The relationship between DNA fragmentation and the intensity of morphologically abnormal human spermatozoa

Objective:To determine the relationship between teratozoospermia and sperm DNA fragmentation(SDF)in the human ejaculate.Methods:This retrospective study included 100 normozoospermic men as a control cohort(abnormal forms>14%),210 patients with a high level of abnormal forms(≤4%)and 65 patients presenting with a moderate level of abnormal forms(>4%to≤14%)based on the World Health Organization definitions.Sperm morphology was assessed using bright field microscopy.Sperm DNA fragmentation was assessed using the sperm chromatin dispersion assay.Non-parametric analyses were conducted to examine the relationship between abnormal sperm morphology and sperm DNA fragmentation;receiver operating characteristic(ROC)analyses were conducted to assess sensitivity and specificity of this relationship.Results:A correlation analysis revealed that the higher the proportion of abnormal spermatozoa in the ejaculate,the higher the level of SDF(Spearman's Rho=-0.230;P<0.001).Significant differences in the proportion of SDF were found when all cohorts were compared(P<0.001);these significant differences were also retained when the different cohorts were compared pairwise.ROC analysis showed a moderate but significant predictive value for SDF to differentiate patients with different levels of teratozoospemia.Conclusions:Although analysis of a more continuous range of values for teratozoospermia would help further clarify any causal relationship with SDF,there is clearly a synergistic or coincident affiliation between these variables that needs to be acknowledged by the clinician when interpreting the spermiogram.

Chromatin condensation but not DNA integrity of pig sperm is greater in the sperm-rich fraction

Background Protamination and condensation of sperm chromatin as well as DNA integrity play an essential role during fertilization and embryo development.In some mammals,like pigs,ejaculates are emitted in three separate fractions:pre-sperm,sperm-rich(SRF)and post sperm-rich(PSRF).These fractions are known to vary in volume,sperm concentration and quality,as well as in the origin and composition of seminal plasma(SP),with differences being also observed within the SRF one.Yet,whether disparities in the DNA integrity and chromatin condensation and pro-tamination of their sperm exist has not been interrogated.Results This study determined chromatin protamination(Chromomycin A3 test,CMA_(3)),condensation(Dibromobi-mane test,DBB),and DNA integrity(Comet assay)in the pig sperm contained in the first 10 m L of the SRF(SRF-P1),the remaining portion of the sperm-rich fraction(SRF-P2),and the post sperm-rich fraction(PSRF).While chromatin protamination was found to be similar between the different ejaculate fractions(P>0.05),chromatin condensation was seen to be greater in SRF-P1 and SRF-P2 than in the PSRF(P=0.018 and P=0.004,respectively).Regarding DNA integrity,no differences between fractions were observed(P>0.05).As the SRF-P1 has the highest sperm concentra-tion and ejaculate fractions are known to differ in antioxidant composition,the oxidative stress index(OSi)in SP,calcu-lated as total oxidant activity divided by total antioxidant capacity,was tested and confirmed to be higher in the SRF-P1 than in SRF-P2 and PSRF(0.42±0.06 vs.0.23±0.09 and 0.08±0.00,respectively;P<0.01);this index,in addition,was observed to be correlated to the sperm concentration of each fraction(Rs=0.973;P<0.001).Conclusion While sperm DNA integrity was not found to differ between ejaculate fractions,SRF-P1 and SRF-P2 were observed to exhibit greater chromatin condensation than the PSRF.This could be related to the OSi of each fraction.

Protective effect of co-enzyme Q10 on testicular tissue and sperm parameters in adult male rats treated with Sunset Yellow FCF

