Reproductive Services, Melbourne IVF, Royal Women's Hospital, Cnr Grattan Street and Flemington Road, Parkville, Vic. 3052, Australia.
Reprod Biomed Online. 2009 Oct;19(4):521-5. doi: 10.1016/j.rbmo.2009.06.002.
Increasing the proportions of embryos and blastomeres which survive cryopreservation would be expected to make a significant contribution to the outcome of assisted reproduction treatment. Despite this, the methodology used for slow cooling of human cleavage-stage embryos has remained largely unchanged for over two decades. Previous studies have demonstrated the value, in terms of cryosurvival, of increasing the extent of intracellular dehydration by increasing the concentration of non-permeating cryoprotectant prior to slow cooling of oocytes and embryos which have been biopsied for preimplantation genetic diagnosis. The present study extends the use of this approach to the slow cooling of non-biopsied day-2 embryos. Dehydration in the presence of 0.2 mol/l sucrose significantly increased the proportions of surviving embryos, surviving blastomeres and fully intact embryos (92.6%, 91.1%, and 80.4%, respectively) relative to those observed after dehydration in 0.1 mol/l sucrose (78.5%, 74.1%, and 54.6%, respectively, all P < 0.001). Post-thaw resumption of mitosis in vitro and implantation were not adversely affected by the increased prefreeze dehydration. This improved method for slow cooling of cleavage-stage embryos should have a major impact on clinical outcome.
增加胚胎和卵裂球在冷冻保存过程中的存活率，有望对辅助生殖治疗的结果产生重大影响。尽管如此，用于人类卵裂期胚胎慢速冷却的方法在过去二十年中基本没有改变。先前的研究表明，在对进行了植入前遗传学诊断活检的卵母细胞和胚胎进行慢速冷却之前，通过增加非渗透型冷冻保护剂的浓度来增加细胞内脱水程度，有助于提高冷冻存活率。本研究将这种方法的应用扩展到了对未活检的第 2 天胚胎的慢速冷却。与在 0.1 mol/l 蔗糖中脱水相比，在 0.2 mol/l 蔗糖中脱水显著增加了存活胚胎、存活卵裂球和完整胚胎的比例（分别为 92.6%、91.1%和 80.4%，均 P<0.001）。体外解冻后有丝分裂的恢复和胚胎着床并没有受到预冷冻脱水增加的不利影响。这种改良的卵裂期胚胎慢速冷却方法应该会对临床结果产生重大影响。
