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.

Mechanism of action of Wuzi Yanzong pill in the treatment of oligoasthenozoospermia in rats determined via serum metabolomics

Objective:To investigate the mechanism of action of Wuzi Yanzong pill(WYP)in rats with oligoasthenozoospermia(OAZ)via metabolomics and to provide a possible basis for improving this WYP-based treatment.Methods:A rat model of OAZ was established by treating male SpragueeDawley rats with glucosides from Tripterygium wilfordii Hook.F.Seventy-two rats were randomly divided into six groups:control,L-carnitine(positive control),model,and low-,medium-,and high-dose WYP groups.Rats in the experimental groups were treated with WYP for 4 weeks.At the end of the treatment period,sperm cell quality(density,motility,and viability)was assessed using a semen analysis system,mitochondrial membrane potential(MMP)was assessed using flow cytometry,and testicular injury was assessed using hematoxylin and eosin staining to validate the therapeutic effect of WYP in OAZ.Further,serum metabolomics-based analysis was performed using high-performance liquid chromatography-mass spectrometry to identify differential metabolic pathways and possible mechanisms of action of WYP in OAZ treatment.Results:A rat model of OAZ was considered successfully-established after comparing the quality of spermatozoa in the model group to that in the control group.WYP-M and WYP-H treatments significantly improved sperm cell density,motility,and viability compared with those in the model group(all P<.05).Compared with the model group,both WYP-M and WYP-H treatments increased MMP values(P=.006 and P=.021 respectively),while there was no significant difference in the L-carnitine group.L-carnitine and WYP administration reversed damage to the testes to varying degrees compared with that in the model group.Further,44 differential metabolites and four metabolic pathways,especially autophagy pathway,related to OAZ were identified via metabolomics.Conclusions:WYP improves sperm cell quality and MMP in OAZ primarily via autophagy regulation.These findings can be employed to improve the efficacy of WYP in humans.

Tales of the Tail and Sperm Head Aches --Changing concepts on the prognostic significance of sperm pathologies affecting the head, neck and tail

This article presents an update on the variable prognostic significance of different sperm pathologies in patients with severe male factor infertility due to morphology and motility disorders. Severe asthenozoospermia is one of the leading causes of male infertility as spermatozoa cannot reach the oocyte and/or penetrate normally. Identifying structural causes of sperm immotility was of great concern before the advent of intracytoplasmic sperm injection （ICSI）, because immotility was the limiting factor in the treatment of these patients. In these cases, in vitro methods are used to identify live spermatozoa or stimulate sperm motility to avoid selection of non-viable cells. With these advances, fertilization and pregnancy results have improved dramatically. The identification of genetic phenotypes in asthenozoospermia is important to adequately inform patients of treatment outcomes and risks. The one sperm characteristic that seriously affects fertility prognosis is teratozoospermia, primarily sperm head and neck anomalies. Defects of chromatin condensation and acrosomal hypoplasia are the two most common abnormalities in severe teratozoospermia. The introduction of microscopic methods to select spermatozoa and the development of new ones to evaluate sperm quality before ICSI will assure that ultrastructural identification ofsperm pathologies will not only be of academic interest, but will also be an essential tool to inform treatment choice. Herein, we review the differential roles played by sperm components in normal fertilization and early embryo development and explore how assisted reproductive technologies have modified our concepts on the prognostic significance of sperm pathologies affecting the head, neck, mid-piece and tail.

Homozygous CCDC146 mutation causes oligoasthenoteratozoospermia in humans and mice

Infertility represents a significant health concern,with sperm quantity and quality being crucial determinants of male fertility.Oligoasthenoteratozoospermia(OAT)is characterized by reduced sperm motility,lower sperm concentration,and morphological abnormalities in sperm heads and flagella.Although variants in several genes have been implicated in OAT,its genetic etiologies and pathogenetic mechanisms remain inadequately understood.In this study,we identified a homozygous nonsense mutation(c.916C>T,p.Arg306*)in the coiled-coil domain containing 146(CCDC146)gene in an infertile male patient with OAT.This mutation resulted in the production of a truncated CCDC146 protein(amino acids 1-305),retaining only two out of five coiled-coil domains.To validate the pathogenicity of the CCDC146 mutation,we generated a mouse model(Ccdc146^(mut/mut))with a similar mutation to that of the patient.Consistently,the Ccdc146mut/mut mice exhibited infertility,characterized by significantly reduced sperm counts,diminished motility,and multiple defects in sperm heads and flagella.Furthermore,the levels of axonemal proteins,including DNAH17,DNAH1,and SPAG6,were significantly reduced in the sperm of Ccdc146^(mut/mut) mice.Additionally,both human and mouse CCDC146 interacted with intraflagellar transport protein 20(IFT20),but this interaction was lost in the mutated versions,leading to the degradation of IFT20.This study identified a novel deleterious homozygous nonsense mutation in CCDC146 that causes male infertility,potentially by disrupting axonemal protein transportation.These findings offer valuable insights for genetic counseling and understanding the mechanisms underlying CCDC146 mutant-associated infertility in human males.

