Objective: To investigate the relationship between DNA fragmentation by TUNEL method and seminogram parameters from fresh and capacitated samples for swim-up and gradient methods, to verify the best method for improving the outcome of in vitro fertilization.

Materials and methods: Samples were obtained from 100 volunteers after 4-5 days of sexual abstinence. Classical semen parameters were analyzed by computer-aided sperm analysis (CASA) according to WHO classification criteria. Semen was washed twice in RPMI medium and every sample was divided into 3 parts. Two parts were used to capacitate the semen by swim-up and gradient methods, and the other was taken as fresh sample. Analysis of apoptosis and vitality were carried out by TUNEL, and by acridine orange and ethidium bromide methods, respectively on both fresh and capacitated samples.

Results: Our findings show a negative correlation between TUNEL-positive spermatozoa and the efficiency of pregnancy as well as concentration and mobility. To recover mobile cells by capacitation methods, gradient was more efficient than swim-up as well as removing apoptotic and necrotic cells, hence, enriching the quality of semen samples.

Conclusion: DNA fragmentation is a useful tool to differentiate between fertile and infertile men, thus, DNA fragmentation analysis should be part of routine semen analysis for patients suffering infertility.