Sperm Chromatin Structure Assay Research Articles

In cases with raised sperm DNA fragmentation, can sperm selection by magnetic-activated cell sorting or testicular sperm aspiration help improve reproductive outcomes?

To evaluate the efficacy of magnetic-activated cell sorting (MACS) or testicular sperm aspiration (TESA) to improve reproductive outcomes in cases with elevated sperm DNA fragmentation undergoing assisted reproduction. This randomized controlled trial included couples with failed IVF cycles and sperm DNA fragmentation > 30%. Sperm DNA fragmentation was assessed using the sperm chromatin structure assay (SCSA) method. Participants were randomly assigned to either the MACS or TESA group. Testicular sperm retrieval was performed for the TESA group, while MACS involved sperm selection using magnetic beads. Extended blastocyst culture, freeze all policy of blastocysts by vitrification, and frozen embryo transfer were undertaken as per clinic's standard operating protocols. Blastocyst formation rate, implantation rate, miscarriage rate, multiple pregnancy rate, and live birth rate were analyzed and compared between MACS and TESA groups. There were no significant differences in female age, male age, or sperm DNA fragmentation index (DFI) between the MACS and TESA groups. The blastocyst conversion rate was slightly higher in the TESA group (39%) compared to the MACS group (32%). However, the MACS group had a higher implantation rate (50%) than the TESA group (35%). Miscarriage rates, multiple pregnancy rates, and live birth rates did not show statistically significant differences between the groups. A chi-squared test was conducted to compare categorical variables, and t-tests were done to compare continuous variables. In cases with raised sperm DNA fragmentation, sperm selection by MACS or TESA seems to offer comparable reproductive outcomes. There seems no superiority of one intervention over the other in cases with raised sperm DNA fragmentation undergoing assisted reproduction. Both interventions seem to be beneficial for couples seeking assisted reproduction with raised sperm DNA fragmentation.

A Review Diagnosing Male Infertility: Beyond Conventional Semen Analysis

Infertility, defined as the inability of couples to conceive after one year of consistent, unprotected sexual contact, is a widespread concern affecting a significant portion of the population. Notably, between 14 to 17% of couples may encounter infertility at some point during their reproductive journey. This review delves into the realm of diagnosing male infertility beyond conventional semen analysis. Conventional semen analysis, which is a globally accepted tool for male infertility, primarily focuses on assessing sperm count, motility, viability, and morphology, leaving certain aspects of sperm functionality unexplored. These limitations necessitate the integration of advanced semen analysis techniques to provide a more comprehensive evaluation. Advanced semen analysis encompasses a range of sophisticated tests that probe deeper into the intricacies of male fertility. These tests include assessing sperm penetration capabilities, acrosomal discharge, and spermatozoa Reactive Oxygen Species (ROS) levels. Moreover, advanced semen analysis encompasses tests like sperm chromatin structure assay, DNA damage assessment, sperm proteomics, sperm metabolomics, and high sperm magnification microscopy, all of which shed light on various facets of sperm function and quality. While advanced semen analysis techniques offer a more comprehensive understanding of male infertility, their uptake and utilization in clinical practice have been limited. This review aims to elucidate the roles, merits, and drawbacks of both conventional and advanced semen analysis in diagnosing male infertility. This review sheds light on the strengths and weaknesses of each approach, it promotes a more nuanced approach to male infertility diagnosis, enhancing the prospects of successful conception for infertility challenged couples.

Transcriptomic and proteomic features of a mouse model of sperm DNA damage induced by benzo(a)pyrene

This study replicated a mouse model of sperm DNA damage induced by benzo(a)pyrene (BaP), and the transcriptomic and proteomic features of the model were examined to clarify the pathways related to BaP-induced damage to sperm DNA. Male mice in the BaP group were subjected to BaP at a dosage of 100 mg/kg/d or an equivalent quantity of saline solution in the control group for 60 days. Subsequently, the DNA fragmentation index (DFI) in sperm was assessed using a sperm chromatin structure assay (SCSA). RNA-seq and data-independent acquisition (DIA) were used to identify the mRNA and protein expression patterns in the testis. The sperm DFI significantly increased in the BaP group. Compared to the control group, the BaP group exhibited differential expression of 240 genes (referred to as DEGs) and 616 proteins (referred to as DEPs). These molecules included Aldh1a1, Cyb5r3, Fads1, Oxsm, Rcn3, and Prss45. Pathways in cancer, the PI3K-Akt signaling pathway, metabolic pathways, and the MAPK signaling pathway were the primary areas where these genes showed enrichment. BaP can damage the DNA of sperm and affect metabolism, the PI3K-Akt pathway, and pathways associated with cancer signaling.

