Activity of antioxidant enzymes in seminal plasma and their relationship with lipid peroxidation of spermatozoa

To determine the activity of seminal plasma catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPX) and their relationship with malondialdehyde (MDA), as a marker of lipid peroxidation, content of spermatozoa and seminal plasma in normozoospermic and asthenozoospermic males. Semen samples were obtained from 15 normozoospermic and 30 asthenozoospermic men. We observed inverse correlations between activities of CAT (k/mL) and SOD (U/mL) in seminal plasma with MDA content of spermatozoa from normozoospermic samples (r =- 0.43, p < 0.05 and r =- 0.5, p < 0.05, respectively). Significant correlations were observed between total activity CAT (k/total seminal plasma) with total SOD (U/total seminal plasma) and GPX activity (mU/total seminal plasma) in seminal plasma from normozoospermic samples (r = 0.67, p = 0.008 and r = 0.455, p = 0.047, respectively). Furthermore, we found positive correlations between total activities of CAT, SOD and GPX with total content of MDA in seminal plasma (nmoL/total seminal plasma) from normozoospermic samples (r = 0.67, p = 0.003; r = 0.73, p = 0.003; r = 0.74, p = 0.004, respectively). In asthenozoospermic samples, there were no significant correlations observed between activities of CAT (k/mL), SOD (U/mL) and GPX (mU/mL) of seminal plasma with MDA content of spermatozoa. However, we found significant correlations between total activities of CAT (k/total seminal plasma) and SOD (U/total seminal plasma) with total content of MDA in seminal plasma (r = 0.4, p = 0.018 and r = 0.34, p = 0.03, respectively). These findings indicate a protective role for antioxidant enzymes of seminal plasma against lipid peroxidation of spermatozoa in normozoospermic samples.