scholarly journals Complete Chromatin Decondensation of Pig Sperm Is Required to Analyze Sperm DNA Breaks With the Comet Assay

2021 ◽  
Vol 9 ◽  
Author(s):  
Jordi Ribas-Maynou ◽  
Ariadna Delgado-Bermúdez ◽  
Estela Garcia-Bonavila ◽  
Elisabeth Pinart ◽  
Marc Yeste ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Comet Assay ◽  
Dnase I ◽  
Proteinase K ◽  
Farm Animals ◽  
Sperm Chromatin ◽  
Dna Breaks ◽  
Chromatin Decondensation ◽  
Sperm Dna

Sperm quality is usually evaluated prior to artificial insemination in farm animals. In addition to conventional semen analysis, other biomarkers, such as mitochondrial activity, integrity and lipid disorder of plasma membrane, generation of reactive oxygen species (ROS) and sperm DNA integrity, have been found to be related to fertility rates in different species. While mounting evidence indicates that the Comet assay is a sensitive method for the detection of DNA breaks, complete sperm chromatin decondensation is required in order to properly analyze the presence of single- and double-strand DNA breaks. In this sense, a previous study showed that longer lysis treatment with proteinase K is needed to achieve complete chromatin decondensation. The current work sought to determine which specific lysis treatment leads to complete chromatin decondensation in pig sperm, as this is needed for the measurement of DNA damage in this species. With this purpose, incubation with a lysis solution containing proteinase K for 0, 30, and 180 min was added to the conventional protocol. The impact of the DNA damage induced by hydrogen peroxide (H2O2; 0.01 and 0.1%) and DNAse I (1U and 4U) was also evaluated. Complete chromatin decondensation was only achieved when a long additional lysis treatment (180 min) was included. Furthermore, olive tail moment (OTM) and percentage of tail DNA (TD) indicated that a higher amount of DNA breaks was detected when hydrogen peroxide and DNAse I treatments were applied (P < 0.05). The comparison of treated and control sperm allowed defining the thresholds for OTM; these thresholds revealed that the percentage of sperm with fragmented DNA determined by the alkaline Comet does not depend on chromatin decondensation (P > 0.05). In conclusion, complete chromatin decondensation prior to alkaline and neutral Comet assays is needed to analyze DNA breaks in pig sperm.

scholarly journals Sperm DNA fragmentation induced by DNAse I and hydrogen peroxide: an in vitro comparative study among different mammalian species

Reproduction ◽  
2010 ◽  
Vol 140 (3) ◽  
pp. 445-452 ◽  
Author(s):  
Paola Villani ◽  
Patrizia Eleuteri ◽  
Maria Giuseppa Grollino ◽  
Michele Rescia ◽  
Pierluigi Altavista ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Comet Assay ◽  
Chromatin Structure ◽  
Dnase I ◽  
Sperm Chromatin ◽  
Sperm Dna Fragmentation ◽  
Dna Breaks ◽  
Sperm Dna

Sperm DNA damage may have adverse effects on reproductive outcome. Sperm DNA breaks can be detected by several tests, which evaluate DNA integrity from different and complementary perspectives and offer a new class of biomarkers of the male reproductive function and of its possible impairment after environmental exposure. The remodeling of sperm chromatin produces an extremely condensed nuclear structure protecting the nuclear genome from adverse environments. This nuclear remodeling is species specific, and differences in chromatin structure may lead to a dissimilar DNA susceptibility to mutagens among species. In this study, the capacity of the comet assay in its two variants (alkaline and neutral) to detect DNA/chromatin integrity has been evaluated in human, mouse, and bull sperm. The hypothesis that chromatin packaging might influence the amount of induced and detectable DNA damage was tested by treating sperm in vitro with DNAse I, whose activity is strictly dependent upon its DNA accessibility. Furthermore, hydrogen peroxide (H2O2) was used to assess whether spermatozoa of the three species showed a different sensitivity to oxidative stress. DNAse I-induced damage was also assessed by the sperm chromatin structure assay and the TUNEL assay, and the performances of these two assays were compared and correlated with the comet assay results. Results showed a different sensitivity to DNAse I treatment among the species with human sperm resulting the most susceptible. On the contrary, no major differences among species were observed after H2O2 treatment. Furthermore, the three tests show a good correlation in revealing sperm with DNA strand breaks.

scholarly journals Species-Specific Differences in Sperm Chromatin Decondensation Between Eutherian Mammals Underlie Distinct Lysis Requirements

2021 ◽  
Vol 9 ◽  
Author(s):  
Jordi Ribas-Maynou ◽  
Estela Garcia-Bonavila ◽  
Carlos O. Hidalgo ◽  
Jaime Catalán ◽  
Jordi Miró ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Condensation ◽  
Proteinase K ◽  
Sperm Chromatin ◽  
Dna Integrity ◽  
Dna Breaks ◽  
Chromatin Decondensation ◽  
The Third ◽  
Core Length ◽  
Sperm Dna

