Assessment Of Sperm DNA Integrity Research Articles

The Assessment of Sperm DNA Integrity: Implications for Assisted Reproductive Technology Fertility Outcomes across Livestock Species.

Sperm DNA integrity is increasingly considered a useful measure of semen quality in mammalian reproduction. However, the definition of DNA integrity, the ideal means by which it should be measured, and its predictive value for fertility remain a topic of much discussion. With an emphasis on livestock species, this review discusses the assays that have been developed to measure DNA integrity as well as their correlation with in vitro and in vivo fertility.

Paternal Age Matters: Association with Sperm Criteria's- Spermatozoa DNA Integrity and Methylation Profile.

Advanced age has been reported to negatively affect sperm parameters and spermatozoa DNA integrity. A decline in sperm criteria was also associated with altered epigenetic marks such as DNA methylation with a potential downstream impact on in vitro fertilization success and clinical outcomes. The aim of the present retrospective study was to clarify the association between advanced paternal age (APA) and sperm parameters, DNA integrity and DNA methylation profile. A total of 671 patients consulting for infertility underwent sperm analysis, sperm DNA integrity assessment and methylation level measurement. The principal finding was that individuals over 40 years of age exhibit a significant increase in DNA fragmentation levels compared to the younger group (15% versus 9%, respectively, p = 0.04). However, there was no significant difference in DNA decondensation and sperm parameters in association with APA. In addition, a drop in the global methylation level was also found in men over 40 years (6% in the young group versus 2% in the old group, p = 0.03). As a conclusion, men over 40 years are at higher risk of elevated sperm DNA fragmentation and lower methylation level. Based on these observations, it is recommended that the assessment of sperm DNA fragmentation should be taken into consideration particularly after the age of 40. Our findings support the idea that paternal age is a crucial factor that should not be neglected during fertility evaluation and treatment since it is associated with epigenetics changes in sperm. Although the underlying mechanism remains to be clarified, we believe that environmental and professional exposure factors are likely involved in the process.

High-throughput sperm DNA analysis at the single-cell and population levels.

Clinical semen quality assessment is critical to the treatment of infertility. Sperm DNA integrity testing provides critical information that can steer treatment and influence outcomes and offspring health. Flow cytometry is the gold standard approach to assess DNA integrity, but it is not commonly applied at the clinical level. The sperm chromatin dispersion (SCD) assay provides a simpler and cheaper alternative. However, SCD is low-throughput and non-quantitative - sperm assessment is serial, manual and suffers inter- and intra-observer variations. Here, an automated SCD analysis method is presented that enables quantitative sperm DNA quality assessment at the single-cell and population levels. Levering automated optical microscopy and a chromatin diffusion-based analysis, a sample of thousands of sperm that would otherwise require 5 hours is assessed in under 10 minutes - a clinically viable workflow. The sperm DNA diffusion coefficient (DDNA) measurement correlates (R2 = 0.96) with DNA fragmentation index (DFI) from the cytometry-based sperm chromatin structure assay (SCSA). The automated measurement of population-level sperm DNA fragmentation (% sDF) prevents inter-observer variations and shows a good agreement with the SCSA % DFI (R2 = 0.98). This automated approach standardizes and accelerates SCD-based sperm DNA analysis, enabling the clinical application of sperm DNA integrity assessment.

Micro-Raman Analysis of Sperm Cells on Glass Slide: Potential Label-Free Assessment of Sperm DNA toward Clinical Applications.

Routine assessment of sperm DNA integrity involves the time-consuming and complex process of staining sperm chromatin. Here, we report a Raman spectroscopy method combined with extended multiplicative signal correction (EMSC) for the extraction of characteristic fingerprints of DNA-intact and DNA-damaged sperm cells directly on glass slides. Raman results of sperm cell DNA integrity on glass substrates were validated one-to-one with clinical sperm cell staining. Although the overall Raman spectral pattern showed considerable similarity between DNA-damaged and DNA-intact sperm cells, differences in specific Raman spectral responses were observed. We then employed and compared multivariate statistical analysis based on principal component analysis-linear discriminant analysis (PCA-LDA) and partial least-squares-discriminant analysis (PLS-DA), and the classifications were validated by leave-one-out-cross-validation (LOOCV) and k-fold cross-validation methods. In comparison, the PLS-DA model showed relatively better results in terms of diagnostic sensitivity, specificity, and the classification rate between the sperm DNA damaged group and the DNA intact group. Our results demonstrate the potential of Raman based label-free DNA assessment of sperm cell on glass substrates as a simple method toward clinical applications.