Elevated sperm DNA fragmentation is correlated with an increased chromosomal aneuploidy rate of miscarried conceptus in women of advanced age undergoing fresh embryo transfer cycle.

Male sperm DNA fragmentation (SDF) may be associated with assisted reproductive technology (ART) outcomes, but the impact of SDF on the occurrence of aneuploid-related miscarriage remains controversial. Genome-wide single-nucleotide polymorphism-based chromosomal microarray analysis was performed on 495 miscarried chorionic villus samples undergone IVF/ICSI treatment from the Reproductive Medicine Center of the First Affiliated Hospital of Zhengzhou University. SDF was assessed using sperm chromatin structure assay. Patients were divided into four groups according to embryo transfer cycle type and maternal age, and the correlation between SDF and chromosome aberration was analyzed. A receiver operating characteristic (ROC) curve was utilized to find the optimal threshold. Total chromosomal aneuploidy rate was 54.95%, and trisomy was the most common abnormality (71.32%). The chromosomally abnormal group had higher SDF than the normal group (11.42% [6.82%, 16.54%] vs. 12.95% [9.61%, 20.58%], P = 0.032). After grouping, elevated SDF was significantly correlated with an increasing chromosome aneuploidy rate only in women of advanced age who underwent fresh embryo transfer (adjusted odds ratio:1.14 [1.00-1.29], adjusted-P = 0.045). The receiver operating characteristic curve showed that SDF can predict the occurrence of chromosomal abnormality of miscarried conceptus in this group ((area under the curve = 0.76 [0.60-0.91], P = 0.005), and 8.5% was the optimum threshold. When SDF was ≥ 8.5%, the risk of such patients increased by 5.76 times (adjusted odds ratio: 6.76 [1.20-37.99], adjusted-P = 0.030). For women of advanced maternal age undergoing fresh embryo transfer, older oocytes fertilized using sperm with high SDF in IVF/ICSI treatment might increase the risk of chromosomal abnormality in miscarried conceptus.

Improved semen parameters and sperm deoxyribonucleic acid fragmentation following microscopic varicocelectomy: short term results of a prospective study

Background: Assessment of sperm deoxyribonucleic acid (DNA) damage post varicocelectomy, has brought about new prospects in treating men with infertility. Improvements in spermatogenesis with decrease in sperm DNA damage has been demonstrated which has led to significant enhancement in fertility rates. Therefore, we evaluated the efficacy of microscopic varicocelectomy on the reduction in sperm DNA damage in concurrence to the conventional improvement of semen parameters. Methods: All patients with a diagnosis of varicocele leading to infertility and planned for microscopic varicocelectomy from January 2013 through September 2019, were included in the study. Sperm chromatin structure assay (SCSA) was done preoperatively and at 3 and 6 months postoperatively for sperm DNA integrity assessment and the results expressed as sperm percentage DFI were compared. A p value <0.05 was considered statistically significant. Results: 105 infertile men underwent microscopic varicocelectomy. Mean age and infertility period from the date of unprotected sex were 26.5±5.6 years and 30 months respectively. Baseline mean sperm concentration was 29 million/ml, mean progressive motility 24% and a percentage DFI ranged from 5–36% with a mean of 16%. Sperm DNA integrity improved significantly with a DFI decrease from 25±11% to 18±6%, 3 months post-surgery which was consistent at 6 months (13±5%). Sperm concentration and progressive motility increased with a mean sperm count improvement by 21.9 million/ml and mean motility by 20.3%. Conclusions: Microscopic varicocelectomy provides durable improvement in DNA integrity and semen parameters. Sperm DNA integrity assessment using SCSA is a useful tool to demonstrate change in the semen quality post treatment.

