Reproductive Medical Centre of Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei 230001, China.
Hum Reprod. 2012 Nov;27(11):3208-14. doi: 10.1093/humrep/des295. Epub 2012 Aug 27.
Before human MII oocytes are vitrified they are usually denuded from their cumulus cells. In this study we wanted to investigate the effects of an intact corona radiata on the vitrification and fertilization of human oocytes.
The study comprised two different parts. In Part 1, 36 MII stage oocytes, from 6 patients, were randomly assigned into a control group, a group of vitrified-warmed oocytes without a corona radiata and a group of vitrified-warmed oocytes with an intact corona radiata. In each group of 12, 6 oocytes were used for evaluation of the zona pellucida solubility (hardening) and another 6 oocytes were used for the analysis of their ultrastructure. In addition, six polyspermically fertilized oocytes were used as positive controls for zona pellucida hardening. In Part 2, 16 patients in total produced 107 fresh and 98 vitrified-warmed oocytes, with or without an intact corona radiata. All oocytes were fertilized via conventional IVF and embryos were transferred according to our standard ET routines. The oocyte survival and fertilization rates, embryo quality and pregnancy and implantation rates were evaluated.
There were no differences in oocyte survival, zona pellucida solubility (hardening) or the number of cortical granules between the vitrified-warmed and fresh oocytes. There were also no differences in the zona pellucida solubility and the number of cortical granules between vitrified-warmed oocytes with or without an intact corona radiata. However, the oocytes with an intact corona radiata had a higher fertilization rate after conventional IVF insemination. No differences were seen in the survival and cleavage rates, the percentage of high-quality embryos or the clinical outcome.
Zona hardening and ultrastructural damage do not seem to occur in vitrified human oocytes. An intact corona radiata in vitrified-warmed oocytes retains their fertilization capacity in conventional IVF, but does not improve the embryo quality. Poor fertilizing capacities of vitrified-warmed oocytes without an intact corona radiata seem to have been due to the complete removal of the cumulus cells.
在人类 MII 卵母细胞被玻璃化之前，通常会从它们的卵丘细胞中去除。在这项研究中，我们想研究完整的放射冠对人类卵母细胞的玻璃化和受精的影响。
该研究包括两个不同的部分。在第一部分中，来自 6 名患者的 36 个 MII 期卵母细胞被随机分为对照组、无放射冠的玻璃化-加热卵母细胞组和有完整放射冠的玻璃化-加热卵母细胞组。在每组 12 个卵母细胞中，6 个用于评估透明带溶解性（硬化），另外 6 个用于分析其超微结构。此外，6 个多精受精的卵母细胞被用作透明带硬化的阳性对照。在第二部分中，总共 16 名患者产生了 107 个新鲜和 98 个玻璃化-加热的卵母细胞，有或没有完整的放射冠。所有卵母细胞都通过常规 IVF 受精，胚胎根据我们的标准 ET 程序进行移植。评估卵母细胞存活率、受精率、胚胎质量以及妊娠和植入率。
玻璃化-加热的卵母细胞与新鲜卵母细胞之间的卵母细胞存活率、透明带溶解性（硬化）或皮质颗粒数量没有差异。有或没有完整放射冠的玻璃化-加热卵母细胞之间的透明带溶解性和皮质颗粒数量也没有差异。然而，带有完整放射冠的卵母细胞在常规 IVF 授精后具有更高的受精率。在存活率和分裂率、高质量胚胎的百分比或临床结局方面没有差异。
玻璃化的人类卵母细胞似乎不会发生透明带硬化和超微结构损伤。在常规 IVF 中，玻璃化-加热的卵母细胞中保留完整的放射冠保留了其受精能力，但不能提高胚胎质量。没有完整放射冠的玻璃化-加热卵母细胞的受精能力差可能是由于完全去除了卵丘细胞。
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