Sperm DNA damage compromises embryo development, but not oocyte fertilisation in pigs

BackgroundThe assessment of sperm DNA integrity has been proposed as a complementary test to conventional mammalian semen analysis. In this sense, single-strand (SSB) and double-strand (DSB) DNA breaks, the two types of sperm DNA fragmentation (SDF), have been reported to have different aetiologies and to be associated to different fertility outcomes in bovine and humans. Considering that no studies in porcine have addressed how SDF may affect sperm quality and fertility outcomes, the present work aimed to determine the impact of global DNA damage, SSB and DSB on sperm quality and in vitro fertilising ability. To this end, 24 ejaculates (one per boar) were split into three aliquots: the first was used to assess sperm quality parameters through a computer-assisted sperm analysis (CASA) system and flow cytometry; the second was used to perform in vitro fertilisation, and the third, to evaluate sperm DNA integrity using alkaline and neutral Comet assays.ResultsThe results showed that global DNA damage negatively correlates (P < 0.05) with normal sperm morphology (R = − 0.460) and progressive motility (R = − 0.419), and positively with the percentage of non-viable sperm (R = 0.507). Multiple regression analyses showed that non-viable sperm were related to SSB (β = − 0.754). In addition, while fertilisation did not seem to be affected by sperm DNA integrity, global DNA damage, DSB and SSB were found to be correlated to embryo development outcomes. Specifically, whereas global DNA damage and DSB negatively affected (P < 0.05) the later preimplantation embryo stages (percentage of early blastocyst/blastocyst D6: for global DNA damage, R = − 0.458, and for DSB, R = − 0.551; and percentage of hatching/hatched blastocyst D6: for global DNA damage, R = − 0.505, and for DSB, R = − 0.447), global DNA damage and SSB had a negative impact (P < 0.05) on the developmental competency of fertilised embryos (R = − 0.532 and R = − 0.515, respectively). Remarkably, multiple regression analyses supported the associations found in correlation analyses. Finally, the present work also found that the inclusion of Comet assays to the conventional sperm quality tests improves the prediction of blastocyst formation (AUC = 0.9021, P < 0.05), but not fertilisation rates (P > 0.05).ConclusionConsidering all these findings, this work sets a useful model to study how SDF negatively influences fertility.

Mixture analysis on associations between semen quality and sperm DNA integrity and occupational exposure to polycyclic aromatic hydrocarbons

The objective of this study was to assess relationships between exposure to PAHs at occupational levels and outcomes of human semen quality and sperm DNA integrity. Personal breathing zone air samples were collected to quantify exposure of 16 targeted PAHs to coke-oven workers at a steel company in southern Taiwan. Semen quality, including concentration, motility, morphology, and viability, were assessed. Sperm DNA fragmentation, 8-oxodGuo, bulky PAH adducts, and benzo[a]pyrene diol epoxide-DNA adducts served as biomarkers for assessment of sperm DNA integrity. The Bayesian Kernel Machine Regression modeling was employed to estimate mixture effects of the PAH mixture on the outcomes of semen quality and sperm DNA integrity and to identify individual compounds of PAH mixtures associated with the mixture effects. Exposure to the PAH mixture was inversely associated with sperm viability, while benzo(b)fluoranthene (B[b]F) was identified as the main predictor for sperm viability. Exposure to the PAH mixture also exhibited a positive trend with sperm DNA fragmentation. B[b]F and benzo(a)anthracene (B[a]A) were identified as individual PAH compounds associated with increased sperm DNA fragmentation.

Role of Female Age in Regulating the Effect of Sperm DNA Fragmentation on the Live Birth Rates in Intracytoplasmic Sperm Injection Cycles with Own and Donor Oocytes.

