Effect of cryoprotectant-free vitrification versus conventional freezing on human testicular sperm motility: a...

This study aimed to demonstrate the effect of conventional freezing versus cryoprotectant-free vitrification on the recovery of testicular sperm motility. Testicular samples were obtained from 50 patients with azoospermia for testicular biopsy ± potential sperm storage. We retrieved 100 spermatozoa from each patient divided equally into two straws. They were frozen using conventional freezing as a control group and cryoprotectant-free vitrification in micro-capillary system using open-pulled straws. Seven days later, cryopreserved straws were thawed and assessed in duplicate. The mean sperm motility between the original spermatozoa sample and the post warming sample was reduced after conventional freezing compared to cryoprotectant-free vitrification (4.48 ± 2.09% versus 3.25 ± 1.92%, p < 0.001; 4.48 ± 2.09% vs 3.68 ± 1.93%, p < 0.001, respectively). There was a significant difference between the two methods regarding the mean sperm motility after warming (3.38 ± 1.86% versus 3.76 ± 1.88%, p = 0.015). The mean recovery percent of testicular sperm motility from the original sperm sample was lower (p = 0.02) after conventional freezing compared to cryoprotectant-free vitrification (78.4 ± 28.17% versus 85.37 ± 23.63%). Overall, the rate of post-thaw recovery of human testicular sperm motility improved using cryoprotectant-free vitrification compared to conventional freezing.