Sperm head morphology is related to high deoxyribonucleic acid stainability assessed by sperm chromatin structure...

To examine the relationship between sperm strict morphology and sperm chromatin integrity.

Prospective study.

Infertility clinic.

Eighty-seven consecutive semen samples from non-azoospermic men presenting for infertility evaluation and 6 samples from fertile donors.

Assessment of standard semen parameters and sperm chromatin structure assay (SCSA) parameters (%DFI [DNA fragmentation index] and %HDS [high DNA stainability]). Evaluation of %HDS and %DFI after treatment with dithiothreitol (a thiol-reducing agent used to decondense sperm nuclei) was also undertaken.

Relationship between sperm strict morphology defects and SCSA parameters (%DFI and %HDS).

We observed significant relationships between the percentage of normal sperm forms and both %HDS (r = -0.40) and sperm motility (r = 0.32). We also found significant relationships between sperm head defects and both %HDS (r = 0.40) and sperm concentration (r = -0.39). Sperm tail, midpiece, and neck defects were not significantly related to the SCSA parameters. Treatment of spermatozoa with dithiothreitol (to induce decondensation) resulted in a substantial increase in %HDS but no measurable change in %DFI.

The observed relationship between sperm head defects and %HDS suggests that sperm head abnormalities may, in part, be due to incomplete sperm chromatin condensation.