Effects of the Membranes of Vitrificated Mouse Oocytes on in vitro Fertilization

To investigate the effect of the membranes of mouse oocyte on fertilization in vitro as a model using oocyte of mouse after vitrification.Under room temperature(25±0.5)℃,oocytes were vitrified in OPS by two steps vitification method with cryprotectant solutions-that is,10%EG+10%DMSO and EDFS30.Oocytes were firstly pretreated in 10% EG+10% DMSO for 30 s,then exposed to EDFS30 for 25 s.The results showed that the cleavage rate of vitrificated oocytes were significantly lower(46.67% vs.86.06%)(P 0.05) than that of controls.The average number of sperm combined on the surface of the oocytes(10.70vs.10.81) and the average number of pronuclears in oocytes(2.49 vs.2.59) were all similar(P 0.05) between vitrificated and no-treated oocytes.After partial zona pellucida incision by piezo micromanipulation(ZIP),the cleavage rate of the vitrificated oocytes was similar(84.73% vs.91.19%)(P 0.05) with that of controls.In conclusion,the change of the zona pellucida of vitrificated mouse oocytes was one of the most important reasons to reduce the fetilization rate.