Spermatozoa of Sminthopsis murina (Mammalia: Metatheria) exhibit an unusually high degree of chromatin stability in the absence of disulphide bonding in protamine 1

2016 ◽  
Vol 28 (9) ◽  
pp. 1268 ◽  
Author(s):  
S. D. Johnston ◽  
C. López-Fernández ◽  
F. Arroyo ◽  
S. Fardell ◽  
R. Roy ◽  
...  

Although all but a single genus (Planigale) of the metatheria so far examined contain no cysteine residues in protamine 1, we report a remarkable level of chromatin stability in the spermatozoa of the common dunnart, Sminthopsis murina. S. murina cauda epididymal spermatozoa and somatic epithelial cells were exposed to a combination of graded treatments to lyse sperm protein and induce sperm DNA damage via standard freeze–thaw protocols and post-thaw incubation at 37°C for 48 h, exposure to sodium nitroprusside (SNP) and the enzyme AluI restriction endonuclease. Sperm DNA fragmentation was assessed using the comet assay and sperm chromatin dispersal test. Although S. murina somatic cells showed DNA fragmentation following protein lysis and after treatment with all the protocols specifically designed to induce chromatin damage, sperm DNA fragmentation was only observed following moderate to severe proteolytic exposure and treatment with the restriction endonuclease; there was also an increase in the baseline halo of spermatozoa treated with an aggressive reducing agent, but no corresponding evidence of fragmented DNA, suggesting that cysteine residues may be functioning to conform tertiary and/or quaternary chromatin structure. Given that the protamine 1 of S. murina contains no cysteine, we suggest that the source of these residues is possibly the histone fraction of the chromatin and that the high level of stability is potentially related to prolonged sperm survival in the female’s reproductive tract.

2020 ◽  
Vol 32 (10) ◽  
pp. 948 ◽  
Author(s):  
Stephen D. Johnston ◽  
Carmen López-Fernández ◽  
Eloise Pappin ◽  
Alexandra Hampe ◽  
Robert Doneley ◽  
...  

Herein we report a simple method for assessing avian sperm DNA fragmentation (SDF) using the sperm chromatin dispersion test (SCDt). The presence of sperm DNA damage was confirmed indirectly by correlating results of the SCDt determined in three bird species with results of a corresponding neutral comet assay (r=0.99; P<0.005). Frozen–thawed spermatozoa of each species were also incubated at 37°C for 5h and the within- and between-species variation of SDF, as an indicator of sperm DNA longevity, examined. The dynamic assessment of SDF using the SCDt revealed species and individual bird (rooster and turkey) differences in sperm DNA longevity.


2013 ◽  
Vol 85 (1) ◽  
pp. 8 ◽  
Author(s):  
Giuseppina Peluso ◽  
Alessandro Palmieri ◽  
Pietro Paolo Cozza ◽  
Giancarlo Morrone ◽  
Paolo Verze ◽  
...  

Introduction: Although the pathophysiology of the testicular damage associated with varicocele remains unclear, sperm DNA damage has been identified as a potential explanation for this cause of male infertility. The current study was designed to determine the extent of sperm nuclear DNA damage in patients with varicocele, and to examine its relationship with parameters of seminal motility. Materials and method: Semen samples from 60 patients with clinical varicocele and 90 infertile men without varicocele were examined. Varicocele sperm samples were classified as normal or pathological according to the 1999 World Health Organizzation guidelines. Sperm DNA damage was evalutated using the Halosperm kit, an improved Sperm Chromatin Dispersion (SCD) test. Results: The DNA fragmentation index (DFI: percentage of sperm with denatured nuclei) values was significantly higher in patients with varicocele, either with normal or abnormal (DFI 25.8 ± 3.2 vs 17.4 ± 2.8 - P < 0,01) semen profiles. In addition, an inverse correlation was found between spermatic motility and the degree of spermatic DNA fragmentation in patients with clinical varicocele. Conclusions: Varicocele is associated with high levels of DNA-damage in spermatozoa. In addition, in subjects with varicocele, abnormal spermatozoa motility is associated with higher levels of sperm DNA fragmentation. DNA fragmentation may therefore be an essential additional diagnostic test that should be recommended for patients with clinical varicocele.


