Evaluating human sperm DNA integrity: relationship between 8-hydroxydeoxyguanosine quantification and the sperm chromatin structure assay

In our work, we have used 8-hydroxy-deoxyguanosine (8-OH-dG), one of the major oxidative products of sperm DNA, in a population of patients consulting for infertility. We found an inverse relationship between sperm concentration and the log of the ratio of 8-OH-dG to dG (P < 0.01). On the same patients' sperm samples, the sperm chromatin structure assay (SCSA) was performed. An inverse relationship was observed between the DNA fragmentation index and sperm concentration (P < 0.001). There was also a positive relationship between SCSA and log 8-OH-dG/dG. This indicates that DNA fragmentation measured by the SCSA originates in part from oxidative products. In a few patients, antioxidant treatment decreased the DNA fragmentation index below the threshold of 30% that is crucial for subfertility.