Increase in digyny explains polyploidy after in-vitro fertilization of frozen-thawed mouse oocytes.
Fewer frozen-thawed mouse oocytes cleaved to the 2-cell stage compared to fresh control oocytes fertilized in vitro (46% vs 79%). The reduced rate of 2-cell formation was only partly explained by a decreased rate of fertilization (63% vs 85%). However, subsequent development to expanded blastocysts was not different (75% vs 78%). An increased frequency of second polar body retention by fertilized frozen-thawed oocytes compared with controls (11.8% vs 1.3%) was shown to be largely responsible for the higher incidence of polyploidy (16.3% vs 3.7%). The frequency of polyspermic fertilization was not different in the two groups (3.9% vs 2.3%).
Carroll
J
J
Department of Obstetrics and Gynaecology, University of Adelaide, Queen Elizabeth Hospital, Woodville, South Australia.
Warnes
G M
GM
Matthews
C D
CD
D000818:Animals; D001755:Blastocyst; D002478:Cells, Cultured; D002970:Cleavage Stage, Ovum; D005307:Fertilization in Vitro; D005615:Freezing; D051379:Mice; D009865:Oocytes / Q000648:ultrastructure*; D011123:Polyploidy; D014021:Tissue Preservation