title: Preparation and incubation conditions affect the DNA integrity of ejaculated human spermatozoa.
abstract: Appropriate semen processing and assessment are critical for successful infertility treatment. We investigated whether laboratory procedures including semen preparation and incubation affect sperm DNA integrity. A total of 153 infertile men were involved. Conventional semen parameters and sperm chromatin structure assay (SCSA) parameters, that is, DNA fragmentation index (%DFI) and high DNA stainability (%HDS), were assessed on the fresh ejaculated semen samples, which were treated and incubated under different conditions. Negative correlations were identified between the %DFI and sperm concentration, motility, progressive motility and morphology. A lower percentage of DFI was detected in spermatozoa when density gradient centrifugation (DGC) was followed by swim-up treatment in comparison with DGC alone (P < 0.01). Although the %DFI increased in a time-dependent manner with incubation both at room temperature (RT) and at 37 degrees C in air, the %DFI after 24 h at RT was significantly lower than that at 37 degrees C (P < 0.05). Incubation with 5% CO2 was effective in maintaining sperm motility (P < 0.01); however, it induced further elevation of %DFI (P < 0.001). Thus, sperm DNA damage was associated with longer incubation periods. Interestingly, common culture conditions, such as maintaining pH and temperature, compromised the sperm DNA integrity.
authors.affiliation: The Reproduction Center, Kiba Park Clinic, Tokyo 135-0042, Japan.
authors.forename: Rieko
authors.initials: R
authors.lastname: Matsuura
authors.forename: Takumi
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Atsumi
authors.initials: A
authors.lastname: Yoshida
mesh_terms: D002245:Carbon Dioxide; D002843:Chromatin / Q000648:ultrastructure; D004247:DNA / Q000235:genetics*; D053938:DNA Fragmentation; D006801:Humans; D008297:Male; D012661:Semen / Q000166:cytology; D013048:Specimen Handling; D013094:Spermatozoa / Q000648:ultrastructure; D013696:Temperature; D013997:Time Factors
chemical_list: D002843:Chromatin; D002245:Carbon Dioxide; D004247:DNA