Successful vitrification of manually punctured equine embryos

Area of Science:

• Reproductive biology
• Cryopreservation techniques
• Equine science

Background:

• Vitrification of equine blastocysts traditionally requires expensive, specialized micromanipulation equipment.
• This equipment necessitates significant user skill, posing a barrier to widespread adoption.

Purpose of the Study:

• To develop an accessible, manual method for equine blastocoele collapse before vitrification.
• To utilize commercially available cryopreservation kits for this manual method.

Main Methods:

• An in vivo experiment involving 79 equine embryos (Day 7-8).
• Validation of commercial human vitrification kits (DMSO/ethylene glycol and sucrose solutions).
• Manual blastocoele collapse using a microneedle on embryos ≤560 µm, followed by vitrification and warming using commercial kits.

Main Results:

• Manual puncture and vitrification of equine embryos ≤560 µm resulted in an 82% pregnancy rate.
• Non-punctured embryos ≤300 µm achieved an 80% pregnancy rate.
• Larger embryos, punctured embryos >560 µm, and extended equilibration times led to significantly lower pregnancy rates.

Conclusions:

• Manual blastocoele collapse is a viable alternative to micromanipulation for equine embryo vitrification.
• Commercial cryopreservation kits can be effectively used with this manual technique.
• This method offers a more accessible approach to equine embryo cryopreservation.