DNA fragmentation in spermatozoa of mammals and methods of its investigation (review)

Purpose: systematization and analysis of scientific information on DNA fragmentation of spermatozoa of farm animals and methods of its research.Not long ago, one of the factors that negatively affects the fertility of male producers was discovered - fragmentation of sperm DNA. Numerous studies have established that DNA fragmentation is the breaking of DNA strands into pieces. According to Agarval A. (2003), sperm DNA fragmentation is the most common disorder of sperm ultrastructure. According to Baumber J. et al. (2003) determination of sperm DNA fragmentation is currently one of the modern methods for assessing sperm quality. Numerous studies have generated a pool of data on factors causing DNA fragmentation in sperm. Thus, Baumber J. et al. (2003) in their studies indicates that the cause of DNA fragmentation may be problems with chromatin remodeling, apoptosis and oxidative processes in sperm. Research conducted by Aboneev V.V. with coauthor. (2021) found that in severe forms of pathozoospermia, the number of sperm with fragmented DNA is higher than in less severe disorders of spermatogenesis [24]. The appearance of abnormal and inactive sperm in the ejaculate is one of the indirect markers of an increase in the index of DNA fragmentation in sperm, which negatively affects fertilizing ability of sperm. In this regard, the study of sperm DNA fragmentation is an effective diagnostic method for determining fertility. Considering some pathophysiological aspects leading to DNA fragmentation, determining the index of this process a priori cannot be routine. Currently, such high-precision methods as TTUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) — marking the ends of a broken molecule, SSCSA (Sperm Chromatin Structure Assay) — study of sperm chromatin dispersion, Comet (Single-cell gel electrophoresis assay, Cometassay) — capable of identifying breaks in single cells, SCD (Sperm Chromatin Dis) — are actively used. persiontest ) — chromatin dispersion test, etc.