Objective:To determine the protective effect of co-enzyme Q10(CoQ10)on testicular tissue and sperm parameters in male rats treated with SunsetYellow FCF.Methods:Sixty male Sprague-Dawley rats were randomly divided into 6 groups of the control,CoQ10(10 mg/kg/day),low dose of Sunset Yellow(2.5 mg/kg),high dose of Sunset Yellow(70 mg/kg),low dose of Sunset Yellow(2.5 mg/kg)plus CoQ10,and high dose of Sunset Yellow(70 mg/kg)plus CoQ10.The drugs were administered via daily oral gavages for 6 weeks.At the end of the experiment,sperm analysis,stereological and histological assessments of the testis were carried out.Results:The normal morphology(by 41.1%)and progressive spermatozoa(by 74.8%),testicle volume(by 33.4%),lumen volume(by 38.3%),interstitial tissue volume(by 44.7%),seminiferous tubule volume(by 40.7%),and number of spermatogonia(by 53.9%)and Leydig cells(by 70.7%)reduced in the rats that received high doses of Sunset Yellow in comparison to the control group.Nonetheless,all these alterations were recovered by CoQ10 treatment in the CoQ10 plus high dose of Sunset Yellow group.Furthermore,low doses of Sunset Yellow did not affect different parameters of the testis and sperm.Conclusions:CoQ10 could,to some extent,prevent structural changes of the testis induced by the high dose of SunsetYellow.

Pig Reproductive and Respiratory Syndrome Virus (PRRSV) Does Not Attach to Boar Sperm;It Affects Only the Velocity Pattern and the Mobility Pattern

The purpose of the study was to evaluate the sperm viability of semen infected with PRRSV viral particles, observing the effect of the Virus on the motility of boar sperm. The work was carried out at the FMVZ-BUAP Genetics and Reproduction Laboratory. 5 stallions were used. Each sample contained 1 × 106 sperm, the PRRS virus strain was ATCC-VR-2332 (0, 102, 104 and 106 copies of RNA/mL in triplicate), it was observed daily at the CASA;Hamilton Thorne®. Cells with MT (P < 0.05) on days 1, 3, 5, 7 and 10 of evaluation with 201 ± 7.3, 167 ± 10.1, 165 ± 14.6, 134 ± 8.2 and 120 ± 8.8, respectively. The % MP between control and virus concentrations (P ≥ 0.05). The LCV on day 1 and 7 PI at 10X2 and 10X6 (P < 0.05) vs control. In the Correlation Matrix, where it is observed that there is a correlation between VSL and VAP, VSL and VCL, VCL and ALH, VAP with ALH. There is a correlation of VSL and ALH, STR and ALH. In this study there were (P ≤ 0.01) in the VCL, in the concentrations (102) 162.81 ± 10.65 and (106) 177.12 ± 5.77 vs 193.04 ± 4.62 of control. This indicates that altering these parameters would be related to fertility and the PRRS virus affects the LCV. Regarding the VSL, it was observed that the sperm infected with viruses 102, 104 and 106 of 48.00 ± 3.38, 49.88 ± 1.83 and 50.55 ± 2.24 Vs. 56.66 ± 1.68 of control respectively, the control would have greater possibilities of fertilizing the oocyte. In this study, it was found (P ≤ 0.01) in the VAP with 102 of 77.26 ± 5.16, 104 with 83.35 ± 2.41 and 106 with 81.29 ± 3.14 vs the control with 90.56 ± 2.07. Regarding the ALH there is (P < 0.05) a 104 with 8.70 ± .26 and 106 with 9.64 ± 0.23 vs control 8.50 ± 0.27. The presence of different concentrations of PRRSV in boar semen induces changes in different types of sperm motility. Infection of ejaculates with the PRRS virus affects sperm motility on days 1, 3, 5, 7, and 10 post-infections.

Low Level of Cystic Fibrosis Transmembrane Conductance Regulator Is Associated with Human Sperm Autophagy and Vitality

Low sperm motility is one of the main causes of male infertility. Cystic fibrosis transmembrane conductance regulator (CFTR, an anion channel protein) is related to the progressive motility of sperm. CFTR disruptor CFTRinh-172 or forskolin (FSK) in this study were used to treat human sperm separately, and the rates of sperm autophagy and progressive motility, mitochondrial membrane potential (MMP) and ATP concentration, and the expression levels of related factors were detected to explore their relationship. It was showed that sperms treated with CFTRinh-172 or FSK reduced the levels of cAMP, CFTR and PKA, but increased sperm autophagy rate, expression levels of AMPK and LC3B. However, reactive oxygen species content had no significant difference. It was indicated that low level of CFTR performed with cAMP and its downstream effectors such as PKA and AMPK to regulate mitochondrial structure and function, leading to increased autophagy rate and reduced vitality of sperm.

