title: Effects of sperm viability on fertilization and embryo cleavage following intracytoplasmic sperm injection.
abstract: OBJECTIVE
  In the human, intracytoplasmic sperm injection is typically performed using "viable" sperm which has been mechanically rendered nonmotile. The purpose of the present study was to determine the ability of nonviable sperm to fertilize human oocytes and the early developmental normalcy of the resulting embryos.
  
  
  METHODS
  In this study, immature, prophase I oocytes from a total of 27 consenting patients were matured in vitro and then randomized into two groups: injection with a viable human sperm or injection with a sperm rendered nonviable by freeze-thawing in liquid nitrogen. The rates of fertilization and cleavage were compared between the two groups.
  
  
  RESULTS
  The results demonstrated a significantly higher two-pronuclear fertilization rate when oocytes were injected with viable sperm (62.2%) compared to when oocytes were injected with nonviable sperm (16.2%). Oocytes injected with viable sperm also demonstrated a higher cleavage rate (91 vs 33%).
  
  
  CONCLUSIONS
  These findings suggest that while the intracytoplasmic injection of nonviable human sperm can result in normal fertilization, it does so at a much reduced rate compared to viable sperm and may not result in normally cleaving embryos.
authors.affiliation: Jones Institute for Reproductive Medicine, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk 23507, USA.
authors.forename: R
authors.initials: R
authors.lastname: Poe-Zeigler
authors.forename: F
authors.initials: F
authors.lastname: Nehchiri
authors.forename: P
authors.initials: P
authors.lastname: Hamacher
authors.forename: C
authors.initials: C
authors.lastname: Boyd
authors.forename: S
authors.initials: S
authors.lastname: Oehninger
authors.forename: S
authors.initials: S
authors.lastname: Muasher
authors.forename: S E
authors.initials: SE
authors.lastname: Lanzendorf
mesh_terms: D002470:Cell Survival; D005314:Embryonic and Fetal Development; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D008297:Male; D008845:Microinjections; D009865:Oocytes; D013094:Spermatozoa / Q000166:cytology*; D015053:Zygote / Q000254:growth & development