Enzymatic Antioxidant Protection

The enzymatic system consists of SOD [134], catalase [135] and GPx [136]. SOD is the most important system in seminal fluid and scavenges intra- and extracellular superoxide, thus preventing LPO of membrane lipids. Considering that this reaction results in the production of hydrogen peroxide, another, but less reactive oxidant, SOD should act together with catalase or GPx [137] . Catalase and GPx detoxify intra- and extracellular hydrogen peroxide to produce water and oxygen [138]. Data by the Zini group suggest that the seminal catalase and SOD activities do not derive from the testis or epididymis, but rather from seminal vesicle or prostate [139].

Recent studies revealed that seminal MDA, nitric oxide and SOD levels were significantly altered in infertile patients as compared to fertile controls [140, 141], confirming earlier observations by Kobayashi et al. [134] and Calamera et al. [142]. Since no difference in the seminal concentration of catalase between fertile and infertile patients could be found, it appears that seminal SOD activity plays a bigger role for the maintenance of sperm motility and the sperm cells' protection against ROS than catalase [ 143] . However, the usefulness of the determination of SOD levels to diagnose male infertility is also questioned by Hsieh et al. [144] who could not find any significant correlation with motility of sperm concentration, neither for the intracellular, nor for the seminal SOD levels. The relationship of seminal SOD levels on various sperm functions such as acrosome reaction, however, did not appear so clear [140, 141, 145].

For the seminal activity of GPx, Hsieh et al. [146] established a positive, but not significant association with sperm motility. However, the intracellular GPx levels appear to be more important as intracellular components of the glutathione system, including GPx and glutathione, seem to be altered in infertile men where it is particularly linked to poor sperm morphology [147] . On the other hand, there is also evidence that intra-spermatozoal expression of phospholipid hydroperoxide glutathione (PHGPx) peroxidase is decreased in about 25% of oligo-asthenozoospermic men. Apparently, this lower expression of the enzyme is not caused by mutations of the PHGPx gene [148].

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100 Pregnancy Tips

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