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Vitrification of mouse embryos at various stages by open-pulled straw (OPS) method
Guang-Bin Zhou1, Yun-Peng Hou, Fang Jin
1Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing, P.R. China.
Animal Biotechnology
|December 13, 2005
Summary
Optimal cryopreservation of mouse embryos was achieved using a two-step Open Pulled Straw (OPS) method. This optimized protocol proved effective for various developmental stages, with early blastocysts showing the highest survival rates.
Area of Science:
- Reproductive Biology
- Developmental Biology
- Cryobiology
Background:
- Cryopreservation of mammalian embryos is crucial for assisted reproductive technologies.
- Optimizing cryopreservation protocols enhances embryo survival and developmental potential.
- Mouse models are essential for studying embryo cryopreservation techniques.
Purpose of the Study:
- To determine the optimal conditions for mouse morula cryopreservation using a two-step Open Pulled Straw (OPS) method.
- To evaluate the feasibility of this optimized protocol for embryos at different developmental stages.
Main Methods:
- Mouse morulae were vitrified using one-step or two-step OPS methods with varying exposure times to EDFS30 solution (15% ethylene glycol, 15% DMSO, Ficoll, sucrose).
- Embryos were assessed morphologically post-warming and evaluated for development to blastocysts, expanded/hatched blastocysts, and term after transfer.
- The optimal protocol was applied to embryos at different developmental stages (one-cell to early blastocyst).
Main Results:
- The optimal two-step OPS protocol involved pre-treatment in 10% EG + 10% DMSO for 0.5 min, followed by exposure to EDFS30 for 25 sec.
- Vitrified-warmed morulae showed high blastocyst rates (91.7%) and developmental rates to expanded (100%) and hatched blastocysts (62.3%).
- In vivo survival rates for vitrified morulae (33.1%) were comparable to fresh embryos (24.6%).
- Cryopreservation of four-cell to early blastocyst stages yielded high recovery rates (93.4-100%) and blastocyst rates (81.7-100%).
- Early blastocysts exhibited the highest in vivo survival rate (40.4%) after cryopreservation.
Conclusions:
- The optimized two-step OPS protocol is effective for cryopreserving mouse morulae.
- This protocol is suitable for mouse embryos from the four-cell stage to early blastocyst.
- Early blastocyst stage is the most feasible for mouse embryo cryopreservation under the tested conditions.