UMR BDR, INRA, ENVA, Université Paris Saclay, Jouy en Josas, France.
Centre de Recherche en Biologie de la Reproduction, Département des Sciences Animales, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Quebec City, Québec, Canada.
Reproduction. 2018 Dec 27;157(2):163-178. doi: 10.1530/REP-18-0439.
Embryo transfer in cattle is performed with blastocysts produced in vivo or in vitro using defined media. However, outdated systems such as those that use serum and co-culture remain of interest for research purposes. Here, we investigated the effect of additional culture time on in vitro-produced embryos. Specifically, we compared embryos that formed a blastocoel at different times after fertilisation to those that stayed in culture for up to two additional days with respect to their development in vivo after temporary transfer to oestrus-synchronised recipients. A pre-transfer set (D6, D6+1, D6+2, D7, D7+1, D8) was examined using microarray analyses and correlated with a post-transfer set that included two different days of transfer (D6-T6, D6+2-T8, D7+1-T8, D8-T8). All surviving conceptuses reached primitive-streak stages and filamentous sizes similarly to in vivo (D18) or in vitro controls (D7/T7). The recovery rate differed between D6 and D8 embryos that were immediately transferred (58 vs 25%). With an intermediate survival rate (33%), the D6 embryos with two additional days in culture produced nine times more IFN-tau (IFNT) at D18 than the D6 embryos that were immediately transferred. At the end of culture, D6 and D6+2 embryos displayed the highest number of gene expression differences. Despite a mortality of 40–60%, no signature was detectable in any of the transferred groups that would account for the embryos’ fates. Initially reputed to be beneficial in producing more blastocysts, our culture system of B2 medium plus serum and co-culture generated blastocysts that were distinct from those developed in vivo (D7).
牛胚胎移植是通过体内或体外使用定义的培养基生产囊胚来进行的。然而，一些过时的系统，如使用血清和共培养的系统，仍然是研究目的的兴趣所在。在这里，我们研究了额外培养时间对体外生产胚胎的影响。具体来说，我们比较了在受精后不同时间形成囊胚腔的胚胎，以及在临时转移到发情同步受体后，在培养中再培养多达两天的胚胎，在体内的发育情况。一组预转移胚胎（D6、D6+1、D6+2、D7、D7+1、D8）使用微阵列分析进行了检查，并与包括两个不同转移天数（D6-T6、D6+2-T8、D7+1-T8、D8-T8）的后转移组进行了比较。所有存活的胚胎都达到了原始条纹阶段和丝状大小，与体内（D18）或体外对照（D7/T7）相似。立即转移的 D6 和 D8 胚胎的回收率不同（58%比 25%）。在中间存活率（33%）下，在培养中再培养两天的 D6 胚胎在 D18 时产生的 IFN-tau（IFNT）比立即转移的 D6 胚胎多九倍。在培养结束时，D6 和 D6+2 胚胎显示出最高数量的基因表达差异。尽管死亡率为 40-60%，但在任何转移组中都没有检测到可以解释胚胎命运的特征。最初被认为有利于产生更多囊胚的我们的 B2 培养基加血清和共培养系统产生的囊胚与体内发育的囊胚（D7）不同。
