title: Microinjection of a single spermatozoon into the perivitelline space of bovine oocytes matured in vitro.
abstract: OBJECTIVE
  To evaluate the outcome of a single sperm injection into the perivitelline space of bovine oocytes.
  
  
  METHODS
  Oocytes obtained from the ovaries of slaughtered heifers and cows were cultured in medium 199 supplemented with 20% fetal calf serum for 24 hours. Fresh or frozen spermatozoa were incubated for two hours in Ham's F-10 medium containing 0.75% bovine serum albumin for capacitation and kept for 30 minutes in culture medium containing 12 mM dibutyryl cyclic guanosine 3',5' monophosphate and 10 mM imridazole for the acrosome reaction. Only one motile spermatozoon was injected into the perivitelline space of each oocyte.
  
  
  RESULTS
  The second polar body and the pronuclear stages were observed in 9.5% and 5.4% of oocytes, respectively. The cleavage rate of the oocytes over the two-cell stage was 4.1% (10 of 242).
  
  
  CONCLUSIONS
  The results of this study suggest that microinjection may be a useful technique for studying sperm-oocyte interaction. However, one spermatozoon is not enough to achieve an acceptable fertilization rate.
authors.affiliation: Department of Obstetrics and Gynecology, University of Kiel, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Mettler
authors.forename: S K
authors.initials: SK
authors.lastname: Kim
authors.forename: A
authors.initials: A
authors.lastname: Kuranty
mesh_terms: D000818:Animals; D002417:Cattle; D002455:Cell Division; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro / Q000379:methods*; D008297:Male; D008845:Microinjections / Q000379:methods*; D009865:Oocytes; D015203:Reproducibility of Results; D012662:Semen Preservation / Q000379:methods; D013084:Sperm-Ovum Interactions