Sperm DNA Fragmentation Rate Research Articles

Reduced sperm DNA longevity is associated with an increased incidence of still born; evidence from a multi-ovulating sequential artificial insemination animal model.

Using a rabbit model, we assessed the influence of sperm DNA longevity on female reproductive outcomes. Semen was collected from 40 bucks, incubated at 38°C for 24h, and the rate of sperm DNA fragmentation (rSDF) was determined using the sperm chromatin dispersion assay. Males were allocated into high rSDF (>0.5 units of increase per hour) or low rSDF (<0.5 units of increase per hour) groups. High and low rSDF semen samples were sequentially artificially inseminated into the same doe to reduce female factor variability, and pregnancy outcomes were recorded. While there was no difference in SDFs between rSDF groups immediately after collection(T0), differences were significant after 2h of incubation; SDFs determined at collection and rSDF behaved as independent characters (Pearson correlation = 0.099; P = 0.542). Following artificial insemination, the rate of stillborn pups was significantly higher in does inseminated by males with a high rSDF (14/21) compared to those with low rSDF (15/6); (contingency χ(2) 5.19; p = 0.022). The risk of stillborn when low rSDF rabbits were used for insemination was 0.16, but increasedto 0.36 when high rSDF animals were used (odds ratio = 2.85; 95% confidence interval = 1.4-2.7). Dynamic assessment of SDF coupled with natural multiple ovulation, high fecundity of the rabbit and control over female factor influence, provided a useful experimental model to demonstrate the adverse effect of reduced sperm DNA longevity on reproductive outcome.

Potential effect of smoking on semen quality through DNA damage and the downregulation of Chk1 in sperm.

Previous studies have found that smoking is associated with decreased male fertility via altering the quality of semen. However, the mechanism by which cigarette smoking affects semen quality remains to be fully elucidated. Heavy smoking-induced DNA damage has been reported to correlate with abnormal spermatozoa and male infertility. It has been reported that, in response to DNA damage, activation of the checkpoint kinase 1 (Chk1) facilitates S and G2 checkpoint arrest. The aim of the present study was to investigate the expression levels of Chk1 in sperm cells of smoking and non-smoking men, and to further examine the correlation between DNA fragmentation rates and the expression levels of Chk1 with smoking. The present study was performed on a cohort of 841 smoking men and 287 non-smoking men. In the investigation, sperm concentration, motility, viability, seminal plasma zinc concentration, acrosin activity and sperm DNA fragmentation were examined. The gene and protein expression levels of Chk1 were detected using reverse transcription quantitative-polymerase chain reaction and western blot analyses, respectively. It was observed that the progressive motility of the sperm was significantly decreased in the moderate and heavy smoking groups, whereas no significant changes were observed in the mild smoking group. The sperm in the medium-term smoking group had significantly decreased progressive motility, and the semen concentration, sperm count and progressive motility vitality were markedly decreased in the long-term smoking group. Compared with the non-smoking group, the abnormal head rates in the heavy smoking group and long-term smoking group were significantly increased. The sperm viability and seminal plasma zinc concentration were markedly increased in the smoking group. Increased DNA fragmentation rates were found in the smoking group. The expression of Chk1 was significantly decreased in the smoking group, compared with the non-smoking group. Progressive motility and sperm concentration showed a nonlinear association with the relative mRNA expression of Chk1. However, an inverse association was found between DNA fragmentation rates and the progressive motility and sperm concentration. These data suggested that the decrease of semen quality caused by cigarette smoking was not only correlated with sperm DNA fragmentation rates, but was also correlated with a decline in the expressive level of Chk1. The expression of Chk1 was associated with DNA damage and apoptosis, the reduction of which may lead to decreased sperm repair and increased sperm apoptosis, with a subsequent effect on semen quality.

