title: Intracytoplasmic single sperm injection of 1-day-old unfertilized human oocytes.
abstract: Although the average fertilization rate in most in-vitro fertilization (IVF) centres is approximately 60-70%, there are cases of complete or virtually complete fertilization failures. The aim of our work was to study the fertilization and the subsequent cleavage characteristics of 1-day-old human oocytes treated by intracytoplasmic single sperm injection (ICSI) after failing to fertilize during the standard IVF procedure. A total of 115 metaphase II 1-day-old unfertilized oocytes were collected from 23 patients. No additional treatment was applied to the oocytes or to the semen sample. A single spermatozoon from the patient's husband was injected into the cytoplasm of each of these oocytes 21-33 h after ovum retrieval. Injected oocytes were observed at 16-18 h and again 42-44 h after the ICSI procedure. Of the injected oocytes, 92% (n = 106) were intact after ICSI, 38% (n = 44) had two distinct pronuclei and there was no difference in the fertilization rate of oocytes when andrological and non-andrological patients were compared. Similarly, there was no difference in the fertilization rate after ICSI where patients with acceptable or good (> 15%) fertilization after standard IVF were compared to patients who had poor (< or = 15%) fertilization after IVF. There was no significant difference in the sperm concentration or in the progressive forward motility (a + b motility) in these groups except where a + b motility of andrological and non-andrological patients was compared. The majority (84%) of the normally fertilized oocytes cleaved and most (77%) of these embryos showed < 20% fragmentation 2 days after the ICSI procedure.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Centre for Reproductive Medicine, University Hospital, Vrije, Belgium.
authors.forename: Z P
authors.initials: ZP
authors.lastname: Nagy
authors.forename: H
authors.initials: H
authors.lastname: Joris
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: C
authors.initials: C
authors.lastname: Staessen
authors.forename: P
authors.initials: P
authors.lastname: Devroey
authors.forename: A C
authors.initials: AC
authors.lastname: Van Steirteghem
mesh_terms: D016922:Cellular Senescence / Q000502:physiology; D002970:Cleavage Stage, Ovum / Q000502:physiology; D003593:Cytoplasm / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D008845:Microinjections; D013084:Sperm-Ovum Interactions / Q000502:physiology*