Do sperm and lubricants gel well with each other? A systematic review

Vaginal lubricants are commonly used to aid sexual pleasure and/or to help combat vaginal dryness and dyspareunia. Several studies have reported their impact on sperm function, however there are no published guidelines to help healthcare professionals and couples select a vaginal lubricant that is 'sperm-safe'. To address this, we conducted a literature search using both PubMed and Scopus to identify and appraise manuscripts that reported the impact of lubricants on sperm function. We did not restrict the literature search by year of publication, and we only included manuscripts that looked at the impact of vaginal lubricants on human sperm. The quality of the eligible studies was assessed using the Björndahl et al., (2016) checklist for semen analysis, as most of the studies reported the findings of a basic semen analysis. A total of 24 articles were eligible for analysis with a total of 35 vaginal lubricants (that were available to buy over the counter) being included, 2 of which studied the effect of vaginal lubricants on sperm function in vivo, and 22 being conducted in vitro. KY Jelly, PreSeed and Astroglide were most studied, with most manuscripts focussing on their impact on sperm motility. A paucity of data on most lubricants combined with methodological variations between studies and limited/no reporting on pregnancy outcomes means greater efforts are required before an evidence-based guideline can be published.

LRRC52 is likely a functional component of human KSper†

Completion of fertilization is orchestrated by various ion channels in sperm membrane. Hyperpolarization of membrane potential, an indispensable event during the capacitation process, is dominated by sperm potassium channel (KSper). In addition to sperm-specific SLO3, which forms the channel pore, the auxiliary subunit leucine-rich-repeat-containing protein 52 (LRRC52) is required to form mKSper to function under physiological conditions. However, in human sperm, although most evidence supports that hSLO3 is the pore-forming subunit, whether hLRRC52 contributes to hKSper conductance and modulates sperm function remains to be understood. Here, using an extracellular segment that is homologous between mice and humans as an antigen, we developed a polyclonal antibody designed as LID1 that specifically detected mLRRC52 and performed co-immunoprecipitation with mSLO3. Additionally, patch-clamp recordings of mouse sperm showed that, physiological activation of mKSper and sperm functions were dramatically attenuated after treatment with LID1, indicating that LID1 functionally disrupted the regulation of mLRRC52 on mKSper. Next, LID1 was used to investigate the significance of hLRRC52 for hKSper activation. As a result, hLRRC52 was expressed in human sperm and might be assembled with hSLO3. More importantly, LID1 inhibited hKSper currents and depolarized sperm membrane potential, supporting essential modulation of hLRRC52 in hKSper. Ca2+ signaling of human sperm was also compromised in the presence of LID1, which impaired sperm motility and acrosome reaction. Because LID1 specifically inhibited both mKSper and hKSper but not mCatSper or hCatSper, our results suggest that hLRRC52 functions as an important component of hKSper and regulates sperm physiological functions.

Both protein and non-protein components in extracellular vesicles of human seminal plasma improve human sperm function via CatSper-mediated calcium signaling

STUDY QUESTION

What is the significance and mechanism of human seminal plasma extracellular vesicles (EVs) in regulating human sperm functions?

SUMMARY ANSWER

EV increases the intracellular Ca2+ concentrations [Ca2+]i via extracellular Ca2+ influx by activating CatSper channels, and subsequently modulate human sperm motility, especially hyperactivated motility, which is attributed to both protein and non-protein components in EV.

WHAT IS KNOWN ALREADY

EVs are functional regulators of human sperm function, and EV cargoes from normal and asthenozoospermic seminal plasma are different. Pre-fusion of EV with sperm in the acidic and non-physiological sucrose buffer solution could elevate [Ca2+]i in human sperm. CatSper, a principle Ca2+ channel in human sperm, is responsible for the [Ca2+]i regulation when sperm respond to diverse extracellular stimuli. However, the role of CatSper in EV-evoked calcium signaling and its potential physiological significance remain unclear.

STUDY DESIGN, SIZE, DURATION

EV isolated from the seminal plasma of normal and asthenozoospermic semen were utilized to investigate the mechanism by which EV regulates calcium signal in human sperm, including the involvement of CatSper and the responsible cargoes in EV. In addition, the clinical application potential of EV and EV protein-derived peptides were also evaluated. This is a laboratory study that went on for more than 5 years and involved more than 200 separate experiments.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Semen donors were recruited in accordance with the Institutional Ethics Committee on human subjects of the Affiliated Hospital of Nantong University and Jiangxi Maternal and Child Health Hospital. The Flow NanoAnalyzer, western blotting, and transmission electron microscope were used to systematically characterize seminal plasma EV. Sperm [Ca2+]i responses were examined by fluorimetric measurement. The whole-cell patch-clamp technique was performed to record CatSper currents. Sperm motility parameters were assessed by computer-assisted sperm analysis. Sperm hyperactivation was also evaluated by examining their penetration ability in viscous methylcellulose media. Protein and non-protein components in EV were analyzed by liquid chromatography-mass spectrum. The levels of prostaglandins, reactive oxygen species, malonaldehyde, and DNA integrity were detected by commercial kits.

MAIN RESULTS AND THE ROLE OF CHANCE

EV increased [Ca2+]i via an extracellular Ca2+ influx, which could be suppressed by a CatSper inhibitor. Also, EV potentiated CatSper currents in human sperm. Furthermore, the EV-in [Ca2+]i increase and CatSper currents were absent in a CatSper-deficient sperm, confirming the crucial role of CatSper in EV induced Ca2+ signaling in human sperm. Both proteins and non-protein components of EV contributed to the increase of [Ca2+]i, which were important for the effects of EV on human sperm. Consequently, EV and its cargos promoted sperm hyperactivated motility. In addition, seminal plasma EV protein-derived peptides, such as NAT1-derived peptide (N-P) and THBS-1-derived peptide (T-P), could activate the sperm calcium signal and enhance sperm function. Interestingly, EV derived from asthenozoospermic semen caused a lower increase of [Ca2+]i than that isolated from normal seminal plasma (N-EV), and N-EV significantly improved sperm motility and function in both asthenozoospermic samples and frozen-thawed sperm.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This was an in vitro study and caution must be taken when extrapolating the physiological relevance to in vivo regulation of sperm.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings demonstrate that the CatSper-mediated-Ca2+ signaling is involved in EV-modulated sperm function under near physiological conditions, and EV and their derivates are a novel CatSper and sperm function regulators with potential for clinical application. They may be developed to improve sperm motility resulting from low [Ca2+]i response and/or freezing and thawing.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the National Natural Science Foundation of China (32271167), the Social Development Project of Jiangsu Province (BE2022765), the Nantong Social and People's Livelihood Science and Technology Plan (MS22022087), the Basic Science Research Program of Nantong (JC22022086), and the Jiangsu Innovation and Entrepreneurship Talent Plan (JSSCRC2021543). The authors declare no conflict of interest.

Phytochemical Screening, Antioxidant Effect and Sperm Quality of the Bomba ceiba Stamen Extracts on Charolais Cattle Sperm Induced by Ferrous Sulfate

Orange Bombax ceiba (B. ceiba) is an indigenous plant, and its stamen is an important ingredient in traditional Lanna food. There are limitations in scientific reports on the effects of the biological activities of B. ceiba stamens on the male reproductive system. This study aims to investigate the phytochemical compounds of the orange B. ceiba stamen and its potential effect on the antioxidant properties and quality of cattle sperm treated with Fe. The orange BUE had the highest total phenolics, total tannins, total monomeric anthocyanins, and maximal antioxidant potential. The orange BAE had the highest concentration of total flavonoids. LC-QTOF/MS showed that the orange BUE contained the highest number of phytochemical compounds related to male reproductive enhancement. The orange BUE enhanced sperm motility, and both the orange BUE and the BAE enhanced sperm viability and normal sperm morphology via free radical scavenging. It might be suggested that B. ceiba stamens have benefits for sperm preservation, sperm quality, and increasing the economic value of local plants, and that they may be developed and used to guard against oxidative stress from cryodamage induced by frozen semen technology.

Lipidomics profiles of human spermatozoa: insights into capacitation and acrosome reaction using UPLC-MS-based approach

Introduction

Lipidomics elucidates the roles of lipids in both physiological and pathological processes, intersecting with many diseases and cellular functions. The maintenance of lipid homeostasis, essential for cell health, significantly influences the survival, maturation, and functionality of sperm during fertilization. While capacitation and the acrosome reaction, key processes before fertilization, involve substantial lipidomic alterations, a comprehensive understanding of the changes in human spermatozoa's lipidomic profiles during these processes remains unknown. This study aims to explicate global lipidomic changes during capacitation and the acrosome reaction in human sperm, employing an untargeted lipidomic strategy using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS).

Methods

Twelve semen specimens, exceeding the WHO reference values for semen parameters, were collected. After discontinuous density gradient separation, sperm concentration was adjusted to 2 x 106 cells/ml and divided into three groups: uncapacitated, capacitated, and acrosome-reacted. UPLC-MS analysis was performed after lipid extraction from these groups. Spectral peak alignment and statistical analysis, using unsupervised principal component analysis (PCA), bidirectional orthogonal partial least squares discriminant analysis (O2PLS-DA) analysis, and supervised partial least-squares-latent structure discriminate analysis (PLS-DA), were employed to identify the most discriminative lipids.