2016 ◽  
Vol 283 (1826) ◽  
pp. 20152708 ◽  
Author(s):  
Javier delBarco-Trillo ◽  
Olga García-Álvarez ◽  
Ana Josefa Soler ◽  
Maximiliano Tourmente ◽  
José Julián Garde ◽  
...  

Sperm competition, a prevalent evolutionary process in which the spermatozoa of two or more males compete for the fertilization of the same ovum, leads to morphological and physiological adaptations, including increases in energetic metabolism that may serve to propel sperm faster but that may have negative effects on DNA integrity. Sperm DNA damage is associated with reduced rates of fertilization, embryo and fetal loss, offspring mortality, and mutations leading to genetic disease. We tested whether high levels of sperm competition affect sperm DNA integrity. We evaluated sperm DNA integrity in 18 species of rodents that differ in their levels of sperm competition using the sperm chromatin structure assay. DNA integrity was assessed upon sperm collection, in response to incubation under capacitating or non-capacitating conditions, and after exposure to physical and chemical stressors. Sperm DNA was very resistant to physical and chemical stressors, whereas incubation in non-capacitating and capacitating conditions resulted in only a small increase in sperm DNA damage. Importantly, levels of sperm competition were positively associated with sperm DNA fragmentation across rodent species. This is the first evidence showing that high levels of sperm competition lead to an important cost in the form of increased sperm DNA damage.


2021 ◽  
Vol 21 (4) ◽  
pp. 89-97
Author(s):  
I. V. Vinogradov ◽  
A. R. Zhivulko

Introduction. Antioxidant supplementation therapy continues to be the main treatment for male infertility associated with high level of sperm DNA damage. Docosahexaenoic acid (DHA) is one of the most promising components of antioxidant supplementation therapy. It also has anti-inflammatory properties that makes it interesting for treatment of patients with high level of sperm DNA damage and inflammation in male accessory glands.Materials and methods.One hundred and seventeen (117) infertile patients with high level of sperm DNA damage were recruited for this randomized, double blind, placebo-controlled study. Semen analysis, MAR-test, SCD test and sperm cryotolerance test were performed to all patients. Subjects were divided into 2 groups with high (>1 mln / ml) and low (<1 mln / ml) semen leucocyte concertation and then randomized into 2 subgroups of active treatment and 2 placebo subgroups. The active treatment subgroups received 1470 mg / day of DHA for 3 months. The placebo group received placebo for the same period. Laboratory tests were repeated after the treatment course had been finished.Results. Statistically significant increase in motility (42 % (25–61 %) vs 25 % (15–47 %), p <0.05), vitality (73 % (63–81 %) vs 41 % (35–64 %), p <0.05), decrease in sperm DNA fragmentation level (21 % (12–28 %) vs 33 % (25–39 %), p <0.05) and leucocyte concentration (1 million / ml (0.7–1.7 million / ml) vs 1,5 million / ml (1.1–2.1 million / ml), p <0.05) were observed in the subgroup with male accessory glands inflammation after treatment. Motility (15 % (8–19 %) vs 8 % (5–11 %), p <0.05) and vitality (37 % (25–46 %) vs 24 % (17–40 %), p <0.05) in this subgroup after a sperm cryotolerance test increased as well. In the subgroup with low semen leucocyte concertation statistically significant increase in motility (43 % (27–63 %) vs 34 % (21–54 %), p <0.05), vitality (77 % (66–85 %) vs 65 % (54.5–76.0 %), p <0.05) and decrease of sperm DNA fragmentation level (9 % (5.5–20.0 %) vs 25 % (18–33 %), p <0.05) were observed. DHA supplementation also resulted in statistically significant increase in motility (17 % (10–23 %) vs 6 % (5.0–10.5 %), p <0.05) and vitality (41 % (32.5–53.0 %) vs 37 % (30–49 %), p <0.05) after a sperm cryotolerance test in that subgroup.Conclusion. DHA supplementation therapy increases motility, vitality, sperm cryotolerance and decreases sperm DNA fragmentation regardless of the presence of an inflammatory process in male accessory glands.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Valeria Maria Iommiello ◽  
Elena Albani ◽  
Alessandra Di Rosa ◽  
Alessandra Marras ◽  
Francesca Menduni ◽  
...  