Sperm present a highly particular DNA condensation that is acquired during their differentiation. Protamines are key elements for DNA condensation. However, whereas the presence of protamine 1 (P1) is conserved across mammalian species, that of protamine 2 (P2) has evolved differentially, existing only few species that use both protamines for sperm DNA condensation. In addition, altered P1/P2 ratios and alterations in the expression of P1 have previously been associated to infertility and DNA damage disorders. On the other hand, different methods evaluating DNA integrity, such as Sperm Chromatin Dispersion (SCD) and Comet tests, need a previous complete DNA decondensation to properly assess DNA breaks. Related with this, the present study aims to analyze the resilience of sperm DNA to decodensation in different eutherian mammals. Sperm samples from humans, horses, cattle, pigs and donkeys were used. Samples were embedded in low melting point agarose and treated with lysis solutions to induce DNA decondensation and formation of sperm haloes. The treatment consisted of three steps: (1) incubation in SDS + DTT for 30 min; (2) incubation in DTT + NaCl for 30 min; and (3) incubation in DTT + NaCl with or without proteinase K for a variable time of 0, 30, or 180 min. How incubation with the third lysis solution (with or without proteinase K) for 0, 30, and 180 min affected DNA decondensation was tested through analyzing core and halo diameters in 50 sperm per sample. Halo/core length ratio was used as an indicator of complete chromatin decondensation. While incubation time with the third lysis solution had no impact on halo/core length ratios in species having P1 and P2 (human, equine and donkey), DNA decondensation of pig and cattle sperm, which only present P1, significantly (P < 0.05) increased following incubation with the third lysis solution for 180 min. In addition, the inclusion of proteinase K was found to accelerate DNA decondensation. In conclusion, longer incubations in lysis solution including proteinase K lead to higher DNA decondensation in porcine and bovine sperm. This suggests that tests intended to analyze DNA damage, such as halo or Comet assays, require complete chromatin deprotamination to achieve high sensitivity in the detection of DNA breaks.

scholarly journals Rapid rates of sperm DNA damage after activation in tench (Tinca tinca: Teleostei, Cyprinidae) measured using a sperm chromatin dispersion test

Reproduction ◽  
2009 ◽  
Vol 138 (2) ◽  
pp. 257-266 ◽  
Author(s):  
Carmen López-Fernández ◽  
Matthew J G Gage ◽  
Francisca Arroyo ◽  
Altea Gosálbez ◽  
Ana M Larrán ◽  
...  
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Dna Fragmentation ◽  
Living Organism ◽  
Sperm Chromatin ◽  
Tinca Tinca ◽  
External Fertilization ◽  
Sperm Dna Damage ◽  
Sperm Dna ◽  
Dispersion Test

Spermatozoal haplotypic DNA is prone to damage, leading to male fertility problems. So far, the assessment of sperm DNA breakage has been challenging because protamines render the nuclear chromatin highly compacted. Here, we report the application of a new test to quantify DNA fragmentation in spermatozoa of an externally fertilizing teleost fish. The sperm chromatin dispersion (SCD) test uses a species-specific lysing solution to generate controlled protein depletion that, followed by DNA-specific fluorescent labelling, allows an easy morphological discrimination between nuclei affected by DNA damage. Using tench (Tinca tinca) as our model, we first trialled the test against established, but more technically demanding, assays employing in situ nick translation (ISNT) and the comet assay. The SCD test showed high concordance with ISNT, comet assay measures and a chromatin-swelling test, confirming the application of this straightforward SCD technique to various aspects of reproductive biology. Second, we examined between-male variation in DNA damage, and measured changes through time following spermatozoal activation. Between-male variation in the basal levels of average DNA damage ranged from 0 to 20% of sperm showing damage, and all showed increases in DNA fragmentation through time (0–60 min). The rates of DNA damage increase are the fastest so far recorded in sperm for a living organism, and may relate to the external fertilization mode. Our findings have relevance for broodstock selection and optimizing IVF protocols routinely used in modern aquaculture.

scholarly journals Evidence that single-stranded DNA breaks are a normal feature of koala sperm chromatin, while double-stranded DNA breaks are indicative of DNA damage

Reproduction ◽  
2009 ◽  
Vol 138 (2) ◽  
pp. 267-278 ◽  
Author(s):  
Yeng Peng Zee ◽  
Carmen López-Fernández ◽  
F Arroyo ◽  
Stephen D Johnston ◽  
William V Holt ◽  
...  
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Dna Fragmentation ◽  
Sperm Nucleus ◽  
Severe Form ◽  
Sperm Chromatin ◽  
Dna Breaks ◽  
Single Stranded Dna ◽  
Double Stranded Dna ◽  
Dispersion Test

