Introduction: Sperm motility is crucial for the ability of sperm to penetrate the oocyte and achieve fertilization. According to the World Health Organization (WHO) 2021 guidelines, less than 42 percent of motility is called asthenozoospermia, which is one of the most common causes of male infertility. Reactive oxygen species (ROS), generated during cryopreservation, can impair sperm function. Melatonin, has antioxidant activities and can reduce the amount of ROS in the cell, so it may protect sperm from ROS- related damage. This study aims to evaluate the impact of melatonin on sperm biochemical parameters during cryopreservation in asthenozoospermic men. Methods: 30 semen samples were collected from Asthenozoospermic patients. Each sample was divided into three groups: Control (fresh), Freeze (treated with cryo-protectant), and Freeze+ Melatonin (treated with cryo-protectant+ 1mM Melatonin solution). In each sample, the level of sperm Malondialdehyde (MDA) and sperm antioxidant enzymes, including Total Antioxidant Capacity (TAC), Catalase (CAT), Glutathione (GSH), and Superoxide dismutase (SOD) were analyzed using Enzyme-linked immunosorbent assay (ELISA). Results: Our results showed a significant decrease in sperm antioxidant enzyme levels and TAC, also significant increase in sperm MDA levels in the freeze group compared to the control group (P<0.05). In contrast, the Freeze+ Melatonin group showed a significant increase in sperm antioxidant enzymes and TAC levels, as well as a significant decrease in sperm MDA levels compared to the freeze group (P<0.05). Conclusion: This study indicates that melatonin supplementation may serve as an effective strategy approach to enhance the quality of cryopreserved sperm in asthenozoospermic men. By reducing ROS levels and protecting sperm from oxidative damage, melatonin has the potential to improve sperm function and increase the likelihood of successful fertilization. Additional research is needed to validate these results and investigate the mechanisms behind melatonin's positivs impact on sperm quality.
