SummaryEmbryos that are produced in vitro frequently present epigenetic modifications. However, maternal supplementation with folic acid (FA) may improve oocyte maturation and embryo development, preventing epigenetic errors in the offspring. We sought to evaluate the influence of FA supplementation during in vitro maturation of grade I (GI) and grade III (GIII) bovine oocytes on embryo production rate and the expression of IGF2 and KCNQ1OT1 genes. The oocytes were matured in vitro with different concentrations of FA (0, 10, 30 and 100 μM), followed by in vitro fertilization and embryo culture. On the seventh day (D7) of culture, embryo production was evaluated and gene expression was measured using real-time qPCR. Supplementation with 10 μM of FA did not affect embryo production for GI and GIII oocytes. Moderate supplementation (30 μM) seemed to be a positive influence, increasing embryo production for GIII (P = 0.012), while the highest dose (100 μM) reduced embryo production (P = 0.010) for GI, and IGF2 expression was not detected. In GIII, only embryos whose oocyte maturation was not supplemented with FA demonstrated detected IGF2 expression. The lowest concentration of FA (10 μM) reduced KCNQ1OT1 expression (P = 0.05) on embryos from GIII oocytes. Different FA concentrations induced different effects on bovine embryo production and gene expression that was related to oocyte quality. Despite the epigenetic effects of FA, supplementation seems to be a promising factor to improve bovine embryo production if used carefully, as concentration is an important factor, especially in oocytes with impaired quality.

中文翻译：

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卵母细胞成熟过程中补充叶酸影响牛胚胎的体外生产和基因表达

摘要产生的胚胎体外经常出现表观遗传修饰。然而，母体补充叶酸 (FA) 可以改善卵母细胞成熟和胚胎发育，防止后代出现表观遗传错误。我们试图评估补充 FA 的影响体外I级（GI）和III级（GIII）牛卵母细胞成熟对胚胎产生率和表达的影响胰岛素样生长因子2和KCNQ1OT1基因。卵母细胞成熟了体外用不同浓度的 FA（0、10、30 和 100 μM），然后体外受精和胚胎培养。在培养的第 7 天 (D7)，评估胚胎生产并使用实时 qPCR 测量基因表达。补充 10 μM FA 不会影响 GI 和 GIII 卵母细胞的胚胎生成。适度补充（30 μM）似乎是一种积极的影响，增加了 GIII 的胚胎产量（磷= 0.012)，而最高剂量 (100 μM) 降低胚胎产量 (磷= 0.010) 对于 GI，和胰岛素样生长因子2未检测到表达。在 GIII 中，仅检测到卵母细胞成熟时未补充 FA 的胚胎胰岛素样生长因子2表达。FA (10 μM) 的最低浓度降低KCNQ1OT1表达 （磷= 0.05) 来自 GIII 卵母细胞的胚胎。不同的 FA 浓度对牛胚胎产生和与卵母细胞质量相关的基因表达有不同的影响。尽管 FA 具有表观遗传效应，但如果谨慎使用，补充剂似乎是改善牛胚胎产量的一个有希望的因素，因为浓度是一个重要因素，尤其是在质量受损的卵母细胞中。