In this study, we have used single and double comet assays to differentiate between single- and double-stranded DNA damage in an effort to refine the interpretation of DNA damage in mature koala spermatozoa. We have also investigated the likelihood that single-stranded DNA breakage is part of the natural spermiogenic process in koalas, where its function would be the generation of structural bends in the DNA molecule so that appropriate packaging and compaction can occur. Koala spermatozoa were examined using the sperm chromatin dispersion test (SCDt) and comet assays to investigate non-orthodox double-stranded DNA. Comet assays were conducted under 1) neutral conditions; and 2) neutral followed by alkaline conditions (double comet assay); the latter technique enabled simultaneous visualisation of both single-stranded and double-stranded DNA breaks. Following the SCDt, there was a continuum of nuclear morphotypes, ranging from no apparent DNA fragmentation to those with highly dispersed and degraded chromatin. Dispersion morphotypes were mirrored by a similar diversity of comet morphologies that could be further differentiated using the double comet assay. The majority of koala spermatozoa had nuclei with DNA abasic-like residues that produced single-tailed comets following the double comet assay. The ubiquity of these residues suggests that constitutive alkali-labile sites are part of the structural configuration of the koala sperm nucleus. Spermatozoa with ‘true’ DNA fragmentation exhibited a continuum of comet morphologies, ranging from a more severe form of alkaline-susceptible DNA with a diffuse single tail to nuclei that exhibited both single- and double-stranded breaks with two comet tails.

scholarly journals Validation of the sperm chromatin dispersion (SCD) test in the amphibian Xenopus laevis using in situ nick translation and comet assay

2015 ◽  
Vol 27 (8) ◽  
pp. 1168 ◽  
Author(s):  
K. Pollock ◽  
J. Gosálvez ◽  
F. Arroyo ◽  
C. López-Fernández ◽  
M. Guille ◽  
...  
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Xenopus Laevis ◽  
Semen Quality ◽  
Sperm Chromatin ◽  
Sperm Dna Fragmentation ◽  
Nick Translation ◽  
In Situ Nick Translation ◽  
Sperm Dna

The integrity of sperm DNA is becoming increasingly recognised as an important parameter of semen quality, but there are no published reports of this procedure for any amphibian. The primary aim of this study was to apply a modified sperm chromatin dispersion (SCD) test (Halomax) to an amphibian sperm model (African clawed frog; Xenopus laevis) and to validate the assay against in situ nick translation (ISNT) and the double-comet assay procedure. Inactivated spermatozoa were collected from fresh testes (n = 3). Sperm DNA fragmentation (SDF) for each sperm sample was conducted immediately following activation (T0) and again after 1 h (T1) and 24 h (T24) of incubation at room temperature in order to produce a range of spermatozoa with differing levels of DNA damage. The SCD procedure resulted in the production of three nuclear morphotypes; amphibian sperm morphotype 1 (ASM-1) and ASM-2 showed no evidence of DNA damage, whereas ASM-3 spermatozoa were highly fragmented with large halos of dispersed DNA fragments and a reduced nuclear core. ISNT confirmed that ASM-3 nuclei contained damaged DNA. There was a significant correlation (r = 0.9613) between the levels of ASM-3 detected by the SCD test and SDF revealed by the double-comet assay.

scholarly journals Single and Double Strand Sperm DNA Damage: Different Reproductive Effects on Male Fertility

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 105 ◽  
Author(s):  
Jordi Ribas-Maynou ◽  
Jordi Benet
Keyword(s):  
Dna Damage ◽  
Male Fertility ◽  
Sperm Chromatin ◽  
Dna Breaks ◽  
Sperm Dna Damage ◽  
Reproductive Effects ◽  
Double Strand Dna Breaks ◽  
Sperm Dna ◽  
Break Points ◽  
Double Strand Dna

Reproductive diseases have become a growing worldwide problem and male factor plays an important role in the reproductive diagnosis, prognosis and design of assisted reproductive treatments. Sperm cell holds the mission of carrying the paternal genetic complement to the oocyte in order to contribute to an euploid zygote with proper DNA integrity. Sperm DNA fragmentation had been used for decades as a male fertility test, however, its usefulness have arisen multiple debates, especially around Intracytoplasmic Sperm Injection (ICSI) treatments. In the recent years, it has been described that different types of sperm DNA breaks (single and double strand DNA breaks) cause different clinical reproductive effects. On one hand, single-strand DNA breaks are present extensively as a multiple break points in all regions of the genome, are related to oxidative stress and cause a lack of clinical pregnancy or an increase of the conception time. On the other hand, double-strand DNA breaks are mainly localized and attached to the sperm nuclear matrix as a very few break points, are possibly related to a lack of DNA repair in meiosis and cause a higher risk of miscarriage, low embryo quality and higher risk of implantation failure in ICSI cycles. The present work also reviews different studies that may contribute in the understanding of sperm chromatin as well as treatments to prevent sperm DNA damage.

