Background: Sperm cryopreservation is presently used for conservation of male gametes in assisted reproduction technologies (ART). Despite the benefits of sperm banking, freeze-thawing process is injurious to sperm integrity due to induced oxidative stress by cold stress. Oxidative stress reduces sperm motility, viability and DNA integrity.
Objective: To investigate the effect of alpha lipoic acid (ALA) on human sperm function during the freeze-thawing process.
Materials and methods: Thirty semen samples were collected and different concentrations (0, 0.05, 0.1, 0.2, 0.4, 0.8, and 8mM) of ALA were added to a sperm freeze medium and its effects on sperm motility, DNA damage, and lipid peroxidation of frozen-thawed spermatozoa were assessed.
Results: The addition of 0.2 mM ALA to the sperm freeze medium resulted in significant improvement in percentage of sperm motility, less DNA damage and decreased lipid peroxidation during freeze-thawing process (p<0.05).
Conclusion: ALA improves the cryo-protective capacity of sperm freeze medium used for human semen by protecting the sperm from ROS attack induced by the freezing-thawing process. We suggest that sperm freeze medium supplemented with 0.2 mM ALA would be beneficial for the cryopreservation of male gametes in ART.