In Vitro Brasil Ltda, Mogi Mirim, São Paulo, SP, Brazil.
Theriogenology. 2013 Sep 1;80(4):372-7. doi: 10.1016/j.theriogenology.2013.04.026. Epub 2013 Jun 6.
In vitro-produced (IVP) bovine embryos are more sensitive to cryopreservation than their in vivo counterparts due to their higher lipid concentrations, whereas Bos indicus IVP embryos are even more sensitive than Bos taurus IVP embryos. To examine the effects of a lipolytic agent, before vitrification of Bos indicus IVP embryos, on embryo survival, viability, and pregnancy rates, two experiments were conducted. In experiment 1, Bos indicus (Nelore) embryos were produced from abattoir-derived ovaries and allocated into two groups. In the treatment group, 10 μM of forskolin was added to the in vitro culture medium on Day 5 and incubated for 48 hours. On Day 7 of culture, IVP-expanded blastocysts from both the control (n = 101) and treatment (n = 112) groups were vitrified with ethylene glycol and DMSO via the Cryotop procedure. Although there was no significant difference between the rates of blastocoel reexpansion and hatching of the embryos exposed to forskolin (87.5% and 70.5%, respectively) compared with the control embryos (79.2% and 63.3%, respectively), the numerically superior rates of the embryos exposed to forskolin led to another experiment. In experiment 2, blastocysts produced from the ovum pick up were exposed or not exposed to the lipolytic agent and vitrified as in experiment 1. Embryos treated with forskolin had higher pregnancy rates than the control group (48.8% vs. 18.5%). In view of these results, 1908 Bos indicus embryos were produced from ovum pick up, exposed to the lipolytic agent, and blastocysts were transferred to recipients, and the pregnancy rates of the embryos of various breeds were compared. The mean pregnancy rate obtained was 43.2%. All data were analyzed by chi-square or by binary logistic regression (P ≤ 0.05). In conclusion, treatment with forskolin before vitrification improved cryotolerance of Bos indicus IVP embryos, resulting in good post-transfer pregnancy rates.
体外生产(IVP)的牛胚胎比体内胚胎对冷冻保存更敏感,因为它们的脂质浓度更高,而印度野牛 IVP 胚胎比黄牛 IVP 胚胎更敏感。为了研究在玻璃化之前,一种脂肪分解剂对印度野牛 IVP 胚胎的存活、活力和妊娠率的影响,进行了两项实验。在实验 1 中,从屠宰场获得的卵巢中产生了印度野牛(Nelore)胚胎,并将其分配到两组中。在处理组中,在第 5 天向体外培养物中添加 10 μM 的 forskolin,并孵育 48 小时。在培养的第 7 天,将来自对照组(n = 101)和处理组(n = 112)的 IVP 扩展囊胚用乙二醇和 DMSO 通过 Cryotop 程序进行玻璃化。尽管暴露于 forskolin 的胚胎的囊胚腔再扩张和孵化率(分别为 87.5%和 70.5%)与对照组胚胎(分别为 79.2%和 63.3%)相比没有显著差异,但暴露于 forskolin 的胚胎的囊胚腔再扩张和孵化率更高,这导致了另一项实验。在实验 2 中,如实验 1 所述,暴露或不暴露于脂肪分解剂,并对卵母细胞采集产生的囊胚进行玻璃化处理。用 forskolin 处理的胚胎的妊娠率高于对照组(48.8%比 18.5%)。鉴于这些结果,从卵母细胞采集产生了 1908 个印度野牛胚胎,暴露于脂肪分解剂,然后将囊胚转移到受体中,并比较了不同品种胚胎的妊娠率。获得的平均妊娠率为 43.2%。所有数据均通过卡方检验或二项逻辑回归进行分析(P ≤ 0.05)。总之,在玻璃化之前用 forskolin 处理可提高印度野牛 IVP 胚胎的抗冻能力,从而获得良好的移植后妊娠率。