sperm dna damage and protamine transcripts content in iranian men with unexplained infertility

Background: incomplete chromatin condensation caused by altered amount of sperm protamines results in dna fragmentation, which in turn leads to a lack of success in the development of the human embryo. objectives: this study evaluated the sperm dna damage and protamine transcripts content in iranian normozoospermic fertile and infertile men. methods: dna damage was analyzed using comet assay. transcript levels of protamine-1 (prm1) and protamine-2 (prm2) in ejaculated spermatozoa were assessed by quantitative real-time polymerase chain reaction (pcr). results: significantly higher levels of dna damage were observed in unexplained infertile men (p = 0.001). dna fragmentation correlated significantly with sperm total motility (r = -0.413, p = 0.032) and normal morphology (r = -0.424, p = 0.028). prm1 and prm2 transcripts contents were significantly lower in normozoospermic infertile men than healthy controls. sperm prm1 and prm2 mrnaratios were significantly higher (p = 0.035) in unexplained infertile patients than fertile men. higher dna damage was found to be significantly associated with reduced transcript levels of prm1 (r = -0.453, p = 0.018) and prm2 (r = -0.492, p = 0.009). protamine transcripts ratios were significantly correlated with sperm normal morphology (r = -0.421, p = 0.029). conclusions: our findings showed the prognostic value and clinical utility of the sperm dna damage and protamine transcripts contents for the discrimination between healthy fertile and unexplained infertile men.