Evaluation of nuclear DNA damage in spermatozoa from infertile men with varicocele

OBJECTIVE: To examine levels of sperm DNA damage and oxidative stress (OS) in infertile men with varicocele. DESIGN: Prospective controlled study. SETTING: Male infertility clinic, Glickman Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio. PATIENT(S): Thirty-one infertility patients and 16 fertile controls. INTERVENTION(S): Sperm DNA fragmentation index (DFI), levels of seminal reactive oxygen species (ROS), and total antioxidant capacity (TAC) were assessed using the sperm chromatin structure assay, chemiluminescence assay, and enhanced chemiluminescence assay, respectively. ROS-TAC score was calculated as a measure of OS. MAIN OUTCOME MEASURE(S): Median (interquartile range) DFI and ROS-TAC scores. RESULT(S): Sixteen of the 31 patients had left varicocele [grade I (n = 3), grade II (n = 10), and grade III(n = 3)], and the remaining 15 had normal genital examination. Patients with varicoceles had significantly higher percent DFI than controls (25%, range: 20%-35%; vs. 15%, range: 10%-22%). Patients with varicoceles had significantly lower ROS-TAC scores (21, range: 9.5-31) than the infertile patients with normal genital examination (34, range: 28-42) or the controls (40.3, range: 38-44). CONCLUSION(S): Infertile men with varicoceles showed significantly increased spermatozoal DNA damage that appears to be related to high levels of OS in semen.