title: Effect of population density on the early post-implantation mouse embryo growth in vitro.
abstract: OBJECTIVE
  To investigate the relationship between embryo population density and embryo development in vitro.
  
  
  METHODS
  Swiss Webster albino mice were used and blastocysts were flushed from the uterine horns. Various numbers of blastocysts were randomly assigned to separate 35 mm dishes and cultured for 9 days.
  
  
  RESULTS
  The effect of duration of culture to the mean success rates was different as the number of embryos in the dish was changed. In early egg cylinder (EEC) stage, the mean success rate was a flat function of the number of embryos. But the mean success rate was a decreasing function in late egg cylinder (LEC) stage and the decreasing rate was faster in early somite (ES) stage. Interestingly, the mean success rate to ES stage was nearly constant when more than 10 embryos were cultured in one dish.
  
  
  CONCLUSIONS
  The success rate to each developmental stage in vitro decreased as the number of embryos in the dish and the duration of cultured increased.
authors.affiliation: Department of Obstetrics and Gynecology, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea.
authors.forename: B M
authors.initials: BM
authors.lastname: Kang
authors.forename: C H
authors.initials: CH
authors.lastname: Kim
authors.forename: Y S
authors.initials: YS
authors.lastname: Chang
authors.forename: J E
authors.initials: JE
authors.lastname: Mok
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D046508:Culture Techniques; D005314:Embryonic and Fetal Development; D051379:Mice; D013997:Time Factors