Culture protocols for horse embryos after ICSI: Effect of myo-inositol and time of media change.

The study investigates the most effective culture protocols for horse embryos produced in vitro using intracytoplasmic sperm injection (ICSI), particularly considering the use of myo-inositol and the timing of media change.

Objective of the Research

• The main objective was to improve the rate of horse embryo blastocyst production, which is usually sub-optimal in ICSI. The researchers explored different factors that could enhance this process in a horse embryo culture system.

Research Methodology

• The study was divided into three experiments, each evaluating a different facet of the process.
• Experiment 1 probed the impact of myo-inositol, a compound found in the horse oviduct and known to enhance blastocyst development in other species. They added 10mM myo-inositol to the embryo culture medium from Day 0 to Day 5.
• Experiment 2 looked at the effects of eliminating a standard post-ICSI holding step, where the embryo culture is held for 30-60 minutes in a medium-based on M199.
• In Experiment 3, they examined the influences of an earlier transition to a second-step medium. They also looked at the impacts of media refreshment at different time points during the embryo culture.

Research Findings

• The research found that there were no significant differences observed in blastocyst development between different groups in the first two experiments.
• In Experiment 3, no significant differences in blastocyst development were witnessed for embryos refreshed at both Day 3 and Day 7, or only at Day 7, or those transferred to second-step medium on Day 4 or Day 5.

Significance of the Study

• This knowledge about culture procedures that are compatible with blastocyst formation in vitro is highly beneficial for laboratories starting to develop procedures for ICSI in horses. These insights could potentially improve fertility treatments in horse breeding and maintain the diversification of the species.