Vacuoles in sperm head are not associated with head morphology, DNA damage and reproductive success

In this retrospective study of 873 men enrolled for assisted reproduction techniques, relationships between sperm quality parameters, motile sperm organelle morphology examination (MSOME), DNA damage and live birth rate were evaluated. The presence of vacuoles in the sperm heads was detected by MSOME. Either chromatin decondensation or DNA fragmentation was used to study DNA damage. Results show that age significantly affected some of the examined parameters. In particular, sperm concentration was positively correlated (R = 0.088; P = 0.01) and chromatin decondensation was negatively correlated (R = −0.102; P = 0.003) with age. Furthermore, live birth rate was significantly lower in men aged 40 years or older (P < 0.02) compared with the younger age groups. The presence of sperm head vacuoles was not associated with head morphology, main sperm quality parameters, DNA fragmentation and live birth rate. Considering sperm heads in relation to the shape (normal/abnormal) and vacuoles (presence/absence), no significant variations in the occurrence of vacuoles in either normal or abnormal heads were found. These data suggest that vacuoles are physiological features that do not alter sperm functionality, and it seems that MSOME is not necessary for increasing the success of assisted reproduction techniques.

Separation efficiency of a microfluidic sperm sorter to minimize sperm DNA damage

To evaluate whether microfluidic sperm sorters (MFSSs) allow effective recovery of sorted motile sperm without DNA damage compared with the centrifugation and swim-up procedure. Experimental laboratory study. All participants completed questionnaires regarding previous and/or current diseases, surgery, reproductive experiences, lifestyle factors, and date of the preceding ejaculation. University research laboratory. Male volunteers were recruited without setting conditions. Semen samples from healthy volunteers (n = 37) were collected in sterile containers by masturbation. Flow cytometric measurement and sperm chromatin structure assay analysis of DNA damage after sperm preparation using MFSS and the centrifugation and swim-up procedure. Efficacy and efficiency of sperm preparation, correlation between sperm DNA fragmentation index (DFI) and semen parameters, and relationship between basic characteristics and DFI after the centrifugation and swim-up procedure. Final sperm concentration and motility were significantly different between the centrifugation and swim-up procedure and MFSS sperm preparations. A significantly lower sperm DNA fragmentation rate was detected with MFSS compared with the centrifugation and swim-up procedure use. No correlation was observed between DFI and smoking or drinking, but significant correlations were observed between DFI and medication use and sexual abstinence duration. MFSSs can be used to efficiently and reliably prepare sperm compared with the centrifugation and swim-up procedure. Further research on the clinical use of MFSSs is required to evaluate the safety and usefulness of this device.

The relationship between sperm viability and DNA fragmentation rates.

BackgroundIn humans, sperm DNA fragmentation rates have been correlated with sperm viability rates. Reduced sperm viability is associated with high sperm DNA fragmentation, while conversely high sperm viability is associated with low rates of sperm DNA fragmentation. Both elevated DNA fragmentation rates and poor viability are correlated with impaired male fertility, with a DNA fragmentation rate of > 30% indicating subfertility. We postulated that in some men, the sperm viability assay could predict the sperm DNA fragmentation rates. This in turn could reduce the need for sperm DNA fragmentation assay testing, simplifying the infertility investigation and saving money for infertile couples.MethodsAll men having semen analyses with both viability and DNA fragmentation testing were identified via a prospectively collected database. Viability was measured by eosin-nigrosin assay. DNA fragmentation was measured using the sperm chromosome structure assay. The relationship between DNA fragmentation and viability was assessed using Pearson’s correlation coefficient.ResultsFrom 2008-2013, 3049 semen analyses had both viability and DNA fragmentation testing. A strong inverse relationship was seen between sperm viability and DNA fragmentation rates, with r = -0.83. If viability was ≤ 50% (n = 301) then DNA fragmentation was ≥ 30% for 95% of the samples. If viability was ≥ 75% (n = 1736), then the DNA fragmentation was ≤ 30% for 95% of the patients. Sperm viability correlates strongly with DNA fragmentation rates.ConclusionsIn men with high levels of sperm viability ≥ 75%, or low levels of sperm viability ≤ 30%, DFI testing may be not be routinely necessary. Given that DNA fragmentation testing is substantially more expensive than vitality testing, this may represent a valuable cost-saving measure for couples undergoing a fertility evaluation.

