Institute of Animal Sciences (IAS), Chinese Academy of Agricultural Sciences (CAAS), No. 2 Yuanmingyuan Western Road, Haidian District, Beijing 100193, China.
Reprod Fertil Dev. 2022 Aug;34(13):889-903. doi: 10.1071/RD22130.
The vitrification of oocytes is important for the conservation of animals, and the effect of vitrification on methylation patterns of bovine oocytes remains unclear.
This article aims to investigate the effect of vitrification on the DNA methylation patterns on vitrified GV oocytes and their in vitro derived MII oocytes.
5-MeC staining and single-cell whole genome bisulphite sequencing (SC-WGBS) were utilised to analyse fresh GV oocytes (F_GV group), MII oocytes (F_MII group), vitrified GV oocytes (V_GV group) and their in vitro derived MII oocytes (V_MII group).
Results of both 5-MeC staining and SC-WGBS showed that no significant difference was found between the F_GV group and the V_GV group, while the methylation level of the V_MII group was significantly lower than that of the F_MII group. Moreover, supplementation of 2μM resveratrol (Res) in IVM medium significantly improved maturation and development ability of vitrified GV oocytes by restoring their DNA methylation levels.
In conclusion, vitrification of bovine GV oocytes significantly decreased the DNA methylation level of their in vitro derived MII oocytes, and 2μM Res improved their development ability by restoring DNA methylation level.
Our results provide an efficient approach to improve the maturation and fertilisation ability of vitrified GV oocytes.
卵母细胞的玻璃化是动物保存的重要手段，但其对牛卵母细胞甲基化模式的影响尚不清楚。
本研究旨在探讨玻璃化对玻璃化GV 卵母细胞及其体外衍生的 MII 卵母细胞 DNA 甲基化模式的影响。
使用 5-MeC 染色和单细胞全基因组亚硫酸氢盐测序（SC-WGBS）分析新鲜 GV 卵母细胞（F_GV 组）、MII 卵母细胞（F_MII 组）、玻璃化 GV 卵母细胞（V_GV 组）及其体外衍生的 MII 卵母细胞（V_MII 组）。
5-MeC 染色和 SC-WGBS 的结果均显示，F_GV 组和 V_GV 组之间无显著差异，而 V_MII 组的甲基化水平明显低于 F_MII 组。此外，在 IVM 培养基中添加 2μM 白藜芦醇（Res）可显著改善玻璃化 GV 卵母细胞的成熟和发育能力，恢复其 DNA 甲基化水平。
总之，牛 GV 卵母细胞的玻璃化显著降低了其体外衍生的 MII 卵母细胞的 DNA 甲基化水平，2μM Res 通过恢复 DNA 甲基化水平提高了其发育能力。
本研究结果为提高玻璃化 GV 卵母细胞的成熟和受精能力提供了一种有效的方法。
