Glutathione Peroxidase and Superoxide Dismutase activities in blood and seminal plasma in colombian stallions

Objective: to measure the activity of the antioxidant enzymes Glutathione Peroxidase (GSH-Px; EC 1.11.1.9) and Superoxide Dismutase (SOD; EC 1.15.1.1) in blood and seminal plasma of Colombian Stallions from four farms and to relate them to changes in semen quality. Methods: semen was collected from 25 horses using an artificial vagina. Blood was collected in EDTA vacutaniers by yugular venipuncture. Basic semen analysis included individual and mass motility, morphology, and sperm concentration. A sub sample was centrifuged to obtain seminal plasma for the evaluating GSH and SOD. Results: mean GSH-Px activity was 514.8 +/- 22.4 U/g Hb and 0.55 +/- 0.05 U/mL in blood and seminal plasma, respectively. Mean SOD activity was 1877 +/- 188 U/g Hb in blood, and 86 +/- 7.1 U/mL in seminal plasma. No correlation was found between the enzyme activities in seminal plasma and blood. However, seminal plasma GSH-Px activity was correlated with sperm concentration. Similarly, GSH-Px activity in blood was correlated to the proportion of sperm cells with progressive motility and morphologically normal. Conclusions: the absence of correlation found between enzymatic activity in blood and seminal plasma suggests that both antioxidant systems are independent.