title: [Microdrop-vitrification for epididymal spermatozoa without cryoprotectants].
abstract: OBJECTIVE
  To explore the feasibility and safety of microdrop-vitrification for epididymal spermatozoa obtained by percutaneous epididymal sperm aspiration (PESA) without cryoprotectants.
  
  
  METHODS
  We treated the epididymal sperm samples from 22 patients by conventional freezing (Group 1) and microdrop-vitrification without cryoprotectants (Group 2), and evaluated the effectiveness of the two methods by comparing their revival rate, retrieval rate and incidence of sperm nuclear DNA fractures.
  
  
  RESULTS
  Motile sperm were found in all but 1 case in Group 1. The revival rates of the frozen sperm were low in both Groups 1 and 2 ([18.16 +/- 9.38]% vs [21.99 +/- 10.95]%, P > 0.05), but statistically significant differences were shown between the two groups in the retrieval rate ([58.39 +/- 12.67]% vs [70.82 +/- 14.94]%, P < 0.01). Before freezing, nuclear DNA fractures existed in the epididymal sperm samples of all the 22 patients, comet sperm were seen after unicellular gel electrophoresis, and the incidence of sperm nuclear DNA fracture was (26.68 +/- 9.45)%. After freezing, no increase was observed in the incidence of sperm nuclear DNA fracture in either Group 1 or 2 ([28.68 +/- 12.54]% vs [27.64 +/- 10.70]%, P > 0.05).
  
  
  CONCLUSIONS
  Microdrop can be used as a suitable freezing carrier for a low number of sperm, and cryoprotectant-free vitrification with microdrop may be a simple, safe and effective method for the cryopreservation of a low number of epididymal sperm.
authors.affiliation: Center of Reproductive Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China. ljin@tjh.tjmu.edu.cn
authors.forename: Lei
authors.initials: L
authors.lastname: Jin
authors.forename: Jia-Feng
authors.initials: JF
authors.lastname: Zheng
authors.forename: Qun
authors.initials: Q
authors.lastname: Liu
authors.forename: Xin-Ling
authors.initials: XL
authors.lastname: Ren
authors.forename: Juan
authors.initials: J
authors.lastname: Hu
authors.forename: Yu-Lan
authors.initials: YL
authors.lastname: Wei
mesh_terms: D000328:Adult; D053713:Azoospermia / Q000601:surgery*; D015925:Cryopreservation / Q000379:methods*; D006801:Humans; D008297:Male; D013094:Spermatozoa; D058989:Vitrification