Oxidative stress parameters in seminal plasma of men with high sperm DNA fragmentation

ABSRACT Introduction. In recent years, increasing attention has been paid to the issue of male reproductive health. The WHO guidelines state that the primary assessment of male fertility is reduced to a “basic semen examination” (concentration, morphology assessment, etc. of sperm). The study of DNA fragmentation, on the other hand, falls under the “expanded” list of tests. At the same time, a thorough evaluation of the antioxidant system’s activity and, in particular, the amount of oxidative modification products of macromolecules, is not included in this list. Sperm are sensitive cells to the effects of reactive oxygen species. Current research focuses on their condition and microenvironment, aimed at detecting the relationship between sperm quality and the development of oxidative stress. However, the question of whether to conduct an expanded and in-depth analysis in cases of normal sperm motility remains unresolved. Objective. The aim of this study was to evaluate the parameters of the antioxidant system and products of oxidative modifications of proteins and DNA of seminal plasma and spermatozoa at a normal level of their mobility and varying DNA fragmentation. Material and methods. This selective pilot single-center cross-sectional study included healthy men with different DNA fragmentation and normal sperm motility. We assessed the oxidative modifications of macromolecules (8-hydroxy-2’-deoxyguanosine; nitrotyrosine) and components of the antioxidant system (total antioxidant activity, catalase activity, superoxide dismutase activity, uric acid, and zinc ions) in seminal plasma and the cellular fraction of the ejaculate. Differences were considered significant at p<0.050. Results. Using the exclusion criteria, we selected 37 patients. In the seminal plasma of men with TUNEL>15, a decrease in superoxide dismutase activity (p<0.010), zinc ion levels (p<0.050) and uric acid content (p<0.050) was observed, while an increase in nitrotyrosine content (p<0.050) was observed only in the cellular fraction of the ejaculate. Conclusions. The obtained data indicate that in men, despite normal sperm motility, a high degree of DNA fragmentation is associated with abnormal head morphology, highlighting the necessity of conducting an “expanded” semen examination. Changes in the components of the antioxidant system are found not within the cells themselves but in their microenvironment, which may likely lead to an increased formation of oxidative modification products of macromolecules in sperm. This is important to consider when collecting samples for ART protocols, as well as in relation to the overall quality and reproductive potential of sperm, which is crucial when planning for pregnancy.