Decreased activity of superoxide dismutase in the seminal plasma of infertile men correlates with increased sperm deoxyribonucleic acid fragmentation during the first hours after sperm donation

摘要

Sperm DNA fragmentation varies between individuals and is more pronounced with increased patient age and time after sperm donation. The intensification of DNA fragmentation depends on the balance of the oxidoreductive system, which is regulated mainly by two enzymes - superoxide dismutase (SOD) and catalase. The objective of this study was to determine the relationship between sperm DNA fragmentation dynamics, fertility and seminal SOD and catalase activity. The study was conducted in 2013 and 2014 at the Non-Public Health Care Unit 'Ovum Reproduction and Andrology' in Lublin, Lublin, Poland, and covered 218 men aged 25-35 (85 fertile and 133 patients treated for infertility). Percentage of fragmented DNA was measured in a modified chromatin dispersion test at four time points after sperm donation (t=0, 3, 6, 12h). SOD and catalase activities were determined spectrophotometrically. We confirmed that the activity of SOD in the seminal plasma of men with reproductive disorders was lower compared with fertile men. Conversely, no significant correlations were found between fertility and catalase activity. Sperm DNA of infertile males was initially more fragmented than fertile male sperm DNA. SOD and catalase activity did not correlate with the degree of DNA fragmentation in fertile men. In men with reproductive disorders, the rate of DNA fragmentation was slow within first 3h after sperm donation and then increased between 6 and 12h. In this group of infertile men, those with higher SOD activity had a lower DNA fragmentation index (DFI) after 12h, and a reduced rate of intensity of fragmentation from 6 to 12h. Alternatively, higher catalase activity among men treated for infertility was accompanied by higher initial DFI and higher rate of DNA fragmentation from 6 to 12h. These results highlight the importance of determining a proper time window between sperm donation and procedures of assisted reproductive technology.