Garcia-Garcia R M, Gonzalez-Bulnes A, Dominguez V, Veiga-Lopez A, Cocero M J
Departamento de Reproducción Animal INIA, Avda Puerta de Hierro s/n, 28040 Madrid, Spain.
Theriogenology. 2005 May;63(8):2233-42. doi: 10.1016/j.theriogenology.2004.10.006. Epub 2004 Nov 25.
The current study assessed both the effects of in vitro culture and developmental stage of early stage in vivo produced ovine embryos on their ability to survive cryopreservation. Early stage embryos (n=226) were recovered from the oviduct, at different days of the early luteal phase, at three different developmental stages: 2- to 4-cell, 5- to 8-cell and 9- to 12-cell. For each stage, half of the embryos were cultured to the blastocyst stage and frozen thereafter (CF), while the remainder was frozen just after recovery (EF). A third experimental group (BF; n=43) included blastocysts obtained from the uterus and frozen immediately after recovery. Embryo viability post-thawing was determined by assessing their rate of development to the hatched blastocyst stage following in vitro culture. Culture negatively affected embryo viability, since survival rate was higher in blastocysts obtained from the uterus than in those from culture (83.7% versus 66.1%; P<0.05); also the cryosurvival of cultured embryos was lower when the timing of blastocyst formation was extended (P<0.01). However, survival following freezing-thawing of early developmental stages was significantly lower when compared to viability of their counterparts cultured to the blastocyst stage (23.1% versus 66.1%, P<0.0001). In conclusion, our results indicate that, despite the deleterious effects of culture per se, the culture of early in vivo produced ovine embryos to the blastocyst stage prior to be frozen improves their survival after thawing.
本研究评估了体外培养以及体内早期产生的绵羊胚胎的发育阶段对其冷冻保存存活能力的影响。在黄体期早期的不同天数，从输卵管中回收早期胚胎（n = 226），处于三个不同发育阶段：2至4细胞、5至8细胞和9至12细胞。对于每个阶段，一半的胚胎培养至囊胚阶段后冷冻（CF），而其余的在回收后立即冷冻（EF）。第三个实验组（BF；n = 43）包括从子宫获得并在回收后立即冷冻的囊胚。解冻后胚胎的活力通过评估其在体外培养后发育至孵化囊胚阶段的速率来确定。培养对胚胎活力有负面影响，因为从子宫获得的囊胚的存活率高于培养获得的囊胚（83.7%对66.1%；P<0.05）；当囊胚形成时间延长时，培养胚胎的冷冻存活率也较低（P<0.01）。然而，与培养至囊胚阶段的对应胚胎的活力相比，早期发育阶段冷冻解冻后的存活率显著较低（23.1%对66.1%，P<0.0001）。总之，我们的结果表明，尽管培养本身有有害影响，但将体内早期产生的绵羊胚胎培养至囊胚阶段后再冷冻可提高其解冻后的存活率。
