title: Effects of cryopreservation on sperm parameters and ultrastructural morphology of human spermatozoa.
abstract: OBJECTIVE
  Cryopreservation of sperm is a widely used technique to maintain and protect the fertility in various occasions such as infertility and malignancy treatments. This study aims to reveal the effects of freezing and thawing on human spermatozoa.
  
  
  METHODS
  To evaluate the effects of freeze-thawing, semen samples were evaluated by light microscopy by means of morphology, motility and viability, by scanning and transmission electron microscopy for detailed ultrastructural changes.
  
  
  RESULTS
  After cryopreservation, a significant decrease in spermatozoa viability was observed (p < 0.01). Group a, b and c motility according to World Health Organization criteria decreased considerably (p < 0.05, p < 0.01, p < 0.05, respectively), whereas there was a substantial increase in group d motility. A strong correlation between rise in number of immotile spermatozoa and decrease in viability was also noted (r = -0.848, p < 0.01). Post-thaw light microscopic studies revealed a considerable decrease in rate of normal spermatozoa (p < 0.05). A considerable decline in the rate of normal sperm was also observed by TEM (p < 0.05). Statistically, acrosomal changes and subacrosomal swelling were found to be significantly increased (both p < 0.05), where the latter appears to be a novel finding in literature.
  
  
  CONCLUSIONS
  Cryopreservation has deleterious effects on spermatozoa, especially on plasmalemma, acrosomes and tails. Electron microscopy is the ultimate modality to investigate spermatogenic cells.
authors.affiliation: Department of Histology and Embryology, Assisted Reproduction Center, Ankara University School of Medicine, Turkey. sinozk@gmail.com
authors.forename: Sinan
authors.initials: S
authors.lastname: Ozkavukcu
authors.forename: Esra
authors.initials: E
authors.lastname: Erdemli
authors.forename: Ayca
authors.initials: A
authors.lastname: Isik
authors.forename: Derya
authors.initials: D
authors.lastname: Oztuna
authors.forename: Sercin
authors.initials: S
authors.lastname: Karahuseyinoglu
mesh_terms: D000328:Adult; D002470:Cell Survival; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology; D005615:Freezing; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning / Q000379:methods; D046529:Microscopy, Electron, Transmission; D012662:Semen Preservation / Q000295:instrumentation / Q000379:methods*; D013048:Specimen Handling; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D013696:Temperature
chemical_list: D003451:Cryoprotective Agents