Embryo aggregation does not improve the development of interspecies somatic cell nuclear transfer embryos in the horse.

The research article focuses on exploring whether embryo aggregation might enhance the success rate of interspecies somatic cell nuclear transfer (iSCNT) in horses. The study concludes that while embryo aggregation does improve in vitro parthenogenetic (PA) embryo development and quality in some species, this method doesn’t lead to significant improvements in equine iSCNT embryos’ development.

Methodology and Results

• The research began by studying the impact of embryo aggregation on in vitro development and blastocyst quality in porcine, bovine, and feline zona-free (ZF) parthenogenetic (PA) embryos.
• Results showed that the diameter of bovine and porcine blastocysts significantly increased when embryos were aggregated, suggesting an improvement in their development.
• In the case of feline and bovine embryos, aggregation led to a higher blastocyst cell count, another indicator of better development.

Application to Equine Embryos

• O’REILLYThese results for PA embryos were then reflected on horse embryos. The scientists attempted to improve the in vitro development of ZF equine iSCNT embryos by reconstructing them with porcine, bovine, and feline ooplasm, using embryo aggregation.
• However, the researchers found that aggregation of equine embryos reconstructed in this way did not improve the iSCNT embryo development rates. In fact, the development of non-aggregated iSCNT embryos mainly stopped at the moment when the transcriptional activation of the embryonic genome occurs in the donor species.

Potential Advancement

• The study suggests that the use of domestic feline-enucleated oocytes may provide some promising results, as they were able to yield equine blastocyst-like structures regardless of embryo aggregation.
• This indicates that feline ooplasm could be the most suitable recipient to partly allow preimplantation embryo development of iSCNT equine embryos among the domestic animals studied.

Conclusions

• The study offers important insights into the ways in which embryo aggregation impacts the development of iSCNT embryos.
• While this technique has shown some promise in enhancing PA embryo development and quality, depending on the species, it does not significantly improve the in vitro development of equine iSCNT embryos.