Evaluation of Sperm DNA Fragmentation via Halosperm Technique and TUNEL Assay Before and After Cryopreservation.

AIM: Human sperm DNA fragmentation is one of the factors suggested for male infertility. The ratio of sperm DNA damage in semen may adversely affect both the fertilization rate and the embryo development of in vitro fertilization/ intracytoplasmic sperm injection cycles. Sperm cryopreservation both increases the success rates in assisted reproductive techniques (ARTs) and contributes to the preservation of fertility before testis surgery, chemotherapy, and radiotherapy. The aim of the current study is to determine sperm DNA fragmentation, following cryopreservation.

METHODS: A cross-sectional, observational study was conducted at a university hospital infertility clinic. One hundred (n = 100) volunteer fertile men (ages between 21 and 39 years) with normozoospermic sperm parameters were involved in the current study. Sperm DNA damage was evaluated with the Halosperm technique and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. Fresh samples were studied in liquid form. The remaining samples were kept frozen and then thawed after 1 month and reevaluated with the Halosperm technique and TUNEL assay. Results were then compared between the fresh and frozen samples.

RESULTS: Sperm DNA fragmentation results with the Halosperm technique both before and after cryopreservation were 25% (5%-65%) and 40% (6%-89%), respectively, with a statistically significant increase (15%; P < .001). Sperm DNA fragmentation results by TUNEL assay before and after cryopreservation were 17% (3%-43%) and 36% (7%-94%), respectively, with a statistically significant increase (19%; P <.001).

CONCLUSION: The current data demonstrate increased sperm DNA damage after cryopreservation. Further studies may contribute to development of less harmful techniques and cryoprotectants in order to improve the results of ART.