Laboratory and Clinical Outcomes of Single Sperm Cryopreservation in Patients Underwent Micro-TESE

For men with severe oligozoospermia, sperm cryopreservation can preserve surgically obtained sperm. How to cryopreserve single sperm in men is still a hot topic in assisted reproduction technology. Aim to analyze the laboratory and pregnancy outcomes of single sperm cryopreservation group, we retrospectively selected 38 cycles underwent single sperm cryopreservation and thawing as the study group and 618 cycles underwent conventional sperm cryopreservation and thawing as the control group, which were performed in the reproductive medicine center of the Sixth Affiliated Hospital, Sun Yatsen University, from April 2014 to October 2023. All the sperm came from microdissection testicular sperm extraction (micro-TESE), and performed intracytoplasmic sperm injection (ICSI) for fertilization. Zygotes were cultured to Day 3 embryo, which were freshly transferred to female uterus. Surplus embryos were cultured to blastosphere and cryopreserved. There was no statistical difference in female/male age, female BMI, infertility duration and female basal sex hormone (FSH, LH E2, AMH), No. of oocytes retrieved per cycle, No. of ICSI oocytes per cycle and No. of embryos transferred per cycle between the two groups (P > 0.05). No significant difference was found in two-pronuclear oocyte fertilization rate (59.23% VS 58.84%), Day 3 available embryo rate (61.81% VS 63.55%), Day 3 good-quality embryo rate (45.73% VS 50.27%), blastocyst formation rate (47.83% VS 49.46%), the implantation rate (47.37% VS 52.16%), clinical pregnancy rate (36.84% VS 47.18%), miscarriage rate (14.29% VS 12.68%) and live birth rate (85.71% VS 81.70%) between two groups (P > 0.05). In conclusion, single-sperm cryopreservation was the optimal method to preserve sperm after micro-TESE. It can increase the utilization of each sperm and lead to clinical pregnancy.

Determination of double-and single-stranded DNA breaks in bovine sperm is predictive of their fertilizing capacity

Background:The analysis of chromatin integrity has become an important determinant of sperm quality.In frozenthawed bovine sperm,neither the sequence of post-thaw injury events nor the dynamics of different types of sperm DNA breaks are well understood.The aim of the present work was to describe such sperm degradation aftermath focusing on DNA damage dynamics,and to assess if this parameter can predict pregnancy rates in cattle.Results:A total of 75 cryopreserved ejaculates from 25 Holstein bulls were evaluated at two post-thawing periods(0-2 h and 2-4 h),analyzing global and double-stranded DNA damage through alkaline and neutral Comet assays,chromatin deprotamination and decondensation,sperm motility,viability,acrosomal status,and intracellular levels of total ROS,superoxides and calcium.Insemination of 59,605 females was conducted using sperm from the same bulls,thus obtaining the non-return to estrus rates after 90 d(NRR).Results showed an increased rate of double-stranded breaks in the first period(0-2 h:1.29±1.01%/h vs.2-4 h:0.13±1.37%/h;P<0.01),whereas the rate of sperm with moderate+high single-stranded breaks was higher in the second period(0-2 h:3.52±7.77%/h vs.2-4h:21.06±11.69%/h;P<0.0001).Regarding sperm physiology,viability decrease rate was different between the two periods(0-2 h:-4.49±1.79%/h vs.2-4 h:-2.50±3.39%/h;P=0.032),but the progressive motility decrease rate was constant throughout post-thawing incubation(0-2 h:-4.70±3.42%/h vs.2-4 h:-1.89±2.97%/h;P>0.05).Finally,whereas no correlations between bull fertility and any dynamic parameter were found,there were correlations between the NRR and the basal percentage of highly-damaged sperm assessed with the alkaline Comet(Rs=-0.563,P=0.003),between NRR and basal progressive motility(Rs=0.511,P=0.009),and between NRR and sperm with high ROS at 4 h post-thaw(Rs=0.564,P=0.003).Conclusion:The statistically significant correlations found between intracellular ROS,sperm viability,sperm motility,DNA damage and chromatin deprotamination suggested a sequence of events all driven by oxidative stress,where viability and motility would be affected first and sperm chromatin would be altered at a later stage,thus suggesting that bovine sperm should be used for fertilization within 2 h post-thaw.Fertility correlations supported that the assessment of global DNA damage through the Comet assay may help predict bull fertility.