Results

The 1176 lipid peaks overlapped across the twelve individuals in the uncapacitated, capacitated, and acrosome-reacted groups: 1180 peaks between the uncapacitated and capacitated groups, 1184 peaks between the uncapacitated and acrosome-reacted groups, and 1178 peaks between the capacitated and acrosome-reacted groups. The count of overlapping peaks varied among individuals, ranging from 739 to 963 across sperm samples. Moreover, 137 lipids had VIP values > 1.0 and twenty-two lipids had VIP > 1.5, based on the O2PLS-DA model. Furthermore, the identified twelve lipids encompassed increases in PI 44:10, LPS 20:4, LPA 20:5, and LPE 20:4, and decreases in 16-phenyl-tetranor-PGE2, PC 40:6, PS 35:4, PA 29:1, 20-carboxy-LTB4, and 2-oxo-4-methylthio-butanoic acid.

Discussion

This study has been the first time to investigate the lipidomics profiles associated with acrosome reaction and capacitation in human sperm, utilizing UPLC-MS in conjunction with multivariate data analysis. These findings corroborate earlier discoveries on lipids during the acrosome reaction and unveil new metabolites. Furthermore, this research highlights the effective utility of UPLC-MS-based lipidomics for exploring diverse physiological states in sperm. This study offers novel insights into lipidomic changes associated with capacitation and the acrosome reaction in human sperm, which are closely related to male reproduction.

New Insights on Sperm Function in Male Infertility of Unknown Origin: A Multimodal Approach

The global trend of rising (male) infertility is concerning, and the unidentifiable causes in half of the cases, the so-called unknown origin male infertility (UOMI), demands a better understanding and assessment of both external/internal factors and mechanisms potentially involved. In this work, it was our aim to obtain new insight on UOMI, specifically on idiopathic (ID) and Unexplained male infertility (UMI), relying on a detailed evaluation of the male gamete, including functional, metabolic and proteomic aspects. For this purpose, 1114 semen samples, from males in couples seeking infertility treatment, were collected at the Reproductive Medicine Unit from the Centro Hospitalar e Universitário de Coimbra (CHUC), from July 2018-July 2022. Based on the couples' clinical data, seminal/hormonal analysis, and strict eligibility criteria, samples were categorized in 3 groups, control (CTRL), ID and UMI. Lifestyle factors and anxiety/depression symptoms were assessed via survey. Sperm samples were evaluated functionally, mitochondrially and using proteomics. The results of Assisted Reproduction Techniques were assessed whenever available. According to our results, ID patients presented the worst sperm functional profile, while UMI patients were similar to controls. The proteomic analysis revealed 145 differentially expressed proteins, 8 of which were specifically altered in ID and UMI samples. Acrosin (ACRO) and sperm acrosome membrane-associated protein 4 (SACA4) were downregulated in ID patients while laminin subunit beta-2 (LAMB2), mannose 6-phosphate isomerase (MPI), ATP-dependent 6-phosphofructokinase liver type (PFKAL), STAR domain-containing protein 10 (STA10), serotransferrin (TRFE) and exportin-2 (XPO2) were downregulated in UMI patients. Using random forest analysis, SACA4 and LAMB2 were identified as the sperm proteins with a higher chance of distinguishing ID and UMI patients, and their function and expression variation were in accordance with the functional results. No alterations were observed in terms of lifestyle and psychological factors among the 3 groups. These findings obtained in an experimental setting based on 3 well-defined groups of subjects, might help to validate new biomarkers for unknown origin male infertility (ID and UMI) that, in the future, can be used to improve diagnostics and treatments.

Regulatory T cells play a crucial role in maintaining sperm tolerance and male fertility

Regulatory T cells (Tregs) modulate tissue homeostatic processes and immune responses. Understanding tissue-Treg biology will contribute to developing precision-targeting treatment strategies. Here, we show that Tregs maintain the tolerogenic state of the testis and epididymis, where sperm are produced and mature. We found that Treg depletion induces severe autoimmune orchitis and epididymitis, manifested by an exacerbated immune cell infiltration [CD4 T cells, monocytes, and mononuclear phagocytes (MPs)] and the development of antisperm antibodies (ASA). In Treg-depleted mice, MPs increased projections toward the epididymal lumen as well as invading the lumen. ASA-bound sperm enhance sperm agglutination and might facilitate sperm phagocytosis. Tolerance breakdown impaired epididymal epithelial function and altered extracellular vesicle cargo, both of which play crucial roles in the acquisition of sperm fertilizing ability and subsequent embryo development. The affected mice had reduced sperm number and motility and severe fertility defects. Deciphering these immunoregulatory mechanisms may help to design new strategies to treat male infertility, as well as to identify potential targets for immunocontraception.

Effect of Atomized Black Maca (Lepidium meyenii) Supplementation in the Cryopreservation of Alpaca (Vicugna pacos) Epididymal Spermatozoa

Artificial insemination is an important assisted reproductive technology that has been applied in several mammalian species. However, successful cryopreservation of semen of South American camelids has been limited, hindering the commercial application of artificial insemination in alpaca species. In this scenario, the addition of antioxidants to semen extenders provides a strategy to improve the freezability of mammalian sperm. Bioactive metabolites from natural extracts of black maca have shown valuable antioxidant properties. Thus, the objective of this study was to evaluate the effect of the addition of atomized black maca in the freezing medium of epididymal spermatozoa of alpacas. Fifteen pairs of epididymis were collected from a local slaughterhouse. Each sample was divided into six groups: (1) fresh, (2) yolk medium (YM), (3) 10 mg/mL maca, (4) 20 mg/mL maca, (5) 30 mg/mL maca, and (6) resveratrol (as an antioxidant control). Sperm cryopreservation was performed through the slow freezing method. Markers associated with functionality, such as motility, viability, and plasma membrane integrity, as well as markers associated with oxidative damage, such as DNA integrity, total ROS production, and mitochondrial function, were analyzed. The results show that the supplementation with black maca (20 mg/mL) improved the sperm motility, viability, plasma membrane integrity, and mitochondrial function evaluated according to an index of formazan deposits. Similarly, the ROS production decreased with maca at 20 mg/mL, although the DNA integrity did not show any differences among the groups. These results suggest that maca at 20 mg/mL has cytoprotective effects during freezing/thawing of epididymal sperm of alpaca species. Further research will be focused on assessing the effects of maca supplementation on semen extenders by using biomolecular markers (proAKAP4) associated with fertility.

Combination of nanoparticle green tea extract in tris-egg yolk extender and 39 °c thawing temperatures improve the sperm quality of post-thawed Kacang goat semen

Kacang goats are small ruminants produced by low-income households in smallholder and farm to reduce poverty and prevent undernutrition. Studies to find a cryopreservation protocol for Kacang goat semen are expected to multiplication of genetically superior animals selected by the paternal lineage. This study evaluated the effect of thawing temperature and supplementation of the green tea extract nanoparticle in skim milk-egg yolk (SM-EY) extender on post-thaw sperm quality of Kacang goat semen. Six ejaculates of Kacang goat were diluted in SM-EY supplemented or not (control group) with 0.001 mg/mL NPs GTE. The diluted semen was packaged with 0.25 mL straws (insemination dose: 60x10⁶ sptz/mL) and cryopreserved. Then, six samples of the control group and NPs GTE groups were thawed at 37°C or 39°C sterile water for 30 s and submitted to sperm quality evaluations. The sperm viability, motility, and intact of the plasma membrane (IPM) were higher (p<0.05) in NPs GTE group than control group. In contrast, the NPs GTE group presented lower (p<0.05) malondialdehyde levels and sperm DNA fragmentation (SDF) compared with the control group. The catalase levels were not significantly different (p > 0.05) between the control and NPs GTE groups. Thawing at 39°C resulted in higher (p<0.05) sperm viability, motility, and IPM than thawing at 37°C. However, thawing at 39°C group presented lower (p<0.05) malondialdehyde levels compared with thawing at 37°C. SDF and catalase levels were similar (p>0.05) between thawing at 37°C and thawing at 37°C. In conclusion, supplementation of 0.001 mg/mL of NPs GTE in SM-EY extender and thawing temperature of 39°C resulted in a better quality of frozen-thawed Kacang goat semen.

Testicular aging, male fertility and beyond

Normal spermatogenesis and sperm function are crucial for male fertility. The effects of healthy testicular aging and testicular premature aging on spermatogenesis, sperm function, and the spermatogenesis microenvironment cannot be ignored. Compared with younger men, the testis of older men tends to have disturbed spermatogenic processes, sperm abnormalities, sperm dysfunction, and impaired Sertoli and Leydig cells, which ultimately results in male infertility. Various exogenous and endogenous factors also contribute to pathological testicular premature aging, such as adverse environmental stressors and gene mutations. Mechanistically, Y-chromosomal microdeletions, increase in telomere length and oxidative stress, accumulation of DNA damage with decreased repair ability, alterations in epigenetic modifications, miRNA and lncRNA expression abnormalities, have been associated with impaired male fertility due to aging. In recent years, the key molecules and signaling pathways that regulate testicular aging and premature aging have been identified, thereby providing new strategies for diagnosis and treatment. This review provides a comprehensive overview of the underlying mechanisms of aging on spermatogenesis. Furthermore, potential rescue measures for reproductive aging have been discussed. Finally, the inadequacy of testicular aging research and future directions for research have been envisaged to aid in the diagnosis and treatment of testicular aging and premature aging.

