title: [Direct fumigation for freeze-thawing of human sperm: an experimental study].
abstract: OBJECTIVE
  To study the effect of direct fumigation on the post-thaw recovery rate of cryopreserved spermatozoa, and to search for a best method for human sperm cryopreservation.
  
  
  METHODS
  We collected semen samples from 100 donors conforming to the normal reference values in WHO Laboratory Manual for the Examination and Processing of Human Semen (5th Ed), divided them into two groups, and subjected them to cryopreservation by programmable freezing (Group A) and direct fumigation (Group B), respectively. We detected the progressive motility of pre-freezing and post-thaw sperm with a computer-assisted semen analyzer, and compared the effects of the two methods on the functional integrity of sperm membrane and the rate of abnormal sperm using the percentage of hypo-osmotic swelling sperm and modified Papanicolaou staining.
  
  
  RESULTS
  Statistically significant differences were found in post-thaw sperm progressive motility between the Groups A and B ([34.0 +/- 18.4]% vs [43.0 +/- 19.5]%, P<0.05), both remarkably decreased as compared with pre-freezing ([57.0 +/- 16.7]%, P<0.05). Such differences were also found in the post-thaw recovery rate of progressively motile sperm between the two groups ([52.2 +/- 20.6]% vs [67.1 +/- 20.0]%, P<0.05). The post-thaw percentage of hypo-osmotic swelling sperm was obviously decreased in both Groups A and B ([67.1 +/- 11.1]% and [70.6 +/- 10.0]%) in comparison with pre-freezing ([84.5 +/- 7.5]%, P<0.05), with significant differences between A and B (P<0.05). However, the rate of sperm abnormality was evidently increased in Groups A and B ([85.0 +/- 8.7% and [85.7 +/- 9.1]%), significantly higher than pre-freezing ([77.8 +/- 9.6]%, P<0.05), but with no significant differences between A and B (P>0.05).
  
  
  CONCLUSIONS
  Direct fumigation is superior to programmable freezing for its easier operation, wider application, and higher sperm recovery rate.
authors.affiliation: Department of Urology/Shanghai Sperm Bank/Laboratory for Genetics and Sperm Development of Shanghai Institute of Andrology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200001, China. lambob1975@hotmail.com
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.forename: Yu-Fang
authors.initials: YF
authors.lastname: Xiao
authors.forename: Dong
authors.initials: D
authors.lastname: Zhao
authors.forename: Wen-Bo
authors.initials: WB
authors.lastname: Shi
authors.forename: Hui
authors.initials: H
authors.lastname: Lu
authors.forename: Ru-Yao
authors.initials: RY
authors.lastname: Wang
authors.forename: Hong-Liang
authors.initials: HL
authors.lastname: Hu
authors.forename: Zheng
authors.initials: Z
authors.lastname: Li
mesh_terms: D000328:Adult; D015925:Cryopreservation / Q000379:methods*; D006801:Humans; D008297:Male; D055101:Semen Analysis; D012662:Semen Preservation / Q000379:methods*; D013081:Sperm Motility; D013094:Spermatozoa; D055815:Young Adult