DNA methylation is an essential epigenetic mark for embryo development and can be susceptible to environment factors such as in vitro conditions. The aim of this study was to verify the effect of in vitro culture until Day (D) 14 of the development on the embryo size and DNA methylation pattern of the insulin-like growth factor 2 (IGF2)-imprinted gene. To achieve this, we produced bovine embryos completely in vivo, completely in vitro, and in vitro until D7 and then in vivo up to D14. The embryos produced in in vitro were smaller than those in other two groups (p = 0.024); no differences in embryo size were observed between genders. The in vitro embryos showed a higher level of DNA methylation in the IGF2 as compared with that in the completely in vivo-produced (IVV) embryos (p = 0.009). Furthermore, totally in vitro-produced male embryos showed higher levels of DNA methylation as compared with those observed for the totally IVV male embryos (p = 0.034). No differences were observed among genders for IGF2 DNA methylation. These results showed that the window between D7 and D14 is critical for embryo development and alterations in the environmental conditions during this period can impair DNA methylation establishment of important developmental imprinted genes. This study brings unprecedented data for bovine embryos regarding the impact of the environmental conditions during the posthatching development.

中文翻译：

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延长牛胚滋养细胞中胰岛素样生长因子2-印迹基因的DNA甲基化：体外培养的影响。

DNA甲基化是胚胎发育必不可少的表观遗传标记，并且可能易受环境因素（例如体外条件）的影响。这项研究的目的是验证直到第14天发育的体外培养对印有胰岛素样生长因子2（IGF2）的基因的胚胎大小和DNA甲基化模式的影响。为了实现这一目标，我们完全在体内，在体外和在体外直至D7，然后在体内直至D14都产生了牛胚胎。体外产生的胚胎要比其他两组小（p = 0.024）。性别之间没有观察到胚胎大小的差异。与完全体内产生的（IVV）胚胎相比，IGF2中的体外胚胎显示出更高的DNA甲基化水平（p = 0.009）。此外，与完全IVV雄性胚胎观察到的结果相比，完全体外产生的雄性胚胎显示出更高的DNA甲基化水平（p = 0.034）。性别之间未观察到IGF2 DNA甲基化差异。这些结果表明，D7和D14之间的窗口对于胚胎发育至关重要，在此期间环境条件的改变会损害重要的发育印迹基因的DNA甲基化的建立。这项研究为牛胚胎带来了有关孵化后发展过程中环境条件影响的空前数据。这些结果表明，D7和D14之间的窗口对于胚胎发育至关重要，在此期间环境条件的改变会损害重要的发育印迹基因的DNA甲基化的建立。这项研究为牛胚胎带来了有关孵化后发展过程中环境条件影响的空前数据。这些结果表明，D7和D14之间的窗口对于胚胎发育至关重要，在此期间环境条件的改变会损害重要的发育印迹基因的DNA甲基化的建立。这项研究为牛胚胎带来了有关孵化后发展过程中环境条件影响的空前数据。