Integration of hepatitis B virus into patients' sperm genome and its clinical risks.

Like the coronavirus disease 2019, the hepatitis B virus is also wreaking havoc worldwide, which has infected over 2 billion people globally. Using an experimental animal model, our previous research observed that the hepatitis B virus genes integrated into human spermatozoa can replicate and express after being transmitted to embryos. However, as of now, this phenomenon has not been confirmed in clinical data from patients. To explore the integration of the hepatitis B virus into patients' sperm genome and its potential clinical risks. Forty-eight patients with chronic hepatitis B virus infection were categorized into two groups: Test Group-1 comprised 23 patients without integration of hepatitis B virus DNA within the sperm genome. Test Group-2 comprised 25 patients with integration of hepatitis B virus DNA within the sperm genome. Forty-eight healthy male donors were included as control. The standard semen parameter analysis, real-time polymerase chain reaction, quantitative real-time polymerase chain reaction, sperm chromatin structure assay, fluorescence in situ hybridization, and immunofluorescence assays were utilized. The difference in the median copy number of hepatitis B virus DNA per mL of sera between Test Group-1 and Group-2 was not statistically significant. In Test Group-2, the integration rate of hepatitis B virus DNA was 0.109%, which showed a significant correlation with the median copy number of hepatitis B virus DNA in motile spermatozoa (1.18×103 /mL). Abnormal semen parameters were found in almost all these 25 patients. The integrated hepatitis B virus S, C, X, and P genes were detected to be introduced into sperm-derived embryos through fertilization and retained their function in replication, transcription, and translation. Our findings suggest that hepatitis B virus infection can lead to sperm quality deterioration and reduced fertilization capacity. Furthermore, viral integration causes instability in the sperm genome, increasing the potential risk of termination, miscarriage, and stillbirth. This study identified an unconventional mode of hepatitis B virus transmission through genes rather than virions. The presence of viral sequences in the embryonic genome poses a risk of liver inflammation and cancer.

Improving human sperm motility via red and near-infrared laser irradiation: in-vitro study

Improved sperm motility is necessary for successful sperm passage through the female genital system, efficacious fertilization, and a greater probability of pregnancy. By stimulating the mitochondrial respiratory chain, low-level laser photobiomodulation has been shown to increase sperm motility and velocity. The respiratory chain in mitochondria is the primary site of action for cytochrome c oxidase because it can absorb light in the visible and infrared ranges. The present study aimed to investigate the effects of red laser 650 nm, near infrared laser (NIR) 980 nm, and combination of both on human spermatozoa motility and DNA integrity at different doses. An in-vitro controlled trial was performed in Al Zahraa university hospital laboratory using thirty fresh human semen specimens. Samples were exposed to red laser 650 nm, near infrared laser (NIR) 980 nm, and combination of both for various irradiation times. Sperm motility for the test and control aliquots was assessed as recommended in the manual of WHO-2021. Sperm chromatin integrity was evaluated using the Sperm Chromatin Structure Assay. Results revealed almost 70%, 80% and 100% increase in the total motility after 3 min of the 650-nm, 980-nm and the combined laser irradiation, respectively. Additionally, the Sperm Chromatin Dispersion assay was carried out on sperm heads utilizing human sperm DNA fragmentation, demonstrating that none of the three laser types had any discernible effects.Graphical abstract

Effects of Varicocele Repair on Sperm DNA Fragmentation and Seminal Malondialdehyde Levels in Infertile Men with Clinical Varicocele: A Systematic Review and Meta-Analysis.

