Effects of temperature and storage time on the motility, viability, DNA integrity and apoptosis of processed human spermatozoa.

The aim of this study was to evaluate motility, viability, DNA integrity and apoptosis of spermatozoa when washed semen samples were kept for up to 12 days at 4-6°C and 25°C. In this experimental study, 26 normozoospermic semen samples were washed twice in Modified Ham's F10 and resuspended in IVF fertilisation medium. Half of the specimens were stored at 4-6°C, and the other half was kept at 25°C for 12 days. The proportions of viable, motile, spermatozoa with double-stranded DNA and apoptotic spermatozoa were examined during storage time. Apoptosis was measured using annexin V-PI staining followed by flow cytometry. Results showed that sperm motility and viability decreased during 12 days of sample storage (p < .001). There was no significant difference between the two temperatures in terms of motility and viability for up to 2 days (p < .05). The percentage of spermatozoa with double-stranded DNA remained unchanged during the 12 days of storage at both temperatures (p > .05). Although there was no difference between the two temperatures in terms of motility, viability and apoptosis during the first two days of storage, storage of spermatozoa at 4-6°C is better than storage for a longer period than storage at 25°C. Sperm DNA resisted against denaturation during storage.