title: The DNA integrity of cryopreserved spermatozoa separated for use in assisted reproductive technology is unaffected by the type of cryoprotectant used but is related to the DNA integrity of the fresh separated preparation.
abstract: OBJECTIVE
  To investigate and compare seven different commercially available cryoprotectant media in terms of the DNA integrity of spermatozoa recovered after cryopreservation and separation using density gradient centrifugation (DGC).
  
  
  METHODS
  A prospective clinical study.
  
  
  METHODS
  Tertiary care fertility clinic.
  
  
  METHODS
  Three hundred twenty men presenting for infertility investigations.
  
  
  METHODS
  Each sample was randomly assigned to one of seven commercially available cryoprotectants or to no cryoprotectant.
  
  
  METHODS
  Percentage sperm DNA fragmentation after cryopreservation and preparation using DGC.
  
  
  RESULTS
  The mean percentage fragmentation was significantly higher post-thaw and post-DGC; however, some patients (26.3%) demonstrated a lower percentage fragmentation post-thaw. No single cryoprotectant was identified as the best at preserving DNA integrity. The difference in fragmentation after thawing and DGC was found to be highly dependent on the prefreeze fragmentation. Motility was also significantly correlated with the difference in fragmentation post-thaw (r = -0.161).
  
  
  CONCLUSIONS
  Neither the presence nor type of cryoprotectant affects the DNA integrity of spermatozoa after cryopreservation and DGC. Individuals with lower prefreeze fragmentation in DGC-prepared spermatozoa have larger increases in fragmentation and are less likely to exhibit lower levels of fragmentation post-thaw. The reverse effect observed in those with higher prefreeze fragmentation gives rise to a possible novel method of reducing fragmentation in sperm used for assisted reproductive technology treatment cycles without the need for testicular sperm retrievals.
authors.affiliation: Fertility First, Hurstville, Australia. Electronic address: lthomson@fertilityfirst.com.au.
authors.forename: Laura Kelly
authors.initials: LK
authors.lastname: Thomson
authors.affiliation: Department of Obstetrics and Gynecology, Westmead Hospital, University of Sydney, Sydney, Australia.
authors.forename: Steven Denis
authors.initials: SD
authors.lastname: Fleming
authors.affiliation: Fertility First, Hurstville, Australia.
authors.forename: Lauren
authors.initials: L
authors.lastname: Schulke
authors.affiliation: Fertility First, Hurstville, Australia.
authors.forename: Katrina
authors.initials: K
authors.lastname: Barone
authors.affiliation: Fertility First, Hurstville, Australia.
authors.forename: Julie-Anne
authors.initials: JA
authors.lastname: Zieschang
authors.affiliation: Fertility First, Hurstville, Australia.
authors.forename: Anne Melton
authors.initials: AM
authors.lastname: Clark
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology; D002469:Cell Separation / Q000379:methods; D002499:Centrifugation, Density Gradient; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000009:adverse effects / Q000494:pharmacology*; D004247:DNA / Q000187:drug effects* / Q000502:physiology*; D053938:DNA Fragmentation / Q000187:drug effects; D006801:Humans; D007248:Infertility, Male / Q000628:therapy; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D027724:Reproductive Techniques, Assisted; D012661:Semen / Q000502:physiology; D012746:Sexual Abstinence / Q000502:physiology; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology*
chemical_list: D003451:Cryoprotective Agents; D004247:DNA