Genipin improves lipid metabolism and sperm parametersin obese mice via regulation of miR-132 expression

Obesity has now surpassed malnutrition and infectious diseases as the most significant contributor to health problems worldwide. In particular, obesity is associated with several metabolic disorders, including hyperlipidemia, hepatic steatosis, and subfertility. Genipin (GNP), the aglycone of geniposide, is isolated from the extract of the traditional Chinese medicine Gardenia jasminoides Ellis and has been used in traditional oriental medicine against several inflammation-driven diseases. However, the effect and molecular mechanism of GNP on obesity-associated dyslipidemia and sperm dysfunction still need to be explored. In this study, we detect the effects of GNP on hyperlipidemia, hepatic lipid accumulation and sperm function using a high-fat diet (HFD)-induced obese mouse model. We find that obese mice treated with GNP show an improvement in body weight, serum triglyceride levels, serum hormone levels, serum inflammatory cytokines, hepatic steatosis and sperm function. At the molecular level, HFD/GNP diversely regulates the expression of miR-132 in a tissue-specific manner. miR-132 further targets and regulates the expression of SREBP-1c in liver cells, as well as the expressions of SREBP-1c and StAR in Leydig cells in the testis, thus modifying lipogenesis and steroidogenesis, respectively. Collectively, our data demonstrate that GNP shows a broad effect on the improvement of HFD-induced metabolic disorder and sperm dysfunction in male mice by tissue-specific regulation of miR-132. Our findings reveal the function GNP in ameliorating hepatic lipid metabolism and sperm function and suggest that this compound is a versatile drug to treat metabolic disorders.

Mitochondria-Targeted Compounds to Assess and Improve Human Sperm Function

Significance: Currently 10%-15% of couples in reproductive age face infertility issues. More importantly, male factor contributes to 50% of these cases (either alone or in combination with female causes). Among various reasons, impaired sperm function is the main cause for male infertility. Furthermore, mitochondrial dysfunction and oxidative stress due to increased reactive oxygen species (ROS) production, particularly of mitochondrial origin, are believed to be the main contributors. Recent Advances: Mitochondrial dysfunction, particularly due to increased ROS production, has often been linked to impaired sperm function/quality. For decades, different methods and approaches have been developed to assess mitochondrial features that might correlate with sperm functionality. This connection is now completely accepted, with mitochondrial functionality assessment used more commonly as a readout of sperm functionality. More recently, mitochondria-targeted compounds are on the frontline for both assessment and therapeutic approaches. Critical Issues: In this review, we summarize the current methods for assessing key mitochondrial parameters known to reflect sperm quality as well as therapeutic strategies using mitochondria-targeted antioxidants aiming to improve sperm function in various situations, particularly after sperm cryopreservation. Future Directions: Although more systematic research is needed, mitochondria-targeted compounds definitely represent a promising tool to assess as well as to protect and improve sperm function. Antioxid. Redox Signal. 37, 451-480.

The in-vitro effect of gonadotropin-releasing hormones, GnRH-I and GnRH-II, on the motility, vitality and acrosome integrity of Vervet monkey (Chlorocebus aethiops) spermatozoa

Two isoforms of the gonadotropin-releasing hormone (GnRH), GnRH-I and GnRH-II, are expressed in mammals, and the presence of one or more GnRH-like peptides has been demonstrated in the male reproductive tract. GnRH and its receptors (GnRHR) are present in human and non-human primate testis, prostate, epididymis, seminal vesicle, spermatozoa and seminal human plasma. GnRH-II is site-specific and acts directly in an inhibitory or stimulatory fashion. Previous studies speculated that GnRH-II could disrupt specific sperm processes, such as sperm motility or capacitation and could be utilized as an effective contraceptive agent. Our study aimed to investigate the in-vitro effects of GnRH-I and GnRH-II on Vervet monkey sperm function. Electro-ejaculated semen samples from 10 Vervet monkeys (Chlorocebus aethiops) were used to select motile sperm populations. Sperm aliquots were incubated with GnRH-I and GnRH-II at different concentrations for 1 h, where after sperm motility and kinematic parameters were assessed using the automated Sperm Class Analyser. Additional sperm aliquots were incubated with two 10-amino acid control peptides, a non-related peptide and an inactive peptide to exclude the possible influence on sperm motility from other peptides with a structure similar to GnRH. Additionally, a GnRHR-I antagonist (GnRHR-A), Cetrorelix, was tested to establish its antagonistic capability on GnRH. The effect of selected concentrations of GnRH-I and GnRH-II on sperm vitality and acrosome intactness was also evaluated after 10- and 60 min exposure. Analysis of the percentage total sperm motility revealed that different concentrations for GnRH-I and GnRH-II inhibited sperm motility significantly. While sperm progressiveness was also notably affected and a trend of decreased sperm kinematics were evident, no effect was found on sperm vitality or acrosome intactness. The non-related and inactive peptides had no impact on sperm motility. The GnRHR-A demonstrated no effect on sperm motility and effectively blocked the inhibitory outcome on the motility of both GnRH isoforms. While GnRH-I or GnRH-II at low-dose concentrations resulted in in-vitro inhibition of sperm motility, it appears to have no adverse effects on other sperm functional parameters evaluated. These collective observations possibly indicate an essential role for GnRH in the in-vivo process of sperm selection in the female reproductive tract.

Sperm selection with hyaluronic acid improved live birth outcomes among older couples and was connected to sperm DNA quality, potentially affecting all treatment outcomes

STUDY QUESTION

What effects did treatment using hyaluronic acid (HA) binding/selection prior to ICSI have on clinical outcomes in the Hyaluronic Acid Binding sperm Selection (HABSelect) clinical trial?

SUMMARY ANSWER

Older women randomized to the trial's experimental arm (selection of sperm bound to immobilized (solid-state) HA) had the same live birth rates as younger women, most likely a result of better avoidance of sperm with damaged DNA.

WHAT IS KNOWN ALREADY

Recent randomized controlled trials (RCTs) investigating the efficacy of HA-based sperm selection prior to ICSI, including HABSelect, have consistently reported reductions in the numbers of miscarriages among couples randomized to the intervention, suggesting a pathological sperm-mediated factor mitigated by prior HA-binding/selection. The mechanism of that protection is unknown.

STUDY DESIGN, SIZE, DURATION

The original HABSelect Phase 3 RCT ran from 2014 to 2017 and included 2752 couples from whom sperm samples used in control (ICSI) and intervention (Physiological IntraCytoplasmic Sperm Injection; PICSI) arms of the trial were stored frozen for later assessment of DNA quality (DNAq). The trial overlapped with its mechanistic arm, running from 2016 to 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

As miscarriage reduction was a significant secondary outcome of the trial, samples (n = 1247) selected for the mechanistic analysis were deliberately enriched for miscarriage outcomes (n = 92 or 7.4%) from a total of 154 miscarriages (5.6%) among all (n = 2752) couples randomized by stratified random sampling. Values from fresh semen samples for sperm concentration (mml), percentage forward progressive motility and percentage HA-binding score (HBS) were obtained before being processed by differential density gradient centrifugation or (rarely) by swim-up on the day of treatment. Surplus sperm pellets were recovered, aliquoted and cryopreserved for later analysis of DNAq using slide-based Comet, TUNEL, acridine orange (AO) and the sperm chromatin dispersion (SCD) assays. Following their classification into normal and abnormal sample subcategories based on reference values for sperm concentration and motility, relationships with HBS and DNAq were examined by Spearman correlation, Student's t-tests, Mann Whitney U tests, and logistic regression (univariable and multivariable). Parsimonious selection enabled the development of models for exploring and explaining data trends. Potential differences in future cumulative pregnancy rates relating to embryo quality were also explored.

MAIN RESULTS AND THE ROLE OF CHANCE

Results from the 1247 sperm samples assayed for HBS and/or DNAq, generated data that were considered in relation to standard physiological measures of (sperm) vitality and to treatment outcomes. All measures of HBS and DNAq discriminated normal from abnormal sperm samples (P < 0.001). SCD correlated negatively with the Comet (r = -0.165; P < 0.001) and TUNEL assays (r = -0.200; P < 0.001). HBS correlated negatively with AO (r = -0.211; P < 0.001), Comet (r = -0.127; P < 0.001) and TUNEL (r = -0.214; P < 0.001) and positively with SCD (r = 0.255; P < 0.001). A model for predicting live birth (and miscarriage) rates included treatment allocation (odds ratio: OR 2.167, 95% CI 1.084-4.464, P = 0.031), female age (OR 0.301, 95% CI 0.133-0.761, P = 0.013, per decade) and the AO assay (OR 0.79, 95% CI 0.60-1. 02.761, P = 0.073, per 10 points rise). A model predicting the expected rate of biochemical pregnancy included male age (OR 0.464, 95% CI 0.314-0.674, P < 0.001, per decade) and the SCD assay (OR 1.04, 95% CI 1.007-1.075, P = 0.018, per 10 point rise). A model for conversion from biochemical to clinical pregnancy did not retain any significant patient or assay variables. A model for post-injection fertilization rates included treatment allocation (OR 0.83, 95% CI 0.75-0.91, P < 0.001) and the Comet assay (OR 0.950, 95% CI 0.91-1.00, P = 0.041).

LIMITATIONS, REASONS FOR CAUTION

HABSelect was a prospective RCT and the mechanistic study group was drawn from its recruitment cohort for retrospective analysis, without the full benefit of randomization. The clinical and mechanistic aspects of the study were mutually exclusive in that measures of DNAq were obtained from residual samples and not from HA-selected versus unselected sperm. Models for fitting mechanistic with baseline and other clinical data were developed to compensate for variable DNAq data quality. HABSelect used a solid-state version of PICSI and we did not assess the efficacy of any liquid-state alternatives. PICSI reduced fertilization rates and did not improve the outlook for cumulative pregnancy rates.

