Evaluation of DNA/protein status and nuclear maturity of human sperm.

Defects of the DNA/protein complex (nuclear immaturity) in chromatin of human spermatozoa with normal and abnormal head morphology in teratozoospermal semen samples (group B) were studied and the findings correlated with normozoospermal samples (group A). Differences were observed in the pattern of thermal DNA stability. Denaturation of native DNA (double strand) from normal and abnormal cells in both groups increased significantly with the time of incubation, compared with their respective controls (p < 0.01). The percentage of denaturation was higher for normal group B sperm (p < 0.05). Differences between groups A and B spermatozoa were detected using cationic dyes, and the DNA/protein complex stability was evaluated by the resistance of sperm samples to acid denaturation; poor chromatin stability was evident in group B. It is suggested that normal and abnormal gametes from group B semen have less stable chromatin (greater nuclear immaturity) than those from group A. This factor may be relevant in assessing the fertilizing capacity of human teratozoospermal samples both in vivo and in vitro.