The influence of the storage temperature and cryopreservation conditions on the extent of human sperm DNA fragmentation

Abstract

We explored the influence of different storage temperature conditions, including different methods of cryopreservation, on the structure of DNA organization in human sperm using a direct labeling procedure for detecting DNA fragmentation. Nineteen sperm samples that were obtained from healthy men with normozoospermia (according to the criteria of the World Health Organization) were used for the investigation. A significant increase in human sperm DNA fragmentation was observed 8 h after the incubation at +39°C (by 76.7%) and at +37°C (by 68.9%). It was found that cooling the sperm with a cryoprotectant immediately after thawing did not produce a significant difference in the extent of DNA fragmentation; however, the samples that contained cryoprotectants showed a sharp increase in the DNA fragmentation 24 h after the incubation, which could suggest cryoprotectant cytotoxicity.