WIDER IMPLICATIONS OF THE FINDINGS

Notwithstanding the interventional effect on fertilization rates and possibly blastocyst formation (neither of which influenced pregnancy rates), poor sperm DNAq, reflected by lower HBS, probably contributed to the depression of all gestational outcomes including live births, in the HABSelect trial. The interventional avoidance of defective sperm is the best explanation for the equalization in live birth rates among older couples randomized to the trial's PICSI arm. As patients going forward for assisted conception cycles globally in future are likely to be dominated by an older demographic, HA-based selection of sperm for ICSI could be considered as part of their treatment plan.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by the National Institute for Health Research (NIHR) EME (Efficacy and Mechanism Evaluation)-11-14-34. National Research Ethics Service approval 11/06/2013: 13/YH/0162. S.L. is CEO of ExamenLab Ltd (company number NI605309).

TRIAL REGISTRATION NUMBER

ISRCTN99214271.

Sperm Physiological Response to Female Serum-Potential New Insights into the Reproductive Incompatibility Diagnostics

Infertility is assumed to arise exclusively from male- and female-dependent pathological factors. However, recent studies have indicated that reproductive failure may also result from the reproductive incompatibility of the partners. Selection against such incompatibilities likely occurs via female-derived reproductive secretions, including follicular fluid (FF), that mediate gamete-level mate choice towards the sperm of specific males. To facilitate potential development of diagnostic tests for human reproductive incompatibility, we examined whether sperm physiological response to female serum indicate male–female compatibility in the presence of FF. We performed a full-factorial experiment, in which the sperm of 10 males were treated with the FF and serum of 6 healthy females. We found that sperm motility and viability in both biofluids were highly similar and that in 70% of the males, sperm serum treatment predicted male–female compatibility. We also identified male human leucocyte antigen (HLA) alleles and female (FF and serum) anti-HLA antibodies and tested whether the number of allele–antibody matches predict sperm physiological response to female fluids. However, no association was found between measured sperm traits and the number of allele–antibody matches. Overall, the present results may open novel possibilities for the future development of reproductive incompatibility tests and may pave the way towards more accurate infertility diagnostics and treatments.

Should All Fractions of the Boar Ejaculate Be Prepared for Insemination Rather Than Using the Sperm Rich Only?

Simple Summary

The swine industry is constantly looking for efficiency improvement, especially focusing on the artificial insemination (AI) process. One of the trends in AI centers is to maximize the number of doses obtained from one ejaculate. Seminal doses are usually prepared with the sperm-rich fraction or the whole ejaculate, but further studies are needed to understand how to prepare them properly. Thus, this study aims to analyze how accumulative ejaculate fractions may influence sperm storage, AI performance, and offspring. The results indicate that the presence of all ejaculate fractions within seminal doses does not affect either sperm quality or AI performance and offspring health. Therefore, this study highlights the possibility to use the bulk ejaculate for seminal dose preparation, leading to successful AI. Additionally, it results in a more time-efficient preparation of a greater number of seminal doses providing an economic advantage.

Abstract

Boar ejaculate is released in several well-characterized fractions, differing in terms of sperm concentration, seminal plasma volume, and composition. However, the inclusion of the last part of the ejaculate for artificial insemination (AI) purposes is still under debate due to its controversial effects. Thus, there is a need to study the potential synergistic impact of the different ejaculate fractions. We aimed to evaluate the effect of accumulative ejaculate fractions on sperm conservation, AI performance, and offspring health. Ejaculates (n = 51) were collected and distributed as follows: F1: sperm-rich fraction; F2: sperm-rich + intermediate fractions; F3: sperm-rich + intermediate + poor fractions. Each group was diluted in a commercial extender, packaged in seminal doses (2000 × 10⁶ sperm/60 mL), and stored at ~16 °C. On day 3 of conservation, sperm were analyzed and used for AI (n = 174). High sperm quality was observed after storage without a significant difference between the groups (p > 0.05). Moreover, no differences were obtained for AI performance (pregnancy and farrowing rates, and litter size; p > 0.05) and offspring health (growth and blood analysis; p > 0.05). Conclusively, the presence of all ejaculate fractions within the seminal doses does not impair the reproductive performance, reporting important economic savings according to the economic model included here.

Sperm bauplan and function and underlying processes of sperm formation and selection

The spermatozoon is a highly differentiated and polarized cell, with two main structures: the head, containing a haploid nucleus and the acrosomal exocytotic granule, and the flagellum, which generates energy and propels the cell; both structures are connected by the neck. The sperm's main aim is to participate in fertilization, thus activating development. Despite this common bauplan and function, there is an enormous diversity in structure and performance of sperm cells. For example, mammalian spermatozoa may exhibit several head patterns and overall sperm lengths ranging from ∼30 to 350 µm. Mechanisms of transport in the female tract, preparation for fertilization, and recognition of and interaction with the oocyte also show considerable variation. There has been much interest in understanding the origin of this diversity, both in evolutionary terms and in relation to mechanisms underlying sperm differentiation in the testis. Here, relationships between sperm bauplan and function are examined at two levels: first, by analyzing the selective forces that drive changes in sperm structure and physiology to understand the adaptive values of this variation and impact on male reproductive success and second, by examining cellular and molecular mechanisms of sperm formation in the testis that may explain how differentiation can give rise to such a wide array of sperm forms and functions.

Novaluron Has Detrimental Effects on Sperm Functions

Although novaluron is an insect growth regulator with a low mammalian acute toxicity and a low risk to the environment and nontarget organisms, toxic effects of novaluron have been reported. However, no studies have yet evaluated the effect of novaluron on reproduction. Therefore, we examined the effects of novaluron on sperm functions. The spermatozoa of ICR mice were incubated with various concentrations of novaluron to induce capacitation. Then, sperm motion parameters and capacitation status were evaluated using CASA program and H33258/chlortetracycline staining. In addition, PKA activity and tyrosine phosphorylation were evaluated by Western blotting. After exposure, various sperm motion parameters were significantly decreased in a dose-dependent manner. The acrosome reaction was also significantly decreased in the high concentration groups. Sperm viability was significantly reduced at the highest concentration. In addition, PKA activity and tyrosine phosphorylation were also significantly altered. Thus, novaluron affects sperm viability, sperm motility, and motion kinematics during capacitation. Furthermore, it may promote the reduction in acrosome reactions. The physiological suppression of sperm function may depend on abnormal tyrosine phosphorylation via the alteration of PKA activity. Therefore, we suggest that it is necessary to consider reproductive toxicity when using novaluron as a pesticide.

Relevance of the Ejaculate Fraction and Dilution Method on Boar Sperm Quality during Processing and Conservation of Seminal Doses

During boar semen processing and distribution, maximizing the work protocols in the laboratories becomes essential for the conservation of seminal doses. One of the recent implementations in the boar studs to improve efficiency has been semi-automatic semen collection systems, which do not allow to discard fractions of the ejaculate. The objective of this work was to evaluate the dilution method and vibrations (simulating delivery transport) effect on sperm quality (motility, viability, morphology, thermo-resistance test) according to the fraction of ejaculate collected. Two different fractions of the ejaculate were obtained [rich fraction (RF); total fractions (TF)] from six boars, and two dilution methods applied [pouring the extender over the semen (control; ES); pouring the semen over the extender (reverse; SE)]. The seminal doses (2000 × 10⁶ sperm/50 mL) were preserved for 5 days. The results showed that the fraction collected affects sperm quality (better total and progressive motility, and faster sperm in TF; p < 0.05) regardless of the dilution method applied. However, these differences diminished after submitting the semen to the thermo-resistance test, with only differences in sperm viability being observed (p < 0.05). When seminal doses were subjected to vibrations, the sperm viability was more affected in the TF than in the RF group (p < 0.05). In conclusion, using the TF ejaculate leads to comparable results to the RF in sperm quality during storage regardless of the dilution method applied. However, the vibrations of seminal doses are more affected in doses prepared with TF than with RF, although more factors should be included to approach the real conditions during transport.

Genetic incompatibility of the reproductive partners: an evolutionary perspective on infertility

In natural fertilisation, the female reproductive tract allows only a strictly selected sperm subpopulation to proceed in the vicinity of an unfertilised oocyte. Female-mediated sperm selection (also known as cryptic female choice (CFC)) is far from a random process, which frequently biases paternity towards particular males over others. Earlier studies have shown that CFC is a ubiquitous phenomenon in the animal kingdom and often promotes assortative fertilisation between genetically compatible mates. Here, I demonstrate that CFC for genetic compatibility likely also occurs in humans and is mediated by a complex network of interacting male and female genes. I also show that the relative contribution of genetic compatibility (i.e. the male-female interaction effect) to reproductive success is generally high and frequently outweighs the effects of individual males and females. Together, these facts indicate that, along with male- and female-dependent pathological factors, reproductive failure can also result from gamete-level incompatibility of the reproductive partners. Therefore, I argue that a deeper understanding of these evolutionary mechanisms of sperm selection can pave the way towards a more inclusive view of infertility and open novel possibilities for the development of more personalised infertility diagnostics and treatments.

Semen Analysis of Total Motile Sperm Count Based on the 1999 and 2010 WHO Criteria

Objective

Approximately 15% of the couples suffer from infertility. Half of the cases of infertility are due to male factors. Several sperm function tests have been proposed to evaluate male fertility, but sperm analysis is still the first and most important diagnostic test for male infertility. The prognostic value of semen characteristics such as concentration, morphology and motility markers are often confused with male infertility. Evaluation of seminal parameters and classification for normality remains a frequent topic of discussion.

Methods

This study evaluated 477 semen samples from men undergoing investigation or infertility treatment between 2011 and 2015.

Results

The spermograms of 401 patients were deemed abnormal based on the 1999 World Health Organization (WHO) criteria; the number changed to 223 when the spermograms were assessed based on the 2010 WHO criteria and to 200 when Total Motile Sperm Count (TMSC) was used as the criterion. Sperm morphology was the item in the criteria that most significantly changed spermogram classification. Normality parameters became less rigid from 1999 to 2010, thereby significantly changing the proportion of individuals no longer described as infertile/subfertile.