Oxidative stress (OS) plays an essential role in male infertility aetiology by affecting sperm quality, function, and also the integrity of sperm DNA. The assessment of oxidative stress in semen may be an important tool to improve the evaluation of sperm reproductive capacity. The purpose of this study was the evaluation of any possible relation between the unbalance of oxidative stress caused by superoxide anion in the ejaculate with the presence of sperm DNA fragmentation and high concentration of round cells. 56 semen samples from males from couples suffering from infertility were evaluated according to World Health Organisation (WHO) 2010 guidelines. Oxidative stress levels from N1 (low) to N4 (high) were assessed in ejaculates using oxiSperm; DFI (sperm DNA fragmentation index) as assessed by the SCSA (Sperm Chromatin Structure Assay) was used for evaluation of sperm chromatin integrity. Our data show that high oxidative stress (N3-N4 levels) correlated positively with aDFI≥30%(P=0.0379)and round cells≥1.500.000/mL(P=0.0084). In conclusion, OS increases sperm DNA damage. Thus evaluation of semen OS extent of sperm DNA damage in infertile man could be useful to develop new therapeutic strategies and improve success of assisted reproduction techniques (ART).


2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Teoman Cem Kadioglu ◽  
Emin Aliyev ◽  
Murad Celtik

Background. Varicocele is associated with high levels of DNA damage in spermatozoa due to oxidative stress and elevated levels of sperm DNA fragmentation, which has been currently proposed to be an essential additional diagnostic test to be recommended for patients with clinical varicocele. The aim of this study was to evaluate the parameters of semen and the DNA fragmentation index (DFI) in patients with varicocele before and after varicocelectomy.Methods. The details of 92 consecutive patients were retrospectively analyzed from January 2010 to December 2012. The sperm samples were evaluated according to the World Health Organization Guidelines. Sperm DNA damage, characterized as DFI, was evaluated by sperm chromatin structure assay using flow cytometry.Results. There was a statistically significant improvement in the semen concentration, the total motile count, the total normal sperm count, and the sperm DNA fragmentation index (DFI; the percentage of sperm with denatured DNA) after varicocelectomy. There was a large decrease in DFI from a preoperative mean of 42.6% to a postoperative mean of 20.5% (P<0.001). A higher preoperative DFI was associated with a larger decrease in postoperative DFI, and significant negative correlations were observed between the DFI and sperm motility (r=-0.42,P<0.01).Conclusion. Our data suggest that varicocelectomy can improve multiple semen parameters and sperm DNA damage in infertile men with varicocele. The patients with preoperative defects in those parameters showed greater improvement postoperatively. Further research in this area is needed to understand the exact mechanisms of DNA damage in infertile men with varicocele.


Zygote ◽  
2021 ◽  
pp. 1-8
Author(s):  
Shikai Wang ◽  
Weihong Tan ◽  
Yueyue Huang ◽  
Xianbao Mao ◽  
Zhengda Li ◽  
...  

