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.

The aim of this study was to investigate the protective and therapeutic effects of thymoquinone against the negative effects of varicocele on testicular tissue and sperm morphology. Five groups were formed by random selection from a total of 40 adult male Wistar rats (n = 8). Thymoquinone (5 mg/kg/day) was administered intraperitoneally to the varicocele‐dimethyl sulfoxide‐olive oil‐thymoquinone (VT) group and the sham‐thymoquinone group. At the end of the 60th day, all groups were anaesthetised and the left testis was removed from the body quickly. One half of the testis tissue, which was divided into two, was separated for biochemical and Western blot analysis, while the other half were fixed in Bouin's fixative. As a result of biochemical, molecular and histopathological analyses, a statistically significant increase was found in the varicocele group testicular tissues in the malondialdehyde level, apoptotic index, Bax expression, cytochrome c expression and Bax/Bcl‐2 ratio compared with the sham group. In addition, histopathological changes characterised by partial or complete degeneration of the germinal epithelium were observed in the seminiferous tubules in the same group. Total oxidant status level and sperm count with abnormal morphology increased in varicocele group, whereas total antioxidant status level decreased. In the VT group, all of the biochemical, molecular and histopathological changes detected in the varicocele group were statistically significantly reduced. When the findings obtained in this study are evaluated, it can be said that thymoquinone has the potential to be used as a preventive and therapeutic pharmacological agent in the medical treatment of varicocele. Although the exact mechanism of action of thymoquinone has not been fully elucidated, the findings obtained in this study support the view that thymoquinone showed a cytoprotective effect by reducing apoptosis, oxidative stress and lipid peroxidation.