Effect of varicocele on sperm function and semen oxidative stress

Abstract

Study Type – Aetiology (case control) Level of Evidence 3b What’s known on the subject? and What does the study add? Varicocele leads to alterations in sperm DNA integrity even when alterations in semen quality are not yet observed in adolescents. In adults, alterations to sperm DNA are associated to altered sperm morphology, indicating that altered spermatogenesis may be an important cause for the increased sperm DNA fragmentation observed in these men. One other important cause of increased DNA fragmentation is oxidative stress, and we wished to verify if this was the case. The study adds the information that, in the adult varicocele, it is most likely that an altered testicular environment is leading to increased DNA fragmentation and decreased mitochondrial activity and acrosome integrity, because no increase in oxidative stress was observed. OBJECTIVE • To assess the effect of varicocele on sperm DNA integrity, mitochondrial activity, lipid peroxidation and acrosome integrity. PATIENTS AND METHODS • In all, 30 patients with a clinically diagnosed varicocele of grade II or III and 32 men without a varicocele were evaluated for sperm DNA fragmentation (comet assay), mitochondrial activity (3,3′‐diaminobenzidine assay), lipid peroxidation (malondialdehyde) and acrosome integrity (fluorescent probe labelled peanut agglutinin). RESULTS • The varicocele group showed fewer spermatozoa with intact DNA (grade II, P = 0.040), more cells with inactive mitochondria (class III, P = 0.001), fewer cells with active mitochondria (class I, P = 0.005) and fewer spermatozoa with intact acrosomes ( P < 0.001). Finally, no significant differences were observed in lipid peroxidation levels. CONCLUSION • Men with varicocele showed an increase in sperm DNA fragmentation and a reduction in mitochondrial activity and acrosome integrity. However, lipid peroxidation levels remained unchanged.