DNA sperm damage correlates with nuclear ultrastructural sperm defects in teratozoospermic men

Sperm morphology has consistently been the best indicator of male fertility. Transmission electron microscopy currently provides the most information on the subcellular details of sperm structure. Recently, assessment of sperm DNA damage has been employed to assess fertility potential. The purpose of this work was to link sperm DNA damage, evaluated by an intercalated fluorescent dye, with the structural characteristics of sperm. Conventional semen analysis was performed on samples from men undergoing fertility evaluation. Thirty men were evaluated and assigned to three subgroups based on strict criteria for sperm morphology: normal morphology (>14% normal forms), intermediate morphology (5-14% normal forms), and poor morphology (<5% normal forms). By quantifying acridine orange-positive cells and ultrastructural sperm defects, we found that the poor morphology pattern group showed a positive association between sperm carrying damaged DNA and the percentage of sperm nucleus with vacuoles (P = 0.01). No statistically significant correlations were established in other ultrastructural characteristics of sperm, including immature chromatin, lytic changes, or abnormal sperm tails. These results suggest that zones without chromatin in the sperm nucleus reflect underlying chromosomal or DNA defects in severe teratozoospermic men. This association should be considered in the evaluation of male fertility.