Background and aim: Cryopreservation is one of the common techniques in the management of infertility, which can damage the sperm cell and its function by producing reactive oxygen species. To determine health and fertility of cryopreserved sperm, we evaluated different markers in infertile men. The aim of this study was to investigate the effect of biotin and folic acid on motility, viablity, shape, chromatin density and membrane integrity of cryopreserved and thawed sperm in normozoospermic men.
Material and Method: In this experimental study, 30 samples were collected from normozoospermic men. Every sample included fresh pre-cryopreservation group, cryopreserved control groups, biotin (10 mM), folic acid (50 nM), and combination of biotin (10 mM) and folic acid (50 nM) groups. Sperms were frozen for two weeks using the usual freezing technique at -196 ° C and then thawed. Samples were evaluated for motility before and after freezing using computer-aided sperm analysis software. We assessed sperm viability by eosin-negrosin staining, chromatin density by toluidine blue staining and membrane integrity by hypo osmotic swelling test.
Results: Before cryopreservation, motility, viability, chromatin density, sperm membrane integrity were higher and the number of immotile sperms were lower in all groups (p <0.001). Quality of chromatin was higher in the groups of folic acid, biotin + folic acid and biotin than in the control group. Mean sperm viability was higher in the three above mentioned groups than in the control group. We found higher sperm membrane integrity in the folic acid, biotin and combination groups than in control group (p <0.001). After cryopreservation, a positive correlation was found between sperm chromatin quality and membrane integrity.
Conclusion: Biotin and folic acid showed a protective effects on chromatin quality, membrane integrity, viability of the sperms and played an important role in maintaining sperm parameters after cryopreservation.