Varicoceles can be a source of elevated seminal oxidative stress (OS) and sperm DNA fragmentation (SDF). However, it remains unclear whether varicocele repair (VR) could reduce these parameters. This systematic review and meta-analysis (SRMA) aims to investigate the impact of VR on SDF and seminal malondialdehyde (MDA). A literature search was performed in Scopus, PubMed, Ovid, Embase, and Cochrane databases. This SRMA included randomized controlled trials and observational studies reporting the pre- and postoperative levels of SDF and seminal OS in infertile men with clinical varicocele that underwent VR. Subgroup analyses included techniques of VR and SDF testing. The effect size was expressed as standardized mean difference (SMD). Out of 1,632 abstracts assessed for eligibility, 29 studies with 1,491 infertile men were included. The analysis showed a significant reduction in SDF after VR, compared to preoperative values (SMD -1.125, 95% confidence interval [CI] -1.410, -0.840; p<0.0001) with high inter-study heterogeneity (I²=90.965%). Reduction in SDF was evident with microsurgical technique and non-microsurgical inguinal approaches (SMD -1.014, 95% CI -1.263, -0.765; p<0.0001, and SMD -1.495, 95% CI -2.116, -0.873; p<0.0001), respectively. Reduction in SDF was significant irrespective of testing was done by sperm chromatin dispersion (SMD -2.197, 95% CI -3.187, -1.207; p<0.0001), sperm chromatin structure assay (SMD -0.857, 95% CI -1.156, -0.559; p<0.0001) or TUNEL (SMD -1.599, 95% CI -2.478, -0.719; p<0.0001). A significant decrease in seminal MDA levels was observed following VR (SMD -2.450, 95% CI -3.903 to -0.997, p=0.001) with high inter-study heterogeneity (I²=93.7%). Using pre- and post-intervention data, this SRMA indicates a significant reduction in SDF and seminal MDA levels in infertile men with clinical varicocele treated with VR. These findings may have important implications for the future management of this selected group of infertile patients.

Sperm proteomic landscape is altered in breeding bulls with greater sperm DNA fragmentation index

Although, it is well understood that sperm DNA damage is associated with infertility, the molecular details of how damaged sperm DNA affects fertility are not fully elucidated. Since sperm proteins play an important role in fertilization and post-fertilization events, the present study aimed to identify the sperm proteomic alterations in bulls with high sperm DNA Fragmentation Index (DFI%). Semen from Holstein-Friesian crossbred breeding bulls (n = 50) was subjected to Sperm Chromatin Structure Assay. Based on DFI%, bulls were classified into either high- (HDFI; n = 6), or low-DFI (LDFI; n = 6) and their spermatozoa were subjected to high throughput proteomic analysis. Liquid chromatography and mass spectrometry analysis identified 4567 proteins in bull spermatozoa. A total of 2660 proteins were found common to both the groups, while 1193 and 714 proteins were unique to HDFI and LDFI group, respectively. A total of 265 proteins were up regulated and 262 proteins were down regulated in HDFI group. It was found that proteins involved in capacitation [heparin binding (molecular function), ERK1 and ERK2 cascade (biological process), PI3K-Akt signalling (pathway), Jak-STAT signalling (pathway)], spermatogenesis [TLR signalling (pathway), gamete generation (biological process)] and DNA repair mechanism (biological process) were significantly altered in the bulls with high DFI%.

#204 : First Recorded Normal Live Birth After ICSI with Electrophoretically Isolated Spermatozoa Using the Felix™ System

Background and Aims: This report describes the first live birth with sperm isolated using the Felix™ system. Methods: Thirty-three couples undergoing ovarian stimulation were recruited based on high raw semen DNA Fragmentation Index (DFI) of &gt;20%, as assessed by the sperm chromatin structure assay. The Felix™ system, which isolates sperm based on charge and size was used as the sperm preparation method, over a six-minute interval. Mature oocytes were injected using Intracytoplasmic Sperm Injection (ICSI). Normally fertilised zygotes were cultured until day three or five. Suitable embryos were vitrified and subsequently transferred in a frozen embryo cycle. Biochemical pregnancy was determined by plasma human chorionic gonadotrophin level of &gt;20 IU and clinical pregnancy was determined by the presence of fetal heat and/or sac on ultrasound. Miscarriage and live births rates were also recorded. Results: Raw semen concentration, progressive motility and total motility levels were in the normal range according to 6[Formula: see text] World Health Organisation criteria. However, sperm DFI was relatively high (range 20% to 80%). The average age of females was 30 years (range 21 to 44). A total of 374 oocytes were collected from the 33 females, with 266 mature oocytes then injected by ICSI. This resulted in 83% fertilisation rate and embryo utilisation of 65%. Four females underwent single embryo transfer, and 29 females underwent double embryo transfer. Of those, 19 (58%) biochemical pregnancies were achieved resulting in 14 (42%) ongoing clinical pregnancies. Three miscarriages and two normal live births have been reported to date. Interestingly, the two live births resulted from men of DFI of 80% and 33%. Conclusion: This report describes the first birth after sperm isolated using the Felix™ system followed by ICSI. The Felix™ system is an efficient procedure to prepare sperm and has the potential to be advantageous for patients with high DFI.

