Van den Abbeel Etienne, Schneider Ulrich, Liu Jun, Agca Yuksel, Critser John K, Van Steirteghem André
Centre for Reproductive Medicine, Academic Hospital, Dutch-speaking Brussels Free University, Laarbeeklaan 101, 1090 Brussels, Belgium.
Hum Reprod. 2007 Jul;22(7):1959-72. doi: 10.1093/humrep/dem083. Epub 2007 Apr 11.
Oocyte cryopreservation remains a realistic objective, provided that more systematic approaches are applied, such as thorough analysis of the oocyte oolemma permeability to water and diverse cryoprotectants.
We prospectively investigated volume changes over time at different temperatures (30 degrees C, 22 degrees C and 8 degrees C) of human metaphase II (MII) oocytes (obtained in stimulated ICSI cycles and matured in vitro from the germinal vesicle stage) when exposed to changes in external osmolality. We also investigated human in vitro matured (IVM) oocytes membrane permeability characteristics at 22 degrees C to 1,2-propanediol (PG) and dimethylsulphoxide (DMSO) and at 30 degrees C, 22 degrees C and 8 degrees C to ethylene glycol (EG), and calculated corresponding oocyte oolemma permeability coefficients (Lp and Pcpa). Furthermore, we investigated the osmotic tolerance limits of IVM oocytes exposed to changes in external osmolality as assessed by their developmental competence during the course of 72 h after ICSI.
The results of our studies describe human oocyte membrane permeability coefficients for EG at 30 degrees C (2.85+/-0.15x10(-3) cm/min), 22 degrees C (1.17+/-0.60x10(-3) cm/min) and 8 degrees C (0.37+/-0.15x10(-3) cm/min). Furthermore, at 22 degrees C the EG oolemma permeability coefficient was lower than that of PG and DMSO (1.17+/-0.60x10(-3) cm/min versus 2.15+/-0.70x10(-3) and 1.56+/-0.38x10(-3) cm/min, respectively). Our results also indicate, that human IVM MII oocytes tolerated exposure to solutions in the range of 39-2264 mOsmol/kg H2O as assessed by the oocytes' developmental competence after exposure.
The results of the present study may contribute to a better understanding of the biology and cryobiology of human oocytes, and to the design of better and more robust cryopreservation (freezing or vitrification) protocols.
只要采用更系统的方法，如深入分析卵母细胞卵膜对水和各种冷冻保护剂的通透性，卵母细胞冷冻保存仍是一个切实可行的目标。
我们前瞻性地研究了人类中期II（MII）卵母细胞（在促排卵ICSI周期中获得并从生发泡期体外成熟）在不同温度（30℃、22℃和8℃）下，当暴露于外部渗透压变化时随时间的体积变化。我们还研究了人类体外成熟（IVM）卵母细胞在22℃时对1,2 - 丙二醇（PG）和二甲基亚砜（DMSO）的膜通透性特征，以及在30℃、22℃和8℃时对乙二醇（EG）的膜通透性特征，并计算了相应的卵母细胞卵膜通透性系数（Lp和Pcpa）。此外，我们通过ICSI后72小时内卵母细胞的发育能力评估了IVM卵母细胞暴露于外部渗透压变化时的渗透耐受极限。
我们的研究结果描述了人类卵母细胞在30℃（2.85±0.15×10⁻³ cm/min）、22℃（1.17±0.60×10⁻³ cm/min）和8℃（0.37±0.15×10⁻³ cm/min）时对EG的膜通透性系数。此外，在22℃时，EG的卵膜通透性系数低于PG和DMSO（分别为1.17±0.60×10⁻³ cm/min 对 2.15±0.70×10⁻³ 和1.56±0.38×10⁻³ cm/min）。我们的结果还表明，通过暴露后卵母细胞的发育能力评估，人类IVM MII卵母细胞能够耐受暴露于39 - 2264 mOsmol/kg H₂O范围内的溶液。
本研究结果可能有助于更好地理解人类卵母细胞的生物学和低温生物学，并有助于设计更好、更可靠的冷冻保存（冷冻或玻璃化）方案。
