Correlation of spermiogram profiles with DNA damage in sperm cells of infertile men: a comet assay study

Abstract

We have investigated a relationship between DNA damage in sperm and spermiogram profiles in the infertile men. Twenty-one non-smoking infertile men <40 years of age with no systemic or genetic disease were randomly selected from the pool of infertile couples applied to our clinic. Sperm samples were collected and evaluated according to WHO guidelines. DNA damage of sperm cells was assessed using neutral comet assay. Fifty cells per slide and two slides per sample were scored to evaluate DNA damage. The cells were visually classified into four categories based on DNA migration such as undamaged (UD), little damage (LD), moderate damage (MD) and significant damage (SD). Total comet scores (TCS) were calculated as: 1×UD + 2×LD + 3×MD + 4×SD. There was a negative correlation between the percentage of slow- and in situ-motion sperm cells in spermiograms and TCS (p < 0.001 and p < 0.05, respectively). The relationship between the percentage of non-motile sperm cells and TCS was negative (p < 0.001). This study provides new evidence that DNA damage in spermatozoa and sperm motility parameters are negatively correlated. We suggest that evaluation of sperm DNA by the neutral comet assay may be valuable to use in fertility research.

Keywords:

• Sperm
• DNA damage
• infertile men
• comet assay
• spermiogram

Acknowledgements

This study is supported by The Scientific and Technological Research Council of Turkey (TUBITAK project No. 104-T-240). We thank Dr. Gulhan Aktas of the Zeynep Kamil Maternity and Children's Hospital in Istanbul for her technical assistance in the Andrology Laboratory.