title: A modified vitrification method reduces spindle and chromosome abnormalities.
abstract: Development of an effective system for oocyte-cryopreservation is of clinical relevance in reproductive medicine. However, oocyte-preservation is not as effective as embryo preservation. In this study, we used a 37°C pre-equilibrium temperature as part of a modified vitrification method for human oocyte cryopreservation. The effect of the new method on spindle configuration, chromosomal arrangement, and mitochondrial distribution was investigated in in vitro-matured human oocytes. A total of 101 in vitro-matured oocytes were randomly assigned for vitrification at pre-equilibrium temperature of 37°C (37°C Group, n=50) or at room temperature (RT Group, 22-24°C, n=51). The time needed for vitrification in the 37°C group was significantly shorter than that in the RT group. Defective spindles were found in 45.5% and 69.0% oocytes in the 37°C group and RT group, respectively (p < 0.05). Abnormal chromosomes were found in 47.7% and 71.4% oocytes, respectively (p < 0.05). There were no significant differences with respect to oocyte survival rate and mitochondrial distribution pattern between the two groups. These results indicate that vitrification at a pre-equilibrium temperature of 37°C may reduce the incidence of defective spindle configuration and chromosomal abnormalities in in-vitro-matured human oocytes.
  
  
  BACKGROUND
  ICSI: intracytoplasmic sperm injection; FSH: follicle-stimulating hormone; MII: metaphase II; EG: ethylene glycol; PROH: 1,2-propanediol.
authors.affiliation: a Medical Center for Human Reproduction , Beijing Chao-Yang Hospital, Capital Medical University , Beijing , China.
authors.forename: Minghui
authors.initials: M
authors.lastname: Liu
authors.affiliation: a Medical Center for Human Reproduction , Beijing Chao-Yang Hospital, Capital Medical University , Beijing , China.
authors.forename: Wenhui
authors.initials: W
authors.lastname: Zhou
authors.affiliation: a Medical Center for Human Reproduction , Beijing Chao-Yang Hospital, Capital Medical University , Beijing , China.
authors.forename: Dapeng
authors.initials: D
authors.lastname: Chu
authors.affiliation: a Medical Center for Human Reproduction , Beijing Chao-Yang Hospital, Capital Medical University , Beijing , China.
authors.forename: Lei
authors.initials: L
authors.lastname: Fu
authors.affiliation: a Medical Center for Human Reproduction , Beijing Chao-Yang Hospital, Capital Medical University , Beijing , China.
authors.forename: Wei
authors.initials: W
authors.lastname: Sha
authors.affiliation: a Medical Center for Human Reproduction , Beijing Chao-Yang Hospital, Capital Medical University , Beijing , China.
authors.forename: Shan
authors.initials: S
authors.lastname: Liu
authors.affiliation: a Medical Center for Human Reproduction , Beijing Chao-Yang Hospital, Capital Medical University , Beijing , China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
mesh_terms: D000328:Adult; D002869:Chromosome Aberrations; D015925:Cryopreservation / Q000379:methods*; D005260:Female; D006801:Humans; D009865:Oocytes; D058989:Vitrification
keywords: Human oocyte; pre-equilibrium temperature; vitrification