National Engineering Laboratory for Animal Breeding, Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing, China.
Department of Biology, University of Texas at San Antonio, San Antonio, Texas, USA.
Biopreserv Biobank. 2021 Jun;19(3):210-218. doi: 10.1089/bio.2020.0074. Epub 2021 Feb 24.
Cryopreservation of embryos is important for long-distance embryo transfer and conservation of genetic resources. Porcine research is important for animal husbandry and biomedical research. However, porcine embryos are difficult to cryopreserve because of their high cytoplasmic lipid content and sensitivity to chilling stress. Vitrification is more efficient than slow freezing, and vitrification is mostly used in embryo cryopreservation. So far, the vitrification process of porcine embryos has been continuously improved, resulting in improved survival rates of warmed embryos and farrowing rates after the transplant procedure. It is worth noting that automatic vitrification has made great progress, which is expected to promote the standardization and application of vitrification. In this article, the vitrification process of porcine embryos at the blastula stage and early development stages is reviewed in detail. In addition, the efficiency of different vitrification systems was compared. In addition, we summarize technology that can improve the survival rate of cryopreserved porcine embryos, such as delipidation methods (including physical delipidation and chemical delipidation) and medium improvements (including chemically defined media and adding antioxidants). Meanwhile, gene expression changes during cryopreservation are also elaborated.
胚胎的冷冻保存对于远距离胚胎移植和遗传资源的保存非常重要。猪的研究对于畜牧业和生物医学研究很重要。然而，由于猪胚胎细胞质脂质含量高，对冷却应激敏感，因此很难进行冷冻保存。玻璃化比慢速冷冻更有效，玻璃化主要用于胚胎冷冻保存。到目前为止，猪胚胎的玻璃化过程不断得到改进，从而提高了解冻胚胎的存活率和移植后的产仔率。值得注意的是，自动玻璃化取得了很大进展，有望促进玻璃化的标准化和应用。本文详细回顾了囊胚期和早期发育阶段猪胚胎的玻璃化过程，并比较了不同玻璃化系统的效率。此外，我们还总结了可以提高冷冻保存猪胚胎存活率的技术，如去脂方法（包括物理去脂和化学去脂）和培养基的改进（包括化学定义的培养基和添加抗氧化剂）。同时，还详细阐述了冷冻保存过程中基因表达的变化。
