Prevalence of abnormal sperm DNA denaturation in fertile and infertile men

OBJECTIVES: To examine the prevalence of abnormal sperm DNA denaturation (DD), a marker of sperm DNA integrity, in a group of fertile and infertile men. METHODS: Eighty-eight nonazoospermic, infertile men and 13 fertile men underwent standard semen analysis and acridine orange sperm DNA integrity studies. Standard semen parameters (sperm concentration, motility, and morphology) and sperm DNA integrity (expressed as the percentage of spermatozoa with DD) were measured. RESULTS: Of the 88 infertile men, 13 had completely normal semen parameters and the remaining 75 had at least one abnormal semen parameter. The mean (+/-SE) sperm DD level was significantly lower in the population of infertile men with normal semen parameters compared with those having abnormal parameters (11.1% +/- 3.7% versus 23.1% +/- 1.8%, respectively, P <0.001). Only 1 (8%) of the 13 men with normal semen parameters had elevated sperm DD (greater than 30%, verified on two separate analyses) compared with 13 (17%) of the 75 infertile men with abnormal semen parameters (P >0.05). None of the fertile controls had elevated sperm DD. We observed significant inverse correlations between the sperm DD and sperm motility, morphology, and concentration (P <0.001). CONCLUSIONS: Our data show that sperm DD negatively correlates with standard semen parameters and that an isolated abnormality of sperm DD, a marker of sperm DNA integrity, is uncommon in infertile men. Additional studies are needed to support the notion that isolated abnormalities of sperm DNA integrity may represent a new diagnosis for men with unexplained infertility.