Spindle and Chromosome Abnormality of Aged, Matured Oocytes in Human

Abstract

There are cases in which the 1-day-old unfertilized oocytes after IVF, or in vitro matured oocytes obtained from denuded immature oocytes after ICSI, are used clinically. We investigated the morphological change of metaphase II spindle and chromosomal alignment in those oocytes. The spindles and chromosome were stained using an anti-α-tubulin antibody and Hoechst 33258 respectively. One-day-old oocytes displayed significant increases in abnormalities o f s p i n d l e s t r u c t u r e ( 4 0 . 4 % v s . 1 7 . 6 % ) a n d chromosomal alignment (40.4% vs. 29.4%). Oocytes matured in vitro from MI and PI oocytes displayed spindle morphological abnormalities at the rates of 41.7% and 36.0% respectively, and chromosomal alignment abnormality at the rates of 45.8% and 44.0% respectively. These results suggest that 1-day-old oocytes and in vitro matured oocytes obtained from denuded immature oocytes after ICSI might have lowered developmental potential. More than 50% of those oocytes were determined to be unsuitable for use as gametes.