Testicular human spermatozoa cryopreservation correlation between sperm head vacuoles, DNA fragmentation and mitochondrial membrane potential

Abstract

Background: There are difficulties associated with testicular sperm freezing. Different methods of sperm cryopreservation developed. Not enough detailed studies about the real efficacy of these techniques exist. For sperm morphologic assessment, motile sperm organelle morphology examination (MSOME) is able to identify not only conventional morphological sperm alterations but also sperm head vacuoles. Objective: To assess the effect of cryopreservation on testicular spermatozoa vacuoles by MSOME and its correlation to DNA fragmentation and mitochondrial membrane potential. Materials and methods: After preparation, testicular sperm extraction samples of 15 azoospermic men, aged 20–40 years old were divided into three groups. Group 1 was assessed freshly. Group 2 was cryopreserved with vitrification method and Group 3 with cooling in liquid nitrogen vapor using droplet. Pre and post warming assessment in terms of spermatozoa head vacuoles by MSOME, DNA fragmentation, and mitochondrial membrane potential were performed. Results: The number of spermatozoa with no vacuoles significantly decreased after two cryopreservation techniques (P 0.05). DNA fragmentation and mitochondrial membrane potential increased after cryopreservation (P < 0.001). There was a significant positive correlation between spermatozoa with large vacuoles in group 2 and DNA fragmentation and a significant positive correlation between spermatozoa with no vacuole and mitochondrial membrane potential in groups 2 and 3. Conclusion: Cryopreservation affects spermatozoa vacuolization, DNA structure, and mitochondrial membrane potential. Using MSOME in the selection of post-thaw morphologically normal testicular spermatozoa for ICSI procedure will be of particular value. Keywords: Spermatozoa, Azoospermia, MSOME, Cryopreservation, Vacuoles, DNA fragmentation