title: Sperm deoxyribonucleic acid fragmentation dynamics in fertile donors.
abstract: OBJECTIVE
  To study the velocity of sperm DNA fragmentation in frozen-thawed sperm samples from male sperm donors of proved fertility.
  
  
  METHODS
  Sperm DNA fragmentation assessment with use of sperm chromatin dispersion methodology after 0, 4, 8, and 24 hours of incubation in IVF medium.
  
  
  METHODS
  Academic biology and reproductive medicine centers.
  
  
  METHODS
  Twenty male fertility donors with proved fertility for a maximum of six births at the reproductive medicine center.
  
  
  METHODS
  None.
  
  
  METHODS
  The velocity of sperm DNA fragmentation between two consecutive incubations was scored. Best adjustment of sperm DNA fragmentation index versus incubation time for linear, logarithmic, or exponential function was tested.
  
  
  RESULTS
  Increase of sperm DNA fragmentation through time accounted for a substantial percentage of the overall variation. The highest velocity of sperm DNA fragmentation was observed in the first 4 hours of incubation, decreasing by 50% during the second incubation period and being of the order of 1% in the final experimental period. The tendency to increase in sperm DNA fragmentation is not homogeneous among donors; they may adjust to a logarithmic, linear, or exponential function rendering high values for R(2).
  
  
  CONCLUSIONS
  Sperm DNA fragmentation occurs rapidly after thawing, and it is an important cause of the rapid decline of sperm quality. Thus, the use of sperm samples as quickly as possible after thawing is highly recommended in clinical practice. Different sperm DNA fragmentation dynamics among individuals were observed.
authors.affiliation: Department of Biology, Genetics Unit, Universidad Autónoma de Madrid, Madrid, Spain. jaime.gosalvez@uam.es
authors.forename: Jaime
authors.initials: J
authors.lastname: Gosálvez
authors.forename: Elva
authors.initials: E
authors.lastname: Cortés-Gutierez
authors.forename: Carmen
authors.initials: C
authors.lastname: López-Fernández
authors.forename: José Luís
authors.initials: JL
authors.lastname: Fernández
authors.forename: Pedro
authors.initials: P
authors.lastname: Caballero
authors.forename: Rocio
authors.initials: R
authors.lastname: Nuñez
mesh_terms: D053938:DNA Fragmentation; D005260:Female; D005298:Fertility; D005306:Fertilization; D006801:Humans; D007700:Kinetics; D008297:Male; D011247:Pregnancy; D013094:Spermatozoa / Q000502:physiology*