Superoxide anion in human semen related to seminal parameters and clinical aspects

To study the possible presence of extracellular superoxide anion (O2-) in untreated semen of normal and pathological subjects and to determine the possible relationship between superoxide anion levels, number of seminal leukocytes (WBCs) and seminal parameters.

Semen samples were analyzed from fertile normospermic subjects (n = 20) and patients (n = 132) attending the Outpatient Department of the 5th Medical Clinic.

We evaluated superoxide anion levels by monitoring the reduction of cytochrome c.

O2- was detected in 55.0% of fertile normospermic subjects. Both the percentage of subjects in whom O2- was detected and the mean values +/- SD of O2- were significantly higher in the male partners of infertile couples, in subjects with varicocele, and in subjects with positive sperm culture than normospermic subjects. No variations were seen in vasectomized subjects or in patients with past cryptorchidism. A high correlation was observed between O2- levels and WBCs (rs = 0.58), nonrapid, immotile sperm (rs = 0.64), percentage decrease of motility within a specified time frame (2 to 6 hours) (rs = 0.73), and sperm abnormalities (rs = 0.49).

Superoxide anion in untreated semen is produced by WBCs and atypical and nonrapid, immotile sperm. A significant increase of superoxide anion was detected in the male partners of infertile couples and in some selected andrological conditions. The toxic effect of superoxide anion on sperm cells is dependent on the time of exposure and superoxide anion concentration.