Micromanipulation of equine blastocysts to allow vitrification.

The research article examines a method for successful cryopreservation of expanded equine blastocysts—specifically, the use of micromanipulation with a Piezo drill for the vitrification process. The improved steps, also involving the modification of cryoprotectants, allow embryos up to 650 µm diameter to be frozen, yielding pregnancy rates that rival those for fresh embryos.

Objective of the Research

• The overarching aim of the study is to devise a successful method for the cryopreservation of equine embryos. This process is vital for banking genetics, especially in equine species where it’s typically challenged by various factors such as the late entry of the embryo into the uterus, quick expansion of the blastocyst, and the creation of the equine embryonic capsule.

Methodology

• The researchers discovered that a Piezo drill could be used to puncture the embryonic capsule and collapse the blastocyst. This significant step makes it possible for the blastocyst to be vitrified, contradicting the previous belief that breaching the capsule would render the embryo nonviable.
• A standard sperm injection pipette was successfully employed for the process, a significant breakthrough in equine embryo cryopreservation.
• The researchers tested and modified cryoprotectants as well as the methods of vitrification and warming to optimize the cryopreservation process. This resulted in an efficient method that allowed for vitrification of expanded equine blastocysts reaching up to 650 µm in diameter.

Results and Conclusion

• The proposed cryopreservation technique, involving blastocyst collapse and vitrification, yielded similar or close-to pregnancy rates as fresh embryos. This outcome highlights the success of the study and the viability of the method.
• Two substances, ethylene glycol and galactose, were used as cryoprotectants for cooling the embryo in a low-volume micropipette tip during the vitrification process.
• By providing a method for the successful vitrification of expanded equine blastocysts, the study presents a valuable tool for preserving genetics in exotic and valued equine species.