title: Visualization of the metaphase II meiotic spindle in living human oocytes using the Polscope enables the prediction of embryonic developmental competence after ICSI.
abstract: BACKGROUND
  Meiotic spindles in living human oocytes can be visualized by the Polscope. This study investigated the relationship between the presence/location of the spindle in metaphase II (MII) oocytes and developmental competence of embryos in vitro.
  
  
  METHODS
  The spindles in 626 MII oocytes were examined by the Polscope and divided into six groups (A-F) based on the presence or absence of the spindles and the angle between the spindle and the first polar body. After ICSI, the fertilization and embryo development were evaluated.
  
  
  RESULTS
  Meiotic spindles were imaged in 523 oocytes (83.5%), while 103 (16.5%) did not have a visible spindle (group F). The majority of oocytes (68.8%) had the spindle directly beneath or adjacent to the first polar body (groups A and B: 48.2 and 20.6%). Oocytes in group C (11.2%) had the spindle located between 60 and 120 degrees angle away from the first polar body, those in group D (2.4%) had the spindle located between 120 and 180 degrees angle and those in group E (1.1%) had the spindle located at 180 degrees angle to the first polar body. The fertilization and embryonic development were similar in the oocytes with spindles regardless of spindle position. However, the rate of high quality embryos was significantly higher in the oocytes (64.2%) with visible spindles than in the oocytes (35.9%) without spindle and multipronuclear proportion showed a slight tendency to increase in oocytes without spindles. (10.7 versus 5.9%, P = 0.12; NS).
  
  
  CONCLUSIONS
  the presence of a bi-refringent meiotic spindle in human oocytes by using the Polscope can predict a higher embryonic developmental competence. However, the relative position of the spindle within the oocyte doesn't appear to influence the developmental potential of embryos.
authors.affiliation: In Vito Fertilization Laboratory, Maria Infertility Hospital, Seoul, Korea. mjhee@yahoo.co.kr
authors.forename: Jeong-Hee
authors.initials: JH
authors.lastname: Moon
authors.forename: Chang-Seop
authors.initials: CS
authors.lastname: Hyun
authors.forename: Seok-Won
authors.initials: SW
authors.lastname: Lee
authors.forename: Weon-Young
authors.initials: WY
authors.lastname: Son
authors.forename: San-Hyun
authors.initials: SH
authors.lastname: Yoon
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Lim
mesh_terms: D000328:Adult; D001718:Birefringence; D002470:Cell Survival; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008677:Metaphase; D009865:Oocytes / Q000502:physiology* / Q000648:ultrastructure*; D011379:Prognosis; D020554:Sperm Injections, Intracytoplasmic; D008941:Spindle Apparatus / Q000648:ultrastructure*