Resolution of sperm quality impairment following SARS-CoV-2 infection:A prospective study

Objective:To investigate the length of time required to resolve COVID-19 effects on semen quality and DNA integrity.Methods:A prospective cohort study was conducted among 42 men who tested positive for SARS-CoV-2 and underwent semen analysis at baseline and four months’post-recovery.Semen samples were collected and evaluated for macroscopic and microscopic parameters,sperm chromatin maturation,and DNA fragmentation.Results:The mean age of participants was 37(±7)years,and 14%had normozoospermia at baseline.After a four-month recovery from COVID-19,48%of patients had normozoospermia.Sperm count,motility,and morphology increased significantly,while sperm DNA fragmentation and sperm chromatin maturation decreased significantly post-recovery from COVID-19.Conclusions:Sperm parameters improve after a four-month recovery from COVID-19.The findings indicate significant improvements in sperm count,motility,morphology,DNA fragmentation,and chromatin maturation after a four-month recovery period.

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.

No relationship between biopsy sites near the main testicular vessels or rete testis and successful sperm retrieval using conventional or microdissection biopsies in 220 non-obstructive azoospermic men

In 220 consecutive patients with non-obstructive azoospermia, sperm retrieval was attempted by a combination of conventional and microdissection testicular sperm extraction （TESE）. For sperm retrieval, 2-3 conventional biopsies were performed followed by a microdissection TESE in cases of negative conventional biopsies. During the surgery, the vasculature of the testis was assessed using the operative microscope, and the location of positive biopsies was registered in relation to the blood supply. The overall sperm retrieval rate was 58.2%. From the initial conventional biopsies, sperm could be retrieved in 46.8% of the patients. With microdissection TESE, sperm could be retrieved from an additional 11.4% of the patients. The further use of microdissection TESE improved the sperm retrieval rate significantly （P=0.017）. No significant accumulation of positive biopsies was found towards the rete testis or the main testicular vessels.

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.

Sperm function, mitochondrial activity and in vivo fertility are associated to their mitochondrial DNA content in pigs

Background Despite their low abundance in sperm, mitochondria have diverse functions in this cell type, includ-ing energy production, signalling and calcium regulation. In humans, sperm mitochondrial DNA content(mtDNAc) has been reported to be negatively linked to sperm function and fertility. Yet, the association between mtDNAc and sperm function in livestock remains unexplored. For this reason, this study aimed to shed some light on the link between mtDNAc and sperm function and fertilising potential in pigs. A qPCR method for mtDNAc quantification was optimised for pig sperm, and the association of this parameter with sperm motility, kinematics, mitochondrial activity, and fertility was subsequently interrogated.Results First, the q PCR method was found to be sensitive and efficient for mtDNAc quantification in pig sperm. By using this technique, mtDNAc was observed to be associated to sperm motility, mitochondrial activity and in vivo, but not in vitro, fertility outcomes. Specifically, sperm with low mtDNAc were seen to exhibit greater motility but decreased mitochondrial activity and intracellular reactive oxygen species. Interestingly, samples with lower mtD-NAc showed higher conception and farrowing rates, but similar in vitro fertilisation rates and embryo development, when compared to those with greater mtDNAc.Conclusions These findings enrich our comprehension of the association of mtDNAc with sperm biology, and lay the foundation for future research into employing this parameter as a molecular predictor for sperm function and fer-tility in livestock.

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.

