Deng Aimin, Wang Wei-Hua
Center for Reproductive Medicine, Changsha Hospital for Maternal and Child Health Care, No. 416, Chengnan East Road, Changsha City, Hunan China.
Houston Fertility Laboratory, Vivere Health, Houston, TX USA ; Houston Fertility Institute, 2500 Fondren Road, Suite 350, Houston, TX 77063 USA.
Mol Cytogenet. 2015 Feb 15;8:12. doi: 10.1186/s13039-015-0117-8. eCollection 2015.
Increased embryo implantation rates were reported after transfer of euploid embryos selected by preimplantation genetic screening (PGS). Egg cryopreservation by vitrification has become one of the most important assisted human reproduction technologies. Although reports indicate that development and implantation of human embryos derived from frozen donor eggs are comparative to fresh eggs, it is still unknown whether egg vitrification increases chromosomal abnormalities in eggs, which in turn causes formation of embryonic aneuploidy. Therefore, in this study, we evaluated the aneuploidy formation in the blastocysts derived from frozen donor eggs and also evaluated the efficiency of egg vitrification as an advanced technology for egg cryopreservation.
In this study, donated human eggs from young women were cryopreserved by vitrification and PGS was performed in the resulted blastocysts by DNA microarray. A total of 764 frozen eggs from 75 egg thawing cycles were warmed and 38 blastocysts were biopsied for PGS before embryo transfer. A 97.1% of egg survival rate was obtained and 59.1% of embryos developed to blastocyst stage. After biopsy and PGS, it was found that 84.2% of blastocysts were euploid and 15.8% were aneuploid. Aneuploidy rates varied among donors. Transfers of blastocysts without PGS resulted in higher clinical pregnancy and implantation rates as compared with transfer of blastocysts with PGS.
Although the overall aneuploidy rate was low in the blastocysts derived from frozen donor eggs, high aneuploidy rates were observed in the embryos resulting from some donated eggs. Clinical pregnancy rate was not improved by PGS of embryos resulting from donor eggs, indicating that PGS may not be necessary for embryos derived from donor eggs in most cases.
据报道，通过植入前基因筛查（PGS）选择的整倍体胚胎移植后，胚胎着床率有所提高。玻璃化卵子冷冻已成为最重要的人类辅助生殖技术之一。尽管有报道表明，冷冻供体卵子来源的人类胚胎的发育和着床情况与新鲜卵子相当，但卵子玻璃化是否会增加卵子中的染色体异常，进而导致胚胎非整倍体的形成仍不清楚。因此，在本研究中，我们评估了冷冻供体卵子来源的囊胚中的非整倍体形成情况，并评估了卵子玻璃化作为一种先进的卵子冷冻技术的效率。
在本研究中，将年轻女性捐赠的人类卵子通过玻璃化进行冷冻，并对所得囊胚通过DNA微阵列进行PGS。来自75个卵子解冻周期的总共764个冷冻卵子被解冻，38个囊胚在胚胎移植前进行活检以进行PGS。获得了97.1%的卵子存活率，59.1%的胚胎发育到囊胚阶段。活检和PGS后发现，84.2%的囊胚为整倍体，15.8%为非整倍体。非整倍体率在不同供体之间有所差异。与移植经过PGS的囊胚相比，移植未经PGS的囊胚导致更高的临床妊娠率和着床率。
尽管冷冻供体卵子来源的囊胚总体非整倍体率较低，但在一些捐赠卵子产生的胚胎中观察到了高非整倍体率。供体卵子来源的胚胎进行PGS并未提高临床妊娠率，这表明在大多数情况下，供体卵子来源的胚胎可能不需要进行PGS。