DNA integrity of canine spermatozoa during chill storage assessed by the sperm chromatin dispersion test using bright-field or fluorescence microscopy

The objective of this study was to evaluate the effect of chill storage on canine sperm DNA fragmentation assessed by the sperm chromatin dispersion test using bright-field microscopy with Wright solution (sDF-B) or fluorescence microscopy with propidium iodide (sDF-F). The relationship and agreement between the results obtained with both staining methods were analyzed. The values of DNA fragmentation indexes (sDF-F and sDF-B) were compared at each time of chill storage (0, 24, 48, 72, and 96 hours). Additionally, the sperm DNA fragmentation rate (slope) was compared between the methods during chill storage. Good agreement and no significant differences between values obtained with both staining procedures were observed. Finally, the effect of chill storage for up to 96 hours was assessed on sperm motility parameters and DNA fragmentation indexes. Significant differences were found after 48 hours of chill storage, obtaining greater values of fragmented DNA. Progressive sperm motility was lower just after 96 hours of chill storage, and no effect was found in total sperm motility. In conclusion, the Sperm-Halomax kit, developed for canine semen and based on the sperm chromatin dispersion test, can be used accurately under bright-field or fluorescence microscopy to assess the sperm DNA integrity of canine semen during chill storage. The sperm DNA fragmentation index increased after 48 hours of chill storage, thereby detecting sperm damage earlier than other routine sperm parameters, such as sperm motility.

Sperm Selection Method in ICSI

Abstract Since the establishment of intracytoplasmic sperm injection (ICSI) in 1992, sperms have been observed, evaluated, and selected under an inverted microscope at 400 × magnification for ICSI. Intracytoplasmic morphologically selected sperm injection (IMSI) is a technique in which sperms are selected for micro insemination by more precisely observing their morphology, at increased magnification under an inverted microscope used for micro-insemination and enhancing the image resolution. Approximately 20 years have passed since IMSI was developed, and its efficacy has only been confirmed in cases with a high rate of sperm aneuploidy, a high rate of sperm DNA fragmentation, and repeated ICSI failures. It is well-known that the quality of sperms has a profound effect on the quality of embryos which may eventually become children. Therefore, when micro-insemination is performed, sperms should be selected by not only paying attention to their motility, but also by closely observing their morphology. Those ...

The relationship between sperm DNA fragmentation and male infertility

Objective To explore the relationship between sperm DNA fragmentation rates and male infertility. Methods Case-control study was used. Sperm DNA fragmentation rates were compared between the primary infertile males for unknown reasons(n= 126) and the males whose spouses undergoing delivery in three months(n= 100). Results Sperm DNA fragmentation rate of the research group was(11.95±4.89)%. Sperm DNA fragmentation rate of the control group was(10.07±3.56)%.Significant difference was found between the two groups on sperm DNA fragmentation rate(t=- 3.326,P= 0.001). The 226 men were divided into group A with sperm DNA fragmentation rates<10%(n= 130)and group B with sperm DNA fragmentation rates≥10%(n= 96). The percentage of male infertility in group A was significantly lower than that in group B(50.00% vs 61.62%)(χ2= 4.105,P= 0.043). Conclusion Correlation is found between sperm DNA fragmentation rates and male infertility. Key words: Infertility, Male; DNA fragmentation rate; Spermatozoa

Effect of cryopreservation on the sperm DNA fragmentation dynamics of the bottlenose dolphin (Tursiops truncatus).

Sperm DNA fragmentation is one of the major causes of infertility; the sperm chromatin dispersion test (SCDt) evaluates this parameter and offers the advantage of species-specific validated protocol and ease of use under field conditions. The main purpose of this study was to evaluate sperm DNA fragmentation dynamics in both fresh and post-thaw bottlenose dolphin sperm using the SCDt following different cryopreservation protocols to gain new information about the post-thaw differential sperm DNA longevity in this species. Fresh and cryopreserved semen samples from five bottlenose dolphins were examined for sperm DNA fragmentation dynamics using the SCDt (Halomax(®)). Sperm DNA fragmentation was assessed immediately at collection and following cryopreservation (T0) and then after 0.5, 1, 4, 8, 24, 48 and 72 h incubation at 37°C. Serially collected ejaculates from four dolphins were frozen using different cryopreservation protocols in a TES-TRIS-fructose buffer (TTF), an egg-yolk-free vegetable lipid LP1 buffer (LP1) and human sperm preservation medium (HSPM). Fresh ejaculated spermatozoa initially showed low levels of DNA fragmentation for up to 48 h. Lower Sperm DNA fragmentation (SDF) was found in the second fresh ejaculate compared to the first when more than one sample was collected on the same day (p < 0.05); this difference was not apparent in any other seminal characteristic. While there was no difference observed in SDF between fresh and frozen-thawed sperm using the different cryopreservation protocols immediately after thawing (T0), frozen-thawed spermatozoa incubated at 37°C showed an increase in the rate of SDF after 24 h. Sperm frozen in the LP1(℗) buffer had higher levels (p < 0.05) of DNA fragmentation after 24- and 48-h incubation than those frozen in TTF or HSPM. No correlation was found between any seminal characteristic and DNA fragmentation in either fresh and/or frozen-thawed samples.

