RESUMO
OBJECTIVE: To investigate the potential effects of TAT-PRDX2 protein supplementation to the cryopreservation medium on post-thaw sperm quality and function. DESIGN: In vitro prospective study. SETTING: Medical university hospital. PATIENT(S): Fifty normozoospermic, 50 asthenozoospermic, and 50 oligoasthenozoospermic men undergoing semen analysis for couple infertility. INTERVENTION(S): Each semen sample was divided into three aliquots: fresh, cryopreserved control (without additive), and cryopreserved with TAT-PRDX2 protein. MAIN OUTCOME MEASURE(S): Sperm motility, viability, mitochondrial potential, and DNA damage as well as reactive oxygen species (ROS) levels and lipid peroxidation were analyzed. Acrosome reaction and zona-free hamster oocyte penetration tests were performed to assess the fertilization ability of cryopreserved spermatozoa. RESULT(S): In normozoospermic and asthenozoospermic groups, the addition of 150 µg/mL TAT-PRDX2 significantly reduced intracellular ROS and malondialdehyde levels and enhanced post-thaw sperm motility and viability when compared with the cryopreserved control of the respective groups but did not produce any significant protective effect in the oligoasthenozoospermic group. Mitochondrial potential was significantly increased, whereas DNA fragmentation was significantly decreased, after TAT-PRDX2 supplementation only in the asthenozoospermic group when compared with the cryopreserved control. Although the penetration rate and the penetration index were not markedly improved, TAT-PRDX2 supplementation obviously reduced spontaneous acrosome reaction and increased calcium ionophore-induced acrosome reaction in the normozoospermic and asthenozoospermic groups. CONCLUSION(S): TAT-PRDX2 protein effectively exerted cryoprotective effects on spermatozoa by reducing intracellular ROS level and thereby improved post-thaw sperm quality and function, especially for asthenozoospermic samples. TAT-PRDX2 protein is a promising additive for developing a new and highly efficient semen cryoprotectant.