Takahashi Toshifumi, Igarashi Hideki, Amita Mitsuyoshi, Hara Shuichiro, Kurachi Hirohisa
Department of Obstetrics and Gynecology Yamagata University Faculty of Medicine 990-9585 Yamagata Japan.
Reprod Med Biol. 2011 Jul 2;10(4):239-249. doi: 10.1007/s12522-011-0099-0. eCollection 2011 Dec.
It is well established that age-related decline of a woman's fertility is related to the poor developmental potential of her gametes. The age-associated decline in female fertility is largely attributable to the oocyte aging caused by ovarian aging. Age-associated oocyte aging results in a decrease in oocyte quality. In contrast to ovarian aging, there is a concept of postovulatory oocyte aging. Postovulatory aging of oocytes, not being fertilized for a prolonged time after ovulation, is known to significantly affect the development of oocytes. Both categories of oocyte aging have similar phenotypes of reproductive failure. However, the mechanisms of the decline in oocyte quality are not necessarily equivalent. An age-dependent increase in aneuploidy is a key determinant of oocyte quality. The reduced expression of molecules regulating cell cycle control during meiosis might be involved in the age-dependent increase in aneuploidy. The mechanism of age-associated oocyte aging might be involved in mitochondrial dysfunction, whose etiologies are still unknown. Alternatively, the mechanism of postovulatory oocyte aging might be involved in reactive oxygen species-induced mitochondrial injury pathways followed by abnormal intracellular Ca regulation of the endoplasmic reticulum. We suggest that future research into the mechanism of oocyte aging will be necessary to develop a method to rescue the poor developmental potential of aged oocytes.
众所周知，女性生育能力随年龄的下降与卵子发育潜力不佳有关。女性生育能力随年龄下降很大程度上归因于卵巢衰老导致的卵母细胞老化。与年龄相关的卵母细胞老化会导致卵母细胞质量下降。与卵巢衰老不同，存在排卵后卵母细胞老化的概念。卵母细胞排卵后老化，即排卵后长时间未受精，已知会显著影响卵母细胞的发育。这两类卵母细胞老化都有类似的生殖失败表型。然而，卵母细胞质量下降的机制不一定相同。非整倍体随年龄增加是卵母细胞质量的关键决定因素。减数分裂过程中调节细胞周期控制的分子表达降低可能与非整倍体随年龄增加有关。与年龄相关的卵母细胞老化机制可能与线粒体功能障碍有关，其病因仍不清楚。或者，排卵后卵母细胞老化机制可能涉及活性氧诱导的线粒体损伤途径，随后是内质网细胞内钙调节异常。我们认为，未来有必要对卵母细胞老化机制进行研究，以开发一种方法来挽救老化卵母细胞不佳的发育潜力。