Conclusions

The classification based on TMSC could not differentiate between fertile and infertile subjects for not taking sperm morphology into account. Nevertheless, it may be helpful in cases where intrauterine insemination is indicated.

Catalyzing momentum in male contraceptive development

Globally, nearly half of all pregnancies are unplanned. Male contraceptives offer the potential to decrease unintended pregnancy and introduce contraceptive equity, but decades of research have yet to bring a novel product to market. New funding avenues from the philanthropic sector seek to stimulate research in male contraceptives through investments, grants, and support for trainees alongside other programs that encourage product development and ultimately commercialization. This Forum outlines the purpose of and funding opportunities provided by Male Contraceptive Initiative, a funding agency and non-profit focused on the advancement of non-hormonal, reversible contraceptive technologies for those who produce sperm.

The expression of human testis-specific actin capping protein predicts in vitro fertilization outcomes: A novel biomarker of sperm function for assisted reproductive technology

PURPOSE

Sperm function tests do not adequately assess fertilization potential, and new indices are required. We have previously reported that human testis-specific actin capping proteins may be involved in both sperm morphology and function. This study aimed to determine whether testis-specific actin capping proteins can be a predictive marker of IVF success.

METHODS

Ninety-seven infertile couples who underwent IVF at an infertility clinic were included. Sperm were immunohistochemically stained to evaluate capping protein expression, and the percentage of sperms with normal staining was calculated. The relationship between actin capping protein expression and IVF outcomes was examined.

RESULTS

The couples were divided into four groups according to the percentage of normally expressing actin capping protein as follows: ≥90% Group Ⅰ, 80%-90% Group Ⅱ, 70%-80% Group Ⅲ, and <70% Group Ⅳ. Multiple regression analysis showed a significant trend in fertilization rates across the 4 groups (p for trend =0.008).There was no significant trend in pregnancy rates (p for trend =0.276).

CONCLUSION

The human testis-specific actin capping protein may be a marker of male contributing factors that predict IVF outcomes.

CRISPs Function to Boost Sperm Power Output and Motility

Fertilization requires sperm to travel long distances through the complex environment of the female reproductive tract. Despite the strong association between poor motility and infertility, the kinetics of sperm tail movement and the role individual proteins play in this process is poorly understood. Here, we use a high spatiotemporal sperm imaging system and an analysis protocol to define the role of CRISPs in the mechanobiology of sperm function. Each of CRISP1, CRISP2, and CRISP4 is required to optimize sperm flagellum waveform. Each plays an autonomous role in defining beat frequency, flexibility, and power dissipation. We thus posit that the expansion of the CRISP family from one member in basal vertebrates, to three in most mammals, and four in numerous rodents, represents an example of neofunctionalization wherein proteins with a common core function, boosting power output, have evolved to optimize different aspects of sperm tail performance.

Impacts of different antioxidants sources on semen quality and sperm fertilizing ability of Muscovy ducks under high ambient temperature

The potentiality of coenzyme Q10 (CoQ10), D-Aspartic acids (D-Asp), Maca or vitamin C, as antioxidant agents, to reduce negative impacts of high ambient temperature on semen quality, oxidative capacity and fertility of Muscovy ducks was investigated. Seventy-five Muscovy males (34-wk of age) were distributed randomly into five experimental groups of fifteen ducks each. The first group was fed a basal diet without supplementation and served as a control. The other four groups were fed a basal diet supplemented with 400 mg CoQ10, 400 mg D-Asp, 500 mg Maca and 200 mg vitamin C (ascorbic acid) per kg diet for 17 consecutive weeks under high ambient temperature conditions. The dietary inclusion of antioxidants significantly maintains better semen variables and a higher fertility rate either for fresh or preserved semen. Among the tested antioxidants, the Maca group showed the best status and outperformed the others in terms of motility, viability, sperm cell concentration, intact acrosome and membrane integrity percentages, total proteins, total antioxidants capacity, glutathione peroxidase, superoxide dismutase (SOD), malondialdehyde (MDA), testosterone, and the fertility rate for the fresh semen, as well as, forward motility, SOD and MDA for the preserved semen. The CoQ10 showed similar results to Maca in some measurements. Conversely, the basal diet had the poorest performance in all examined variables. The dietary incorporation of antioxidants (Maca or CoQ10) enhances fresh and preserved semen quantity and quality, as well as the fertility rate of Muscovy males under high ambient temperature conditions.

Myeloperoxidase inhibitor AZD5904 enhances human sperm function in vitro

STUDY QUESTION

Does AZD5904, a myeloperoxidase inhibitor (MPOi), have any effect on human sperm function in vitro?

SUMMARY ANSWER

AZD5904 improves sperm function in an in vitro model of oxidative stress (OS) and potentially offers a novel treatment approach for male infertility.

WHAT IS KNOWN ALREADY

Male infertility is an underlying or contributory cause in half of all couples experiencing difficulties conceiving, yet there is currently no effective treatment or cure. OS is a common pathology in a significant proportion of infertile men. It can negatively affect sperm motility and the ability to fertilize a mature oocyte, as well as DNA integrity, and therefore represents an attractive target for therapeutic intervention.

STUDY DESIGN, SIZE, DURATION

This study included population-based samples from men (23-50 years) attending Ninewells Assisted Conception Unit, Dundee for diagnostic semen analysis, July 2017-September 2018. Semen samples (n = 47) from 45 patients were used.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Neutrophils activated using zymosan were incubated with prepared human spermatozoa for 2 h (T2) and 24 h (T24) to create an in vitro model of OS. Parallel samples were co-incubated with AZD5904, an MPOi, to examine its effects. Sperm motility was assessed by computer-assisted sperm analysis at T2 and T24. Functional motility was assessed by sperm penetration assay. Statistical analysis was performed using GraphPad Prism.

MAIN RESULTS AND THE ROLE OF CHANCE

There was no significant difference in total or progressive sperm motility between any treatment and control groups at T2 or T24. Nonetheless, significant positive effects on sperm function were observed with AZD5904, with 16/45 (35.6%) samples (with both normal and abnormal baseline semen analysis characteristics) displaying a ≥20% increase in sperm penetrated through viscous media (P < 0.003).

LIMITATIONS, REASONS FOR CAUTION

This was an in vitro study.

WIDER IMPLICATIONS OF THE FINDINGS

Treatment with AZD5904 resulted in significant increased sperm penetration in one of three samples treated, which is likely to represent improvement in sperm function required for fertilization. We are now planning a clinical trial to validate these results and hope that this could represent a new treatment for male infertility.

STUDY FUNDING/COMPETING INTEREST(S)

AZD5904 was shared through the AstraZeneca Open Innovation program. The study was funded by AstraZeneca and sponsored by the University of Dundee. Additional funding was provided by Chief Scientist Office/NHS Research Scotland (S.J.M.d.S.). A.W. and H.J.S. are both full time employees of AstraZeneca. A.W. and H.J.S. are inventors on a patent filed by AstraZeneca titled MPOi for use in medicine which includes MPOi for use in the treatment of male infertility (WO 2019/016074 Al). S.J.M.d.S. is Associate Editor of Human Reproduction and Editorial Board member of Reproduction & Fertility. C.L.R.B. is Editor of RBMO and has received lecturing fees from Merck and Ferring and is on the Scientific Advisory Panel for Ohana BioSciences. C.L.R.B. was chair of the World Health Organization Expert Synthesis Group on Diagnosis of Male infertility (2012-2016). C.L.R.B. has a patent WO2013054111 A1 issued. The other authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Hepatitis B virus surface protein induces sperm dysfunction through the activation of a Bcl2/Bax signaling cascade triggering AIF/Endo G-mediated apoptosis

BACKGROUND

Hepatitis B virus (HBV) was found to exist in semen and male germ cells of patients with chronic HBV infection. Our previous studies demonstrated that HBV surface protein (HBs) could induce sperm dysfunction by activating a calcium signaling cascade and triggering caspase-dependent apoptosis. However, the relationship between sperm dysfunction caused by HBs and caspase-independent apoptosis has not been investigated.

OBJECTIVES

To evaluate the effects of HBs exposure on sperm dysfunction by activating caspase-independent apoptosis.

MATERIALS AND METHODS

Spermatozoa were exposed to HBs at concentrations of 0, 25, 50, and 100 μg/mL for 3 h. Flow cytometry, qRT-PCR, immunofluorescence assay, ELISA, and zona-free hamster oocyte penetration assays were performed.

RESULTS

With increasing concentrations of HBs, various parameters of the spermatozoa changed. The number of Bcl2-positive cells declined and that of both Bax-positive cells and Apaf-1-positive cells increased. The transcription level of Bcl2 increased and that of both Bax and Apaf-1 declined. The average levels of AIF and Endo G declined in mitochondria and increased in the cytoplasm and nucleus. The sperm DNA fragmentation index increased. The mean percentages of live spermatozoa declined and that of both injured and dead spermatozoa increased; and the sperm penetration rate declined. For the aforementioned parameters, the differences between the test and the control groups were statistically significant.

CONCLUSION

HBs exposure can activate the Bax/Bcl2 signaling cascade that triggers AIF/Endo G-mediated apoptosis, resulting in sperm DNA fragmentation, sperm injury, and death, and a decrease in the sperm fertilizing capacity. This new knowledge will help to evaluate the negative impact of HBV on male fertility in HBV-infected patients.

Multigenerational and transgenerational impact of paternal bisphenol A exposure on male fertility in a mouse model

STUDY QUESTION

How does paternal exposure to bisphenol A (BPA) affect the fertility of male offspring in mice in future generations?

