Effect of cryopreservation on the cellular integrity of equine embryos.

This research is about the effects of cryopreservation on horse embryos. The study inspects the viability of methods such as using trypsin to thin the blastocyst capsule or cytochalasin-B to stabilise the cytoskeleton to mitigate damage on freezing.

Objective of the Study

• The main aim of this study was to check the effects of cryopreservation on the structural integrity of equine (horse) embryos.
• The research analyzed whether the potential damage to cells could be lessened by using trypsin to lessen the thickness of the embryo’s outer layer (blastocyst capsule) or using cytochalasin-B (cyto-B) to stabilize the support structure within cells (cytoskeleton).

Methodology

• The research worked with a total of 69 embryos collected seven days post-ovulation. The embryos were equilibrated in a 10% glycerol solution, with or without pretreatment with 0.2% trypsin or 7.5 micrograms/milliliters of cyto-B.
• Of these, 42 embryos were subject to freezing, while the rest were used to deduce if the pre-freezing treatment alone caused cell damage.
• After cryopreservation, the embryos were treated with fluorescent markers and substances to identify dead cells and check the integrity of the cytoskeleton.

Findings

• The study found that without freezing, no treatments affected cell survival rate. Cyto-B, however, changed actin distribution, but normalcy was restored within a four-hour culture duration.
• Post-cryopreservation, the number of dead cells (averaging at 11.1%) did not vary much across different processes.
• Comparison showed fewer cells died in small embryos as opposed to larger ones when not pretreated. Although not found to be significant, the size factor was negated when pretreatment with either trypsin or cyto-B was used.
• The study demonstrated that pretreating with trypsin helped maintain an intact cytoskeleton after thawing, but resulted in a sticky outer layer, complicating further handling.
• It was also found that the cyto-B-induced actin depolymerization was not reversed even after a six-hour post-thaw incubation.

Conclusion

• While pretreatment with trypsin appears to help in maintaining the cytoskeleton and both trypsin and cyto-B could possibly reduce cell death in cryopreservation of large embryos, these treatments also induce changes that may compromise the survival of the embryo.