title: Optimal timing of oocyte maturation and its relationship with the spindle assembly and developmental competence of in vitro matured human oocytes.
abstract: OBJECTIVE
  To develop and test a simple, feasible approach to improve spindle assembly and developmental competence of human in vitro matured oocytes by parthenogenetic activation in maturation medium.
  
  
  METHODS
  Prospective, randomized study.
  
  
  METHODS
  University research laboratory-based assisted reproductive technology laboratory.
  
  
  METHODS
  Four hundred thirty-two patients with male factor infertility undergoing intracytoplasmic sperm injection (ICSI) cycles.
  
  
  METHODS
  In vivo failed-to-mature oocytes from the ICSI cycles were divided into four groups according to differing duration after the extrusion of first polar body (0-1, 2-3, 4-5, and 8-9 hours). Oocytes spindles in each group were immunostained for α-tubulin and chromosomes, and observed by confocal microscopy.
  
  
  METHODS
  Rate from pronuclear stage to blastocyst, embryo grading at the eight-cell and blastocyst stages, and spindle assembly.
  
  
  RESULTS
  There was a statistically significantly higher rate of development at the eight-cell and blastocyst stages in the 2- to 3-hour and 4- to 5-hour groups. The grading results at the eight-cell and blastocyst stages also showed that the proportion of embryos of high quality was similar among the 2- to 3-hour and 4- to 5-hour groups, and in these groups it was statistically significantly higher than the 0- to 1-hour and 8- to 9-hour groups. The results of immunofluorescence demonstrated that there was a statistically significantly higher rate of normal spindle assembly in the 2- to 3-hour and 4- to 5-hour groups.
  
  
  CONCLUSIONS
  Optimal timing of maturation benefits the development of competence of in vitro matured oocytes by promoting normal spindle assembly.
authors.affiliation: State Key Laboratory of Reproductive Biology, Institute of Zoology, Beijing, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.forename: Jie
authors.initials: J
authors.lastname: Yan
authors.forename: Zi C
authors.initials: ZC
authors.lastname: Liu
authors.forename: Li Y
authors.initials: LY
authors.lastname: Yan
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhou
authors.forename: Jie
authors.initials: J
authors.lastname: Qiao
mesh_terms: D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods / Q000592:standards; D006801:Humans; D008297:Male; D009865:Oocytes / Q000166:cytology* / Q000254:growth & development*; D009866:Oogenesis / Q000502:physiology*; D011446:Prospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods* / Q000592:standards; D008941:Spindle Apparatus / Q000502:physiology*; D013997:Time Factors