Abstract

BACKGROUND: Single sperm cryopreservation (SSC) is a method that preserves the limited number of spermatozoa in testicular sperm. But testicular spermatozoa are characterized with low movement, which is not ideal for sperm selection before SSC. OBJECTIVE: This study was designed to investigate in vitro incubation (IVC) as a sperm selection technique before SSC on biological factors of testicular spermatozoa. MATERIALS AND METHODS: Testicular tissue was obtained from 15 azoospermia men. One part of the testicular samples was used as a Control group, which was assessed fresh. One portion was cryopreserved by a vitrification (Vit) method and the two other portions were in vitro cultured for 24 h, with (IVC-Vit) or without (IVC) vitrification. Sperm motility, viability, morphology, DNA fragmentation and mitochondrial membrane potential were evaluated. RESULTS: Sperm motility and viability were better maintained in the IVC-Vit group compared to the Vit group (P=0.04 and P= 0.003, respectively). Sperm morphology, the fresh, Vit, IVC, and IVC-Vit groups all showed similar results (P >0.05). Mitochondrial activity was significantly lower in the Vit group compared to the Control fresh group (P = 0.0001). The IVC group had a significantly higher DFI as compared to the Control (P <0.0001). Compared to the IVC group, the IVC-Vit sperm had a significant increase in DFI (P= 0.0009). There was a statistically significant difference between post warm DFI of the Vit group and IVC-Vit group (P <0.0001). CONCLUSION: IVC as a sperm selection method increased motility and viability of testicular spermatozoa before single sperm vitrification. As DNA fragmentation increased by this technique, this method is not ideal for selecting viable sperm. © CryoLetters, editor@cryoletters.org.