title: Effect of sperm entry on blastocyst development after in vitro fertilization and intracytoplasmic sperm injection - mouse model.
abstract: OBJECTIVE
  To investigate whether in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), influence the embryo's development and its quality using the mouse as a model.
  
  
  METHODS
  Assisted fertilization was performed using ICSI and IVF. Fluorescent beads were adhered to the fertilization cone or place of previous sperm injection in the natural mated (NM), IVF and ICSI embryos, respectively. Embryo examination was carried out at the two-cell and blastocyst stage to determine the position of fluorescent bead. Protein expression was detected by fluorescence immunocytochemical staining and confocal microscopic imaging of blastocysts.
  
  
  RESULTS
  IVF and ICSI embryos developed at rates comparable to NM group. Embryos show similar expression patterns of two transcription factors, Oct4 and Cdx2. The most preferred place for spermatozoa attachment was the equatorial site of the egg, whether fertilization occurred in vitro or under natural conditions. We also link the sperm entry position (SEP) to embryo morphology and the number of cells at the blastocyst stage, with no influence of the method of fertilization.
  
  
  CONCLUSIONS
  IVF and ICSI, do not compromise in vitro pre-implantation development. Additional data, related to sperm entry, could offer further criteria to predict embryos that will implant successfully. Based on embryo morphology, developmental rate and protein expression level of key transcription factors, our results support the view that ART techniques, such as IVF and ICSI, do not perturb embryonic development or quality.
authors.affiliation: Yerkes National Primate Research Center, 954 Gatewood Rd., N.E., Atlanta, GA 30329, USA. karolina@piotrowska-nitsche.com
authors.forename: Karolina
authors.initials: K
authors.lastname: Piotrowska-Nitsche
authors.forename: Anthony W S
authors.initials: AW
authors.lastname: Chan
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D000071616:CDX2 Transcription Factor; D046149:Embryo Culture Techniques / Q000379:methods; D047108:Embryonic Development; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro / Q000379:methods*; D005456:Fluorescent Dyes; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D059471:In Vitro Oocyte Maturation Techniques; D008297:Male; D051379:Mice; D023421:Models, Animal; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D054315:Oocyte Retrieval; D009865:Oocytes / Q000166:cytology / Q000502:physiology; D061848:Optical Imaging; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*; D013094:Spermatozoa / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D000071616:CDX2 Transcription Factor; C487514:Cdx2 protein, mouse; D005456:Fluorescent Dyes; D018398:Homeodomain Proteins; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D014157:Transcription Factors