Increased testicular 8-hydroxy-2'-deoxyguanosine in patients with varicocele

To assess immunohistochemically 8-hydroxy-2'-deoxyguanosine (8-OHdG, a sensitive biological marker of oxidative damage and stress) in testicular tissue from patients with varicocele, to determine whether 8-OHdG is related to spermatogenesis, as oxidative stress in testicular DNA is associated with poor semen quality and reduced fertility.

Testicular tissue samples were collected from the testes of 36 patients with varicocele and five normal volunteers. The mean (sd) age of the patients was 35.3 (5.4) years. The prevalence of immunostained germ cells among all the germ cells in >20 seminiferous tubules was calculated.

The mean (sd) sperm concentration and Johnsen's score in the varicocele group was lower than in the normal group, at 27.6 (11.8) vs 80.4 (21.7) million/mL (P < 0.001) and 7.6 (1.1) vs 9.0 (0.7), respectively (P < 0.05). In all patients, 8-OHdG was mainly expressed in the spermatogonia and spermatocytes in the seminiferous tubule. Immunostained germ cells correlated negatively with sperm concentration (r = -0.48, P = 0.01) and Johnsen's score (r = -0.46, P = 0.02), but not with follicle-stimulating hormone, luteinizing hormone or testosterone level. Immunostained germ cells were significantly more prevalent in the varicocele group, at 53.6 (5.7)%, than that in the normal group, at 14.3 (2.3)% (P < 0.001). The prevalence of immunostained germ cells and clinical grades were positively related; the ratio recorded for varicocele grades I, II and III was 38.0 (10.0)%, 41.0 (9.1)%, and 57.0 (9.3)%, respectively (grade I vs grade III, P < 0.05).

Increased 8-OHdG expression in the testis was associated with deficient spermatogenesis in infertile men with varicocele.