Bull spermatozoa selected by thermotaxis exhibit high DNA integrity,specific head morphometry,and improve ICSI outcome

Background Sperm migration by thermotaxis is a guidance mechanism that operates along the oviduct and it has proved to be a valid method for selecting spermatozoa with low DNA fragmentation(SDF)in mice,humans,and stallions.This study aimed to analyse if bull spermatozoa could be selected by thermotaxis and to assess their quality in terms of SDF as well as determine the presence of a specific sperm subpopulation based on sperm morphometry and assess their fertilizing capacity by ICSI.Methods We used frozen-thawed sperm from 6 bulls and sperm selection by thermotaxis was performed with TALP medium supplemented with 25 mmol/L of HEPES and 5 mmol/L of caffeine.In these conditions,sperm selection was achieved,obtaining a net thermotaxis of 3.6%.Subsequently,we analysed the SDF of the migrated and not-migrated spermatozoa using the neutral COMET assay,and we evaluated the size of the sperm head using Hemacolor■ staining with Motic Images Plus 3 software.Additionally,migrated and not-migrated spermatozoa by thermotaxis were used to fertilize bovine in vitro matured(IVM)oocytes by ICSI,a very inefficient procedure in cattle that is only successful when the oocyte is artificially activated.Results The results showed lower SDF(χ^(2),P<0.001,13.3%reduction,n=8)and lower head size parameters(length and width,P<0.01;and perimeter and area,P<0.001;n=4)in those spermatozoa migrated in comparison to those not-migrated.The distribution of sperm subpopulations structure varied between groups,highlighting cluster 2,characterized by spermatozoa with small head size,and high ellipticity and elongated heads,as the most abundant in the thermotaxis migrated group.When performed ICSI(without oocyte artificial activation)with the thermotactic sperm,the blastocyst rate was 32.2%±9.3%in the group microinjected with the thermotactic spermatozoa vs.8.3%±7.8%in the group of not-migrated sperm(χ^(2),P<0.05).Conclusion Our results showed that bull sperm selection by thermotaxis has a much higher DNA integrity,small and elongated head size parameters,and different sperm subpopulation structure than the not-selected spermatozoa.Additionally,we evidenced that thermotactic spermatozoa improve ICSI success rates.

Bacteriospermia among smallholder artificial insemination boars in the Philippines and potential associated factors

Objective:To determine the prevalence of bacteriospermia,the bacterial load,and the potential factors associated with bacterial contamination in boar semen collected by local smallholder artificial insemination operators.Methods:Fifteen individual raw semen samples were collected from locally available artificial insemination boars owned by different smallholder boar operators within the 5th district of Leyte,Philippines and were subjected to standard bacteriological culture and identification,including a survey of potentially associated factors.Prevalence and bacterial count were determined accordingly,while boar characteristics and collection practices were clustered following agglomerative hierarchical clustering technique.Results:One hundred percent contamination with a bacterial count of(2.01±0.38)×10^(3) CFU/mL was observed.At least 73.33%of the samples were positive for Bacillus spp.,while other identified isolates included Enterobacter spp.,Staphylococcus spp.,E.coli,Pseudomonas spp.,Citrobacter spp.,and Klebsiella spp.Conclusions:Despite the high prevalence of bacteriospermia,the bacterial count is low.Nevertheless,on-farm practices on boar health and management,semen collection,and sanitation as well as the enhancement of basic protocols to control contamination should be conscientiously considered in smallholder artificial insemination operation.

Can the Prediction of Intrauterine Insemination Results by Used Aniline Blue Stain (ABS) and Sperm Chromatin Dispersion (SCD) Levels?