Estudio de la dinámica de fragmentación del ácido desoxirribonucleico espermático en jóvenes varones

ObjectiveTo describe and analyze sperm DNA fragmentation and its dynamics after ejaculation in young men. Material and methodThis is a cross-sectional study conducted between 2010 and 2011 in young university students (n=114) from the Murcia Region (Spain). Sperm DNA fragmentation index (SDF) was defined as the percentage of sperm with fragmented DNA divided by the total amount of assessed sperm. The rate of sperm DNA fragmentation (rSDF) was determined by periods of incubation according to the sperm chromatin dispersion test. SDF and its dynamics were evaluated after incubation for 2.5, 17 and 24h at 37°C. Parametric and non-parametric tests were used for statistical analyses. ResultsMean basal SDF was 27.2% (SD 14.4) and rSDF was significantly higher in the first period of incubation compared to the following periods of incubations. The rate of sperm DNA degradation during the first 2.5h (5,5%/h) was significantly higher in those samples with a basal SDF above 30%. ConclusionsThese results indicate that our mean values of SDF are relatively higher compared to other published studies and corroborate that rSDF is significantly higher during the first hours after ejaculation. Moreover, samples with basal SDF above 30% showed higher rSDF during the first hours of incubation compared to the samples with basal SDF below 15%.

Sperm DNA fragmentation in zebrafish (Danio rerio) and its impact on fertility and embryo viability — Implications for fisheries and aquaculture

Abstract Sperm DNA damage is one of the many factors that have been associated with male infertility. However, sperm DNA fragmentation (SDF) assessment has been challenging because protamines render the nuclear chromatin highly compacted. For those fish species having sperm with protamines, one hypothesis is that the less compacted DNA could be more vulnerable to iatrogenic damage when used in artificial reproduction. The present investigation included three objectives: 1) apply the Sperm Chromatin Dispersion (SCD) technique using the Halomax-SCD test kit (Halotech DNA, Madrid, Spain) for the rapid assessment of SDF in zebrafish (Danio rerio); 2) assess the dynamic aspects of SCD to determine zebrafish sperm DNA longevity in both activated and unactivated samples; and 3) to analyze if the dynamic level of zebrafish sperm DNA fragmentation has any impact on fertility and embryo viability. The results demonstrate the use of the Halomax-SCD test for assessing SDF in zebrafish and are congruent with results of DNA Breakage Detection-Fluorescence In Situ Hybridization (DBD-FISH) and Comet Assay. The averaged SDF values derived from 10 individuals were low immediately after sperm motility activation (1.4% ± 0.96) compared to 15 min later (10.6% ± 9.96), with increasing and very high rates of SDF (r-SDF), 0.6% units/min. Although SDF did not significantly influence oocyte fertilization capacity, it significantly impacted later embryo development and overall reproductive success, i.e., fertility rates higher than embryo viability values.

Vitrification of neat semen alters sperm parameters and DNA integrity.

