Kasapi Evangelia, Asimakopoulos Byron, Chatzimeletiou Katerina, Petousis Stamatios, Panagiotidis Yannis, Prapas Nikos, Nikolettos Nikos
Iakentro Fertility Centre, IVF Laboratory, Thessaloniki, Greece.
Democritus University of Thrace, Laboratory of Physiology, Faculty of Medicine, School of Health Sciences, Alexandroupolis, Greece.
Int J Fertil Steril. 2017 Jul-Sep;11(2):85-92. doi: 10.22074/ijfs.2017.4717. Epub 2017 Feb 16.
The use of immature oocytes derived from stimulated cycles could be of great importance, particularly for urgent fertility preservation cases. The current study aimed to determine whether maturation (IVM) was more successful before or after vitrification of these oocytes.
This prospective study was performed in a private fertilization (IVF) center. We collected 318 germinal vesicle (GV) oocytes from 104 stimulated oocyte donation cycles. Oocytes were divided into two groups according to whether vitrification was applied at the GV stage (group 1) or matured to the metaphase II (MII) stage and then vitrified (group 2). In the control group (group 3), oocytes were matured without vitrification. In all three groups, we assessed survival rate after warming, maturation rate, and MII-spindle/chromosome configurations. The chi-square test was used to compare rates between the three groups. Statistical significance was defined at P<0.05 and we used Bonferroni criterion to assess statistical significance regarding the various pairs of groups. The Statistical Package for the Social Sciences version 17.0 was used to perform statistical analysis.
There was no significant difference in the survival rate after vitrification and warming of GV (93.5%) and MII oocytes (90.8%). A significantly higher maturation rate occurred when IVM was performed before vitrification (82.9%) compared to after vitrification (51%). There was no significant difference in the incidence of normal spindle/ chromosome configurations among warmed oocytes matured before (50.0%) or after (41.2%) vitrification. However, a higher incidence of normal spindle/chromosome configurations existed in the matured oocytes which were not subjected to vitrification (fresh oocytes, 77.9%).
In stimulated cycles, vitrification of matured MII oocytes rather than GV oocytes seems to be more efficient. This approach needs to be verified in nonstimulated fertility preservation cases.
使用来自促排卵周期的未成熟卵母细胞可能具有重要意义，特别是对于紧急生育力保存的情况。本研究旨在确定这些卵母细胞玻璃化冷冻前还是冷冻后进行体外成熟（IVM）更成功。
这项前瞻性研究在一家私立体外受精（IVF）中心进行。我们从104个促排卵卵母细胞捐赠周期中收集了318个生发泡（GV）期卵母细胞。根据GV期是否进行玻璃化冷冻（第1组）或成熟至中期II（MII）期后再进行玻璃化冷冻（第2组），将卵母细胞分为两组。在对照组（第3组）中，卵母细胞不进行玻璃化冷冻而直接成熟。在所有三组中，我们评估了复苏后的存活率、成熟率以及MII期纺锤体/染色体形态。采用卡方检验比较三组之间的比率。统计学显著性定义为P<0.05，我们使用Bonferroni标准评估各配对组之间的统计学显著性。使用社会科学统计软件包第17.0版进行统计分析。
GV期卵母细胞（93.5%）和MII期卵母细胞（90.8%）玻璃化冷冻及复苏后的存活率无显著差异。与玻璃化冷冻后进行IVM（51%）相比，玻璃化冷冻前进行IVM时成熟率显著更高（82.9%）。玻璃化冷冻前（50.0%）或后（41.2%）成熟的复苏卵母细胞中，正常纺锤体/染色体形态的发生率无显著差异。然而，未进行玻璃化冷冻的成熟卵母细胞（新鲜卵母细胞，77.9%）中正常纺锤体/染色体形态的发生率更高。
在促排卵周期中，玻璃化冷冻成熟的MII期卵母细胞而非GV期卵母细胞似乎更有效。这种方法需要在非促排卵生育力保存病例中得到验证。
