[Methods of cryopreservation in animal experiments]

Area of Science:

• Reproductive Biology
• Cryobiology
• Developmental Biology

Context:

• Cryopreservation is crucial for preserving genetic material and enabling assisted reproduction technologies.
• Mouse embryos are a standard model for studying early developmental processes and cryopreservation techniques.
• Optimizing cryopreservation methods is essential for maximizing embryo survival rates and reproductive success.

Purpose:

• To compare the efficacy of a slow computer-controlled cryopreservation program with different ultrarapid cooling methods for mouse embryos.
• To evaluate the impact of cryoprotectant equilibration time on embryo survival during ultrarapid cooling.
• To determine the optimal cryopreservation strategy for achieving high blastocyst development rates post-thaw.

Summary:

• A slow computer-controlled program resulted in 79% blastocyst development from 104 mouse embryos.
• Vitrification yielded 81% blastocyst development from 63 embryos.
• Ultrarapid cooling program A (4-step equilibration) achieved 62% survival, while program B (2-step equilibration) resulted in only 12% survival, likely due to insufficient cryoprotectant uptake and intracellular ice formation.

Impact:

• Demonstrates that longer cryoprotectant equilibration times are critical for successful ultrarapid cryopreservation of mouse embryos.
• Provides insights into the mechanisms of cryodamage, specifically intracellular ice formation, during rapid cooling.
• Informs the development of improved cryopreservation protocols for mammalian embryos, potentially enhancing fertility preservation and research applications.