#163 : Stress and Occupation Impair Male Fertility

Background and Aims: Jakarta is a metropolitan city of Indonesia and most people in Jakarta are working on various occupation such as technology-based and highly skilled occupations are common (construction workers, engineers, programmer, entrepreneurs) and desk-based workers. Those occupation, stress from those occupation and environment may impair male fertility. This study was aimed to determine specific occupations, occupational stress and environment and their association with sperm parameter. Method: A descriptive cross-sectional study was used, and 24 male participants underwent IUI treatment in Yasmin Fertility Clinic, Jakarta were recruited. Sperm concentration, motility, morphology, velocity was analyzed using Computer Assisted Sperm Analysis (CASA) and sperm DNA fragmentation index was assessed using Sperm Chromatin Structure Assay (SCSA). Interview was also conducted to obtain information on age, length of marriage, biological children, occupational exposure, occupational-related psychological stress. The results were compared to parameter in WHO manual 6th edition. Results: All 24 participants experienced exposure to potential disruptor to fertility such as vehicle emission, smoke inhalation and computer radiation (Fig. 1). Their raw semen parameters were lower compared to WHO manual 6th edition. Further results indicated that washing increased the value of all standard parameters and reduced sperm DNA fragmentation index in all samples. Further results showed abnormal morphology and sperm on fresh ejaculate are affected by stress intensity and frequency. However, total motility and abnormal morphology are significant correlated to stress intensity and frequency on both before and after sperm washing (Table 1). Conclusion: Types of occupation and highly exposed to air pollution and/or demands prolonged time of sitting behaviour pose higher risk of sperm quality deterioration. Also, psychological stress resulted from workload may associate with sperm parameters outcome.

Sperm DNA Fragmentation: Causes, Effects and Relevance in IVF Outcomes

Sperm DNA fragmentation, characterized by damaged or broken DNA strands within sperm cells, has been recognized as an important factor in male infertility and poor ART outcome. This lecture aims to provide an overview of the causes, effects, and relevance of sperm DNA fragmentation in in vitro fertilization (IVF) outcomes and look into the latest evidences from the literatures. Causes: Sperm DNA fragmentation can result from various factors, including oxidative stress, advanced paternal age, lifestyle factors such as smoking and excessive alcohol consumption, environmental exposures, genotoxic agents, and underlying genetic abnormalities. These factors can induce DNA damage during sperm development, during the transit of sperm through the male reproductive tract or during the storage of the sperm in epididymis. Relevance in IVF Outcomes: The assessment of sperm DNA fragmentation has emerged as a valuable tool in evaluating male infertility and predicting IVF success. Several methods, including the sperm chromatin structure assay (SCSA), terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL), comet assay, and other commercial detection kits, are available to measure sperm DNA fragmentation. Previous small cohort studies have demonstrated that higher levels of sperm DNA fragmentation are associated with lower pregnancy rates, decreased embryo quality, and an increased risk of pregnancy loss in IVF cycles. Therefore, incorporating sperm DNA fragmentation analysis into the routine assessment of male infertility can aid in optimizing treatment strategies and improving IVF outcomes. Recent evidences: Latest large clinical studies showed a limited association to IVF outcome. The DFI remains controversial as a predictive tool. Nonetheless, sperm DNA fragmentation is still believed to be a significant factor affecting male fertility and IVF outcomes. Further research is warranted to explore the mechanisms underlying DNA fragmentation, develop standardized assessment methods, and explore potential interventions to mitigate the adverse effects of sperm DNA damage on IVF success.