scholarly journals Protection of sperm DNA against oxidative stress in vivo by accessory sex gland secretions in male hamsters

Reproduction ◽  
2002 ◽  
pp. 491-499 ◽  
Author(s):  
H Chen ◽  
MP Cheung ◽  
PH Chow ◽  
AL Cheung ◽  
W Liu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Prostate Gland ◽  
Single Strand ◽  
Ventral Prostate ◽  
Control Group ◽  
Dna Breakage ◽  
Accessory Glands ◽  
Sperm Dna ◽  
Epididymal Spermatozoa

Reactive oxygen species scavengers present in male accessory sex gland secretions might afford antioxidant protection to sperm DNA. This study was conducted to determine whether accessory sex gland secretions protect the genome and function of spermatozoa against oxidative damage in the uterus. Male golden hamsters were divided into four experimental groups: (i) all accessory sex glands removed; (ii) ampullary glands removed; (iii) ventral prostate gland removed and (iv) sham-operated controls. Ejaculated spermatozoa recovered from uteri 15-30 min after mating with experimental males and caput and cauda epididymal spermatozoa obtained from intact males were incubated in 0-20 mmol NADPH l(-1) for 2 h. These spermatozoa and untreated uterine spermatozoa were processed for two types of comet assay (single cell gel electrophoresis): alkaline comet assay (pH > 13) which revealed single-strand DNA breakage and neutral comet assay (pH 9) which revealed double-strand DNA breakage. In comparison with the sham-operated controls, spermatozoa that had not been exposed to accessory sex gland secretions had a higher incidence and more extensive single-strand DNA damage with increasing concentrations of NADPH. Spermatozoa from hamsters without ampullary glands and from hamsters without the ventral prostate glands were similar to those of the control group. After incubation with NADPH, the capacity of spermatozoa from hamsters without accessory glands and from sham-operated controls to fuse with oocytes in vitro was reduced. However, only hamsters without accessory glands showed a negative correlation between single-strand DNA damage and sperm-oocyte fusion. Cauda epididymal spermatozoa were less susceptible to NADPH treatment compared with caput epididymal spermatozoa. The results of the present study showed that male accessory sex gland secretions can preserve the integrity of the sperm genome.

The assessment of sperm DNA fragmentation in the saltwater crocodile (Crocodylus porosus)

2017 ◽  
Vol 29 (3) ◽  
pp. 630 ◽  
Author(s):  
S. D. Johnston ◽  
C. López-Fernández ◽  
F. Arroyo ◽  
J. L. Fernández ◽  
J. Gosálvez
Keyword(s):  
Dna Damage ◽  
Dna Fragmentation ◽  
Sperm Chromatin ◽  
Sperm Dna Fragmentation ◽  
Fragmented Dna ◽  
Sperm Dna ◽  
Saltwater Crocodile ◽  
Crocodylus Porosus ◽  
Dispersion Test ◽  
Sperm Nuclei

Herein we report a method of assessing DNA fragmentation in the saltwater crocodile using the sperm chromatin dispersion test (SCDt) after including frozen–thawed spermatozoa in a microgel (Halomax; Halotech DNA, Madrid, Spain). Following controlled protein depletion, which included a reducing agent, sperm nuclei with fragmented DNA showed a homogeneous and larger halo of chromatin dispersion with a corresponding reduced nucleoid core compared with sperm with non-fragmented DNA. The presence of DNA damage was confirmed directly by incorporation of modified nucleotides using in situ nick translation (ISNT) and indirectly by studying the correlation of the SCDt with the results of DNA damage visualisation using a two-tailed comet assay (r = 0.90; P = 0.037). Results of the SCDt immediately following thawing and after 5 h incubation at 37°C in order to induce a range of DNA damage revealed individual crocodile differences in both the baseline level of DNA damage and DNA longevity.

Sperm DNA damage output parameters measured by the alkaline Comet assay and their importance

Andrologia ◽  
2016 ◽  
Vol 49 (2) ◽  
pp. e12608 ◽  
Author(s):  
L. Simon ◽  
K. I. Aston ◽  
B. R. Emery ◽  
J. Hotaling ◽  
D. T. Carrell
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Alkaline Comet Assay ◽  
Sperm Dna Damage ◽  
Sperm Dna

Sperm DNA Damage Measured by Comet Assay

2012 ◽  
pp. 137-146 ◽  
Author(s):  
Luke Simon ◽  
Douglas T. Carrell
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Sperm Dna Damage ◽  
Sperm Dna
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