Related Experiment Videos
Embryonic behavior of two-cell mouse embryos frozen by the one- and two-step ultrarapid techniques
S Vasuthevan1, S C Ng, A Bongso
1Department of Obstetrics and Gynaecology, National University Hospital, Singapore.
Purpose:
A modified two-step ultrarapid freezing technique was compared to the one-step ultrarapid freezing technique. Two-cell mouse embryos were frozen-thawed using the two freezing protocols, and postthaw cryoprotectant removal was carried out in either a single- or a multiple-step procedure.
Results:
Statistically similar cryosurvival (96.95-100%) and blastocyst formation rates (87.95-91.47%) were obtained with both freezing groups. In addition, the method of cryoprotectant removal did not have any significant effect on the survival and development of the frozen-thawed embryos in both groups. Blastocysts formed following single-step cryoprotectant removal had significantly lower inner cell mass counts in the one-step than in the two-step group (26.14 and 27.59, respectively; P < 0.05). Embryo transfer studies showed that the implantation and fetal formation rates of embryos frozen by the two-step technique (61.67 and 60.0%, respectively) were similar to those of embryos frozen by the one-step technique (74.12 and 71.76%, respectively).
Conclusion:
These results demonstrate that the ultrarapid two-step technique is as effective in cryopreserving two-cell mouse embryos as the ultrarapid one-step technique.