Correlation between classical semen parameters, sperm nuclear condensation and DNA fragmentation index in infertile, oligozoospermic males

Background: The diagnosis and classification of male factor infertility, in a large part depends on the results of conventional semen analysis, although it is generally accepted that quantitative assessments of semen have a poor prognostic value in predicting the outcome of assisted reproductive cycles. Besides quantitative analysis there are many standardised methods to obtain qualitative data on sperm quality.
Aim: To look for a correlation between classical semen parameters and qualitative sperm characteristics.
Material and Methods: Semen samples of 15 infertile, oligozoospermic men and 15 age-matched fertile men were analysed (mean age:33.1 years; 24-42 years). Classical semen analysis was performed. DNA fragmentation index was determined with fluorescent acridine-orange staining. The percentage of sperm with decondensed chromatin was determined with aniline-blue staining.
Results: The mean sperm concentration was 7.1 x106/mL in the oligozoospermic group and 78.5 x106/mL in the normozoospermic group. There was a significant difference in the sperm progressive motility (16.8% vs. 39%), total motility (37.4% vs. 59.5%), and morphology (3.7% vs. 12.7%) between the oligozoospermic and normozoospermic groups. The DNA fragmentation was significantly increased in the infertile, oligozoospermic group (26.4% vs.14.5%). Chromatin condensation failure was present in the patient group in 45%, and in 17.9% of the control group (p<0.001).
Correlation analysis revealed a connection between sperm concentration and DNA fragmentation(r=-0.72; p<0.05) and a stronger relationship between sperm concentration and chromatin decondensation (r=-0.85; p<0.05).
Conclusion: The correlation between quantitative and qualitative semen parameters can be explained by a common regulative mechanism, which plays a role in spermiogenesis. A high DNA fragmentation Index as well as increased chromatin condensation failure is known to reflect the fertility of the semen sample. By using both qualitative and quantitative methods in the analysis of sperm, essential diagnostics can be provided on the fertility of sperm; especially in cases of unexplained male infertility or recurrent pregnancy loss.