Characterization of Prohibitins in Male Reproductive System and their Expression under Oxidative Stress.

PURPOSE: We investigated the expression and location of prohibitin 1 and 2 of the prohibitin family in the male reproductive system and their potential roles during the oxidative stress response in a rat model. MATERIALS AND METHODS: Semiquantitative polymerase chain reaction, Western blot, immunohistochemistry and indirect immunofluorescence were performed to examine the expression and localization of prohibitins. Oxidative damage was evaluated using a commercially available malondialdehyde kit. Histological damage induced by doxorubicin injection was examined by hematoxylin and eosin staining. RESULTS: Prohibitin 1 and 2 were ubiquitously expressed in various human tissues with distinct high expression in the epididymis. In the human testis and epididymis they were localized in the cytoplasm of diverse cell types. Prohibitin 1 was located on the entire tail region of human ejaculated spermatozoa while prohibitin 2 was specifically localized on the equatorial region. In spermatozoa from young men with asthenozoospermia the percent of spermatozoa with positive staining as well as the fluorescence intensity of prohibitin 2 was much lower than in the spermatozoa of healthy donors. Uniform expression of prohibitins in the testis and epididymis of the rat during postnatal development suggested conserved and vital biological functions. Moreover under oxidative stress induced by doxorubicin injection the expression of prohibitin 1 and 2 was significantly down-regulated in the rat testis with significant histomorphological changes. CONCLUSIONS: To our knowledge this research represents the first systematic study of prohibitins in the male reproductive system. It lays the foundation for further functional studies and provides potential therapeutic targets for infertility induced by oxidative stress.

TAT-peroxiredoxin 2 Fusion Protein Supplementation Improves Sperm Motility and DNA Integrity in Sperm Samples from Asthenozoospermic Men.

PURPOSE: We compared levels of peroxiredoxin 2 in semen samples from normozoospermic and asthenozoospermic men. The potential effects of TAT-peroxiredoxin 2 fusion protein on sperm motility and DNA integrity were also evaluated. MATERIALS AND METHODS: Semen samples were obtained from 50 normozoospermic and 50 asthenozoospermic men. Lipid peroxidation of semen was determined using a commercial malondialdehyde kit. Sperm DNA fragmentation was evaluated by TUNEL assay. Western blot and immunofluorescence were performed to detect the amount of peroxiredoxin 2 protein in seminal plasma and spermatozoa. Sperm motility, DNA damage and levels of reactive oxygen species were evaluated after TAT-peroxiredoxin 2 fusion protein supplementation to the sperm suspension for 2 and 12 hours of incubation. RESULTS: In asthenozoospermic semen samples a significantly higher level of malondialdehyde and DNA damage was discovered. However, the expression of peroxiredoxin 2 was significantly lower in seminal plasma and spermatozoa compared with that of normozoospermic men. TAT-peroxiredoxin 2 fusion protein was successfully prepared and delivered to the spermatozoa. Interestingly adding TAT-peroxiredoxin 2 in asthenozoospermic sperm suspension effectively defended against the decrease in progressive motility and the increase in DNA damage. CONCLUSIONS: This study shows that supplementation of TAT-peroxiredoxin 2 fusion protein in the sperm suspension from asthenozoospermic men effectively improved sperm motility and DNA integrity by reducing levels of reactive oxygen species. Therefore, we speculate that peroxiredoxin 2 may have an important role as an antioxidant defense in semen and would provide new prevention and therapy alternatives for asthenozoospermia.