Research and Clinical Center for Infertility, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
J Assist Reprod Genet. 2017 Nov;34(11):1413-1426. doi: 10.1007/s10815-017-1005-4. Epub 2017 Aug 18.
The use of immature oocytes subjected to in vitro maturation (IVM) opens interesting perspectives for fertility preservation where ovarian reserves are damaged by pathologies or therapies, as in PCO/PCOS and cancer patients. Human oocyte cryopreservation may offer some advantages compared to embryo freezing, such as fertility preservation in women at risk of losing fertility due to oncological treatment or chronic disease, egg donation and postponing childbirth. It also eliminates religious and/or other ethical, legal, and moral concerns of embryo freezing. In addition, a successful oocyte cryopreservation program could eliminate the need for donor and recipient menstrual cycle synchronization. Recent advances in vitrification technology have markedly improved the oocyte survival rate after warming, with fertilization and implantation rates comparable with those of fresh oocytes. Healthy live births can be achieved from the combination of IVM and vitrification, even if vitrification of in vivo matured oocytes is still more effective. Recently, attention is given to highlight whether vitrification procedures are more successful when performed before or after IVM, on immature GV-stage oocytes, or on in vitro matured MII-stage oocytes. In this review, we emphasize that, even if there are no differences in survival rates between oocytes vitrified prior to or post-IVM, reduced maturation rates of immature oocytes vitrified prior to IVM can be, at least in part, explained by underlying ultrastructural and biomolecular alterations.
不成熟卵母细胞经体外成熟（IVM）的应用为生育力保存开辟了新的途径，因为卵巢储备在病理或治疗中受到损害，如多囊卵巢综合征（PCOS）和癌症患者。与胚胎冷冻相比，人类卵母细胞冷冻可能具有一些优势，例如可以为因肿瘤治疗或慢性疾病而有生育力丧失风险的女性、卵子捐赠者和推迟生育的女性保存生育力。它还消除了胚胎冷冻的宗教和/或其他伦理、法律和道德问题。此外，一个成功的卵母细胞冷冻保存计划可以消除对供体和受体月经周期同步的需求。玻璃化技术的最新进展显著提高了卵母细胞解冻后的存活率，其受精率和着床率与新鲜卵母细胞相当。即使体内成熟的卵母细胞的玻璃化仍然更有效，也可以通过 IVM 和玻璃化的结合实现健康的活产。最近，人们关注的焦点是，在不成熟的GV 期卵母细胞或体外成熟的 MII 期卵母细胞上进行玻璃化之前或之后进行玻璃化程序是否更成功。在这篇综述中，我们强调，即使在 IVM 之前或之后进行玻璃化的卵母细胞的存活率没有差异，但是在 IVM 之前进行玻璃化的不成熟卵母细胞的成熟率降低至少可以部分解释为潜在的超微结构和生物分子改变。
