Transfer of germinal vesicle to ooplasm of young mice could not rescue ageing-associated chromosome misalignment in meiosis of oocytes from aged mice.
BACKGROUND
[corrected] Transferring a germinal vesicle (GV) from an aged woman's oocyte into ooplasm from a younger woman has been proposed as a possible way to overcome the problem of age-related decline in female fertility. Here we assessed this possibility by determining whether ooplasts derived from young mice could rescue ageing-associated chromosome misalignment in meiosis of oocytes from aged mice.


METHODS
Three groups of reconstructed oocytes, young GV-young cytoplast (group YY), aged GV-young cytoplast (group AY), and young GV-aged cytoplast (group YA), were created by micromanipulation and electrofusion.


RESULTS
Nuclear transplantation was successful in 89.8-94.4% of GV-ooplast complexes, and maturation rate of the reconstructed oocytes was 93.5-97.9%. Confocal microscopy analysis showed a significantly higher rate (49.2%) of chromosome misalignment in ageing mice than in young mice (16.9%), and 57.1% of oocytes in group AY exhibited chromosome misalignment, while the abnormality rate in groups YY and YA was 16.3 and 16.7% respectively. Calcium imaging showed that the three groups of reconstructed oocytes exhibited a similar pattern of calcium oscillations upon stimulation with bovine sperm extracts. Fertilization rate and developmental capacity to 2-cell embryos were also similar among the three groups of oocytes.


CONCLUSIONS
Our findings suggest that: (i) the ooplasm from young mice could not rescue ageing-associated chromosome misalignment in meiosis of GV from aged mice; and (ii) behaviour of chromosome alignment over metaphase spindle is predominantly determined by GV material.
Cui
Long-Bo
LB
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100080, China.
Huang
Xiu-Ying
XY
Sun
Fang-Zhen
FZ
D000367:Age Factors; D000818:Animals; D020013:Calcium Signaling; D002467:Cell Nucleus / Q000235:genetics; D017690:Cell Transplantation / Q000379:methods; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000235:genetics*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D008540:Meiosis; D051379:Mice; D008815:Mice, Inbred Strains; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D008941:Spindle Apparatus / Q000235:genetics / Q000502:physiology