title: Comparison of the DNA Fragmentation and the Sperm Parameters after Processing by the Density Gradient and the Swim up Methods.
abstract: BACKGROUND
  The swim up and the density-gradient centrifugation are the two main techniques which are used to separate the viable motile sperm fraction in the assisted reproductive technology. However, there are several published studies about these methods, but there is no sufficient evidence for recommending the superiority of one of them. This study was designed to study the efficiency of the swim-up and the density gradient techniques to recover the spermatozoa with a high degree of motility, a normal morphology and a low level of DNA fragmentation.
  
  
  METHODS
  A total of 35 semen samples were included in the study. The semen samples were collected, one part of the semen was spread on a slide and the remainder was prepared by using the swim-up or the density gradient techniques. The recovered spermatozoa were evaluated for concentration, motility, and normal morphology. A comet assay was carried out to assay the DNA fragmentation in all the samples.
  
  
  RESULTS
  There were significant differences in the sperm parameters between the density gradient and the swim up techniques. Also, the swim-up technique showed a significantly higher level of DNA fragmentation as compare to the density gradient technique.
  
  
  CONCLUSIONS
  The results of this study demonstrated several benefits of the gradients method in the separation of normal and motile spermatozoa with healthy DNA, in comparison to the swim up method.
authors.affiliation: Fatemieh Infertility Center, Fatemieh Hospital, Hamadan University of Medical Sciences.
authors.forename: Iraj
authors.initials: I
authors.lastname: Amiri
authors.forename: Marzieh
authors.initials: M
authors.lastname: Ghorbani
authors.forename: Safora
authors.initials: S
authors.lastname: Heshmati
keywords: Comet assay; Gradients sperm separation; Sperm; Swim up