Evaluation of sperm DNA fragmentation in male infertility

Sperm DNA integrity could be considered a biological marker of sperm quality and may affect fertilization, embryonic development, and pregnancy outcome. The study aimed to investigate the connection between semen characteristics and sperm DNA damage in infertile patients. Standard semen analysis of 536 samples was carried out following the World Health Organization (WHO) 5th edition recommendations. Sperm DNA damage was assessed by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, after preparation by direct swim-up. The slides were evaluated using a fluorescence microscope and the percentage of TUNEL-positive spermatozoa was expressed as the DNA fragmentation index (DFI). Patients were classified according to their DFI levels: group A (DFI < 15%) and group B (DFI >= 15%). Sperm total count, concentration, total and progressive motility, vitality, and normal morphology were significantly higher in group A compared to group B (p < 0.001). The results show a significant inverse correlation between DFI and patient's age, sperm total count, concentration, total and progressive motility, vitality and normal morphology. Higher DFI values were found to be strongly associated with poor sperm quality. In conclusion, combined with conventional semen analysis, assessment of sperm DFI could improve diagnostic accuracy and treatment management for patients with male infertility.