Effect of cryopreservation on sperm DNA integrity in patients with teratospermia

Objective

To test whether sperm with abnormal head morphology are more likely to undergo DNA damage and/or chromatin modification during the process of freeze-thawing.

Design

In this prospective study, the semen samples from forty-four men attending the infertility clinic were included. Samples were divided into aliquots to allow direct comparison of fresh and frozen spermatozoa from the same ejaculate. The sperm morphology and the sperm DNA damage were evaluated before and after cryopreservation. The relationship between sperm head abnormalities and freeze-thaw–induced DNA modification was assessed.

Setting(s)

University hospital fertility center.

Patient(s)

Men attending infertility clinic for semen analysis.

Intervention(s)

The normospermic and teratospermic semen samples were evaluated for DNA damage before and after cryopreservation by comet assay and acridine orange bindability test.

Main Outcome Measure(s)

Elucidation of association between sperm morphologic defect and cryodamage.

Result(s)

A threefold increase in the amount of DNA damage was observed in teratospermic samples compared with their normospermic counterparts, indicating a higher susceptibility of morphologically abnormal sperm to cryodamage.

Conclusion(s)

The susceptibility of morphologically abnormal sperm to DNA damage/chromatin modification during the freeze-thaw process is significantly higher than that of sperm with normal morphology.

Key Words: Cryopreservation, teratozoospermia, DNA damage, chromatin denaturation