Department of Production and Population Health, The Royal Veterinary College, North Mymms, Hatfield, Hertfordshire, UK.
Theriogenology. 2013 Jul 15;80(2):161-8. doi: 10.1016/j.theriogenology.2013.04.008. Epub 2013 May 15.
Linoleic acid (LA; n-6, 18:2) is the most abundant polyunsaturated fatty acid in the ovarian follicular fluid and is known to inhibit oocyte maturation and its subsequent development. In the present study, we investigated how its effects on cumulus cell expansion, oocyte nuclear maturation, and blastocyst development are altered by supplementation of the media with vitamin E (VE; 100 μM) and glutathione peroxidase (GPx; 1 μM) either alone or in combination, and whether it has any effect on the mRNA expression of GPx1, GPx4, or superoxide dismutase (SOD2) in the bovine cumulus oocyte complexes (COCs). LA supplementation of the culture media significantly (P ≤ 0.05) reduced the percentage of COCs exhibiting full cumulus cell expansion and the percentage of oocytes reaching metaphase II stage, and lowered the blastocyst rate compared with controls. And these inhibitory effects were associated with a reduction in the relative mRNA expression of GPx1 and SOD2 but not of GPx4 compared with controls. However, VE and GPx, both alone and in combination, completely abrogated the inhibitory effects of LA on nuclear maturation of oocytes and blastocyst rate but failed to do so for cumulus cell expansion. In conclusion, these data suggest that the detrimental effects of LA on oocyte developmental competence are mediated, at least in part, by a reduction in GPx1 and SOD2 mRNA expression. Moreover, VE and GPx may provide protection to most of the inhibitory effects of LA.
亚油酸（LA；n-6，18:2）是卵巢卵泡液中含量最丰富的多不饱和脂肪酸，已知其能抑制卵母细胞成熟及其随后的发育。在本研究中，我们研究了维生素 E（VE；100 μM）和谷胱甘肽过氧化物酶（GPx；1 μM）单独或联合补充培养基后，其对卵丘细胞扩展、卵母细胞核成熟和囊胚发育的影响如何改变，以及它是否对牛卵丘卵母细胞复合体（COCs）中的 GPx1、GPx4 或超氧化物歧化酶（SOD2）的 mRNA 表达有任何影响。与对照组相比，培养基中添加 LA 显著（P ≤ 0.05）降低了完全卵丘细胞扩展的 COC 百分比和达到中期 II 阶段的卵母细胞百分比，并降低了囊胚率。与对照组相比，这些抑制作用与 GPx1 和 SOD2 的相对 mRNA 表达减少有关，但与对照组相比，GPx4 的相对 mRNA 表达没有减少。然而，VE 和 GPx 单独或联合使用完全消除了 LA 对卵母细胞核成熟和囊胚率的抑制作用，但未能完全消除卵丘细胞扩展的抑制作用。总之，这些数据表明，LA 对卵母细胞发育能力的有害影响至少部分是通过降低 GPx1 和 SOD2 mRNA 表达介导的。此外，VE 和 GPx 可能为 LA 的大部分抑制作用提供保护。
