Prolonged interval between fusion and activation impairs embryonic development by inducing chromosome scattering and nuclear aneuploidy in pig somatic cell nuclear transfer

• Published in: Reproduction fertility and development Vol. 22; no. 6; pp. 977 - 986
• Main Authors: You, Jinyoung, Song, Kilyoung, Lee, Eunsong
• Format: Journal Article
• Language: English
• Published: Australia Collingwood, Victoria: CSIRO Publishing 2010
• Subjects: Aneuploidy; Animals; Cells, Cultured; Embryo Culture Techniques; Embryonic Development - genetics; maturation-promoting factor; nuclear ploidy; nuclear remodelling; Nuclear Transfer Techniques; Oocytes - physiology; pseudopronucleus; Swine; Time Factors
• ISSN: 1031-3613
• DOI: 10.1071/RD09309

The aim of the present study was to examine the effect of various intervals between electrofusion and activation (FA interval) on the nuclear remodelling and development of somatic cell nuclear transfer (SCNT) embryos in pigs. Reconstructed oocytes were activated at 0 (simultaneous fusion and activation; SFA), 1, 2 and 3h (delayed activation) after electrofusion; these groups were designated as DA1, DA2 and DA3, respectively. When oocyte nuclear status was examined at 0.5, 1, 2 and 3h after electrofusion, the incidence of chromosome scattering was increased (P<0.01) as the FA interval was extended (0.0%, 12.0%, 77.3% and 78.0%, respectively). Extending the FA interval led to an increase (P<0.01) in the percentage of oocytes containing multiple (≥3) pseudopronuclei (PPN) (0.0% of SFA; 5.3% of DA1; 21.7% of DA2; and 33.5% of DA3). The development of SCNT embryos to the blastocyst stage was decreased (P<0.05) in DA2 (5.7%) and DA3 (5.0%) compared with SFA (18.1%) and DA1 (19.5%). Our results demonstrate that extending the FA interval impairs the development of SCNT pig embryos by inducing chromosome scattering and the formation of multiple PPN, which may result in increased nuclear aneuploidy.