Summary To determine the effects of sperm DNA fragmentation (SDF) on embryo morphokinetic parameters, cleavage patterns and embryo quality, this retrospective study analyzed 151 intracytoplasmic sperm injection (ICSI) cycles (1152 embryos collected) between November 2016 and June 2019. SDF was assessed using sperm chromatin dispersion. The cycles were divided into two groups based on the SDF rate: SDF < 15% (n = 114) and SDF ≥ 15% (n = 37). The embryo morphokinetic parameters, cleavage patterns, and embryo quality were compared between the two groups. The morphokinetic parameters tPNf, t2, t3, t4, t5, t6, and t8 were achieved significantly earlier in the SDF < 15% group compared with in the SDF ≥ 15% group. The fertilization and 2PN rates seemed to be significantly higher in the SDF < 15% group compared with in the SDF ≥ 15% group, while the abnormal cleavage rates were similar. However, a significantly higher rate of chaotic cleavage (CC) was observed in the SDF ≥ 15% group. The D3 high-quality embryo and available embryo rates were similar between the two groups. The blastocyst formation, high-quality blastocyst, and available blastocyst rates in the SDF < 15% group were significantly higher than those in the SDF ≥ 15% group. With an increase in SDF level, the chemical pregnancy, clinical pregnancy and implantation rates tended to decrease, while the miscarriage rate increased. This study demonstrated that SDF ≥ 15% reduces the fertilization rate of ICSI cycles and affects certain morphokinetic parameters. A higher SDF level can also induce a higher rate of CC, with subsequent decreases in the blastocyst formation rate and blastocyst quality.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 83-84
Author(s):  
Marina Fortes ◽  
Wei Liang Andre Tan ◽  
Laercio R Porto-Neto ◽  
Antonio Reverter ◽  
Gry B Boe-Hansen

Abstract Traits such as sperm morphology and motility are routine in veterinarian evaluations of bull fertility. However, they rarely are included in livestock breeding programs, which typically use only scrotal circumference (SC) and some female traits for fertility selection. We studied 25 male fertility traits measured in two research populations of bulls (1,099 Brahman, and 1,719 Tropical Composite) and one commercial population (2,490 Santa Gertrude bulls). Measurements included standard semen evaluation (e.g. sperm motility and morphology) and SC. In the research data, we also measured sperm DNA fragmentation and sperm protamine deficiency for about 50% of the bulls. Using a mixture of genomic and pedigree analyses, we estimated heritabilities and genetic correlations for all traits, in each population. Our analyses suggest that bull fertility traits have a heritable component, which makes selective breeding possible. The phenotype variation in sperm DNA fragmentation and sperm protamine deficiency traits also have a heritable component (h2 ~ 0.05–0.22). These first estimates for heritability of sperm chromatin phenotypes require further studies, with larger datasets, to corroborate present results. In all three populations, we observed genetic correlations across traits that were favorable, but not high. For example, the percentage of normal sperm (PNS) from the sperm morphology evaluation was positively correlated with SC. In the research data, sperm DNA fragmentation was negatively correlated with PNS (r2 ~ 0.23–0.33), meaning that bulls with a higher PNS had less DNA fragmentation, being therefore more fertile according to both indicators. Given the favorable and yet not high genetic correlations between traits, it is possible to envision that sperm chromatin phenotypes might form a panel, together with PNS and SC, for a comprehensive bull fertility index. Selection indices that include fertility traits are being implemented in the dairy industry and could be recommended for beef cattle, too. An index that benefits from the favorable genetic correlations between traits that describe different aspects of bull fertility is a sensible approach to selective breeding. The clinical use of complementary indicators for male fertility is largely accepted, when deciding on bull fitness for the mating season. We propose extending this rationale to create a multi-trait index that captures genetic merit for bull fertility. In addition, we performed genome-wide association analyses in the research data and identified eight QTLs in the X chromosome. Correlations and shared SNP associations support the hypothesis that these phenotypes have the same underlying cause: abnormal spermatogenesis. In conclusion, it is possible to improve bull fertility through selective breeding, by measuring complementary fertility traits. Genomic selection for bull fertility might be more accurate if the X chromosome mutations that underlie the discovered QTL are included in the analyses. Polymorphisms associated with fertility in the bull accumulate in the X chromosome, as they do in humans and mice, thus suggesting specialization of this chromosome.


2017 ◽  
Vol 29 (3) ◽  
pp. 630 ◽  
Author(s):  
S. D. Johnston ◽  
C. López-Fernández ◽  
F. Arroyo ◽  
J. L. Fernández ◽  
J. Gosálvez

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.


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