title: The effect of human cumulus cells on the maturation and developmental potential of immature oocytes in ICSI cycles.
abstract: OBJECTIVE
  To investigate the effect of human cumulus cells on the maturation and developmental potential of immature oocytes in ICSI cycles.
  
  
  METHODS
  Immature oocytes were randomly divided into two groups: the cumulus-denuded oocyte group (group A) and the cumulus-intact oocyte group (group B). Only oocytes that reached metaphase II (MII) stage after in vitro maturation were used in the ICSI procedure. In vivo mature sibling MII oocytes served as the control group. Maturation rate, fertilization rate, embryo quality and developmental potential were examined.
  
  
  RESULTS
  There was no significant difference in maturation rate between group A (68.16%) and group B (70.49%; P > 0.05). The total fertilization rate among the three groups was comparable (P > 0.05), while the zygotes with two pronuclei in group A (74.59%) or group B (75.97%) were significantly lower than those in control group (84.29%; P < 0.05). The available embryo rate in group A (11.49%) was markedly lower than that in group B (27.66%; P < 0.05), and both of them were significantly lower than that in control group (62.38%; P < 0.05). The proportion of ≥6-cell embryos in group B (45.74%) was notably higher than in group A (26.44%; P < 0.05), and both were markedly lower than in control group (65.92%; P < 0.05). The proportion of embryos with <10% fragmentation in group A (13.79%) was significantly lower than in group B (29.79%; P < 0.05), and both were notably lower than in control group (42.98%; P < 0.05).
  
  
  CONCLUSIONS
  The presence of cumulus cells surrounding the immature oocytes during IVM before ICSI had no influence on nuclear maturation and fertilization, but leads to better subsequent embryonic development. This is perhaps mediated by an improvement in cytoplasmic maturation.
authors.affiliation: Department of Histology and Embryology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
authors.forename: Aijun
authors.initials: A
authors.lastname: Zhang
authors.forename: Bufang
authors.initials: B
authors.lastname: Xu
authors.forename: Yijuan
authors.initials: Y
authors.lastname: Sun
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Lu
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Niu
authors.forename: Qian
authors.initials: Q
authors.lastname: Chen
authors.forename: Yun
authors.initials: Y
authors.lastname: Feng
authors.forename: Chen
authors.initials: C
authors.lastname: Xu
mesh_terms: D000328:Adult; D054885:Cumulus Cells / Q000166:cytology*; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D059471:In Vitro Oocyte Maturation Techniques / Q000379:methods*; D008677:Metaphase / Q000502:physiology; D009865:Oocytes / Q000166:cytology / Q000254:growth & development*; D011247:Pregnancy; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods