In vitro development of horse oocytes reconstructed with the nuclei of fetal and adult cells.

The research article explores the conditions required to produce horse embryos through the injection of fetal and adult fibroblast cells into oocytes without a nucleus. The study suggests that the potential for creating horse embryos in vitro after transferring nuclei from these cells into recipient cells is quite minimal.

Methodology

The researchers used horse oocytes and two specific types of cells for this study:

• Fetal Fibroblast Cells (FFC): These cells were extracted from a 32-day-old Thoroughbred x Pony fetus.
• Adult Skin Fibroblast Cells (SFC): These were harvested from subdermal biopsies of a 4-year-old female pony.

The oocytes were obtained from horse ovaries recovered from abattoirs and matured in vitro (in a lab setting) with the help of cocultures with equine oviduct epithelial cells.

Procedure

The researchers went on to merge these fibroblast cells with the enucleated (without a nuclear core) oocytes, observing the fusion rates in two different conditions:

• The use of Direct Current (DC) pulses and Sendai virus.
• The use of Direct Current (DC) pulses alone.

Findings

After the procedure, the research showed that the rate of fusion was significantly higher with the combination of DC pulses and Sendai virus rather than just DC pulses alone. 

They also compared the rates of nuclear programming between FFC and SFC and found that there were no significant differences. However, the rate of cleavage (division of cells) of the resulting embryos to the 2-cell stage was higher when FFC was used as compared to SFC. 

Conclusion

From the resulting embryos, blastocysts were developed, but the overall proportion was very low in both cases (4% with FFC and 7% with SFC). These findings suggest a very limited potential for in vitro development of horse embryos after nuclear reprogramming following the transfer of nuclei from either fetal or adult fibroblasts into recipient enucleated oocytes.