Evaluation of the p53 and Thioredoxin reductase in sperm from asthenozoospermic males in comparison to normozoospermic males

Thioredoxin (Trx) system has a defensive role against the harmful effect of oxidative stress in sperm. p53 is an important regulator of apoptosis and normal process of spermatogenesis. Regulation of p53 by redox state of the cell and Thioredoxin system has been reported. The aim of this study was to evaluate the ROS level, Thioredoxin reductase (TrxR) activity and p53 protein levels in sperm of asthenozoospermic and normozoospermic males. Semen samples from 80 donors were divided into asthenozoospermic (n = 40) and normozoospermic (n = 40) groups using the WHO criteria. DNA fragmentation (TUNEL assay) of spermatozoa was identified·H₂O₂ and O₂•- were determined by flow cytometry. p53 protein levels and TrxR activity were measured in sperm cell lysate by appropriate kit. Total antioxidant capacity (TAC) and thiol groups in seminal plasma were measured spectrophotometery. MDA content in seminal plasma was determined fluorometrically.

Results: The percentage of cells with H₂O₂, O₂•- and DNA fragmentation was higher in asthenozoospermic compared to normozoospermic groups (p < 0.05). The p53 protein level was significantly higher in asthenozoospermic group (P < 0.001). TrxR activity in normozoospermic was significantly higher than asthenozoospermic group (P < 0.001). Total thiol groups and TAC levels were significantly higher in normozoospermic samples (P < 0.05). A significantly high negative correlation was seen between p53 protein levels with TrxR activity (r = - 0.49, P < 0.001), total motility (r = - 0.65, P < 0.001). p53 and ROS levels were increased in asthenozoospermic males while the TrxR activity was decreased. These changes lead to an increase in apoptotic, immotile and immature spermatozoa in the ejaculatory semen.