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Antioxidative system parameters in boars spermatozoa separated in iodixanol density solution

Spermatozoa are particularly susceptible to the oxidative damage due to the excessive production of reactive oxygen species (ROS), and because of the large proportion of unsaturated fatty acids in the plasma membrane and a relatively low concentration of antioxidant enzymes in the cytoplasm. Porcine semen is composed of heterogeneous subpopulations of sperm that are distinguished by their functional and structural features, and the share of each subpopulation is associated with the ability of fertilization and storing semen. The aim of this study was to separate the boar’s sperm in iodixanol density gradient solution, and to investigate antioxidative parameters in different sperm fractions. Semen samples of 27 boars aged between 1.5 and 3 years were collected by gloved-hand technique, once, in autumn. Following evaluation of semen quality, native semen was centrifuged in a discontinuous iodixanol density gradient solution for 20 min at 1500 x g at 20°C. After centrifugation three sperm fractions were obtained: sperms with progressive mobility greater than 90%, sperms with progressive mobility less than 20% and abnormal sperms. The concentration of total antioxidant status (TAS) and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were measured in each sperm fraction on automatic analyser Olympus AU 400. In the abnormal sperm fraction the concentration of TAS, and the activities of SOD and GSH-Px were significantly higher (P<0.001) than in fractions of high and very low sperms motility. The lowest values of TAS and SOD and GSH-Px were obtained in sperms with very low motility (P<0.001). The results indicate a decrease in antioxidative protection of sperms with very low motility in relation to sperms with high motility. The highest levels of TAS, SOD and GSH-Px found in abnormal sperms could indicate the enhanced antioxidative defence due to excessive production of ROS in that sperm fraction. Sperm fraction of high motility and normal morphology has applications in assisted reproduction, and the results of antioxidant parameters and their comparison between the obtained sperm fractions may help explain the causes of infertility.

boars; sperm; iodixanol; antioxidant

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