Introduction: This study aimed to perform routine seminal fluid analysis, sperm DNA fragmentation, and sperm function tests at the chromatin maturation level and evaluate pregnancy in the patients passing intrauterine insemination before starting Intrauterine Insemination (IUI) method. Materials and Methods: In this prospective study, 111 couples who underwent Intrauterine Insemination (IUI) in unexplained infertility patients were admitted to Al-Farah IVF and assisted reproductive center in Baghdad, Iraq between November 2020 and February 2021 were evaluated. Semen fluid analysis was performed based on (WHO 4th) guiding rules. In addition, Sperm Chromatin Dispersion (halo test) and sperm maturation were performed with Aniline Blue Stain (ABS). Results: Sperm Chromatin Dispersion (SCD) groups were compared in terms of pregnancy outcome;the positive pregnancy rate was found to be above in the normal SCD groups (p = 0.0005). In addition, Aniline Blue Stain (ABS) groups were compared in the terms of pregnancy outcome;the positive pregnancy rate was found to be higher in the normal ABS group (p = 0.017). Conclusion: Our study showed that the use of DNA fragmentation (SCD) and sperm maturation tests (ABS) together with routine semen analysis in intrauterine insemination cases will make a significant contribution to the prediction of Intrauterine Insemination (IUI) increased results. So, these results indicate a defect in the effect of DNA fragmentation on the outcome of intrauterine insemination.

Intervention of Xuduan Zhongzi Formula on spermatogenesis epididymal morphological changes in a mice model of oligospermia

Objective:To investigate the intervention of Xuduan Zhongzi Formula on the epididymis structure of model of oligospermia mice.Methods:Ten of the 45 male mice were labeled as the normal group,and the remaining 35 mice were injected with chloral hydrate for five consecutive days,and the randomly selected five mice were anesthetized with chloral hydrate.The left epididymis was removed,and a few sperm were found in the epididymis under the optical microscope,indicating successful construction of the model.They were randomly divided into three groups:the normal group,the L-carnitine group and the Xuduan group with 10 rats in each group.The the L-carnitine group and the Xuduan group were administrated with equivalent dose of human solvent,and the normal group and the model group were administrated with normal saline.After 8 weeks of intragastric administration,all experimental mice were killed,and the left epididymis was extracted for sperm detection,seminal plasma biochemical detection,HE staining,and electron microscopy.Results:In the model group,enlarged epididymal epithelial cells,vacuolar degeneration of primary and basal cells,and edema of interstitial cells and vascular dilation were found.Compared with the normal group,semen concentration,activity,SOD,A-glucosidase and fructose in the model group were significantly decreased,and the difference was statistically significant(P<0.01).After eight weeks of drug intragastric treatment,the semen concentration,activity,SOD,A-glucosidase and fructose in the Xuduan group were significantly increased compared with the model group,and the difference was statistically significant(P<0.01).Conclusion:Xuduan Zhongzi Formula can significantly improve the epididymal structure,the microenvironment of epididymal sperm maturation and the stability of epididymal epithelial structure of oligospermia model mice,creating conditions for sperm maturation in the epididymis.

Sperm collection in Black-legged Kittiwakes and characterization of sperm velocity and morphology

Background:Collecting and studying live sperm is central to many important fields of biology.Yet,a simple method to collect live sperm is lacking in wild seabird species.Here,we describe a non?invasive method to collect viable sperm samples based on a simple massage technique applied to male Black?legged Kittiwakes(Rissa tridactyla).Methods:We studied a colony breeding at Kongsfjorden,Svalbard and successfully obtained sperm samples from 32 males.With a subset of samples(n = 12 males),we compared the suitability of several extenders(0.9% NaCl,PBS,Earle's balance salt solution,Dulbecco's modified Eagle medium) in maintaining sperm alive long enough for analyses.With another 18 ejaculates,we conducted computer assisted sperm analyses using the CASA plugin for ImageJ.We provide details about the settings to be used for such analyses.Lastly,droplets from 20 ejaculates were smeared on glass slides and preserved with formalin to characterize sperm morphology in terms of total sperm length,sperm head length,midpiece length and flagellum length,and percentage of abnormal sperm.Results:With this method and under field conditions,we were able to obtain sufficient amounts of live sperm to assess traits related to sperm quality(e.g.sperm morphology,percentage of motile sperm,sperm velocity).We found that two extenders,Earle's balanced salt solution and Dulbecco modified Eagle's medium,yielded similarly good results.Additionally,we investigated whether specific behaviours were associated with successful sperm collection and whether sperm collection success depended on how long before laying sperm collection was attempted.Finally,we provide mean values for sperm morphology,sperm swimming ability and percentage of motile sperm,which may prove useful for future comparative analyses,and we report high levels of sperm abnormality and within?ejaculate variation in sperm morphology.Conclusions:We discuss the high percentage of abnormal sperm and high within?ejaculate variation in sperm morphology in light of sperm competition theory and conclude that these figures are likely due to relaxed post?cop?ulatory sexual selection,kittiwakes being strictly monogamous.Finally,we suggest that this method could be applied to other seabird species sharing similar ecology.