Microfluidic thermotaxic selection of highlymotile sperm and in vitro fertilization

The selection of the most motile and functionally competent sperm is an essential basis for in vitro fertilization(IVF)and normal embryonic development.Widely adopted clinical approaches for sperm sample processing intensely rely on centrifugation and wash steps that may induce mechanical damage and oxidative stress to sperm.Although a few microfluidic sperm sorting devices may avoid these adverse effects by exploiting intrinsic guidance mechanisms of sperm swimming,none of these approaches have been fully validated by clinical-grade assessment criteria.In this study,a microfluidic sperm sorting device that enables the selection of highly motile and functional sperm via their intrinsic thermotaxis is presented.Bioinspired by the temperature microenvironment in the fallopian tube during natural sperm selection,a microfluidic device with controllable temperature gradients along the sperm separation channel was designed and fabricated.This study investigated the optimal temperature conditions for human sperm selection and fully characterized thermotaxis-selected sperm with 45 human sperm samples.Results indicated that a temperature range of 35–36.5℃along the separation channel significantly improves human sperm motility rate((85.25±6.28)%vs.(60.72±1.37)%;P=0.0484),increases normal sperm morphology rate((16.42±1.43)%vs.(12.55±0.88)%;P<0.0001),and reduces DNA fragmentation((7.44±0.79)%vs.(10.36±0.72)%;P=0.0485)compared to the nonthermotaxis group.Sperm thermotaxis is species-specific,and selected mouse sperm displayed the highest motility in response to a temperature range of 36–37.5℃ along the separation channel.Furthermore,IVF experiments indicated that the selected sperm permitted an increased fertilization rate and improved embryonic development from zygote to blastocyst.This microfluidic thermotaxic selection approach will be translated into clinical practice to improve the IVF success rate for patients with oligozoospermia and asthenozoospermia.

PRSS50-mediated inhibition of MKP3/ERK signaling is crucial for meiotic progression and sperm quality

Serine protease 50(PRSS50/TSP50)is highly expressed in spermatocytes.Our study investigated its role in testicular development and spermatogenesis.Initially,PRSS50 knockdown was observed to impair DNA synthesis in spermatocytes.To further explore this,we generated PRSS50 knockout(Prss50^(−/−))mice(Mus musculus),which exhibited abnormal spermatid nuclear compression and reduced male fertility.Furthermore,dysplastic seminiferous tubules and decreased sex hormones were observed in 4-week-old Prss50^(−/−)mice,accompanied by meiotic progression defects and increased apoptosis of spermatogenic cells.Mechanistic analysis indicated that PRSS50 deletion resulted in increased phosphorylation of extracellular signal-regulated protein kinases 1 and 2(ERK1/2)and elevated levels of MAP kinase phosphatase 3(MKP3),a specific ERK antagonist,potentially accounting for testicular dysplasia in adolescent Prss50−/−mice.Taken together,these findings suggest that PRSS50 plays an important role in testicular development and spermatogenesis,with the MKP3/ERK signaling pathway playing a significant role in this process.

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.

Human circBOULE RNAs as potential biomarkers for sperm quality and male infertility

Reliable molecular biomarkers to predict fertility remain scarce.The current study investigated the potential of testis-specific circBOULE RNAs as biomarkers for male infertility and sperm quality.Using reverse transcription-PCR and real-time reverse transcription-PCR assays,we identified seven circular RNAs from the human BOULE gene in human sperm.We observed that the expression level of circEx3-6 was significantly reduced in asthenozoospermia,while the expression levels of both circEx2-6 and circEx2-7 were decreased in terato-zoospermia,compared with the controls.Furthermore,we demonstrated that the expression level of circEx2-6 was negatively correlated with the sperm DNA fragmentation index,and the expression level of circEx2-7 was correlated with both fertilization and cleavage rates in those treated with the assisted reproductive technologies.Further functional analyses in a transgenic fly model supported the roles of circBOULE RNAs in sperm development and human male fertility.Collectively,our findings support that sperm circBOULE RNAs may serve as diagnostic biomarkers for assessing sperm motility and DNA quality.Therefore,clinical application and significance of sperm circBOULE RNAs in the assisted reproductive technologies warrant further investigation.

Role of the epididymis in sperm competition

Although it is generally understood that the testes recruited kidney ducts for reproductive function during the evolution of vertebrates, little is understood of the biological significance of the adaptation. In the context of the evolution of the mammalian epididymis, this report provides evidence that a major role of the epididymis is to enhance a male＇s chance of achieving paternity in a competitive mating system. A unique example of sperm cooperation in monotremes is used as evidence that the epididymis produces sperm competition proteins to form groups of 100 sperm into bundles that have a forward motility nearly thrice that of individual spermatozoa. As it required 3-h incubation in vitro under capacitation conditions to release motile sperm from the bundles, it is suggested that the monotremes provide an example of capacitation that is quite different from capacitation in higher mammals. It is suggested that variation between species in the intensity of sperm competition could explain the variation that occurs between species in the amount of post-testicular sperm maturation and storage in the epididymis, an explanation of why the human epididymis does not play as important a role in reproduction as the epididymis of most mammals. （Asian J Androl 2007 July; 9： 493-499）