Magata F, Ideta A, Matsuda F, Urakawa M, Oono Y
Research and Development Group, Zen-noh Embryo Transfer Center, Kamishihoro, Hokkaido, Japan; Department of Veterinary Medical Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
Research and Development Group, Zen-noh Embryo Transfer Center, Kamishihoro, Hokkaido, Japan.
Theriogenology. 2021 Jun;167:37-43. doi: 10.1016/j.theriogenology.2021.03.004. Epub 2021 Mar 10.
The aberrant redox regulation and anti-oxidative defense is one of the main causes of age-induced decline in oocytes quality and embryo development in mammals. The present study aimed to elucidate the effect of glutathione ethyl ester (GSH-OEt), a cell-permeable glutathione (GSH) donor, on the developmental competence of oocytes in cows with advanced reproductive age. Oocytes were collected from cows aged 30-50 months or >120 months, which were defined as young or aged, respectively, and subjected to in vitro maturation (IVM) in the presence of 5 mM of GSH-OEt. In aged cows, the GSH level in follicular fluid was lower, and the intracellular levels of reactive oxygen species (ROS) in post-IVM oocytes was higher than those in young cows. GSH-OEt supplementation during IVM reduced the ROS contents of oocyte in aged cows but not in young cows. GSH-OEt treatment promoted the meiotic progression and increased the proportion of oocytes with mature cytoplasm containing evenly dispersed cortical granules in aged cows. After in vitro fertilization, the normal fertilization and development to the blastocyst stage were enhanced by GSH-OEt in aged cows to levels comparable to those in young cows. Further, oocyte maturation in the presence of GSH-OEt increased the proportion of diploid blastocyst in aged cows. In contrast, GSH-OEt failed to enhance the oocyte maturation, fertilization, and embryo development in young cows. Taken together, the exogenous supplementation of GSH-OEt during IVM modulated the age-related oxidative damage of bovine oocytes and improved the developmental competence of oocytes in aged cows. Oocytes presented a distinct response to GSH-OEt treatment depending on the donor age. GSH-OEt supplementation during IVM could be of practical value through the efficiency improvement of chromosomally normal embryo production in aged cows.
异常的氧化还原调节和抗氧化防御是哺乳动物中年龄诱导的卵母细胞质量和胚胎发育下降的主要原因之一。本研究旨在阐明细胞可渗透的谷胱甘肽（GSH）供体谷胱甘肽乙酯（GSH-OEt）对高龄繁殖奶牛卵母细胞发育能力的影响。从30-50个月龄或>120个月龄的奶牛中收集卵母细胞，分别定义为年轻或老龄，并在5 mM GSH-OEt存在下进行体外成熟（IVM）。在老龄奶牛中，卵泡液中的GSH水平较低，IVM后卵母细胞内活性氧（ROS）水平高于年轻奶牛。IVM期间补充GSH-OEt可降低老龄奶牛卵母细胞的ROS含量，但对年轻奶牛无效。GSH-OEt处理促进了老龄奶牛的减数分裂进程，并增加了具有均匀分散皮质颗粒的成熟细胞质卵母细胞的比例。体外受精后，GSH-OEt可将老龄奶牛的正常受精和发育至囊胚阶段的能力提高到与年轻奶牛相当的水平。此外，在GSH-OEt存在下的卵母细胞成熟增加了老龄奶牛中二倍体囊胚的比例。相比之下，GSH-OEt未能增强年轻奶牛的卵母细胞成熟、受精和胚胎发育。综上所述，IVM期间外源性补充GSH-OEt可调节牛卵母细胞与年龄相关的氧化损伤，并提高老龄奶牛卵母细胞的发育能力。根据供体年龄，卵母细胞对GSH-OEt处理表现出不同的反应。IVM期间补充GSH-OEt通过提高老龄奶牛染色体正常胚胎生产的效率可能具有实际价值。
