程序化冷冻对小鼠胚胎发育的影响

取小鼠原核(220枚)、2～4细胞胚胎(227枚)、桑椹胚(127枚),将其分为3组,每一时期胚胎分成两半,一半取出后立即冷冻复苏并体外培养至囊胚,另一半体外培养至囊胚后冷冻复苏,子宫冲取囊胚(78枚)冷冻复苏为对照组;各组囊胚均移植至于宫,比较程序化冷冻对小鼠早期胚胎存活率的影响.结果表明:原核、2～4细胞胚胎、桑椹胚体外培养至囊胚后冷冻复苏率分别为56.4%、72.2%、81.6%,移植产仔率分别为38.1%、41.6%、56.8%,原核、2～4细胞组复苏率和产仔率极显著或显著低于对照组,桑椹胚组与对照组差异不显著,显示体外培养对早期胚胎冷冻存活有影响;原核、2～4细胞胚胎、桑椹胚冷冻后体外培养至囊胚,胚胎移植后产仔率分别为25.3%、28.2%、42.1%,与对应胚胎时期体外培养至囊胚冷冻复苏后移植产仔率相比,原核、2～4细胞组均存在显著差异,而桑椹胚组差异不显著,显示原核、2～4细胞的早期胚胎体外培养至囊胚后冷冻可提高冷冻存活率.

The effect of cryopreservation on the development of mouse embryos

The three different development stages of pronuclear(n=220),2-4 cell(n=227)and morula(n=127)were recovered.For each stage,half of the embryos were cultured to the blastocyst and frozen thereafter,while the remainder as control group was frozen just recovery and cultured to the blastocyst;the experimental group of the blastocyst was obtained from uterus and frozen immediately after recovery.The effects on mouse embryos from in vitro culture of early stage to blastocyst stage and on their ability to surviving from cyropreservation were assessed.The survival and birth rate of blastocyst derived from in vitro culture of pronuelear,2-4 cell,morula and blastocyst of in vivo were 56.4%,72.2%,81.6%,95.1% and 38.1%,41.6%,56.8%,74.3%,respectively.The survival and birth rate of pronuclear and 2-4 cell were significantly lower than the control group(P<0.01,P<0.05),which suggests that the viability of early embryos is affected by in vitro culture.The rate of blastocyst derived from in vitro culture of pronuclear and 2-4 cell after thawing is lower than their counterpart(P<0.05):the results indicate that the in vitro culture of pronuclear and 2-4 cell of mouse to the blastocyst stage prior to be frozen improves their survival after thawing.