Effect of insulin on functional parameters of human cryopreserved sperms

Cryopreservation of sperms is common therapy but with multiple damages to sperms. The aim of this study was to assess the effect of insulin as a prosurvival factor on the most important functional parameters of human spermatozoa during cryopreservation. Semen samples were obtained from 15 normozoospermic men at age 25–40 years of old through masturbation. Cryopreservation of sperms was conducted along with adding 10, 100, 500 and 1000 (ng/ml) insulin and a control group was also considered by adding distilled water. Samples were cryopreserved for 2 weeks in liquid nitrogen. Then, after thawing sperm motility; cytosolic/mitochondrial reactive oxygen species (ROS) levels; and DNA fragmentation were analyzed. Data were analyzed by SPSS software using one-way ANOVA. Results showed that insulin at all doses significantly decreased cytosolic ROS especially in 10 ng/ml group (P˂0.05). Mitochondrial ROS also decreased by adding insulin in comparison to the control group, although unmeaningfully (P˃0.05). Insulin at 1000 (ng/ml) decreased DNA fragmentation, significantly (P˂0.05). Also, the number of motile sperms increased in all insulin groups but it wasn't meaningful (P˃0.05). Based on our findings adding insulin to semen leads to protecting effects against cryopreservation damages and increases sperms motility. Therefore, using insulin for human semen seems to could be suggested for future clinical applications.