Vladimirov Iavor K, Tacheva Desislava, Diez Antonio
In vitro Fertilization Unit Sofia Hospital of Obstetrics, Gynaecology and Reproductive Medicine Sofia Bulgaria.
Faculty of Biology Sofia University "St. Kliment Ohridski" Sofia Bulgaria.
Reprod Med Biol. 2017 Apr 5;16(2):118-125. doi: 10.1002/rmb2.12027. eCollection 2017 Apr.
To create hypothesis, which can give a logical explanation related to the benefits of freezing/thawing embryos. Cryopreservation is not only a technology used for storing embryos, but also a method of embryo treatment that can potentially improve the success rate in infertile couples.
From the analysis of multiple results in assisted reproductive technology, which have no satisfactory explanation to date, we found evidence to support a 'therapeutic' effect of the freezing/thawing of embryos on the process of recovery of the embryo and its subsequent implantation.
Freezing/thawing is a way to activate the endogenous survival and repair responses in preimplantation embryos. Several molecular mechanisms can explain the higher success rate of ET using thawed embryos compared to fresh ET in women of advanced reproductive age, the higher miscarriage rate in cases of thawed blastocyst ET compared to thawed ET at early cleavage embryo, and the higher perinatal parameters of born children after thawed ET. Embryo thawing induces a stress. Controlled stress is not necessarily detrimental, because it generates a phenomenon that is counteracted by several known biological responses aimed to repair mitochondrial damage of membrane and protein misfolding. The term for favorable biological responses to low exposures to stress is called hormesis.
This thesis will summarize the role of cryopreservation in the activation of a hormetic response, preserving the mitochondrial function, improving survival, and having an impact on the process of implantation, miscarriage, and the development of pregnancy.
为了提出假设，以对胚胎冷冻/解冻的益处作出合理的解释。冷冻保存不仅是一种用于储存胚胎的技术，也是一种胚胎治疗方法，有可能提高不孕夫妇的成功率。
通过对辅助生殖技术中多个尚无满意解释的结果进行分析，我们发现了证据支持胚胎冷冻/解冻对胚胎恢复及其随后着床过程具有“治疗”作用。
冷冻/解冻是一种激活植入前胚胎内源性存活和修复反应的方式。几种分子机制可以解释，与高龄女性新鲜胚胎移植相比，解冻胚胎移植成功率更高；与早期卵裂期胚胎解冻移植相比，解冻囊胚移植流产率更高；解冻胚胎移植后出生儿童围产期参数更高。胚胎解冻会引发应激。可控应激不一定有害，因为它会引发一种现象，这种现象会被几种旨在修复线粒体膜损伤和蛋白质错误折叠的已知生物学反应所抵消。对低水平应激产生有利生物学反应的术语称为兴奋效应。
本论文将总结冷冻保存在激活兴奋效应反应、维持线粒体功能、提高存活率以及对着床、流产和妊娠发育过程产生影响方面的作用。