Microdissection testicular sperm extraction： an update

Patients with non-obstructive azoospermia （NOA） were once considered to be infertile with few treatment options due to the absence of sperm in the ejaculate. In the last two decades, the advent of intracytoplasmic sperm injection （ICSI）, and the application of various testicular sperm retrieval techniques, including fine needle aspiration （FNA）, conventional testicular sperm extraction （TESE） and microdissection testicular sperm extraction （micro-TESE） have revolutionized treatment in this group of men. Because most men with NOA will have isolated regions of spermatogenesis within the testis, studies have illustrated that sperm can be retrieved in most men with NOA, including Klinefelter＇s syndrome （KS）, prior history of chemotherapy and cryptorchidism. Micro-TESE, when compared with conventional TESE has a higher sperm retrieval rate （SRR） with fewer postoperative complications and negative effects on testicular function. In this article, we will compare the efficacy of the different procedures of sperm extraction, discuss the medical treatment and the role of testosterone optimization in men with NOA and describe the micro-TESE surgical technique. Furthermore, we will update our overall experience to allow counseling on the prognosis of sperm retrieval for the specific subsets of NOA.

Assessing human sperm morphology： top models, underdogs or biometrics？

The assessment of the percentage of spermatozoa having an ＇ideal＇ morphology using so-called strict method is the method recommended in the latest edition of the World Health Organization （WHO） laboratory manual for semen analysis. This recommendation is a result of the statistical association between ＇ideal＇ sperm morphology and fertility, and of the current general belief that sperm morphology assessment should be used primarily as a fertility tool. The notion of an ＇ideal＇ sperm morphology has persisted despite the very low percentage of such spermatozoa in the semen of fertile men, a subject of intense controversy. The detailed categorization of each abnormal spermatozoon has thus, for a long time, been considered optional and partially redundant, an idea which is reflected in the earlier editions of the WHO manual. However, several recent studies have shown the importance of carefully assessing abnormal sperm morphology for use in the diagnosis ＆infertility, to determine fertility prognosis, and for basic or public health studies. One approach, which combines videomicroscopy and computer vision, and is the only approach able to assess the continuum of sperm biometrics, has been used successfully in several recent clinical, basic and toxicology studies. In summary, the visual assessment of detailed sperm morphology--including the categorization of anomalies allowing arithmetically derived indices of teratozoospermia--and the more modern computer-based approaches, although often considered to be redundant, are in fact complementary. The choice of the most appropriate method depends on the field of investigation （clinical, research, toxicology） and the problem being addressed. Each approach has advantages as well as certain limitations, which will be discussed briefly herein.

Outcome of repeated micro-surgical testicular sperm extraction in patients with non-obstructive azoospermia

Aim： To evaluate the outcome of repetitive micro-surgical testicular sperm extraction （mTESE） attempts in non-obstructive azoospermia （NOA） cases, in relation to patients＇ initial testicular histology results. Methods： A total of 68 patients with NOA in whom mTESE had been performed in previous intracytoplasmic sperm injection （ICSI） attempts were reviewed. Results： Among the 68 patients with NOA, the first mTESE yielded mature sperm for ICSI in 44 （64%） （Sp^＋）, and failed in the remaining 24 （36%） （Sp^-）. Following their first trial, 24 patients decided to undergo a second mTESE. Of these 24 patients, no spermatozoa were obtained in 5 patients, and Sp^＋ but no fertilization/pregnancy were achieved in 19. In these 24 cases, mTESE was successively repeated for two （n = 24）, three （n = 4） and four （n = 1） times. The second attempt yielded mature sperm in 3/5 patients from the Sp group and 16/19 patients from the Sp^＋ group. At the third and fourth trials, 4/4 and 1/1 of the original Sp^＋ patients were Sp^＋ again, respectively. Distribution of main testicular histology included Sertoli cell-only syndrome （16%）, maturation arrest （22%）, hypospermatogenesis （21%） and focal spermatogenesis （41%）. Overall, in repetitive mTESE, 24/29 （82%） of the attempts were finally Sp^＋. Conclusion： Repeated mTESE in patients with NOA is a feasible option, yielding considerably high sperm recovery rate. In patients with NOA, mTESE may safely be repeated one or more times to increase sperm retrieval rate, as well as to increase the chance of retrieving fresh spermatozoa to enable ICSI.