SUMMARY ANSWER

Paternal exposure to BPA adversely affects spermatogenesis, several important sperm functions and DNA methylation patterns in spermatozoa, which have both multigenerational (in F0 and F1) and partial transgenerational (mainly noticed in F2, but F3) impacts on the fertility of the offspring.

WHAT IS KNOWN ALREADY

BPA, a synthetic endocrine disruptor, is used extensively to manufacture polycarbonate plastics and epoxy resins. Growing evidence suggests that exposure to BPA during the developmental stages results in atypical reproductive phenotypes that could persist for generations to come.

STUDY DESIGN, SIZE, DURATION

CD-1 male mice (F0) were treated with BPA (5 or 50 mg/kg body weight per day (bw/day)) or ethinylestradiol (EE) (0.4 μg/kg bw/day) for 6 weeks. Control mice were treated with vehicle (corn oil) only. The treated male mice were bred with untreated female mice to produce first filial generation (F1 offspring). The F2 and F3 offspring were produced similarly, without further exposure to BPA.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Histological changes in the testis along with functional, biochemical and epigenetic (DNA methylation) properties of spermatozoa were investigated. Subsequently, each parameter of the F0-F3 generations was compared between BPA-treated mice and control mice.

MAIN RESULTS AND THE ROLE OF CHANCE

Paternal BPA exposure disrupted spermatogenesis by decreasing the size and number of testicular seminiferous epithelial cells, which eventually led to a decline in the total sperm count of F0-F2 offspring (P < 0.05). We further showed that a high BPA dose decreased sperm motility in F0-F2 males by mediating the overproduction of reactive oxygen species (F0-F1) and decreasing intracellular ATP (F0-F2) in spermatozoa (P < 0.05). These changes in spermatozoa were associated with altered global DNA methylation patterns in the spermatozoa of F0-F3 males (P < 0.05). Furthermore, we noticed that BPA compromised sperm fertility in mice from the F0-F2 (in the both dose groups) and F3 generations (in the high-dose group only). The overall reproductive toxicity of BPA was equivalent to or higher (high dose) than that of the tested dose of EE.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Further research is required to determine the variables (e.g. lowest BPA dose) that are capable of producing changes in sperm function and fertility in future generations.

WIDER IMPLICATIONS OF THE FINDINGS

These results may shed light on how occupational exposure to BPA can affect offspring fertility in humans.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant No. NRF-2018R1A6A1A03025159). M.S.R. was supported by Korea Research Fellowship Program through the NRF funded by the Ministry of Science and ICT (Grant No. 2017H1D3A1A02013844). There are no competing interests.

Transgenerational Effects of Di(2-Ethylhexyl) Phthalate on Anogenital Distance, Sperm Functions and DNA Methylation in Rat Offspring

Di(2-ethylhexyl) phthalate (DEHP) is widely used as a plasticizer in the manufacture of polyvinylchloride plastics and has been associated with concerns regarding male reproductive toxicity. In this study, we hypothesized that maternal exposure to DEHP induces transgenerational inheritance of adult-onset adverse reproductive outcomes through the male germline in the F1, F2, and F3 generations of male offspring. Pregnant rats were treated with 5 or 500 mg of DEHP/kg/day through gavage from gestation day 0 to birth. The offspring body weight, anogenital distance (AGD), anogenital index (AGI), sperm count, motility, and DNA fragmentation index (DFI) were measured for all generations. Methyl-CpG binding domain sequencing was performed to analyze sperm DNA methylation status in the F3. DEHP exposure at 500 mg/kg affected AGD, AGI, sperm count, mean DFI, and %DFI in the F1; AGD, sperm count, and mean DFI in the F2; and AGD, AGI, mean DFI, and %DFI in the F3. DEHP exposure at 5 mg/kg affected AGD, AGI, sperm count, and %DFI in the F1; sperm count in the F2; and AGD and AGI in F3. Compared with the control group, 15 and 45 differentially hypermethylated genes were identified in the groups administered 5 mg/kg and 500 mg/kg DEHP, respectively. Moreover, 130 and 6 differentially hypomethylated genes were observed in the groups administered 5 mg/kg and 500 mg/kg DEHP. Overall, these results demonstrated that prenatal exposure to DEHP caused transgenerational epigenetic effects, which may explain the observed phenotypic changes in the male reproductive system.

What is the Impact of Bisphenol A on Sperm Function and Related Signaling Pathways: A Mini-review?

Bisphenol A (BPA) is an organic synthetic compound that is ubiquitously present in daily life. It is a typical environmental endocrine disruptor that affects the functions of endogenous hormones. There is a significant negative correlation between BPA and male reproduction. This mini-review describes current research data on the negative effects of BPA on sperm functions in humans and animal models, as well as on its supposed mechanisms of action, such as CATSPER-Ca2+ signaling, cAMP-protein kinase A signaling, and epigenetic changes. The published evidence showed an adverse impact of BPA on sperm tail morphology, counts, motility, and acrosome reaction action. Sperm function related signaling pathways, such as CATSPER-Ca2+ signaling, cAMP-protein kinase A signaling, and phosphorylation signaling, as well as epigenetic changes and sperm aging, are associated with BPA exposure in human and animal models. The clear risks of BPA exposure can provide greater awareness of the potential threat of environmental contaminants on male fertility.

The functions of CAP superfamily proteins in mammalian fertility and disease

BACKGROUND

Members of the cysteine-rich secretory proteins (CRISPS), antigen 5 (Ag5) and pathogenesis-related 1 (Pr-1) (CAP) superfamily of proteins are found across the bacterial, fungal, plant and animal kingdoms. Although many CAP superfamily proteins remain poorly characterized, over the past decade evidence has accumulated, which provides insights into the functional roles of these proteins in various processes, including fertilization, immune defence and subversion, pathogen virulence, venom toxicology and cancer biology.

OBJECTIVE AND RATIONALE

The aim of this article is to summarize the current state of knowledge on CAP superfamily proteins in mammalian fertility, organismal homeostasis and disease pathogenesis.

SEARCH METHODS

The scientific literature search was undertaken via PubMed database on all articles published prior to November 2019. Search terms were based on following keywords: 'CAP superfamily', 'CRISP', 'Cysteine-rich secretory proteins', 'Antigen 5', 'Pathogenesis-related 1', 'male fertility', 'CAP and CTL domain containing', 'CRISPLD1', 'CRISPLD2', 'bacterial SCP', 'ion channel regulator', 'CatSper', 'PI15', 'PI16', 'CLEC', 'PRY proteins', 'ASP proteins', 'spermatogenesis', 'epididymal maturation', 'capacitation' and 'snake CRISP'. In addition to that, reference lists of primary and review article were reviewed for additional relevant publications.

OUTCOMES

In this review, we discuss the breadth of knowledge on CAP superfamily proteins with regards to their protein structure, biological functions and emerging significance in reproduction, health and disease. We discuss the evolution of CAP superfamily proteins from their otherwise unembellished prokaryotic predecessors into the multi-domain and neofunctionalized members found in eukaryotic organisms today. At least in part because of the rapid evolution of these proteins, many inconsistencies in nomenclature exist within the literature. As such, and in part through the use of a maximum likelihood phylogenetic analysis of the vertebrate CRISP subfamily, we have attempted to clarify this confusion, thus allowing for a comparison of orthologous protein function between species. This framework also allows the prediction of functional relevance between species based on sequence and structural conservation.

WIDER IMPLICATIONS

This review generates a picture of critical roles for CAP proteins in ion channel regulation, sterol and lipid binding and protease inhibition, and as ligands involved in the induction of multiple cellular processes.

Sperm viability varies with buffer and genotype in Drosophila melanogaster

Sperm quality, an important male fitness trait, is commonly compared between studies. However, few studies consider how genetic and environmental variation affect sperm quality, even in the genetic model Drosophila melanogaster. Here we show that sperm viability, the proportion of live sperm, differed across the genotypes Oregon-R, Dahomey, and Canton-S by more than 15%, and across buffers (phosphate-buffered saline (PBS), Grace's Medium and Drosophila Ringer solution) by more than 20%. In terms of genotype-buffer pair comparisons, nearly half of the comparisons would produce significant differences in sperm viability (15 in 36), or its temporal decrease in a stress medium (19 in 36). Grace's medium produced the longest-lived sperm in vitro and the smallest differences between genotypes, Drosophila Ringer Solution produced the shortest lifespan and the largest differences. Our results suggest that fly and other sperm researchers would benefit from a standardized protocol of measuring sperm viability.

Programmed Cell Death 2-Like (Pdcd2l) Is Required for Mouse Embryonic Development

Globozoospermia is a rare form of male infertility where men produce round-headed sperm that are incapable of fertilizing an oocyte naturally. In a previous study where we undertook a whole exome screen to define novel genetic causes of globozoospermia, we identified homozygous mutations in the gene PDCD2L. Two brothers carried a p.(Leu225Val) variant predicted to introduce a novel splice donor site, thus presenting PDCD2L as a potential regulator of male fertility. In this study, we generated a Pdcd2l knockout mouse to test its role in male fertility. Contrary to the phenotype predicted from its testis-enriched expression pattern, Pdcd2l null mice died during embryogenesis. Specifically, we identified that Pdcd2l is essential for post-implantation embryonic development. Pdcd2l^−/− embryos were resorbed at embryonic days 12.5-17.5 and no knockout pups were born, while adult heterozygous Pdcd2l males had comparable fertility to wildtype males. To specifically investigate the role of PDCD2L in germ cells, we employed Drosophila melanogaster as a model system. Consistent with the mouse data, global knockdown of trus, the fly ortholog of PDCD2L, resulted in lethality in flies at the third instar larval stage. However, germ cell-specific knockdown with two germ cell drivers did not affect male fertility. Collectively, these data suggest that PDCD2L is not essential for male fertility. By contrast, our results demonstrate an evolutionarily conserved role of PDCD2L in development.

