThe aim of this study was to investigate the effect of cyanocobalamin supplementation on in vitro maturation (IVM), in vitro fertilization (IVF), and subsequent embryonic development competence to the blastocyst stage, and in vitro development of mouse 2-cell embryos. Cumulus cells were prepared from mouse cumulus–oocyte complexes (COCs) and incubated for 24 h in an in vitro culture (IVC) medium that contained different concentrations of cyanocobalamin (100, 200, 300 or 500 pM). We collected 2-cell embryos from superovulated NMRI mice and cultured them in the same concentrations of cyanocobalamin (100, 200, 300 or 500 pM). After 42 h of IVM, we observed significantly increased oocyte maturation in the 200 pM cyanocobalamin-treated group compared with the control group (P < 0.0001). Mature oocytes cultured in 200 pM cyanocobalamin were fertilized and cultured in IVC medium with cyanocobalamin (100, 200, 300 or 500 pM) during early embryogenesis. The matured oocytes that were cultured in 200 pM cyanocobalamin had significantly higher 2-cell development rates compared with the control oocytes (P < 0.01). Embryos obtained from in vitro mature oocytes and in vivo fertilized oocytes that were cultured in 200 pM cyanocobalamin had significantly greater frequencies of development to the blastocyst stage and a significant reduction in 2-cell blocked and degenerated embryos compared with the control embryos (P < 0.0001). Embryos derived from oocytes fertilized in vivo with 200 pM cyanocobalamin had a higher percentage of blastocyst embryos compared with those derived from matured oocytes cultured in vitro (P < 0.0001). These finding demonstrated that the effects of cyanocobalamin on oocyte maturation, fertilization, and embryo development in mice depend on the concentration used in IVC medium.

中文翻译：

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氰钴胺对小鼠卵母细胞成熟、体外受精和胚胎发育的影响

摘要本研究的目的是调查补充氰钴胺对体外成熟（IVM），体外受精（IVF），以及随后的胚胎发育到囊胚阶段的能力，以及体外小鼠2细胞胚胎的发育。由小鼠卵丘-卵母细胞复合物 (COC) 制备卵丘细胞，并在体外含有不同浓度氰钴胺（100、200、300 或 500 pM）的培养 (IVC) 培养基。我们从超排卵 NMRI 小鼠中收集 2 细胞胚胎，并在相同浓度的氰钴胺素（100、200、300 或 500 pM）中培养它们。IVM 42 小时后，我们观察到与对照组相比，200 pM 氰钴胺处理组的卵母细胞成熟显着增加（磷< 0.0001)。在早期胚胎发生过程中，将在 200 pM 氰钴胺中培养的成熟卵母细胞受精并在含有氰钴胺（100、200、300 或 500 pM）的 IVC 培养基中培养。与对照卵母细胞相比，在 200 pM 氰钴胺中培养的成熟卵母细胞具有显着更高的 2 细胞发育率（磷< 0.01)。胚胎获得自体外成熟的卵母细胞和体内与对照胚胎相比，在 200 pM 氰钴胺中培养的受精卵母细胞发育至囊胚阶段的频率显着增加，2 细胞受阻和退化的胚胎显着减少。磷< 0.0001)。来自受精卵的胚胎体内与来自培养的成熟卵母细胞的胚胎相比，含有 200 pM 氰钴胺素的胚泡胚胎百分比更高体外(磷< 0.0001)。这些发现表明，氰钴胺对小鼠卵母细胞成熟、受精和胚胎发育的影响取决于 IVC 培养基中使用的浓度。