Analysis of Change in Sperm Quality of Chinese FertileMen druing 1981～1996

By literature search, 114 papers for fertile m ale sperm quality including 256 set data w ere collected from 9 292 personsand 11 726 assaysinvolving 39 citiesand coun- ties. Results of analysis show ed a decrease in m ean concentration of sperm from 103.02×106 /m l (1983) to 83.84×106/m l (1996), sperm m otility w as decreased from 75.11(1982) to 67.27(1996) and percentage of sperm w ith norm alm or- phology w asreduced from 85.02(1983) to 77.89(1996), thusshow ing thedefi- nite negative correlation and being statistically significant (P< 0.05). Total sperm countsw ere decreased from 355.34×106(1984) to 262.26×106(1996) and the m ean sem inalvolum ew asdecreased from 3.31 m l(1981) to 2.97 m l(1996), both tending to decline butnotbeing statistically significant(P> 0.05). Itisinteresting to notethat although Chinese sperm quality is better, itdeclines significantly faster than thatof w estern countriesatthesam eperiod. Itispossible thatthe decline of sperm quality is due to problem of environm entalquality. Theauthorssuggesttheemphasisof basicre- search in relevantfields.

Comparison of four methods to evaluate sperm DNA integrity between mouse caput and cauda epididymidis

It is well known that transit through the epididymis involves an increase in the compaction of sperm chromatin, which acquires fully condensed status at the caput epididymidis. The purpose of this study was to compare the terminal deoxyribonucleotidyl transferase-mediated dUTP nick end-labelling （TUNEL） assay, the comet assay, the sperm chromatin structure assay （SCSA） and the sperm chromatin dispersion （SCD） test by analysing spermatozoa from the caput and cauda epididymidis in order to demonstrate the ability of each technique to discriminate between different degrees of sperm maturity related to chromatin compaction and DNA fragmentation. Our results suggest that some populations of DNA-fragmented spermatozoa associated with immature sperm can only be identified using the comet assay and the SCSA but not with the SCD test or the TUNEL assay.

No difference in high-magnification morphology and hyaluronic acid binding in the selection of euploid spermatozoa with intact DNA

In this study, we compared conventional sperm selection with high-magnification morphology based on the motile sperm organellar morphology examination （MSOME） criteria, and hyaluronic acid （HA） binding for sperm chromosome aneuploidy and DNA fragmentation rates. Semen from 50 severe male factor cases was processed through density gradient centrifugation, and subjected to sperm selection by using the conventional method （control）, high magnification at x6650 or HA binding. Aneuploidy was detected by fluorescence in situ hybridization with probes for chromosomes 13, 18, 21, X and Y, and DNA fragmentation by the terminal deoxynucleotidyl transferase dUTP nick end labelling （TUNEL） method. Spermatozoa selected under high-magnification had a lower DNA fragmentation rate （2.6% vs. 1.7%; P=0.032）, with no significant difference in aneuploidy rate （0.8% vs0.7%; P=0.583）, than those selected by the HA binding method. Spermatozoa selected by both methods had much lower aneuploidy and DNA fragmentation rate than the controls （7% aneuploidy and 26.8% DNA fragmentation rates, respectively）. In the high-magnification group, the aneuploidy rate was lower when the best spermatozoa were selected than when only the second-best spermatozoa were available for selection, but the DNA fragmentation rate was not different. In conclusion, sperm selection under high magnification was more effective than under HA binding in selecting spermatozoa with low DNA fragmentation rate, but the small difference （0.9%） might not be clinically meaningful. Both methods were better than the conventional method of sperm selection.

