title: Effects of Vitrification on Outcomes of In Vivo-Mature, In Vitro-Mature and Immature Human Oocytes.
abstract: OBJECTIVE
  To observe the effects of vitrification on spindle, zona pellucida, embryonic aneuploidy and DNA injury in in vivo-maruted, in vitro-mature and immature human oocytes.
  
  
  METHODS
  Between January 2009 and February 2015, 223 immature oocytes from 450 infertile patients, and 31 in vivo-mature oocytes from 3 infertile couples were collected. Of the 223 immature oocytes, 113 were used for in vitro culture before vitrification. Some oocytes were randomly divided into in vivo-mature group (group A, n = 15), in vitro-mature group (group B, n = 88) and immature group (group C, n = 85), and then the oocytes with spindle in these three groups after freezing-thawing were selected to use for Polscope imaging, embryonic aneuploidy screening and embryo development evaluation. Other oocytes were randomly divided into group A (n = 16), group B (n = 25) and group C (n = 25) for detecting DNA injury.
  
  
  RESULTS
  After thawing, spindle occurrence rate, spindle Retardance value, and cleavage rate were significantly higher in groups A and B than in group C (all P < 0.05), but there were no statistical differences in fertility rate, high-quality embryo rate, blastulation rate and aneuploidy rate amongst the three groups (all P > 0.05). Zona pellucida density (ZPD) was significantly lower in group A than in groups B and C both before and after vitrification (all P < 0.05). ZPD was significantly higher after thawing than before vitrification (all P < 0.05), but zona pellucida thickness (ZPT) was not significantly changed in all the three groups (all P > 0.05). Rate of comet cells was significantly lower in group A than in groups B and C (all P < 0.01). Comet tail was significantly longer in group C than in groups B and A (all P < 0.05).
  
  
  CONCLUSIONS
  In vivo- and in vitro-mature human oocytes are more suitable to vitrification than immature human oocytes. Spindle Retardance value has more predictive value for embryonic development potential than ZPD and ZPT.
authors.forename: Wen-Yan
authors.initials: WY
authors.lastname: Song
authors.forename: Zhao-Feng
authors.initials: ZF
authors.lastname: Peng
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Chen
authors.forename: Hai-Xia
authors.initials: HX
authors.lastname: Jin
authors.forename: Gui-Dong
authors.initials: GD
authors.lastname: Yao
authors.forename: Sen-Lin
authors.initials: SL
authors.lastname: Shi
authors.forename: Hong-Yi
authors.initials: HY
authors.lastname: Yang
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Zhang
authors.forename: Ying-Pu
authors.initials: YP
authors.lastname: Sun
mesh_terms: D000328:Adult; D000782:Aneuploidy; D015925:Cryopreservation; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D005615:Freezing; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007247:Infertility, Female / Q000473:pathology; D009865:Oocytes / Q000502:physiology*; D055815:Young Adult