title: Dead spermatozoa in raw semen samples impair in vitro fertilization outcomes of frozen-thawed spermatozoa.
abstract: OBJECTIVE
  To evaluate the influence of dead spermatozoa present in raw semen samples before and during freezing on the functionality and fertilization ability of frozen-thawed spermatozoa.
  
  
  METHODS
  Cryopreservation of raw semen samples with different known proportions of dead spermatozoa: native semen samples (<10%) and samples with 25%, 50%, and 75% dead spermatozoa.
  
  
  METHODS
  A university-based veterinary andrology laboratory.
  
  
  METHODS
  Five healthy and sexually mature boars.
  
  
  METHODS
  Sperm killed by three fast-freezing cycles.
  
  
  METHODS
  Assessment of intracellular generation of reactive oxygen species (ROS), nuclear DNA fragmentation, in vitro fertilization (IVF), and embryo development.
  
  
  RESULTS
  High proportions of dead spermatozoa in raw semen samples before and during freezing induce statistically significantly increased ROS generation and nuclear DNA fragmentation in frozen-thawed spermatozoa. These dysfunctional changes resulted in low ratios of in vitro penetrated oocytes and healthy developing embryos.
  
  
  CONCLUSIONS
  A high proportion of dead spermatozoa present in raw semen samples before and during freezing negatively influences the functionality and IVF outcomes of frozen-thawed spermatozoa.
authors.affiliation: Andrology Laboratory, Department of Medicine and Animal Surgery, Veterinary Teaching Hospital, University of Murcia, Murcia, Spain. roca@um.es
authors.forename: Jordi
authors.initials: J
authors.lastname: Roca
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Martinez-Alborcia
authors.forename: Maria A
authors.initials: MA
authors.lastname: Gil
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Parrilla
authors.forename: Emilio A
authors.initials: EA
authors.lastname: Martinez
mesh_terms: D000818:Animals; D016923:Cell Death / Q000502:physiology; D002478:Cells, Cultured; D046149:Embryo Culture Techniques; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary; D005615:Freezing / Q000009:adverse effects; D059471:In Vitro Oocyte Maturation Techniques / Q000662:veterinary; D008297:Male; D017382:Reactive Oxygen Species / Q000032:analysis / Q000378:metabolism; D012662:Semen Preservation / Q000009:adverse effects / Q000379:methods; D013076:Sperm Count; D053625:Sperm Retrieval / Q000009:adverse effects / Q000662:veterinary; D013094:Spermatozoa / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism / Q000502:physiology*; D013552:Swine; D016896:Treatment Outcome
chemical_list: D017382:Reactive Oxygen Species
keywords: DNA fragmentation; Dead sperm in raw semen; ROS generation; embryo development; in vitro fertilization; sperm cryopreservation