Study of the effect of different methods for mature oocytes cryopreservation in rats

Objective To explore the effect of different methods on in vitro fertilization(IVF)and embryonic developmental capacity of thawed metaphage Ⅱ(MⅡ)stage oocytes.Methods The oocytes on MⅡstage were collected,then were cryopreserved by programmed cryopreservation and vitrification cryopreservation.The thawed oocytes were cultured to observe the rates of survival,IVF,cleavage and bastocyst.Results The survival rate of oocytes by vitrification cryopreservation was significantly higher than those by programmed cryopreservation(80.1% vs.55.5%,P0.01).There was also significant difference in the rates of bastocyst in different groups(28.6% vs.19.4%,P0.05).Conclusion Vitrification cryopreservation is more effective in oocytes cryopreservation on MⅡstage.