Sperm chromatin structure assay (SCSA®) and flow cytometry-assisted TUNEL assay provide a concordant assessment of sperm DNA fragmentation as a function of age in a large cohort of approximately 10,000 patients

BackgroundSperm DNA integrity is increasingly seen as a critical characteristic determining reproductive success, both in natural reproduction and in assisted reproductive technologies (ART). Despite this awareness, sperm DNA and nuclear integrity tests are still not part of routine examinations for either infertile men or fertile men wishing to assess their reproductive capacity. This is not due to the unavailability of DNA and sperm nuclear integrity tests. On the contrary, several relevant but distinct tests are available and have been used in many clinical trials, which has led to conflicting results and confusion. The reasons for this are mainly the lack of standardization between different clinics and between the tests themselves. In addition, the small number of samples analyzed in these trials has often weakened the value of the analyses performed. In the present work, we used a large cohort of semen samples, covering a wide age range, which were simultaneously evaluated for sperm DNA fragmentation (SDF) using two of the most frequently used SDF assays, namely the TUNEL assay and the sperm chromatin structure assay (SCSA®). At the same time, as standard seminal parameters (sperm motility, sperm morphology, sperm count) were available for these samples, correlations between age, SDF and conventional seminal parameters were analyzed.ResultsWe show that the SCSA® and TUNEL assessments of SDF produce concordant data. However, the SDF assessed by TUNEL is systematically lower than that assessed by SCSA®. Regardless of the test used, the SDF increases steadily during aging, while the HDS parameter (High DNA stainability assessed via SCSA®) remains unchanged. In the cohort analyzed, conventional sperm parameters do not seem to discriminate with aging. Only sperm volume and motility were significantly lower in the oldest age group analyzed [50–59 years of age].ConclusionsIn the large cohort analyzed, SDF is an age-dependent parameter, increasing linearly with aging. The SCSA® assessment of SDF and the flow cytometry-assisted TUNEL assessment are well correlated, although TUNEL is less sensitive than SCSA®. This difference in sensitivity should be taken into account in the final assessment of the true level of fragmentation of the sperm nucleus of a given sample. The classical sperm parameters (motility, morphology, sperm count) do not change dramatically with age, making them inadequate to assess the fertility potential of an individual.

External quality assessment scheme for sperm DNA fragmentation: a pilot study in China

BackgroundThe aim of this article is to establish an external quality assessment (EQA) scheme for sperm Deoxyribonucleic acid (DNA) fragmentation (SDF) detection, and to assess the feasibility of the scheme. In addition, this article provides some case analysis of abnormal results in order to really help improve the performance of the laboratory.ResultsIn 2021 and 2022, 10 and 28 laboratories in China volunteered to participate in the EQA program respectively. Two samples were selected for EQA each year, a large spread of results was obtained for the four samples, and the highest values were 13.7, 4.2, 8.0 and 4.0 times the lowest respectively. The coefficients of variation (CVs) were very high for the four samples, at 46.6%, 30.1%, 26.7% and 30.3%, respectively. The CVs of the samples with high SDF values were lower than those of the samples with low SDF values. There was no significant difference between the results of sperm chromatin structure assay (SCSA) and sperm chromatin dispersion (SCD). For the 10 laboratories that participated in EQA in 2021 and 2022, the CVs of low SDF value samples and high SDF value samples decreased from 46.6% and 30.1% in 2021 to 32.5% and 22.7% in 2022, respectively.ConclusionThis is the first study to evaluate the EQA program on SDF, which involved a number of laboratories and was demonstrated to be feasible. It is recommended that all laboratories participate in the EQA of SDF to ensure the accuracy of the results.

