Semen DNA fragmentation index, evaluated with both TUNEL and comet assay, and the ICSI outcome

Background: In intracytoplasmic sperm injection (ICSI), there is always a risk of using spermatozoa with damaged DNA. The purpose of this study was to evaluate the percentage of spermatozoa with DNA fragmentation in processed semen samples used in ICSI cycles and to investigate the relationship between the DNA fragmentation index (DFI) and the ICSI outcome. Patients and Methods: Fifty-six couples undergoing ICSI treatment were included. DFI was evaluated, by both terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL) and single cell gel electrophoresis (Comet) assays, in the processed semen samples used for ICSI. Results: Of the processed semen samples 17.85% had ≥10% spermatozoa with fragmented DNA. There was no correlation between DFI and the ICSI outcome. DFI assessed by the TUNEL assay was negatively correlated with sperm concentration, progressive motility and sperm morphology. Conclusion: A considerable proportion of processed semen samples used for ICSI have a high DFI. However, DFI of the processed semen samples does not seem to be related to the ICSI outcome.