Correlations between two markers of sperm DNA integrity, DNA denaturation and DNA fragmentation, in fertile and infertile men

Abstract

Objective: To evaluate two different assays of human sperm DNA integrity, DNA denaturation (DD) and DNA fragmentation (DF), and to correlate these with standard semen parameters. Design: Prospective, observational study. Setting: University infertility clinic. Patient(s): Forty consecutive semen samples from 33 nonazoospermic men presenting for infertility evaluation and 7 fertile men presenting for vasectomy. Intervention(s): Assessment of sperm concentration, motility, morphology, DD and DF. Main Outcome Measure(s): Sperm DD and DF in fertile and infertile men. Result(s): The mean (±SE) rates of DD and DF were significantly higher in infertile subjects compared to fertile controls, respectively: 25.4 ± 3.0 vs. 10.2 ± 2.3 ( P=.028) and 27.6 ± 2.5 vs. 13.3 ± 2.5% ( P=.016). DF and DD correlated strongly (r = 0.71, P<.0001). Also, DD and DF correlated negatively with standard semen parameters (concentration, motility, and morphology), the strongest correlation being with sperm motility. Conclusion(s): The strong correlation between sperm DD and DF, and the higher levels of sperm DNA damage in infertile compared with fertile men, indicate that male infertility is associated with poor sperm DNA integrity. Although infertile men may father children with assisted conception, fertilization with DNA-damaged spermatozoa may increase the risk of genetic disease in the offspring.