State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio Resources, Guangxi University, Nanning, Guangxi, China.
College of Animal Science and Technology, Guangxi University, Nanning, Guangxi, China.
J Cell Physiol. 2019 Aug;234(8):13413-13422. doi: 10.1002/jcp.28018. Epub 2019 Jan 4.
Induction of repeated superovulation with exogenous hormones is widely used in assisted reproductive technology (ART). Though it is generally safe, emerging evidence has indicated that repeated superovulation may compromise oocyte quality. However, few studies have explored how to ameliorate such impairment. Because melatonin has beneficial influences on oocytes in various detrimental environments, we aimed to explore whether melatonin could protect mouse oocytes after repeated superovulation. We found that repeated superovulation markedly reduced meiotic maturation and disrupted spindle organization and chromosome alignment. Furthermore, we observed reduced mitochondrial content and enhanced early apoptosis in oocytes from mice subjected to repeated superovulation. In addition, 5-methylcytosine (5mc) fluorescence intensity was lower in oocytes from experimental mice than in those from control mice, indicating that repeated superovulation disrupts genomic DNA methylation, and elevations in reactive oxygen species levels indicated that repeated superovulation also induces oxidative stress. Conversely, melatonin administration improved oocyte maturation and attenuated the observed defects. Interestingly, supplementation with melatonin during in vitro maturation had the same protective effects on oocytes as in vivo melatonin administration. In summary, our results show that melatonin can improve oocyte quality after repeated superovulation and thus provide a potential strategy to improve ART efficiency.
外源性激素诱导的重复超排卵广泛应用于辅助生殖技术（ART）。虽然它通常是安全的，但新出现的证据表明，重复超排卵可能会损害卵母细胞质量。然而，很少有研究探讨如何改善这种损害。由于褪黑素对各种不利环境下的卵母细胞有有益的影响，我们旨在探讨褪黑素是否可以在重复超排卵后保护小鼠卵母细胞。我们发现，重复超排卵明显降低了减数分裂成熟，并破坏了纺锤体的组织和染色体的排列。此外，我们观察到重复超排卵小鼠的卵母细胞中线粒体含量减少，早期凋亡增加。此外，实验小鼠的卵母细胞中 5-甲基胞嘧啶（5mc）荧光强度低于对照小鼠，表明重复超排卵破坏了基因组 DNA 的甲基化，而活性氧水平的升高表明重复超排卵也诱导了氧化应激。相反，褪黑素的给药改善了卵母细胞的成熟，并减轻了观察到的缺陷。有趣的是，在体外成熟过程中补充褪黑素对卵母细胞的保护作用与体内褪黑素给药相同。总之，我们的结果表明，褪黑素可以改善重复超排卵后的卵母细胞质量，从而为提高辅助生殖技术的效率提供了一种潜在的策略。
