Sperm DNA fragmentation in mammals: etiology, detection, fertility assessment under radiation exposure

Environmental factors, including radiation-related factors, can adversely affect the male reproductive health, so it is necessary to promptly assess the condition of male germ cells. Currently, there is an urgent need to identify adequate indicators and methods for assessing the quality of male gametes. One such reliable indicator of male fertility and sperm quality, which reflects the integrity of the genetic material, is the level of sperm DNA fragmentation. This article, using literature data, reviews the causes, consequences, and potential mechanisms leading to sperm DNA fragmentation in mammals, as well as analyses the main methods for its detection. The diagnostic significance of assessing chromatin structure abnormalities in the analysis of male infertility is demonstrated. The authors present results indicating the high sensitivity of the SCD test (Sperm Chromatin Dispersion test) in evaluating sperm DNA fragmentation in tundra voles (Alexandromys oeconomus Pall.) under conditions of chronic exposure to ionizing radiation (a dose of 40 cGy). Thus, both the literature data and our own findings have demonstrated that sperm DNA fragmentation levels are a reliable biomarker of male fertility. Furthermore, the Sperm Chromatin Dispersion (SCD) test can be recommended as a sensitive method for assessing the condition of male germ cells in radiobiological research.