ABSTRACTBackground:Sperm DNA integrity assessment has been progressively used as an unfettered measure of sperm as it proffers more prognostic and diagnostic information than routine semen analysis. The contentious effect of sperm DNA fragmentation (SDF) on clinical outcomes can be attributed to female factors such as age, oocyte quality and ovarian reserve.Aims:The study is mainly aimed to know the influence of SDF on the live birth rates in intracytoplasmic sperm injection (ICSI) cycles with own and donor oocytes. Second, to know the role of female age in regulating the effect of SDF on the live birth rates in ICSI cycles with own and donor oocytes.Setting and Design:A prospective cohort study was done at our tertiary care centre attached to the reproductive medicine unit in medical college.Materials and Methods:The study included 356 patients who underwent first ICSI cycles either with own or donor-oocytes along with day 5 fresh embryo transfers only. The main outcome measures were live birth rates and miscarriage rates.Statistical Analysis Used:Chi-squared test was used to compare the categorical variables between the groups. The receiver operating characteristic curve was developed to correlate the female age with the live birth rate.Results:A significant decrease in the live birth rates (42.85% vs. 26.15%, P = 0.023) and an increase in the miscarriage rates (12.30% vs. 34.61%, P = 0.013) were observed in the high-SDF group ICSI cycles of own-oocyte patients. However, there was no significant difference in the live birth rates and miscarriage rates in the low- and high-SDF groups of donor oocyte ICSI cycle patients (P > 0.05). The own-oocyte ICSI cycle patients were further stratified based on the female age. In the female age group ≤30 years there was no significant difference in the live birth and miscarriage rates (P > 0.05) similar to donor oocyte ICSI cycles. Whereas, there was a significant difference in the live birth rates in the females of age >30 years (13.79% vs. 34.37%, P = 0.040).Conclusion:In conclusion, high-SDF has a negative influence on the live birth rates and a positive influence on the miscarriage rates in patients with own-oocyte ICSI cycles. A similar influence was not observed in patients with donor-oocyte ICSI cycles and in young female patients (age ≤30 years) with own-oocyte ICSI cycles.

Sperm DNA Integrity and Male Fertility in Farm Animals: A Review.

The accurate prediction of male fertility is of major economic importance in the animal breeding industry. However, the results of conventional semen analysis do not always correlate with field fertility outcomes. There is evidence to indicate that mammalian fertilization and subsequent embryo development depend, in part, on the inherent integrity of the sperm DNA. Understanding the complex packaging of mammalian sperm chromatin and assessment of DNA integrity could potentially provide a benchmark in clinical infertility. In the era of assisted reproduction, especially when in-vitro fertilization or gamete intrafallopian transfer or intracytoplasmic sperm injection is used, assessment of sperm DNA integrity is important because spermatozoa are not subjected to the selection process occurring naturally in the female reproductive tract. Although sperm DNA integrity testing measures a significant biological parameter, its precise role in the infertility evaluation in farm animals remains unclear. In this review, the earlier findings on sperm DNA integrity in relation to male fertility are compiled and analyzed. Furthermore, the causes and consequences of sperm DNA damage are described, together with a review of advances in methods for detection of sperm DNA damage, and the prognostic value of sperm DNA quality on male fertility.

The correlation between mammalian target of rapamycin (mTOR) gene expression and sperm DNA damage among infertile patients with and without varicocele.

This study aimed to assess the possible correlation between mammalian target of rapamycin (mTOR) gene expression and sperm DNA damage among infertile patients with and without varicocele. The study included sixty infertile males and fifty fertile males as controls. The infertile group was subdivided into the following subgroups: thirty males with varicocele and thirty males without varicocele. All subjects underwent medical history collection, clinical examination, semen analysis, sperm DNA integrity assessment, mTOR gene expression assessment and scrotal colour Doppler ultrasound. The mean mTOR gene expression in infertile patients with varicocele (23.52±14.65) was significantly higher than that in infertile patients without varicocele (12.24±12.44) and fertile control subjects (3.92±3.26; p=0.003 and p<0.001 respectively). In the infertile varicocele-positive group, mTOR gene expression showed a significant negative correlation with sperm count (p=0.028, r=-0.400) and progressive sperm motility (p=0.038, r=-0.381), as well as a significant positive correlation with the sperm DNA fragmentation index (DFI; p=0.001, r=0.578). In the infertile varicocele-negative group, mTOR gene expression showed a significant negative correlation with progressive sperm motility (p=0.018, r=-0.429) and a significant positive correlation with sperm DFI (p<0.001, r=0.673). In conclusion, according to these results, there is a significant positive correlation between mTOR gene expression and sperm DFI among infertile patients with and without varicocele.