Our aim was to evaluate the effect of neat semen vitrification on human sperm vital parameters and DNA integrity in men with normal and abnormal sperm parameters. Semen samples were 17 normozoospermic samples and 17 specimens with abnormal sperm parameters. Semen analysis was performed according to World Health Organization (WHO) criteria. Then, the smear was provided from each sample and fixed for terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Vitrification of neat semen was done by plunging cryoloops directly into liquid nitrogen and preserved for 7 days. The samples were warmed and re-evaluated for sperm parameters as well as DNA integrity. Besides, the correlation between sperm parameters and DNA fragmentation was assessed pre- and post vitrification. Cryopreserved spermatozoa showed significant decrease in sperm motility, viability and normal morphology after thawing in both normal and abnormal semen. Also, the rate of sperm DNA fragmentation was significantly higher after vitrification compared to fresh samples in normal (24.76 &plusmn; 5.03 and 16.41 &plusmn; 4.53, P = .002) and abnormal (34.29 &plusmn; 10.02 and 23.5 &plusmn; 8.31, P < .0001), respectively. There was negative correlation between sperm motility and sperm DNA integrity in both groups after vitrification. Vitrification of neat ejaculates has negative impact on sperm parameters as well as DNA integrity, particularly among abnormal semen subjects. It is, therefore, recommend to process semen samples and vitrify the sperm pellets.

In Subfertile Couple, Abdominal Fat Loss in Men Is Associated with Improvement of Sperm Quality and Pregnancy: A Case-Series

BackgroundThe impact of overweight among men of reproductive-age may affect fertility. Abdominal fat, more than body mass index, is an indicator of higher metabolic risk, which seems to be involved in decreasing sperm quality. This study aims to assess the relationship between abdominal fat and sperm DNA fragmentation and the effect of abdominal fat loss, among 6 men in subfertile couples.MethodsSperm DNA fragmentation, abdominal fat and metabolic and hormonal profiles were measured in the 6 men before and after dietary advices. Seminal oxidative stress and antioxidant markers were determined.ResultsAfter several months of a lifestyle program, all 6 men lost abdominal fat (patient 1: loss of 3 points of abdominal fat, patient 2: loss of 3 points, patient 3: loss of 2 points, patient 4: loss of 1 point, patient 5: loss of 4 points and patient 6: loss of 13 points). At the same time, their rate of sperm DNA fragmentation decreased: 9.5% vs 31%, 24% vs 43%, 18% vs 47%, 26.3% vs 66%, 25.4% vs 35% and 1.7% vs 25%. Also, an improvement in both metabolic (significant decrease in triglycerides and total cholesterol; p = 0.0139) and hormonal (significant increase in testosterone/oestradiol ratio; p = 0.0139) blood profiles was observed after following the lifestyle program. In seminal plasma, the amount of SOD2 has significantly increased (p = 0.0139) while in parallel carbonylated proteins have decreased. Furthermore, all spouses got pregnant. All pregnancies were brought to term.ConclusionThis study shows specifically that sperm DNA fragmentation among men in subfertile couples could be affected by abdominal fat, but improvement of lifestyle factor may correct this alteration. The effect of specific abdominal fat loss on sperm quality needs further investigation. The reduction of oxidative stress may be a contributing factor.

Vitrification is not superior to rapid freezing of normozoospermic spermatozoa: effects on sperm parameters, DNA fragmentation and hyaluronan binding

