Effects of oocyte vitrification on epigenetic status in early bovine embryos
Effects of oocyte vitrification on epigenetic status in early bovine embryos
复制标题
卵母细胞玻璃化冷冻对早期牛胚胎表观遗传状态的影响
DOI：
10.1016/j.theriogenology.2016.03.008
复制
发表时间：
2016-08-01
期刊：
影响因子：
2.8
通讯作者：
Zhang, Yong
中科院分区：
文献类型：
--
作者：
Chen, Huanhuan;Zhang, Lei;Zhang, Yong
卵母细胞冷冻保存对胚胎的后续发育有很大的影响。目前，一些研究主要集中在玻璃化的后果和细胞结构的发展潜力。本研究确定了卵母细胞玻璃化是否会引起牛胚胎的表观遗传不稳定性。研究了卵母细胞玻璃化对卵胞浆内单精子注射获得的早期胚胎DNA甲基化、组蛋白修饰和可能的印迹基因表达的影响。结果表明，卵母细胞玻璃化对受精卵卵裂率无影响（67.0% vs. 73.8%, P < 0.05），但使囊胚率降低（9.6% vs. 23.0%, P < 0.05）。卵裂早期卵母细胞和卵裂早期胚胎的DNA甲基化和H3K9me3水平低于对照组（P < 0.05），而在卵裂早期，玻璃化组的acH3K9水平升高（P < 0.05）。囊胚内细胞团中DNA甲基化、H3K9me3和acH3K9水平无差异，而TE细胞玻璃化后DNA甲基化和acH3K9水平降低（P < 0.05）。在囊胚中，推测印迹基因PEG10、XIST和kcnq101t的表达上调。这些表观遗传异常可以部分解释为与表观遗传调控相关的基因表达改变。DNA甲基化和H3K9修饰表明，卵母细胞玻璃化可能使卵母细胞和早期卵裂胚胎的染色体过度松弛。综上所述，这些表观遗传指标可作为胚胎早期发育过程中卵母细胞玻璃化的损伤标记，为评价卵母细胞玻璃化提供了新的思路。(C) 2016 Elsevier Inc.版权所有。
Oocyte cryopreservation has a great impact on subsequent embryonic development. Currently, several studies have primarily focused on the consequences of vitrification and the development potential of cellular structures. This study determined whether oocyte vitrification caused epigenetic instabilities of bovine embryos. The effects of oocyte vitrification on DNA methylation, histone modifications, and putative imprinted genes' expression in early embryos derived by intracytoplasmic sperm injection were examined. Results showed that oocyte vitrification did not affect zygote cleavage rates (67.0% vs. 73.8% control, P > 0.05) but reduced the blastocyst rate (9.6% vs. 23.0%, P < 0.05). The levels of DNA methylation and H3K9me3 in oocytes and early cleavage embryos were lower (P < 0.05) than those in control group, but the level of acH3K9 increased (P < 0.05) in the vitrification group during the early cleavage phases. No differences were observed for DNA methylation, H3K9me3, and acH3K9 in the inner cell mass of blastocysts, whereas decreased levels of DNA methylation and acH3K9 (P < 0.05) existed in TE cells after vitrification. The expression of putative-imprinted genes PEG10, XIST, and KCNQ1O1T was upregulated in blastocysts. These epigenetic abnormalities may be partially explained by altered expression of genes associated with epigenetic regulations. DNA methylation and H3K9 modification suggest that oocyte vitrification may excessively relax the chromosomes of oocytes and early cleavage embryos. In conclusion, these epigenetic indexes could be used as damage markers of oocyte vitrification during early embryonic development, which offers a new insight to assess oocyte vitrification. (C) 2016 Elsevier Inc. All rights reserved.