INVESTIGATION OF SPERM DNA FRAGMENTA- TION BY SPERM DNA INTEGRITY ASSAY

Male-factor infertility plays a role in approximately 50% of infertile couples. In at least 30% of cases, repeated standard semen analyses of the male partner of an infertile couple reveal normal results. When diagnostic work-up of the female partner is also normal, they are classified as unexplained or idiopathic. The objective of this study was to evaluate the levels of sperm DNA fragmentation, respectively a sperm nuclear DNA integrity, in normospermic infertile men, by a flow cytometric method. Materials and methods: Semen samples were obtained from 53 normospermic infertile men and 30 fertile donors. Flow cytometry was used to study sperm DNA fragmentation by Sperm DNA Integrity assay and the results were expressed as a percentage of sperm DNA fragmentation index (DFI). Results: Increase levels of DFI were observed in 21 of 53 (39,62%) normospermic infertile men. The %DFI in normospermic infertile men was significantly higher than fertile donors (P = 0.03). There were statistically significant negative correlations between DFI and sperm motility ( r = –0.48, P = 0.0001) and normal morphology (r = –0.37, P = 0.022) in normospermic infertile men, but not in fertile donors. Conclusion: Our study indicates that the levels of sperm DNA fragmentation in normospermic infertile men were significantly higher compared with the levels in the fertile group. Sperm DNA Integrity assay is an independent test of sperm quality that may have better diagnostic capabilities than standard sperm parameters.