Low temperature preservation of rabbit embryos

Area of Science:

• Reproductive Biology
• Cryobiology
• Developmental Biology

Background:

• Cryopreservation is crucial for preserving genetic material.
• Dimethyl sulfoxide (DMSO) is a common cryoprotective agent.
• Optimizing freezing and thawing protocols is essential for successful embryo survival.

Purpose of the Study:

• To evaluate the survival rates of rabbit embryos at different developmental stages (4-cell, 8-cell, morula) after cryopreservation.
• To determine the optimal cooling and thawing rates for rabbit embryo cryopreservation.
• To assess the impact of cooling temperature transfer to liquid nitrogen on embryo integrity.

Main Methods:

• Rabbit embryos (4-cell, 8-cell, morula) were frozen using 1-5 M-DMSO.
• Cooling rates ranged from 0.74 to 0.90 degrees C/min.
• Thawing rates were approximately 12 and 15 degrees C/min.
• Embryo development was assessed in vitro for 48-72 hours.
• Embryos were transferred directly to liquid nitrogen after cooling to -110 degrees C or -80 degrees C.

Main Results:

• Highest in vitro survival rates (76-83%) were achieved with specific cooling and thawing rates.
• Cooling to -110 degrees C before transfer to liquid nitrogen reduced zona pellucida and mucin coat rupture.
• This improved recovery rates compared to cooling to -80 degrees C.
• Post-transfer viability was low (7% liveborn).

Conclusions:

• Cryopreservation protocols using DMSO can yield high in vitro survival rates for rabbit embryos.
• Optimized cooling and thawing parameters are critical for cryopreservation success.
• Transferring embryos to liquid nitrogen at -110 degrees C improves structural integrity post-thaw.
• Further research is needed to improve in vivo viability after cryopreservation and transfer.