Comparison of apoptotic markers and protamine deficiency in sperm of infertile individuals with varicocele and fertile men

Background: Heat and oxidative stress are the main pathophysiological elements of varicocele. One of the most important molecular pathways which is triggered by them is apoptosis and can be identified by various markers such as phosphatidylserine externalization and DNA fragmentation. Protamine deficiency is another phenomenon associated with varicocele. Therefore, the aim of this study was to evaluate apoptotic markers in infertile men with varicocele and correlation of these markers with sperm parameters and chromatin maturation.

Methods: In the current study, semen samples of 15 infertile men with varicocele and 15 fertile men who referred to Isfahan fertility and infertility center were used. Firstly, sperm parameters (sperm concentration, motility and morphology) were assessed based on World Health Organization guidelines (2010). Phosphatidylserine translocation, DNA fragmentation and protamine deficiency were evaluated by flow cytometry, TUNEL assay and chromomycin A3 (CMA3) staining, respectively.

Results: The results showed that mean values of sperm parameters have reduced significantly in varicocele group compared to fertile group. Phosphatidylserine externalization showed no difference between two groups but percentage of DNA fragmentation and protamine deficiency was significantly higher in study group compared to control group.

Conclusion: In infertile men with varicocele, increase in levels of DNA fragmentation, protamine deficiency and low quality of sperm parameters may be due to disturbance of testicular thermos-regulation. Further studies are needed to confirm these results. Moreover, no difference was observed in phosphatidylserine externalization which can be due to the small sample size of this study or result of transition of sperm from early to late stages of apoptosis.