Human sperm vitrification is a new cryopreservation method. This study compared the effects of rapid freezing and vitrification on various sperm parameters, hyaluronan-binding assay and DNA fragmentation and assessed the impact of cryoprotectant agents (CPA) with vitrification. A total of 30 normo-ejaculates were prepared by swim up and the motile sperm fraction was divided into four: fresh (control), rapid freezing, and two vitrification groups (a, lacking CPA; b, with CPA). For rapid freezing, a cryovial of sperm suspension was held just above the liquid nitrogen surface, and for vitrification, 30μl suspension was dropped directly into liquid nitrogen. Sperm parameters, including motility, viability and morphology, declined after cryopreservation in both groups. DNA fragmentation was not significantly higher in the vitrification (15.7±4.4%) or rapid freezing (16.6±5.6%) groups when compared with controls (11.6±4.5%). The rates of hyaluronan binding were similar between the control and cryopreserved groups. Moreover, addition of CPA for vitrification had a neutral effect on rates of sperm recovery. In conclusion, vitrification has great potential for human sperm cryopreservation and does not require CPA, with its possible toxicity. However, it is not superior to rapid cryopreservation regarding sperm recovery rate in normozoospermia.Human sperm vitrification is a new cryopreservation method that has been introduced recently. This study compared the effects of rapid freezing with vitrification on rates of sperm parameters, hyaluronan-binding assay and DNA fragmentation after thawing/warming and assessed the impact of cryoprotectant agent (CPA) on vitrification. The study was performed on 30 ejaculates prepared using the swim-up technique. Each motile sperm suspension was divided into four: control (fresh); rapid freezing; and two vitrification groups (a, lacking CPA; b, with CPA). For rapid freezing, a cryovial of sperm suspension was held above the surface of liquid nitrogen. For vitrification, 30μl sperm suspension was dropped into liquid nitrogen directly. The rates of progressive motility (86.6±5.9%) and viability (95.8±3.9%) in controls declined significantly, to 40.0±13.0% and 63.2±7.7% for rapid freezing and 41.9±10.3% and 64.4±10.0% for vitrification, respectively. Normal sperm morphology was also significantly decreased after cryopreservation in all groups. DNA fragmentation was higher with rapid freezing compared with fresh controls (16.6±5.6% vs. 11.6±4.5%, P=0.01), but DNA fragmentation did not increase significantly in vitrified samples (15.7±4.4%). The rates of hyaluronan binding were similar between the control and cryopreserved groups. Moreover, addition of CPA for vitrification had a neutral effect on rates of sperm recovery. In conclusion, vitrification has great potential for human sperm cryopreservation and does not require CPA, with its possible toxicity. However, it is not superior to rapid cryopreservation regarding sperm recovery rate in normozoospermia.

Incipient post‐zygotic barrier in a model system of ecological speciation with gene flow

The role of post-zygotic isolation in nonallopatric ecological speciation is still mostly unknown and information on the nature and strength of these barriers in well-known speciation models is essential for a deeper understanding of such processes. The Galician ecotypes of the marine snail Littorina saxatilis represent one of the best studied cases of nonallopatric ecological speciation. Here, we test the existence of incipient post-zygotic isolation by comparing the fertility of male hybrids with that of both pure forms [ridged and banded (RB) and smooth and unbanded (SU) ecotypes]. We analysed the degree of sperm DNA fragmentation (SDF) of individuals morphologically classified as RB, SU and hybrids, sampled from two locations. SDF analyses were chosen to study sperm quality because, in other animal species, SDF rates correlate with important parameters for speciation research, such as fertilization and abortion rates and viability of adult progeny. In the present work, hybrids showed significantly higher SDF rates than RB and SU males in one location and significantly higher variances in both locations. These results suggest the existence of an incipient post-zygotic barrier, the strength of which may vary across the Galician shore, and highlight the potential of SDF analyses for speciation research.

Basic diagnostics in andrology

Basic andrological diagnosis consists of taking the patient's medical history and the couple's history as well as performing a physical examination including genital ultrasound, spermiogram, and hormonal analysis. If needed, a testicular biopsy and genetic testing may also be performed. Recent studies have shown the effect of lifestyle factors on male fertility. Thus, the patient history and clinical/andrological examinations have been broadened to include information on metabolic disorders like obesity and diabetes mellitus. The biggest changes occurred with the publication of the fifth edition of the WHO laboratory manual in 2010 and the introduction of a section on semen analysis in the German Medical Association guidelines (RiliBÄK). The reference values for almost all spermiogram parameters were adapted in an evidence-based approach using worldwide prospective population studies. For central parameters such as sperm motility and morphology, the assessment criteria were changed. New independent markers such as sperm DNA fragmentation rate are now routinely used in clinical diagnosis. For German andrological laboratories, there are now mandatory quality assurance measures for semen analysis (in the German "Rili-BÄK" guidelines). These include duplicate testing of all standard semen parameters and inter-laboratory comparison at regular intervals.

¿A qué velocidad «muere» el ácido desoxirribonucleico del espermatozoide tras descongelar muestras seminales procedentes de donantes?