IP3R Channels in Male Reproduction

As a second messenger in cellular signal transduction, calcium signaling extensively participates in various physiological activities, including spermatogenesis and the regulation of sperm function. Abnormal calcium signaling is highly correlated with male infertility. Calcium signaling is mainly regulated by both extracellular calcium influx and the release of calcium stores. Inositol 1,4,5-trisphosphate receptor (IP3R) is a widely expressed channel for calcium stores. After being activated by inositol 1,4,5-trisphosphate (IP3) and calcium signaling at a lower concentration, IP3R can regulate the release of Ca²⁺ from stores into cytoplasm, and eventually trigger downstream events. The closure of the IP3R channel caused by a rise in intracellular calcium signals and the activation of the calcium pump jointly restores the calcium store to a normal level. In this review, we aim to discuss structural features of IP3R channels and the underlying mechanism of IP3R channel-mediated calcium signaling and further focus on the research progress of IP3R expression and function in the male reproductive system. Finally, we propose key directions and strategies for research of IP3R in spermatogenesis and the regulation of sperm function to provide more understanding of the function and mechanism of IP3R channel actions in male reproduction.

Expanding the Limits of Computer-Assisted Sperm Analysis through the Development of Open Software

Computer assisted sperm analysis (CASA) systems can reduce errors occurring in manual analysis. However, commercial CASA systems are frequently not applicable at the forefront of challenging research endeavors. The development of open source software may offer important solutions for researchers working in related areas. Here, we present an example of this, with the development of three new modules for the OpenCASA software (hosted at Github). The first is the Chemotactic Sperm Accumulation Module, a powerful tool for studying sperm chemotactic behavior, analyzing the sperm accumulation in the direct vicinity of the stimuli. This module was validated by comparing fish sperm accumulation, with or without the influence of an attractant. The analysis clearly indicated cell accumulation in the treatment group, while the distribution of sperm was random in the control group. The second is the Sperm Functionality Module, based on the ability to recognize five sperm subpopulations according to their fluorescence patterns associated with the plasma membrane and acrosomal status. The last module is the Sperm Concentration Module, which expands the utilities of OpenCASA. These last two modules were validated, using bull sperm, by comparing them with visual counting by an observer. A high level of correlation was achieved in almost all the data, and a good agreement between both methods was obtained. With these newly developed modules, OpenCASA is consolidated as a powerful free and open-source tool that allows different aspects of sperm quality to be evaluated, with many potential applications for researchers.

Immuno-histological mapping and functional association of seminal proteins in testis and excurrent ducts with sperm function in buffalo

The region-specific expression of seminal proteins in testis and excurrent duct system determines the quality and function of the spermatozoa. In the present study, localization and expression of some of the seminal proteins such as insulin-like growth factor receptor 1β (IGF-1Rβ), phosphatidylethanolamine-binding protein 4 (PEBP4), α-tubulin and tissue factor pathway inhibitor 2 (TFPI2) were carried out in testis, excurrent duct system and spermatozoa of buffalo. IGF-1Rβ was localized in the cells of the seminiferous tubules of the testis, except in primary spermatocytes. The PEBP4 was localized only in the elongated spermatid, whereas α-tubulin and TFPI2 proteins were localized in all cells of the seminiferous tubule including spermatocyte. In the buffalo spermatozoa, IGF-1Rβ, PEBP4, α-tubulin and TFPI2 were localized in the acrosome region, the post-acrosomal region till the tail end, post-acrosome to the entire tail region and the equatorial region, respectively. The study indicates that IGF-1R, α-tubulin and PEBP4 proteins regulate spermatogenesis, whereas TFPI2 may be involved during the zona binding process of the buffalo spermatozoa.

Different approaches for assessing sperm function

Different approaches can be used to assess sperm function in different conditions, i.e. sperm storage, freezing-thawing or activation by induction of capacitation and acrosome reaction. In this review we will focus on the assays routinely performed in our laboratories, giving a literature support to critically analyse different approaches. In fact, researchers usually tend to look for the "one shot" parameter that could explain itself a specific process; it is our conviction that a multiparametric approach is still more valid, as some changes in sperm function are very complex and could be explained only by operating in different ways. Sperm motility, the most evident sperm characteristic, should be assessed by computer-aided sperm analysers that permit an objective evaluation of the motility and its kinematic parameters. Commercial and open source instruments are available and could be profitably used together with specific statistical approaches. The use of microscopy, and particularly fluorescent microscopy, could be a very useful tool to assess different parameters in sperm cells both by fluorophores that give indication of a determined function, and by immunolocalization of proteins, that permits the discover of new features or to explain particular sperm functions. The same substrates could be used also in flow cytometry: the difference is that it permits to study wider sperm populations (and their sub-population distribution). Flow cytometry is undergoing a very wide use in spermatology and technical and experimental rigor is needed to obtain reliable results. Metabolic assessment of sperm features, particularly energetic supply, ATP formation and other enzyme activities, could represent a very important challenge to acquire new information and complete/integrate those derived from other techniques. Finally, functional assays such as oocyte binding and in vitro fertilization, represent a very strong tool to assess sperm function in vitro, as they could evidence the functional intactness of some pathways.

High Salt Diet Affects the Reproductive Health in Animals: An Overview

Simple summary

Halophytic plants are a promising animal feed source. However, the extreme NaCl₂ salt content constraints their use. Excess diet salt adversely affects growth performance and animal’s reproduction worldwide. This review focuses on the impact of high salt intake on growth performance and reproduction ability in animals.

Abstract

Salinity is a reliable issue of crop productivity loss in the world and in certain tropical and subtropical zones. However, tremendous progress in the genetic improvement of plants for salinity tolerance has been made over several decades. In light of this, halophytic plants can be used as animal feeds and have promising features because they are a good feed resource. However, the main constraint of saline pasture systems is the extreme concentration of NaCl salt in drinking water and forage plants for grazing animals. Ecological reports revealed that excess diet salt causes mortality and morbidity worldwide. Animal fed halophytic forages may have adverse effects on growth performance and reproductive function in males and females due to inducing reductions in hormone regulation, such as testosterone, FSH, LH, and leptin. It was indicated that high salt intake promotes circulating inflammatory factors in the placenta and is associated with adversative effects on pregnancy. This review focuses on the scientific evidence related to the effect of high salt intake on growth performance, spermatogenesis, sperm function, and testicular morphology changes in male animals. In addition, the review will also focus on its effect on some female reproductive features (e.g., ovarian follicle developments, placental indices, and granulosa cell function).

Pharmacological Activity of Honeybush (Cyclopia intermedia) in Boar Spermatozoa during Semen Storage and under Oxidative Stress

Simple Summary

Nowadays, pig breeding is mostly conducted by artificial insemination using diluted semen stored for 1 to 5 days. During semen handling and storage, sperm quality usually declines, mainly because of oxidative stress and bacterial contamination. As cheap and natural sources of antioxidants, medicinal plants have become an alternative to the most common additives used in semen extenders. In this regard, several indigenous plants from Southern Africa have shown pharmacological activity in different animal cell types, although their effects on sperm cells have not been explored extensively. In the present study, we tested the effects of honeybush (Cyclopia intermedia) aqueous extract as a preservative of boar semen during 5 days of storage and under induced oxidative stress. Overall, this plant extract enhanced several sperm quality parameters and did not show any toxic effects. Supplementation with honeybush extract was able to improve the preservative properties of a long-term semen extender, thus confirming the beneficial use of plant extracts as natural additives for boar sperm.

Abstract

In recent decades, an increasing number of ethnopharmacological studies have been dedicated to medicinal plants from South African fynbos. Among these plants, honeybush (Cyclopia spp.) has become a popular tea, mainly due to its healthy properties and caffeine-free status. The antioxidant, antimutagenic, and antimicrobial properties of this plant have been reported in several cell types, but its effects on reproductive function are still unknown. Here, we assessed the effects of honeybush (Cyclopia intermedia) on boar sperm parameters under induced oxidative stress (Fe²⁺/ascorbate) and during five days of semen storage at 17 °C without oxidative stress. In both experiments, four concentrations (200, 50, 12.5, and 3.125 µg/mL) of fermented honeybush were tested. Our results show that honeybush enhances sperm parameters, and no toxic effects were observed at any of the tested extract concentrations. Interestingly, honeybush (12.5 µg/mL) improved the sperm motility and kinetic parameters, preserved the plasma membrane integrity, and reduced the lipid peroxidation in the samples exposed to Fe²⁺/ascorbate (p < 0.05). In the stored samples, positive effects of honeybush on sperm parameters (motility, kinetics, acrosome, and mitochondria) were observed from 48 h until 120 h of semen storage (p < 0.05). Our results clearly show the protective effects of honeybush on sperm samples, thus promoting its use as a natural source of antioxidants for boar semen.

New Biological Insights on X and Y Chromosome-Bearing Spermatozoa

A spermatozoon is a male germ cell capable of fertilizing an oocyte and carries genetic information for determining the sex of the offspring. It comprises autosomes and an X (X spermatozoa) or a Y chromosome (Y spermatozoa). The origin and maturation of both X and Y spermatozoa are the same, however, certain differences may exist. Previous studies proposed a substantial difference between X and Y spermatozoa, however, recent studies suggest negligible or no differences between these spermatozoa with respect to ratio, shape and size, motility and swimming pattern, strength, electric charge, pH, stress response, and aneuploidy. The only difference between X and Y spermatozoa lies in their DNA content. Moreover, recent proteomic and genomic studies have identified a set of proteins and genes that are differentially expressed between X and Y spermatozoa. Therefore, the difference in DNA content might be responsible for the differential expression of certain genes and proteins between these cells. In this review, we have compiled our present knowledge to compare X and Y spermatozoa with respect to their structural, functional, and molecular features. In addition, we have highlighted several areas that could be explored in future studies in this field.

