Culture of 5-day horse embryos in microdroplets for 10 to 20 days.

The research paper discussed the successful long-term in vitro culture (IVC) of horse embryos for 10 to 20 days.

Research Methodology

• The researchers collected embryos from the uteri of mares five days after ovulation.
• Six embryos at the morula stage were cultured individually in 200-ul droplets of Ham’s F-12 media complemented with 10% fetal calf serum.
• The culture setup maintained a temperature of 37 degrees Celsius in a 5% CO2 atmosphere.

Research Findings

• By the third day of in vitro culture, all embryos grew enough to form blastocysts.
• Unlike in vivo conditions where the outermost layer (zona pellucida) thins out and flakes off during embryo development, in this in vitro study, the blastocysts hatched from their zones pellucida.
• This hatching process began on the third day of culture and was completed in five of the six embryos by the sixth day.
• In a typical in vivo scenario, an embryonic capsule forms around equine embryos after Day 6. However, these in vitro cultured embryos did not exhibit any embryonic capsule.
• Despite the absence of this capsule, the blastocysts continued to expand until 15 to 17 days of age (equivalent to 10 to 12 days in culture), after which they either collapsed or contracted.
• On average, these blastocysts attained a diameter of about 2052 ± 290 μm.

Research Implication

• The findings of this study affirmed that horse embryos could be cultivated in an in vitro condition over an extended period. Notably, the embryos showed continued growth and expansion even without the presence of the embryonic capsule.