Assessment of sperm DNA integrity within the Palaemon longirostris (H. ) population of the Seine estuary

The interpretation of biomarkers in natura should be based on a referential of expected values in uncontaminated conditions. Nevertheless, to build a reference data set of biomarker responses in estuarine areas, which receive chronic pollution loads due to their transition position between continent and sea, is impossible. In this context, the aim of the present work was to propose the use of laboratory recovery period to define a baseline for the measurement of sperm DNA damage by Comet assay in the estuarine prawn Palaemon longirostris. For that, sperm DNA integrity was observed after both a passive (i.e. 20 days in a clean environment) and an active (i.e. forced renewal of spermatophores) recovery of wild P. longirostris specimens from the Seine estuary, in laboratory conditions. Then, the levels of sperm DNA damage recorded within the P. longirostris population of the Seine estuary, during six campaigns of sampling from April 2015 to October 2017, have been interpreted according to the defined threshold values. The results showed a persistence in the level of DNA damage after 20-day in clean environment with the passive recovery. This strategy was inconclusive to reach a baseline level but it revealed the lack of DNA repair mechanisms. For the active recovery, a decrease of 54% of the level of DNA damage has been observed after the first renewal of spermatophores and this level stabilized after the second renewal. On the basis of this second strategy, we defined a mean basal value of sperm DNA damage of 54.9 A.U. and a maximum threshold of 69.7 A.U. (i.e. 95 %CI). The analysis of the results using the reference value highlighted significant abnormal sperm DNA damage within the native population of P. longirostris from the Seine estuary on all stations during the six-sampling campaigns.

Sperm chromatin dispersion test (SCDt) for the assessment of sperm DNA fragmentation in black tiger prawn, Penaeus monodon

The decapod sperm cell possesses no flagellum so that sperm evaluation has been primarily limited to the integrity of the plasma membrane and acrosome morphology. More recently, andrologists are turning to methods that are capable of assessing sperm DNA quality in an attempt to help understand infertility that cannot be explained by traditional sperm parameters. This study has successfully validated and applied a sperm chromatin dispersion test (SCDt) for the assessment of sperm DNA fragmentation of Penaeus monodon. After selecting an appropriate lysing solution, prawn sperm nuclear morphotypes were confirmed with respect to their DNA status using the two-tail comet assay. Once the SCDt methodology was established, we investigated and compared baseline levels of sperm DNA fragmentation (SDF) present in domesticated and wild male broodstock. Additionally, given that mature prawn sperm possess relatively uncondensed chromatin, the susceptibility of the nucleus to mechanical stress (vortex shearing forces) was investigated in an attempt to artificially induce sperm DNA damage. Results revealed that (1) the percentages of SDF indicated by the SCDt were strongly correlated (Pearson R2 = 0.989; P = .01) with those identified using the two-tailed comet assay, (2) mechanical stress associated with vortexing did not increase SDF level (P = .76) and (3) domesticated male broodstock had a higher (P < .001) SDF level (6.8 ± 4.5%) than that of the wild male broodstock (3.3 ± 1.5%). This study has provided a technique that allows for the assessment of sperm DNA integrity and with further development it could be incorporated as a potential index for male prawn fertility evaluation. We propose that the SCDt can be considered as one of the male fertility parameters in the routine management of male broodstock in prawn aquaculture.

Effects of boar variability on comet-detected sperm-DNA damage following cryopreservation

Assessment of sperm-DNA integrity is a crucial issue in male fertility. In the present study, parameters derived from the image analysis of comets after single-cell gel electrophoresis were used to analyse the types of DNA damage of frozen–thawed boar spermatozoa. Semen, frozen in a cryoprotectant-free extender or in cryoprotectant-based extenders, was analysed for DNA fragmentation and with the following comet tail measures: percentage DNA in comet tail, comet tail length and olive tail moment. The percentages of sperm DNA damage in the comet tails were classified as Type 0 (no DNA damage), Type I (very low DNA damage), Type II (light DNA damage), Type III (medium DNA damage) and Type IV (heavy DNA damage). Sperm motility characteristics and membrane integrity were assessed in the pre-freeze and frozen–thawed semen samples. Assessment of sperm DNA fragmentation and comet tail measures showed marked inter-boar variability following cryopreservation. However, consistent differences among the boars, with respect to cryo-induced sperm DNA damage, were detected by the comet tail length and olive tail moment. Besides Type IV, all types of DNA damage were detected in the cryoprotectant-based extenders. It was found that the frequency of Type II and Type III of DNA damage of frozen–thawed spermatozoa was significantly greater in the cryoprotectant-based and cryoprotectant-free extenders respectively. Deterioration in the quality of the sperm DNA integrity was concomitant with a marked decline in sperm motility characteristics, reduced plasma membrane integrity and higher lipid peroxidation and aspartate aminotransferase activity after cryopreservation. It can be suggested that the comet-assay parameters, coupled with routine laboratory tests, are useful to improve the sperm evaluations of post-thaw quality of semen from individual boars and would offer more comprehensive information for a better understanding of the degree of cryo-induced sperm-DNA damage.

