Could high DNA stainability (HDS) be a valuable indicator of sperm nuclear integrity?

Z Mohammadi,M H Nasr-Esfahani,M Tavalaee,P Gharagozloo,J R Drevet

doi:10.1186/s12610-020-00110-8

Abstract

BackgroundThe Sperm Chromatin Structure Assay (SCSA®), in addition to identifying the DNA Fragmentation Index (DFI) also identifies High DNA satiability (HDS), supposed to reflect the nuclear compaction of spermatozoa. However, data on what exactly this parameter reveals, its relevance and usefulness are contradictory. In order to shed light on this situation, spermatozoa of a cohort (N = 397) of infertile men were subjected to the SCSA®, TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling) and CMA3 (Chromomycin A3) tests. In a smaller subcohort (N = 100), aniline blue (AB) and toluidine blue (TB) staining were performed in addition. The objective of this study was thus to answer the question of whether HDS is a relevant and reliable parameter to be taken into account?ResultsHDS does not appear to be a reliable indicator of nuclear immaturity because it shows a weak correlation with the CMA3, AB and TB stains. The low correlation of HDS with sperm DNA fragmentation (TUNEL and SCSA®) and DNA condensation (CMA3, AB and TB) tests suggests that these two parameters could be decoupled. Unlike DFI and TUNEL, HDS has not been shown to correlate with classic clinical situations of male infertility (asthenozoospermia, teratozoospermia or astheno-teratozoospermia).ConclusionHDS correlates poorly with most tests that focus specifically on the level of maturity of the sperm nucleus. To our knowledge, this study is the first to compare SCSA®, TUNEL, AB, TB and CMA3 assays on identical samples. It shows the potency, consistency and limitations of each test and the care that must be taken in their interpretation.

Highlights

Optimal nuclear sperm condensation is one of the major issues in the male germ cell differentiation program and, to achieve this, mammalian sperm go through a complex process during spermiogenesis and post-testicular maturation
It should be noted that in both cases (“abnormal sperm morphology” and “abnormal head morphology”), the correlations were stronger with chromomycin A3 (CMA3) (r > 0.2; see Table 2)
In response to the question whether TUNEL, Deoxyribo nucleic acid (DNA) Fragmentation Index (DFI), High DNA satiability (HDS) and CMA3 were correlated with each other, we found that HDS was weakly positively correlated with DFI and CMA3 (r = 0.14, p < 0.001 and r = 0.2, p < 0.001, respectively) while it was not correlated with TUNEL at all (r = 0.01, p = 0.78)

Summary

Introduction

Optimal nuclear sperm condensation is one of the major issues in the male germ cell differentiation program and, to achieve this, mammalian sperm go through a complex process during spermiogenesis and post-testicular maturation (for recent reviews, see: [1,2,3]). The increased worldwide use of the most invasive ART procedure (intracytoplasmic sperm injection = ICSI) has rendered these evaluations non-essentials in terms of reproductive success. In this context, it appears that in order to improve our understanding of the etiology of male infertility, further and deeper testing is needed. The Sperm Chromatin Structure Assay (SCSA®), in addition to identifying the DNA Fragmentation Index (DFI) identifies High DNA satiability (HDS), supposed to reflect the nuclear compaction of spermatozoa. The objective of this study was to answer the question of whether HDS is a relevant and reliable parameter to be taken into account?

Objectives

Methods

Results

Discussion

Conclusion