The Beneficial Role of Anchomanes difformis in STZ-Induced Reproductive Dysfunction in Male Wistar Rats

BACKGROUND

Progression of diabetes mellitus has increasingly led to several diabetic complications. Diabetes is one of the major factors implicated in male reproductive system damage. Recent approaches such as the use of medicinal plants have been explored in the management of diabetes and associated complications. Anchomanes difformis (common name: children's umbrella) has been shown to possess anti-diabetic ability in animal model. Therefore, this study seeks to investigate the potency of Achomanes difformis in ameliorating diabetes-induced reproductive dysfunction.

METHODS

Type 2 diabetes was induced in male Wistar rats with 10% fructose administration for 2 weeks and an intraperitoneal injection of 40mg/kgBW of streptozotocin. Aqueous extract (200mg and 400mg/kgBW) of Anchomanes difformis leaves was administered daily for 6 weeks. The rats were randomly divided into 7 groups with a minimum of eight rats in each (8 rats in normal groups and 10 in diabetic groups). The impact of diabetes and treatment was investigated by estimating sperm concentration, motility indices, viability and morphological parameters in the normal, treatment controls and diabetic rats using CASA-SCA system. Histological examination of the testes and epididymis was performed.

RESULTS

Diabetes induction resulted in significant decrease in sperm concentration, viability and some motility parameters with 40% abnormalities in sperm morphology. The administration of Anchomanes difformis significantly increased sperm concentration and sperm viability, while it significantly improved the percentage of morphologically normal sperm in diabetic rats. Anchomanes difformis ameliorated testicular damage such as vacuolization and loss of germinal epithelium in the diabetic-treated rats when compared to the diabetic controls.

CONCLUSION

The potency Anchomanes difformis displayed against diabetic-induced damage in the reproductive system might be a new and promising tool in the management of male reproductive dysfunctions and associated complications in diabetes mellitus.

Dietary Micronutrient Supplementation for 12 Days in Obese Male Mice Restores Sperm Oxidative Stress

Male obesity, which often co-presents with micronutrient deficiencies, is associated with sub-fertility. Here we investigate whether short-term dietary supplementation of micronutrients (zinc, selenium, lycopene, vitamins E and C, folic acid, and green tea extract) to obese mice for 12 days (designed to span the epididymal transit) could improve sperm quality and fetal outcomes. Five-week-old C57BL6 males were fed a control diet (CD, n = 24) or high fat diet (HFD, n = 24) for 10 weeks before allocation to the 12-day intervention of maintaining their original diets (CD, n = 12, HFD n = 12) or with micronutrient supplementation (CD + S, n = 12, HFD + S, n = 12). Measures of sperm quality (motility, morphology, capacitation, binding), sperm oxidative stress (DCFDA, MSR, and 8OHdG), early embryo development (2-cell cleavage, 8OHdG), and fetal outcomes were assessed. HFD + S males had reduced sperm intracellular reactive oxygen species (ROS) concentrations and 8OHdG lesions, which resulted in reduced 8OHdG lesions in the male pronucleus, increased 2-cell cleavage rates, and partial restoration of fetal weight similar to controls. Sub-fertility associated with male obesity may be restored with very short-term micronutrient supplementation that targets the timing of the transit of sperm through the epididymis, which is the developmental window where sperm are the most susceptible to oxidative damage.

In vitro antioxidation effect of Quercetin on sperm function from the infertile patients with leukocytospermia

PROBLEM

Quercetin has been shown to display intensive antioxidant activity against ROS-mediated damage in chilled semen, and the effects and molecular mechanisms of Quercetin on sperm function in the infertile patients with leukocytospermia remain largely unknown.

METHODS

Semen samples were collected from the infertile men with leukocytospermia (n = 56) and fertile men (n = 44). Computer-assisted semen analysis (CASA) was used to determine sperm motility before and after Quercetin incubation (10 μmol/L). Changes in H₂ O₂ , sperm mitochondrial DNA (mtDNA), cytochrome B (Cty B), and NADH dehydrogenase 5 (NADH5) contents were measured. Furthermore, hyperactivated motility (HA) and acrosome reaction rates were detected after the stimulation by progesterone with or without Quercetin, respectively.

RESULTS

Quercetin could significantly improve sperm motility from the leukocytospermic patients. The level of H₂ O₂ was significantly decreased in the supernatant of leukocytospermic patients after Quercetin treatment. The content of mtDNA in sperm was significantly decreased, whereas the contents of Cyt B and NADH 5 in sperm were significantly increased. Sperm hyperactivated motility and acrosome reaction induced by progesterone were enhanced by Quercetin in sperm from the infertile men with leukocytospermia.

CONCLUSION

These data indicate Quercetin could display protective effects against oxidative damage on sperm from the infertile men with leukocytospermia.

Oxidative stress and sperm function: A systematic review on evaluation and management

Objective: To review and present the most distinct concepts on the association of reactive oxygen species (ROS) with male reproduction.

Methods: The Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines were used to search PubMed, Medline, EMBASE, and the Cochrane electronic databases for studies investigating the role of oxidative stress (OS) on sperm function.

Results: The literature search yielded 1857 studies, of which 1791 articles were excluded because of irrelevance of data, non-English language, non-human nature or because they were case reports or commentaries. All included studies were reviews (46), meta-analyses (one), original research studies (18) and guideline articles (one). The studies were published between 1984 and 2018. Under normal physiological conditions, ROS are vital for sperm maturation, hyperactivation, capacitation, acrosome reaction, as well as fertilisation. However, a number of endogenous and exogenous causes may induce supra-physiological levels of ROS resulting in lipid peroxidation, sperm DNA fragmentation and apoptosis, and consequently infertility. Several laboratory testing methods can be used in infertile men to diagnose OS. Treatment usually involves antioxidant supplementation and, when possible, elimination of the causative factor.

Conclusion: OS is an important cause of male factor infertility. Its assessment provides essential information that can guide treatment strategies aimed at improving the male’s reproductive potential.

Abbreviations: bp: base-pair; CAT: catalase; LPO: lipid peroxidation; MDA: malondialdehyde; MiOXSYS: Male Infertility Oxidative System; mtDNA: mitochondrial DNA; NAD(PH): nicotinamide adenine dinucleotide (phosphate); NO: nitric oxide; 8-OHdG: 8-hydroxy-2’-deoxyguanosine; ORP: oxidation–reduction potential; OS: oxidative stress; PKA: protein kinase A; PLA2: phospholipase A2; PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses; PUFA: poly-unsaturated fatty acid; ROS: reactive oxygen species; SOD: superoxide dismutase; TAC: total antioxidant capacity; TBA: thiobarbituric acid

Maternal bisphenol A exposure disrupts spermatogenesis in adult rat offspring

Bisphenol A (BPA) is an endocrine-disrupting chemical (EDC) that is widely used in the manufacturing of plastics and inner linings of food cans. Previously, it was reported that BPA disturbed the sexual dimorphic nucleus of the hypothalamus and delaying the onset of puberty attributed to an estrogenic action. In addition, BPA during the perinatal period increased LH serum concentrations in male offspring of dams at doses below the reproductive NOAEL (No Observable Adverse Effect Level) based upon World Health Organization guidelines. Based upon these findings, the objective of this study was to (1) determine the effects of perinatal treatment with low doses of BPA on regulation of spermatogenesis in adult offspring and (2) elucidate molecular mechanisms involved in the pathogenesis of gonadal dysfunction. The expression of genes related to spermatogenesis was disrupted with adverse consequences on sperm production, reserves, and function. Both BPA treated groups exhibited reduction in sperm production and epithelial height of seminiferous tubules, accompanied by diminished integrity of the acrosome and plasma membrane, decreased mitochondrial activity and increased incidence of morphological abnormalities. The sperm transit time was also slower. However, only in the group receiving the higher BPA dose was transcript expression of genes affected (reduced Ar and increased Esr1). It is of interest that serum testosterone levels were elevated in the same group where Ar was decreased. Data suggest that exposure to low BPA doses during hypothalamic sexual differentiation period produces permanent deleterious effects on spermatogenesis in adulthood.

ENU-induced mutant allele of Dnah1, ferf1, causes abnormal sperm behavior and fertilization failure in mice

Given attention to both contraception and treatment of infertility, there is a need to identify genes and sequence variants required for mammalian fertility. Recent unbiased mutagenesis strategies have expanded horizons of genetic control of reproduction. Here we show that male mice homozygous for the ethyl-nitroso-urea-induced ferf1 (fertilization failure 1) mutation are infertile, producing apparently normal sperm that does not fertilize oocytes in standard fertilization in vitro fertilization assays. The ferf1 mutation is a single-base change in the Dnah1 gene, encoding an axoneme-associated dynein heavy chain, and previously associated with male infertility in both mice and humans. This missense mutation causes a single-amino-acid change in the DNAH1 protein in ferf1 mutant mice that leads to abnormal sperm clumping, aberrant sperm motility, and the inability of sperm to penetrate the oocyte's zona pellucida; however, the ferf1 mutant sperm is competent to fertilize zona-free oocytes. Taken together, the various mutations affecting the DNAH1 protein in both mouse and human produce a diversity of phenotypes with both subtle and considerable differences. Thus, future identification of the interacting partners of DNAH1 might lead to understanding its unique function among the sperm dyneins.