Use of Semen Quality to Predict Pregnancy in Couples Undergoing ICSI

The objective of this study was to determine how fertilization, implantation and pregnancy depend on two basic sperm parameters, sperm concentration and sperm motility in ICSI procedure. Primary outcome as fertilization rate (FR), implantation rate (IR), βhCG/cycle, clinical pregnancy rate (PR) and live births rate (LBR) to be stated. In our center 44 cycles of ICSI were carried out in natural and stimulated cycle. Male subfertility was defined as semen quality not meeting the criteria for normality as defined by the World Health Organization (WHO, 1999). FR, IR, βhCG/cycle, PR and LBR were not significantly different between the 5 form male subfertility (normo-, oligo-, astheno-, oligo-astheno- and oligoasthenoteratozoospermia) in ICSI (P < 0.05). In oligoasthenoteratozoospermia IR, βhCG/cycle, PR and LBR was higher than in other cases. The best results are achieved in the case of fertilization rate. PR and LBR had the lowest values in the case oligoasthenozoospermia. In normozoospermia were extremely low values PR and LBR. The only factor that obviously impacts on ICSI-related pregnancy is maternal age, impairing oocyte/embryo quality. The answer to the question of how to predict and increase the success of the ICSI procedure should be sought in assessment of sperm DNA integrity.

Is Sperm DNA Integrity Assessment Useful?

Is Sperm DNA Integrity Assessment Useful?

Improved Bovine ICSI Outcomes by Sperm Selected after Combined Heparin-Glutathione Treatment

Despite widespread application of intracytoplasmic sperm injection (ICSI) in human-assisted reproductive techniques (ART), the efficiency of this method is still far from satisfactory in livestock, particularly in the bovine species with its unique sperm condensation. On the basis of the natural chemical structure of chromatin in condensed sperm, we developed a novel combined heparin-reduced glutathione (GSH) sperm pretreatment that improves the efficiency of bovine ICSI via selection of the most appropriate sperm at the time of ICSI. Assessment of sperm DNA integrity revealed that this pretreatment can be considered as a safe and efficient approach for in vitro sperm decondensation when compared to conventional sperm pretreatments with dithiothreitol (DTT). Injection of completely decondensed bull sperm derived from this pretreatment significantly improved fertilization and blastocyst formation rates compared to untreated or intact sperm injection (34.8 ± 2.7 and 29.1 ± 1.5 vs. 12.0 ± 3.2 and 15.9 ± 1.2%, respectively; p<0.05). Real-time PCR analysis revealed that expression of pluripotent and anti-apoptosis markers in blastocysts derived by injection of completely decondensed sperm from heparin-GSH pretreatment were comparable to IVF when compared to the DTT pretreatment and control ICSI groups (p<0.05). The results of this study suggested that the degree of sperm decondensation derived from heparin-GSH pretreatment may affect ICSI efficiency in bovine.

Sperm DNA damage

The true impact of the current sperm DNA fragmentation testing needs further scrutiny to assess whether clinically meaningful information is conveyed. Various studies have suggested different or no threshold values with assorted tests for the percentage of DNA fragmentation in the ejaculated sperm above which natural conception, fertilization or embryo development and/or clinical pregnancy rates are compromised. Current DNA fragmentation assessment methods provide very little specific information on the nature and severity of the DNA damage detected. Although sperm DNA fragmentation is associated with lower pregnancy rates through natural conception or intrauterine insemination, it does not seem to affect intracytoplasmic sperm injection outcome. Although animal studies demonstrated adverse reproductive effects of sperm DNA fragmentation, any conclusive evidence in humans is yet to be demonstrated. It is not clear whether interventions aimed at enrichment of sperm with decreased DNA fragmentation are effective in preventing the potential adverse effects of sperm DNA fragmentation in humans. Major concern about the use of sperm DNA integrity tests as prognostic parameters is that the direct evaluation of DNA fragmentation in individual sperm fertilizing the oocyte is not possible. The lack of consensus in defining a clinically relevant standard DNA fragmentation test with a meaningful cut-off level brings challenges in implementing the routine use of sperm DNA integrity assessment in daily practice.

