Nuclear transplantation in bovine embryos

Area of Science:

• Reproductive Biology
• Developmental Biology
• Animal Biotechnology

Background:

• Nuclear transplantation is a key technique in reproductive technologies.
• Optimizing methods for bovine nuclear transfer is crucial for livestock improvement and research.

Purpose of the Study:

• To establish an efficient nuclear transplantation technique for bovine embryos.
• To evaluate the developmental potential of donor nuclei from various bovine embryonic stages following transplantation into enucleated zygotes.

Main Methods:

• Pronuclear bovine embryos were centrifuged to isolate membrane-bound karyoplasts.
• Nuclei were inserted into enucleated zygotes using electrically induced cell fusion.
• Fusion efficiency was optimized using Zimmerman Cell Fusion medium at specific voltage and duration.

Main Results:

• Optimal fusion rates (79%) were achieved at 100 V for 20-40 microseconds with parallel membrane orientation.
• Nuclear transplant embryos showed reduced development to morulae/blastocysts (17%) compared to controls (37%).
• Two nuclear transplant embryos developed into normal live bovine offspring.

Conclusions:

• Successful bovine nuclear transplantation resulting in live offspring was demonstrated.
• The developmental potential of transplanted nuclei is stage-dependent, with early pronuclear stage nuclei being most viable.
• Further research is needed to improve efficiency and understand developmental limitations in bovine nuclear transfer.