Increased Sperm DNA Fragmentation in Infertile Men with Varicocele: Relationship with Apoptosis, Seminal Oxidative Stress, and Spermatic Parameters

This study intends to determine the extent of nuclear sperm injury in patients with varicocele and to investigate its relationship with apoptosis and oxidative stress (OS). Ejaculated sperm samples from 51 patients diagnosed with varicocele and 29 fertile men were examined. According to the guidelines, the patient's sperm samples were classified into varicocele with normal semen parameters (n = 11) and varicocele with abnormal semen parameters (n = 40). Sperm DNA fragmentation was assessed using terminal deoxynucleotidyl transferase dUTP nick end labeling assay. The proportion of both viable and dead spermatozoa with externalized phosphatidylserine (PS) was detected by the bivariate annexin V/6-CFDA staining method. Seminal malondialdehyde (MDA) amounts and antioxidant enzymes activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were measured spectrophotometrically. Sperm DNA fragmentation, viable spermatozoa with externalized PS, and MDA levels were significantly higher in studied subgroups of patients with varicocele, either with normal or with abnormal semen parameters than controls. The seminal antioxidant enzymes activities were significantly reduced in both subgroups of patients with varicocele compared to the controls. The percentage of spermatozoa with fragmented DNA was positively correlated to the MDA level as well as the proportion of viable spermatozoa with externalized PS. However, the decreased seminal antioxidant status was negatively correlated with the increased proportion of sperm DNA fragmentation and apoptotic spermatozoa. Impaired seminal antioxidant profile and increased seminal level of lipid peroxidation may be involved in the pathophysiological mechanisms of cell death-mediated DNA breaks in patients with varicocele.