Characterization of DNA cleavage produced by seminal plasma using leukocytes as a cell target

Abstract

Numerous studies have shown the presence of DNA lesions in human spermatozoa affecting sperm quality. However, the nature of this anomaly and its relationship with patient etiology are poorly understood since different mechanisms can be involved in the formation of these novel DNA configurations including the action of a seminal plasma nuclease activity. The objective of this study was to assess the capacity of seminal plasma for producing endogenous DNA cleavage using nuclei of peripheral blood leukocytes as external targets. For this purpose, we used seminal plasma from fertile males with normal semen parameters to produce DNA cleavage in a sample of leukocytes. Three different tests were performed to visualize DNA cleavage: (a) DNase activity detection, (b) DNA Breakage Detection-Fluorescence In Situ Hybridization (DBD-FISH), and (c) Two-dimensional comet assay (Two-tail comet assay). Our results demonstrate that: (i) the seminal plasma is able to cleave DNA compacted with histones in the leukocytes; (ii) this DNA cleavage can be associated with DNase activity and (iii) DNA damage mainly corresponds to single-strand DNA breaks. In conclusion, capacity of seminal plasma for producing DNA cleavage represents a solid contribution to expand the analysis of the standard seminal profile and could constitute a putative diagnostic tool for evaluating male infertility.

Sperm DNA damage in men with spinal cord injury: the relative incidence of single‐ and double‐strand DNA breaks

“…We do not yet have enough scientific evidence to understand the role that the DNase activity is playing in DNA degradation observed in men with SCI, but this activity cannot be discarded as a main actor in this process. In fact, in a previous investigation, our group demonstrated the capacity of seminal plasma to produce DNA degradation when leukocytes were incubated with seminal plasma of normal individuals 25 . The known capacity of DNases present in the seminal plasma to transverse the plasma membrane of leukocytes, is consistent with a putative ability of the DNases present in the seminal plasma to affect sperm DNA.…”

“…In fact, in a previous investigation, our group demonstrated the capacity of seminal plasma to produce DNA degradation when leukocytes were incubated with seminal plasma of normal individuals. 25 The known capacity of DNases present in the seminal plasma to transverse the plasma membrane of leukocytes, is consistent with a putative ability of the DNases present in the seminal plasma to affect sperm DNA. Oxidative stress, mainly associated with endogenous reactive oxygen species (ROS), is a common source of DNA damage.…”

Sperm DNA fragmentation testing: Summary evidence and clinical practice recommendations

“…It has been shown that spermatozoa from several species, including humans, have an endogenous nuclease that directly participates in apoptosis (Sotolongo et al., 2005). Moreover, the presence of DNase activity at the seminal plasma can be an additional source of DNA cleavage (Cortés‐Gutiérrez et al., 2019; Sotolongo et al., 2003).…”

DNA fragmentation of human spermatozoa: Simple assessment of single‐ and double‐strand DNA breaks and their respective dynamic behavioral response

“…Exposure to damaging agents, including certain pesticides, chemicals, radiation, antineoplastic drugs, tobacco, or diseases such as neoplasms, infections, varicocele, and even fever episodes, may trigger SDF production, through one or several of the mechanisms previously described 12 . Furthermore, the presence of DNase has been shown to adversely affect sperm DNA 13,14 . It is also likely that some spermatozoa may be more susceptible to SDF induction, due to a failure or alteration in chromatin compaction, for example, when the protamine 1/protamine 2 ratio is altered 15 …”