Establishing the normal range of sperm DNA fragmentation index (% DFI) for rhesus macaques

The Sperm Chromatin Structure Assay (SCSA) is a robust test with high repeatability and precision. It is a clinically accepted assay that defines risk for infertility in men by measuring the degree of DNA fragmentation (% DFI) in sperm. The objective of this study was to adapt and validate the SCSA for rhesus macaques (Macaca mulatta) and establish a range for % DFI in fertile males. Sperm samples from two different males were used to produce a % DFI validation curve before establishing a range using additional samples from n = 11 males. Sperm labeled with acridine orange were analyzed by flow cytometry to measure green fluorescence (native or intact DNA) and red fluorescence (fragmented DNA). Data were exported to FlowJo software to determine the % DFI for each sample. DNA fragmentation ranged from 0.1 to 2.4% DFI, with a mean ± SD = 1.1 ± 0.7% DFI (validation curve optimized to R2 > 0.95). In conclusion, we were able to successfully validate the SCSA in our institution and establish the first normal range for sperm DNA fragmentation in rhesus macaques. Our study provides a quantitative baseline for future evaluations to assess macaque fertility through the SCSA test.

Sperm Chromatin Status and DNA Fragmentation in Mouse Species with Divergent Mating Systems.

Sperm DNA integrity and chromatin status serve as pivotal indicators of sperm quality, given their intricate link to sperm function, embryo development, and overall fertility. Defects in chromatin compaction, which are often associated with compromised protamine content, can lead to damaged DNA strands. In this study, the chromatin status and possible correlation with DNA damage was assessed in males of three mouse species: Mus musculus, M. spretus, and M. spicilegus. We employed various staining methods, including aniline blue, methylene blue (Diff-Quik), toluidine blue, and chromomycin A3, to assess chromatin compaction in cauda epididymal sperm. Samples were also analyzed by the sperm chromatin structure assay (SCSA) to estimate DNA fragmentation (%tDFI, %HDS). Analyses were carried out on freshly collected sperm and cells incubated for 3 h in a HEPES-buffered modified Tyrode's medium simulating conditions of the female reproductive tract. Notably, the analysis of chromatin status yielded minimal abnormal values across all three species employing diverse methodologies. SCSA analyses revealed distinct variations in %tDFI between species. Following sperm incubation, the percentages of sperm stained with methylene blue exhibited differences among the species and were significantly correlated to the DNA fragmentation index. HDS demonstrated correlations with the percentages of sperm stained by aniline blue, methylene blue, and chromomycin A3. Overall, chromatin compaction was high across all species, with limited differences among them. The relationship between chromatin status and DNA integrity appeared to be related to levels of sperm competition among species.

Unraveling the Impact of Sperm DNA Fragmentation on Reproductive Outcomes.

In recent years, there has been a growing interest in identifying subcellular causes of male infertility, and sperm DNA fragmentation (SDF) research has been at the forefront of this focus. DNA damage can occur during spermatogenesis due to faulty chromatin compaction or excessive abortive apoptosis. It can also happen as sperm transit through the genital tract, often induced by oxidative stress. There are several methods for SDF testing, with the sperm chromatin structure assay, terminal deoxynucleotidyl transferase d-UTI nick end labeling (TUNEL) assay, comet assay, and sperm chromatin dispersion test being the most commonly used. Numerous studies strongly support the negative impact of SDF on male fertility potential. DNA damage has been linked to various morphological and functional sperm abnormalities, ultimately affecting natural conception and assisted reproductive technology outcomes. This evidence-based review aims to explore how SDF influences male reproduction and provide insights into available therapeutic options to minimize its detrimental impact.

Number of Available Embryos: A Prediction Tool for Analyzing the Effect of Sperm DNA Fragmentation on Pregnancy Outcome of Patients Undergoing IVF Cycles from Embryology

