title: Improvement in blastocyst hatching of mouse embryos cocultured with human placental cells.
abstract: OBJECTIVE
  Although the hatching of embryos is an important phenomenon, the mechanism of hatching remains controversial. Therefore, we attempted to develop a new coculture system with human placental cells to investigate the hatching of mouse embryos.
  
  
  RESULTS
  In our new system there was no difference in development from the two-cell stage to blastocysts between embryos cultured with a T6 medium and embryos cocultured with human placental cells at 1 x 10(5), 5 x 10(5), and 1 x 10(6) cells/ml. However, the hatching-rate cell number increased significantly in embryos cocultured with placental cells compared to embryos cultured without placental cells. [3H]Thymidine uptake did not show any significant difference from the beginning of in vitro culture to the hatching stage between the coculture group and the control group. Nevertheless, the [3H]uridine uptake was significantly different in the two groups, measuring 2167 +/- 532 cpm/10 embryos in the coculture group and 804 +/- 86 cpm/10 embryos in the control group at 114 hr after human chorionic gonadotropin injection (P < 0.01).
  
  
  CONCLUSIONS
  These results therefore seem to indicate that the hatching of blastocysts depends on the protein synthesis of the embryos and not on DNA duplications.
authors.affiliation: Department of Gynecology and Obstetrics, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Morishita
authors.forename: M
authors.initials: M
authors.lastname: Yokoyama
authors.forename: M
authors.initials: M
authors.lastname: Nozaki
authors.forename: M
authors.initials: M
authors.lastname: Sano
authors.forename: H
authors.initials: H
authors.lastname: Nakano
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology* / Q000378:metabolism; D002478:Cells, Cultured; D003433:Crosses, Genetic; D004247:DNA / Q000096:biosynthesis; D005314:Embryonic and Fetal Development; D005260:Female; D006801:Humans; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D010920:Placenta / Q000166:cytology*; D011247:Pregnancy; D012313:RNA / Q000096:biosynthesis
chemical_list: D012313:RNA; D004247:DNA