Background: Asthenozoospermia is a kind of male infertility that reduces sperm motility. Sperm cryopreservation is used in assisted reproductive technology (ART), gamete preserva- tion before radiotherapy or chemotherapy, and sperm banking. Freezing process causes oxidative stress on sperms which is the main reason of sperm disruption. The sperm cells protection against oxidative reactions during cryopreservation process is done by antioxidant and amino acids agents. In this study we evaluated the effect of Sildenafil Citrate (SC) and Alpha Lipoic Acid (ALA) Co-treatment, in preventing sperm damage during Cryopreservation in the asthenozoospermic patients. Materials and Methods: 30 semen samples were collected from the asthenozoospermic patients attended the Andrology unit of the Qom Infertility Treatment Center. Each semen sam- ple was divided into 4 equal aliquots: Control (were treated with cryo-protectant alone), SC (were treated with cryo-protectant + 0.67µM SC), ALA (were treated with cryo-protectant + 0.5mM ALA), SC+ALA. In each sample, sperm motility according to WHO criteria, sperm viability with eosin-nigrosin assay and sperm morphology with Diff-Quick assay were assessed. Results: Our result showed that sperm parameters were sig- nificantly higher in ALA group compared to control, SC and SC+ALA groups (p<0.05). And SC+ALA group compared to SC group had more positive impact. Conclusion: All ALA, SC and SC+ALA groups improved se- men sample parameters after cryopreservation. But ALA group performed several percent better than the other groups.
