IVF Namba Clinic, Osaka, Japan.
J Assist Reprod Genet. 2013 Mar;30(3):371-6. doi: 10.1007/s10815-012-9928-2. Epub 2013 Jan 12.
Closed-system vitrification may enable the risk of contamination to be minimised. We performed three studies to compare the developmental competence of human embryos vitrified using either a closed vitrification system (CVS; Rapid-i®) or an open vitrification system (OVS; Cryo-top®).
The first study was performed in vitro using 66 zygotes previously vitrified at pronuclear stage. These were warmed and randomised 1:1 to revitrification using either the OVS or the CVS. After re-warming, embryo development and blastocyst cell number were assessed. For the second study, also performed in vitro, 60 vitrified-warmed blastocysts were randomised 1:1:1 into three groups (OVS or CVS revitrification, or no revitrification). The proportion of dead cells was assessed by staining. The third study was performed in vivo, using 263 high-grade blastocysts randomly assigned to vitrification using either the CVS (n = 100) or the OVS (n = 163). After warming, single blastocyst transfer was performed.
There were no differences between the CVS and the OVS in survival rate (100 % vs. 97 %), blastulation rate (96 h: 50 % vs. 50 %; 120 h: 68 % vs. 56 %), proportion of good blastocysts (96 h: 32 % vs. 22 %, 120 h: 47 % vs. 41 %), or mean number of cells (137 vs. 138). The proportion of dead cells in blastocysts re-vitrified by CVS (31 %) was similar to that for OVS (38 %) and non-revitrification (32 %). In vivo, the implantation rate for blastocysts vitrified using the CVS (54 %) was similar to that with the OVS (53 %).
Our studies consistently indicate that human embryos may be vitrified using a CVS without impairment of developmental competence.
封闭系统的玻璃化可能使污染风险最小化。我们进行了三项研究，比较了使用封闭系统（CVS；Rapid-i®）或开放系统（OVS；Cryo-top®）对人类胚胎进行玻璃化的胚胎发育能力。
第一项研究在体外进行，使用 66 个先前在原核期进行玻璃化的受精卵。这些受精卵被解冻，并随机分为 1:1 比例，分别使用 OVS 或 CVS 进行再玻璃化。重新解冻后，评估胚胎发育和囊胚细胞数量。第二项研究也在体外进行，将 60 个玻璃化解冻的囊胚随机分为 1:1:1 三组（OVS 或 CVS 再玻璃化，或不进行再玻璃化）。通过染色评估死细胞的比例。第三项研究在体内进行，使用 263 个高等级囊胚随机分配使用 CVS（n=100）或 OVS（n=163）进行玻璃化。解冻后，进行单个囊胚转移。
CVS 和 OVS 之间在存活率（100%与 97%）、囊胚形成率（96 小时：50%与 50%；120 小时：68%与 56%）、优质囊胚比例（96 小时：32%与 22%，120 小时：47%与 41%）或平均细胞数（137 与 138）方面均无差异。CVS 再玻璃化的囊胚中的死细胞比例（31%）与 OVS（38%）和不进行再玻璃化（32%）相似。在体内，使用 CVS 进行玻璃化的囊胚的着床率（54%）与使用 OVS 的相似（53%）。
我们的研究一致表明，人类胚胎可以使用 CVS 进行玻璃化，而不会损害其发育能力。
