Background: As thenozoospermia reduces sperm motility re- sulting in infertility. Reactive oxygen species (ROS), produced during cryopreservation, impair sperm function. The effect of Sildenafil Citrate (SC) supplementation on oxidative s tress pa- rameters during cryopreservation of semen samples of As the- nozoospermia men was assessed. Materials and Methods: 30 semen samples were collected from As thenozoospermic patients. Each sample was divided into three groups: Control (fresh), Freeze (treated with cryo- protectant), and Freeze+SC (treated with cryo-protectant+ 0.67µM SC solution). In each sample, the level of sperm Tu- mor necrosis factor alpha (TNF-α), Malondialdehyde (MDA) and sperm antioxidant enzymes, including Catalase (CAT), Glutathione (GSH), and Superoxide dismutase (SOD) were analyzed using Enzyme-linked immunosorbent assay (ELISA). Results: Our results showed a significant reduction in the level of sperm antioxidant enzymes and also a significant increase in sperm TNF-α and MDA level in the freeze group compared to the control group (P<0.05). whereas in the Freeze+SC group, a significant increase in sperm antioxidant enzymes level and a significant decrease in sperm TNF-α and MDA level was ob- served compared to the freeze group (P<0.05). Conclusion: SC supplementation in cryopreserved sperms of as thenozoospermic men, leads to a major improvement of pos t- thaw sperm quality and sperm biochemical parameters through reducing ROS and preventing the undesired effects of ROS on sperm function.
