Use of time-lapse imaging to evaluate morphokinetics of in vitro equine blastocyst development after oocyte holding for two days at 15°C versus room temperature before intracytoplasmic sperm injection.

The research article discusses how time-lapse imaging was used to study the embryo development of horses to the blastocyst stage after invitro oocyte maturation, intracytoplasmic sperm injection, and embryo culture. It was found that keeping oocytes for 2 days at 15°C before maturation resulted in a significantly higher rate of blastocyst development.

Use of Time-Lapse Imaging and In Vitro Maturation

• Time-lapse imaging is a method that allowed the researchers to closely observe and record the embryo development of horses in real time, offering insights into the morphokinetics of equine blastocyst development.
• Through this technique, embryos were observed at various stages including precleavage cytoplasmic extrusion and cleavage to the 2-, 3-, and 4-cell stages.
• Embryos that developed to the blastocyst stage underwent these stages significantly earlier than embryos that arrested in development, exposing important differences between healthy and arrested embryonic development.

Impact of Oocyte Holding Temperature on Blastocyst Formation

• As part of the study, the research team determined the rate of blastocyst formation in oocytes that were held for 2 days at either 15°C or room temperature before undergoing In Vitro Maturation.
• The results demonstrated that the rate of blastocyst development was significantly higher in oocytes held at 15°C than at room temperature (13% vs 0% respectively).
• This groundbreaking finding indicates the drastic effects of temperature on the viability of equine oocytes and suggests 15°C as a potentially ideal temperature for oocyte storage before maturation.

Predictive Morphokinetic Parameters for Embryo Development

• The research team was able to establish morphokinetic parameters that predicted successful embryo development to the blastocyst stage after Intracytoplasmic Sperm Injection procedure in horses.
• Embryo development to the blastocyst stage was characterized by earlier cytoplasmic extrusion before cleavage and earlier cleavage to 2- and 4-cell stages. The time spent at the 2-cell stage was also significantly reduced in comparison with embryos that were non-competent.
• The researchers propose that these findings can be used as predictive markers for successful embryo development to the blastocyst stage after In Vitro Maturation and Intracytoplasmic Sperm Injection.

Conclusion

• The study conclusively demonstrated that time-lapse imaging can provide precise evaluation of different treatments on equine embryo development.
• Furthermore, it was established that holding oocytes at 15°C for 2 days before In Vitro Maturation resulted in a significantly higher rate of successful blastocyst development.