玻璃化冷冻对小鼠卵母细胞透明带超微结构变化及体外受精效果的影响

本实验采用OPS法玻璃化冷冻小鼠卵母细胞,通过扫描电镜观察透明带表面物理特性的变化。旨在研究冷冻导致小鼠卵母细胞透明带表面超微结构的变化以及冷冻卵母细胞体外受精后胚胎发育率和精子穿透透明带能力的影响。结果表明:冷冻后透明带表面网状结构消退或消失,发生熔融样变化。冷冻组中A型透明带比例(57.14%)显著低于毒性实验组(79.32%)及对照组(81.25%)(P<0.05),而发生熔融样变化的比例显著高于其他两组(P<0.05)。体外受精后,冷冻组的卵裂率和囊胚发育率(60.90%,39.51%)均显著低于毒性实验组及对照组(81.74%,55.72%;87.47%,61.63%)。体外受精4 h,冷冻组透明带平均结合精子数(10.56)与毒性实验组和对照组(10.26,10.21)间均无显著性差异(P>0.05);但受精后对透明带消化处理发现,冷冻组紧密结合精子的平均个数(3.28)与其他两组(5.11,5.21)存在显著性差异(P<0.05)。结果显示,冷冻导致透明带表面物理特性的变化,进而造成受精率下降。

Effects of Vitrification on Mouse ZP Ultrastructural Changes and in vitro Fertilization

The aim of our study is to investgate the effect of freezing on the ultrastructural changes of zona pellucida(ZP) surface,embryo subsequential development in vitro fertilization and the capacity of sperm penetrating ZP.The results showed that,compared with the other two groups,the ZP surface network structure of frozen group fades or disappears,with the occurrence of surface melting-like and smaller-pore-like changes.The proportion of A-type ZP in Frozen-group(57.14%) is significantly lower than the toxicity of the experimental group(79.32%)and control-group(81.25%)(P<0.05),while the proportion of melt-like changes(C-type) is significantly higher than the other two groups(P<0.05).The cleavage and blastocyst rates of frozen-group are significantly lower(P<0.05) than these of the toxicitygroup and control-group(60.90%,81.74%,87.47%;39.51%,55.72%,61.63%).After in vitro fertilization,there shows no significant difference(P>0.05) among the 3 groups in the the number of sperm binding to ZP(10.56,10.26,10.21),but digestion treatment after IVF,the number of sperm binding to oocytes tightly of frozen-group(3.28) is significant lower(P<0.05)than that of the other 2 groups(5.11,5.21).Thus,freezing does lead changes in the ultrastructure of ZP,and decrease the fertilization rate in vitro.