The study of spermatic DNA fragmentation and sperm motility in infertile subjects

INTRODUCTION: Although the pathophysiology of the testicular damage associated with varicocele remains unclear, sperm DNA damage has been identified as a potential explanation for this cause of male infertility. The current study was designed to determine the extent of sperm nuclear DNA damage in patients with varicocele, and to examine its relationship with parameters of seminal motility. MATERIALS AND METHODS: Semen samples from 60 patients with clinical varicocele and 90 infertile men without varicocele were examined. Varicocele sperm samples were classified as normal or pathological according to the 1999 World Health Organizzation guidelines. Sperm DNA damage was evalutated using the Halosperm kit, an improved Sperm Chromatin Dispersion (SCD) test. RESULTS: The DNA fragmentation index (DFI: percentage of sperm with denatured nuclei) values was significantly higher in patients with varicocele, either with normal or abnormal (DFI 25.8 ± 3.2 vs 17.4 ± 2.8 - P < 0,01) semen profiles. In addition, an inverse correlation was found between spermatic motility and the degree of spermatic DNA fragmentation in patients with clinical varicocele. CONCLUSIONS: Varicocele is associated with high levels of DNA-damage in spermatozoa. In addition, in subjects with varicocele, abnormal spermatozoa motility is associated with higher levels of sperm DNA fragmentation. DNA fragmentation may therefore be an essential additional diagnostic test that should be recommended for patients with clinical varicocele.