Sperm DNA fragmentation (SDF) can affect the pregnancy outcome of assisted reproduction technology. The cumulative live birth rate (CLBR), a new parameter of pregnancy outcome, attracts the attention of researchers to study the effect of SDF on CLBR. This study will focus on whether the number of available embryos (AEN) can be used as a predictor to investigate the effect of SDF on CLBR of in vitro fertilization (IVF) cycles. Our study included 1,347 couples who underwent IVF cycles and detected their SDF results by the sperm chromatin structure assay. Subsequently, CLBR and AEN on Day 3 were examined and compared between the SDF ≤ 30% and SDF &gt; 30% group. The finding by the correlation analysis showed a strong correlation in CLBR and AEN, suggesting that AEN can be used as a predictor of CLBR. When comparing the two groups, significant differences were noticed in CLBR (81.1% vs. 71.5%, P = 0.009 ) and AEN (8.10 ± 4.43 vs. 7.21 ± 4.27, P = 0.021 ), revealing that SDF has an influence on both indicators. The results of the covariance analysis suggested that the available embryo rate per maturity oocyte was higher in the SDF ≤ 30% group, and the embryologic parameters showed a significant difference in the available embryo formation rate on Day 3, but not in the fertilization and cleavage rates, suggesting that SDF reduced the quality of embryos, which did not reach the morphological standard of the available embryos, and further reduced AEN and CLBR in the IVF cycles.

High sperm DNA fragmentation increased embryo aneuploidy rate in patients undergoing preimplantation genetic testing

Is high sperm DNA fragmentation (SDF) associated with a high embryonic aneuploidy rate in patients undergoing intracytoplasmic sperm injection (ICSI)-preimplantation genetic testing (PGT)? This was a retrospective study of 426 couples with normal karyotypes undergoing ICSI-PGT at the authors' centre from March 2017 to March 2021. SDF was assessed using the sperm chromatin structure assay. The population was divided into low and high SDF groups according to cut-off values found by the receiver operating characteristic (ROC) curve. A 1:1 ratio propensity score matching (PSM) method was used to control for potential confounding factors, and a generalized linear mixed model was established to evaluate the relationship between SDF and the embryonic aneuploidy rate. The ROC curve indicated a threshold of 30%. In total, 132 couples were included after PSM, and the high SDF group (>30%) had significantly higher SDF (40.74% ± 9.78% versus 15.54% ± 7.86%, P < 0.001) and a higher embryo aneuploidy rate (69.36% versus 53.96%, P < 0.001) compared with the low SDF group (≤30%). The two pronuclear fertilization rate, cleavage rate, rate of high-quality embryos at day 3 rate, blastocyst rate, biochemical pregnancy rate, clinical pregnancy rate, miscarriage rate, live birth rate, caesarean section rate, preterm birth rate, singleton rate and low birthweight rate were similar in both groups (P > 0.05). After PSM, SDF > 30% was significantly correlated with an increased embryo aneuploidy rate after adjusting for all confounding variables (adjusted odds ratio 1.70, 95% CI 1.00-2.88, P = 0.049). SDF > 30% was associated with an increased embryo aneuploidy rate in couples with normal karyotypes undergoing PGT, but did not affect embryonic and clinical outcomes after transfer of euploid embryos.

Intra-individual changes in sperm DNA fragmentation levels over short and long time periods.

We aimed to examine the longitudinal, intra-personal changes in DNA fragmentation index (DFI) over time. Men who performed at least two DFI measurements (using sperm chromatin structure assay (SCSA) between 2003 and 2019 were included in this study and allocated to groups by time between DFI tests: < 1 year, 1-3 years, 3-5 years, and > 5 years. An analysis of DFI change over time according to age groups was additionally performed. Regression models were developed to predict changes in DFI with time. Overall, 225 patients had two or more DFI measurements done at least a month apart (mean of 586.7± 710.0 days). The < 1 year (n = 124) and 1-3 years (n = 68) groups demonstrated decreased DFI levels, while an increase in DFI was shown in 3-5 years (n = 21) and more than 5 years (n = 12) groups - 7.1 ± 14.9%, - 4.5 ± 13.4%, + 3.2 ± 8.4%, and + 10.8 ± 18.0%, respectively, p < 0.001). This trend was similarly shown in age subgroups of under 40 years and 40-50 years at baseline DFI. Linear regression models showed that the factors predictive of DFI increase are baseline DFI and > 3 years between DFI tests. This study shows that DFI, in men being investigated for infertility, initially decreases in the first 3 years of follow-up, and then increases over time with the highest increase occurring after 5 years interval (an average increase of 10.8%). Testing infertile men's DFI levels at first evaluation may contribute to personalized consult regarding future reproductive outcomes.