ObjectiveThe study was made to analyze the baseline levels of damage recorded in sperm DNA fragmentation (SDF) and to estimate sperm DNA longevity as observed in donors after thawing. Material and methodsFifty donors and forty individuals attending a clinic and classified as a normo-zoospermic population were compared. The baseline SDF levels and the increasing rate of SDF (r-SDF) obtained after thawing when the sperm was incubated for a period of 24h with different sub-sampling performed after 2, 6 and 24h of incubation were considered as the independent variables and compared. ResultsCryopreserved donor sperm exhibited baseline SDF values approximately 2 times lower than those observed in the control group. DNA stability was 2.5 times higher than that observed in the control cohort. Baseline values of SDF of approximately 8% generates 65% sensitivity and 82% specificity to discriminate between the donors and controls. Values of increase of damage of 1.8% per hour, analyzed during the first hours of incubation, identify the donor characteristics with 77% sensibility and 65% specificity. Neither value show any correlation within the control and donor cohorts group. ConclusionThe establishment of these types of threshold values can be used to identify donors considered as “super-donors” in relation to their low levels of SDF and high chromatin stability. The donors selected from the different clinics participating in this study showed similar characteristics for these parameters.

DNA fragmentation is higher in spermatozoa with chromosomally unbalanced content in men with a structural chromosomal rearrangement

It has been previously shown that men with chromosomal structural abnormality had a higher rate of sperm DNA fragmentation. We studied 11 male carriers of a chromosomal structural abnormality (seven with a balanced reciprocal translocation, three with a Robertsonian translocation, one with a pericentric inversion) to determine whether spermatozoa with unbalanced chromosomes were more likely to have fragmented DNA. A sequential method combining analysis of DNA fragmentation using the TUNEL assay followed by analysis of meiotic segregation by fluorescent in situ hybridization was performed on the same spermatozoa. A statistically significant higher number of spermatozoa with unbalanced chromosomal content were found to have fragmented DNA for each man. The rate of spermatozoa with DNA fragmentation was higher than the rate of those without fragmented DNA in particular modes of segregation. Our findings provide a better understanding of the mechanisms involved in male infertility ascribable to chromosomal structural abnormality.

Detecting and Minimizing Sperm DNA Damage

In recent years, with the advancement in sperm cell biology and the development of additional testing techniques, sperm DNA fragmentation has been recognized as one of the important causes of reduced fertility potential. Elevated sperm DNA fragmentation rates also significantly diminish the chance of success in assisted pregnancies. Sperm DNA damage can impair fertilization, disrupt embryonic development, and increase rates of miscarriage and poor conception rates. Newer studies suggest the possibility of an increased risk of childhood cancer when an embryo develops from DNA-damaged sperm. There is limited data from large, randomized, controlled trials to support improvement in male fertility with current interventions such as antioxidant therapy, varicocelectomy, and antibiotics treatment in genital tract infections. Nonetheless, research efforts have shown improvements in semen parameters and these interventions are low risk. Therefore, when the external risk factors are known, every effort should be made to minimize sperm DNA damage.

Prolonged incubation of processed human spermatozoa will increase DNA fragmentation

One of the causes of failure in ART is sperm DNA fragmentation which may be associated with long period of spermatozoa incubation at 37°C. The objective was to evaluate the rate of sperm DNA fragmentation using the sperm chromatin dispersion (SCD) test after swim-up at different time intervals prior to use. In this prospective study, 21 normozoospermic specimens were analysed. The samples were incubated at 37°C after preparation by direct swim-up. DNA fragmentation was assessed at different time intervals (0, 1, 2 and 3h) using SCD test. Spermatozoa with no DNA fragmentation showed large- or medium-sized halos, and sperm cells with DNA fragmentation showed either a small halo or no halo. The rates of normal morphology and progressive motility after sperm processing were 72.33±2.53% and 90±1.02%, respectively. The rate of sperm DNA fragmentation was significantly higher after 2h (8.81±0.93%, P=0.004) and 3h (10.76±0.89%, P<0.0001) of incubation compared to 0h (4.38±0.8%). A positive correlation was found between the incubation time and sperm DNA damage (P<0.0001). Prolonged incubation of prepared normozoospermic samples at 37°C is associated with higher rates of sperm DNA fragmentation. Therefore, sperm samples intended for ART procedures should be used within 2h of incubation at 37°C.