Sperm DNA integrity assessment: a new tool in diagnosis and treatment of fertility.

Infertility affects 15% of all couples. Although male infertility factors with reduced semen quality are contributing to about half of all involuntary childlessness, the value of standard semen parameters in prediction of fertility in vivo and choice of proper method for assisted reproduction is limited. In the search for better markers of male fertility, during the last 10 years, assessment of sperm DNA integrity has emerged as a strong new biomarker of semen quality that may have the potential to discriminate between infertile and fertile men. Sperm DNA Fragmentation Index (DFI) as assessed by the flow cytometric Sperm Chromatin Structure Assay (SCSA) can be used for evaluation of sperm chromatin integrity. The biological background for abnormal DFI is not completely known, but clinical data show that DFI above 30% is associated with very low chance for achieving pregnancy in natural way or by insemination, but not in vitro. Already when the DFI is above 20%, the chance of natural pregnancy may be reduced, despite other sperm parameters being normal. Thus this method may explain a significant proportion of cases of unexplained infertility and can be beneficial in counselling involuntary childless couples need of in vitro fertilisation.

Standardization and documentation of varicocele evaluation

Our present understanding of the clinical impact of varicocele on male fertility and the efficacy of varicocele treatment is limited by the absence of an objective, reproducible, and standardized diagnostic evaluation. Herein we review the clinical evaluation of varicocele. The prognostic relevance of varicocele grade and venous diameter measured with ultrasound is explored. A directed history, physical examination of the warmed scrotum, and results of one or multiple semen analyses must be documented in all men with varicoceles. Color Doppler ultrasonography is indicated in cases when the physical examination is indeterminate. Unfortunately, physical examination is limited by intraobserver and interobserver bias, and standardized criteria for the ultrasonographic diagnosis of varicocele do not exist. Despite these limitations, both varicocele grade and venous diameter measured on ultrasound are prognostically useful parameters. In select cases, measurement of serum testosterone and assessment of sperm DNA integrity may also be clinically helpful. The absence of standardized, reproducible clinical, and radiographic evaluations for varicocele has contributed substantially to our present difficulties in selecting patients who are likely to benefit from varicocele treatment and in counseling affected men. Consensus regarding the optimal evaluation of varicoceles and widespread acceptance of a standardized evaluation is necessary.

Ganglioside GT1b protects human spermatozoa from hydrogen peroxide‐induced DNA and membrane damage

We have reported previously that various gangliosides, the sialic acid containing glycosphingolipids, provide protection against sperm injury caused by reactive oxygen species (ROS). In this study, we investigated the effect of treatment of human spermatozoa with ganglioside GT1b on hydrogen peroxide (H(2)O(2))-induced DNA fragmentation and plasma membrane damage. Single-cell gel electrophoresis (Comet assay) used in the assessment of sperm DNA integrity showed that in vitro supplemented GT1b (100 microm) significantly reduced DNA damage induced by H(2)O(2) (200 microm) (p < 0.05). Measurements of Annexin V binding in combination with the propidium iodide vital dye labelling demonstrated that the spermatozoa pre-treated with GT1b exhibited a significant increase (p < 0.05) in the percentage of live cells with intact membrane and decreased phosphatidylserine translocation after exposure to H(2)O(2). Flow cytometry using the intracellular ROS-sensitive fluorescence dichlorodihydrofluorescein diacetate dye employed to investigate the transport of the extracellularly supplied H(2)O(2) into the cell interior revealed that ganglioside GT1b completely inhibited the passage of H(2)O(2) through the sperm membrane. These results suggest that ganglioside GT1b may protect human spermatozoa from H(2)O(2)-induced damage by rendering sperm membrane more hydrophobic, thus inhibiting the diffusion of H(2)O(2) across the membrane.

Sperm DNA integrity assessment in prediction of assisted reproduction technology outcome

Sperm DNA integrity assessment in prediction of assisted reproduction technology outcome