Expression of miR‑138 in cryopreserved bovine sperm is related to their fertility potential

Background MicroRNAs(miRNAs)are small,single-stranded,non-coding RNA molecules of 22–24 nucleotides that regulate gene expression.In the last decade,miRNAs have been described in sperm of several mammals,including cattle.It is known that miRNAs can act as key gene regulators of early embryogenesis in mice and humans;however,little is known about the content,expression,and function of sperm-borne miRNAs in early bovine embryo.In this study,total sperm RNA was isolated from 29 cryopreserved sperm samples(each coming from a separate bull)using a RNeasy kit and treatment with DNase I.RNA concentration and purity were determined through an Epoch spectrophotometer and an Agilent Bioanalyzer.The expression of 10 candidate miRNAs in bovine sperm(bta-miR-10a,bta-miR-10b,bta-miR-138,bta-miR-146b,bta-miR-19b,bta-miR-26a,bta-miR-34a,bta-miR-449a,bta-miR-495 and btamiR-7),previously identified in testis and/or epididymis,was evaluated with RT-qPCR.The cel-miR-39-3p was used as a spike-in exogenous control.Nonparametric Mann–Whitney tests were run to evaluate which miRNAs were differentially expressed between bulls with high fertility[HF;non-return rates(NRR)ranging from 39.5 to 43.5]and those with subfertility(SF;NRR ranging from 33.3 to 39.3).Several sperm functionality parameters(e.g.,viability,membrane stability or oxygen consumption,among others)were measured by multiplexing flow cytometry and oxygen sensing technologies.Results RNA concentration and purity(260/280 nm ratio)(mean±SD)from the 29 samples were 99.3±84.6 ng/μL and 1.97±0.72,respectively.Bioanalyzer results confirmed the lack of RNA from somatic cells.In terms of the presence or absence of miRNAs,and after applying the Livak method,8 out of 10 miRNAs(bta-miR-10b,-138,-146b,-19b,-26a,-449a,-495,-7)were consistently detected in bovine sperm,whereas the other two(bta-miR-10a,and-34a)were absent.Interestingly,the relative expression of one miRNA(bta-miR-138)in sperm was significantly lower in the SF than in the HF group(P=0.038).In addition to being associated to fertility potential,the presence of this miRNA was found to be negatively correlated with sperm oxygen consumption.The expression of three other miRNAs(bta-miR-19b,bta-miR-26a and bta-miR-7)was also correlated with sperm function variables.Conclusions In conclusion,although functional validation studies are required to confirm these results,this study suggests that sperm bta-miR-138 is involved in fertilization events and beyond,and supports its use as a fertility biomarker in cattle.

Minimizing sperm oxidative stress using nanotechnology for breeding programs in rams

Background Artificial insemination(AI)is a routine breeding technology in animal reproduction.Nevertheless,the temperature-sensitive nature and short fertile lifespan of ram sperm samples hamper its use in AI.In this sense,nanotechnology is an interesting tool to improve sperm protection due to the development of nanomaterials for AI,which could be used as delivery vehicles.In this work,we explored the feasibility of vitamin E nanoemulsion(NE)for improving sperm quality during transport.Results With the aim of evaluating this proposal,ejaculates of 7 mature rams of Manchega breed were collected by artificial vagina and extended to 60×10^(6)spz/mL in AndromedR.Samples containing control and NE(12 mmol/L)with and without exogenous oxidative stress(100μmol/L Fe2+/ascorbate)were stored at 22 and 15℃and motility(CASA),viability(YO-PRO/PI),acrosomal integrity(PNA-FITC/PI),mitochondrial membrane potential(Mitotracker Deep Red 633),lipoperoxidation(C11 BODIPY 581/591),intracellular reactive oxygen species(ROS)production and DNA status(SCSAR)monitored during 96 h.Our results show that NE could be used to maintain ram spermatozoa during transport at 15 and 22℃for up to 96 h,with no appreciable loss of kinematic and physiological characteristics of freshly collected samples.Conclusions The storage of ram spermatozoa in liquid form for 2-5 d with vitamin E nanoemulsions may lead more flexibility to breeders in AI programs.In view of the potential and high versatility of these nanodevices,further studies are being carried out to assess the proposed sperm preservation medium on fertility after artificial insemination.