Puncture of the Equine Embryonic Capsule and Its Repair In Vivo and In Vitro.

This study investigates the effect of puncturing the glycoprotein capsule of horse embryos on their capacity for survival and repair, with particular reference to extensive punctures. The findings revealed that smaller puncture holes encouraged higher rates of pregnancy and more successful in-vivo repair.

Research Goals and Methodology

The study aimed to identify the suitable size of a hole in the glycoprotein capsule of horse embryos that is compatible with embryo survival. This information is crucial for refining techniques to vitrify large horse embryos.

• Experimentation involved week-old embryos that were punctured using different instruments in order to vary the size of the holes.
• Three different puncturing methods were used: A 30-µm micromanipulator-controlled glass biopsy pipette, an acupuncture needle resulting in approximately 100-µm diameter holes, and a microneedle, with a tip less than 1 µm wide, generating holes that are about 30-µm in diameter.
• The embryos were either moved to recipient mares following puncture, or they were first cultured in-vitro for 48 hours. Furthermore, some of these in-vitro cultured embryos were transferred to recipient mares, facilitating comparison between in-vitro only, in-vivo only, and a combination of in-vitro and in-vivo environments following puncturing.

Key Findings

The findings revealed that the hole size and the subsequent environment play key roles in the embryos’ repair ability and survival probabilities.

• No pregnancies resulted when embryos had been punctured using the acupuncture needle, suggesting that the larger holes created were detrimental to embryo survival.
• With puncturing using micromanipulators or microneedles, the subsequent pregnancy rates were higher, at 75% and 67% respectively. These results indicate that smaller holes were more compatible with embryo survival and implantation.
• Neither of the embryos punctured using the acupuncture needle or the microneedle repaired their capsules while cultured in-vitro, indicating that the in-vitro environment is not conducive to capsule repair.
• Embryos punctured using the acupuncture needle failed to repair after 48 hours in-vivo whereas microneedle-induced punctured embryos did repair, suggesting that smaller holes enable better repair processes in-vivo.

Conclusion

The study concluded that smaller puncture holes, particularly those produced using a microneedle, are more compatible with horse embryo survival and implantation. Puncturing the embryo capsule using a microneedle opens the possibility for a manual method to vitrify horse embryos, which is of significant interest to embryo transfer and preservation professionals in veterinary settings.