慢速程序冷冻对透明带显微操作后人类胚胎冻存率及发育的影响

Effects of Slow Freezing on Embryo Survival Rate and Development after Zona Pellucida Micromanipulation

【目的】探讨慢速程序冷冻对透明带显微操作后胚胎冻存率及继续发育的影响。【方法】将 96个Ⅱ级以上人类多精受精胚胎随机分为单纯透明带打孔组 (n =2 4) ,胚胎活检组 (n =40 )及对照组 (n =32 )。为模拟临床种植前诊断活检后胚胎冷冻过程 ,将透明带显微操作后胚胎继续培养 6～ 10h再进行慢速程序冷冻 ,观察各组胚胎冷冻解冻后的冻存率及胚胎继续发育能力。【结果】活检及透明带打孔后冻融胚胎中发生裂解的卵裂球多位于透明带破口附近。活检组胚胎完整率、胚胎存活率及卵裂球存活率分别为 10 % ,2 5 0 %和 2 9 0 % ,较对照组 (4 3 7% ,6 6 0 %和 6 2 4% )明显降低 (P <0 0 1)。虽然单纯透明带打孔组冷冻后胚胎完整率及胚胎存活率与活检组无明显差异 ,但卵裂球存活率较胚胎活检组高 (分别为 40 9%和 2 9 0 % ) (P<0 0 1) ,以上各组存活胚胎继续发育率差异无显著性 (P>0 0 5 )。【结论】以丙二醇和蔗糖为冷冻保护剂的人类分裂期胚胎慢速冷冻程序并不适用于化学法透明带打孔活检胚胎的冷冻保存 。

To investigate the effects of freezing and thawing procedure on human embryos survival rate and development after zona pellucida micromanipulation. 96 polyspermic human embryos were randomly divided into three groups: drilling only group (n=24), biopsy group (n=40), and control group (n=32). To mimic the cryopreservation process of biopsied embryos in preimplantation genetic diagnosis, embryos were cryopreserved for 6～10 hours after zona pellucida micromanipulation. Intact embryo rate, embryo surviving rate, blastomere surviving rate and embryo further developmental rate were observed after embryo freezing and thawing. Degenerated blastomeres were mainly located around the drilling holes on zona pellucida in both drilling only group and biopsy group. Intact embryo rate, embryo surviving rate and blastomere surviving rate in biopsy group were 10%, 25% and 29% respectively, much lower than that in control group (43 7%, 66 0%, 62 4%, respectively.)(P<0 01). Though similar intact embryo rate and embryo surviving rate were obtained between drilling only group and embryo biopsy group, blastomere surviving rate in embryo biopsy group were significantly lower than that in drilling only group(40 9%,29 0%)(P<0 01). The embryo further developmental rates were similar among three groups (P>0 05). [Conclusion] Conventional freezing program using 1,2 propanediol and sucrose as croprotectants for cleavage stage embryos is not suitable for biopsied human embryos after chemical zona drilling. More attention should be paid to increase embryo surviving rate after biopsy.