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 pronuclear,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(P0.01,P0.05),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(P0.05);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.