Abstract
BACKGROUND: Reactive oxygen species (ROS) play a crucial role in etiology of DNA fragmentation and lipid peroxidation in sperm, leading to infertility in men. The silent information regulators SIRT1 and SIRT3 are members of the sirtuins protein family known to be involved in cancer genetics, aging and oxidative stress responses. The aim ofthis study is to determine the correlation between SIRT1 and SIRT3 with antioxidants, oxidative stress biomarkers, and DNA fragmentation in the semen of asthenoteratozoospermic and normozoospermic men. MATERIALS AND METHODS: In this case-control study, after spermogram analysis the specimens were divided into two groups, normozospermic (n=40) and asthenoteratozoospermic (n=40), according to World Health Organization (WHO) standards. Sperm DNA fragmentation was evaluatedusing the sperm chromatin dispersion (SCD) test.Catalase activity was measured using the Aebi spectrophotometeric method. Total antioxidant capacity (TAC) level and superoxide dismutase (SOD) activitywere measured by using commercially available colorimetric assays. Enzyme-linked immune sorbent assay (ELISA) was used to measure SIRT1 and SIRT3 protein levels of seminal plasma. Malondialdehyde (MDA) level in seminal plasma was determined by high-performance liquid chromatography (HPLC). RESULTS: The asthenoteratozoospermic group had significantly lower catalase and SOD activities and TAC levels in comparison with the normozoospermic group (P<0.001).The percentage of DNA fragmentation and MDA level in the asthenoteratozoospermic group were remarkably higher than in the normozoospermic group. The SIRT1 and SIRT3 protein levels in seminal plasmawere remarkably lower in asthenoteratozoospermic group than the normozoospermic group (P<0.001). CONCLUSION: The results of this study suggest that SIRT1 and SIRT3 protein levels are negatively correlated with oxidative stress and DNA fragmentation in semen. The low levels of SIRT1 and SIRT3 in asthenoteratozoospermic men may lead to an increase in oxidative stress, DNA fragmentation, and lipid peroxidation that eventually result in immotile and immature spermatozoa (asthenoteratozoospermia).