Superoxide dismutase content in sperm correlates with motility recovery after thawing of cryopreserved human spermatozoa

Abstract

Objective To investigate the correlation between sperm superoxide dismutase (SOD) content and motility recovery after thawing of cryopreserved human sperm, based on the rationale that this antioxidant enzyme provides protection against reactive oxygen species-induced damage during cryopreservation. Design Prospective study. Setting Private infertility institute and university-based research laboratory. Patient(s) Forty-two consenting normozoospermic patients consulting for infertility. Intervention(s) The SOD content was measured in sperm from unfractionated samples and in sperm recovered from the pellet fraction obtained after discontinuous density gradient centrifugation. Main Outcome Measure(s) Sperm motility was evaluated post-thaw in the two sets of samples and motility recovery was plotted against the sperm SOD content to determine their correlation. Result(s) There was a significant positive correlation between motility recovery after thawing and SOD content in sperm from the 90% gradient pellet containing highly purified mature sperm. There was also a significant negative correlation between motility after thawing and SOD content in the unfractionated sample. Conclusion(s) The positive correlation between post-thaw motility recovery and SOD content in mature spermatozoa provides a good predictor of post-thaw motility recovery after cryopreservation.