Ability of deoxyribonucleic acid-damaged sperm to withstand freeze-thaw-induced damage during cryopreservation

Objective: To understand the association between sperm DNA damage and the ability of DNA-damaged sperm to withstand the freeze-thaw process during cryopreservation. Design: Experimental prospective study. Setting(s): Embryology research laboratory. Animals: Eight- to 12-week-old Swiss strain male albino mice (Mus musculus). Intervention(s): Sperm carrying a known amount of DNA damage was subjected to cryopreservation and thereafter evaluated for survival and freeze-thaw-induced DNA damage. Main Outcome Measure(s): Elucidation of association between the amount of initial sperm DNA damage, cryosurvival, and freeze-thaw-induced DNA modification. Result(s): A strong correlation (R = -0.87) was observed between the amount of initial sperm DNA damage and postthaw survival. However, no significant enhancement in DNA damage was observed by the cryopreservation of spermatozoa with various amounts of DNA damage. Conclusion(s): Cryopreservation of DNA-damaged sperm does not deteriorate the DNA quality, but sperm survival is compromised.