In the present study, four experimental groups were used: fresh embryos, cultured during in vitro maturation and in vitro culture in media supplemented with bovine serum albumin (BSA) (fresh BSA) or fetal bovine serum (FBS) (fresh FBS); and two groups of cryopreserved and thawed embryos, produced under the same conditions (frozen BSA and frozen FBS). Experiment 1 evaluated the protein source effect on embryo development and response to cryopreservation. At day 7, half of the expanded blastocysts (Bx) from each group were cryopreserved and warmed and the other half were used as controls. After warming, embryos were incubated under the same conditions for 48 hours, and the hatching rate was measured at 24 and 48 hours. The total and the apoptotic cell numbers were measured in a subset of Bx after 24 hours. Experiment 2 used the Bx of experiment 1 to compare the expression of KRT8, PLAC8, FOSL1, HSP1A1, and HSPA5 genes in hatched blastocysts at 24 and 48 hours for all groups. The FBS group showed a higher percentage (p < 0.05) of embryos (42.8% vs. 27.9%) and higher rates of Bx (75.0% vs. 63.8%) on day 7, compared with the BSA group. At 24 hours postwarming, the fresh FBS group showed the highest hatching rate (p < 0.05) in comparison with other treatments. However, at 48 hours, the hatching rate was similar (p > 0.05) among groups: fresh FBS (68.1% ± 23.3%), fresh BSA (70.0% ± 31.0%), frozen FBS (39.2 ± 27.1), and frozen BSA (38.2 ± 23.9). After 24 hours, frozen BSA showed a higher number of cells compared with frozen FBS (p < 0.05). The expression of the PLAC8 gene was higher (p < 0.05) in fresh BSA embryos compared with frozen FBS embryos at 24 hours. In the present study, BSA replacement reduced embryo development, but did not affect the response to cryopreservation. However, upregulation of the PLAC8 gene suggests that embryos cultured in BSA might have better quality to support further development.

中文翻译：

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缓慢冷冻冷冻保存后，在卵母细胞成熟和胚胎培养过程中用牛血清白蛋白替代胎牛血清不能改善胚泡质量。

在本研究中，使用了四个实验组：新鲜胚胎，在体外成熟和体外培养在补充了牛血清白蛋白（BSA）（新鲜的BSA）或胎牛血清（FBS）（新鲜的FBS）的培养基中进行培养; 以及两组在相同条件下冷冻保存和融化的胚胎（冷冻BSA和冷冻FBS）。实验1评估了蛋白质来源对胚胎发育和冷冻保存反应的影响。在第7天，将每组一半的膨胀胚泡（Bx）冷冻保存并加热，另一半用作对照。温热后，将胚胎在相同条件下孵育48小时，并在24和48小时测量孵化率。24小时后，在Bx的一个子集中测量总数和凋亡细胞数。实验2使用实验1的Bx来比较KRT8，PLAC8，所有组在第24和48小时孵化的囊胚中的FOSL1，HSP1A1和HSPA5基因。 与BSA组相比，FBS组在第7天的胚胎百分比更高（p <0.05）（42.8％vs. 27.9％），Bx发生率更高（75.0％vs. 63.8％）。变暖后24小时，新鲜FBS组的孵化率最高（p  <0.05）。但是，在48小时时， 各组之间的孵化率相似（p > 0.05）：新鲜FBS（68.1％±23.3％），新鲜BSA（70.0％±31.0％），冷冻FBS（39.2±27.1）和冷冻BSA （38.2±23.9）。24小时后，冷冻的BSA与冷冻的FBS相比显示出更多的细胞（p <0.05）。 与24小时冷冻FBS胚胎相比，新鲜BSA胚胎中PLAC8基因的表达更高（p <0.05）。在本研究中，BSA替代可减少胚胎发育，但不影响对冷冻保存的反应。但是，PLAC8基因的上调表明，在BSA中培养的胚胎可能具有更好的质量以支持进一步的发育。