Nitric oxide and cyclic nucleotides: their roles in junction dynamics and spermatogenesis

Comprehensive analysis of the differential expression of mRNAs, lncRNAs, and miRNAs in Zi goose testis with high and low sperm mobility

Sperm mobility (SM) is an objective index for measuring sperm motility; however, the mechanisms underlying its regulation in geese remain unclear. The present study sought to elucidate the genetic mechanism underlying SM traits in Zi geese (Anser cygnoides L.). To this end, three successive experiments were performed. In Experiment I, SM was determined in 40 ganders; the 3 ganders with the highest mobility and three with the lowest mobility were assigned to the high and low sperm mobility rank (SMR) groups, respectively. In Experiment II, the differences in fertility between the two SMR groups were assessed within two breeding flocks comprising the selected six ganders from Experiment I and 30 females (each flock had 3 ganders and 15 females). In Experiment III, the testes of the 6 ganders were harvested for histological observation and whole-transcriptome sequencing. Results revealed better fertility, well-developed seminiferous tubules, and abundant mature sperm in the high-SMR-flock compared to those of the low-SMR-flock (89 vs. 81%) (P < 0.05). Differential expression (DE) analysis identified 76 mRNAs, 344 lncRNAs, and 17 miRNAs between the SMR groups, with LOC106049708, XPNPEP3, GNB3, ADCY8, PRKAG3, oha-miR-182-5p, and ocu-miR-10b-5p identified as key mRNAs and miRNAs contributing to SM. Enrichment analysis implicated these DE RNAs in pathways related to ATP binding, cell metabolism, apelin signaling, Wnt signaling, and Adherens junctions. Additionally, competing endogenous RNA (ceRNA) networks comprising 9 DE mRNAs, 17 DE miRNAs, and 169 DE lncRNAs were constructed. Two ceRNA network pathways (LOC106049708-oha-miR-182-5p-MSTRG.2479.6 and PRKAG3-ocu-miR-10b-5p-MSTRG.9047.14) were identified as key regulators of SM in geese. These findings offer crucial insights into the identification of key genes and ceRNA pathways influencing sperm mobility in geese.

Gut microbiota is involved in male reproductive function: a review

Globally, ~8%-12% of couples confront infertility issues, male-related issues being accountable for 50%. This review focuses on the influence of gut microbiota and their metabolites on the male reproductive system from five perspectives: sperm quality, testicular structure, sex hormones, sexual behavior, and probiotic supplementation. To improve sperm quality, gut microbiota can secrete metabolites by themselves or regulate host metabolites. Endotoxemia is a key factor in testicular structure damage that causes orchitis and disrupts the blood-testis barrier (BTB). In addition, the gut microbiota can regulate sex hormone levels by participating in the synthesis of sex hormone-related enzymes directly and participating in the enterohepatic circulation of sex hormones, and affect the hypothalamic-pituitary-testis (HPT) axis. They can also activate areas of the brain that control sexual arousal and behavior through metabolites. Probiotic supplementation can improve male reproductive function. Therefore, the gut microbiota may affect male reproductive function and behavior; however, further research is needed to better understand the mechanisms underlying microbiota-mediated male infertility.

Oxidative Stress Biomarkers in Male Infertility: Established Methodologies and Future Perspectives

Male fertility can be affected by oxidative stress (OS), which occurs when an imbalance between the production of reactive oxygen species (ROS) and the body's ability to neutralize them arises. OS can damage cells and influence sperm production. High levels of lipid peroxidation have been linked to reduced sperm motility and decreased fertilization ability. This literature review discusses the most commonly used biomarkers to measure sperm damage caused by ROS, such as the high level of OS in seminal plasma as an indicator of imbalance in antioxidant activity. The investigated biomarkers include 8-hydroxy-2-deoxyguanosine acid (8-OHdG), a marker of DNA damage caused by ROS, and F2 isoprostanoids (8-isoprostanes) produced by lipid peroxidation. Furthermore, this review focuses on recent methodologies including the NGS polymorphisms and differentially expressed gene (DEG) analysis, as well as the epigenetic mechanisms linked to ROS during spermatogenesis along with new methodologies developed to evaluate OS biomarkers. Finally, this review addresses a valuable insight into the mechanisms of male infertility provided by these advances and how they have led to new treatment possibilities. Overall, the use of biomarkers to evaluate OS in male infertility has supplied innovative diagnostic and therapeutic approaches, enhancing our understanding of male infertility mechanisms.

Nitric oxide-induced lipophagic defects contribute to testosterone deficiency in rats with spinal cord injury

Introduction

Males with acute spinal cord injury (SCI) frequently exhibit testosterone deficiency and reproductive dysfunction. While such incidence rates are high in chronic patients, the underlying mechanisms remain elusive.

Methods and results

Herein, we generated a rat SCI model, which recapitulated complications in human males, including low testosterone levels and spermatogenic disorders. Proteomics analyses showed that the differentially expressed proteins were mostly enriched in lipid metabolism and steroid metabolism and biosynthesis. In SCI rats, we observed that testicular nitric oxide (NO) levels were elevated and lipid droplet-autophagosome co-localization in testicular interstitial cells was decreased. We hypothesized that NO impaired lipophagy in Leydig cells (LCs) to disrupt testosterone biosynthesis and spermatogenesis. As postulated, exogenous NO donor (S-nitroso-N-acetylpenicillamine (SNAP)) treatment markedly raised NO levels and disturbed lipophagy via the AMPK/mTOR/ULK1 pathway, and ultimately impaired testosterone production in mouse LCs. However, such alterations were not fully observed when cells were treated with an endogenous NO donor (L-arginine), suggesting that mouse LCs were devoid of an endogenous NO-production system. Alternatively, activated (M1) macrophages were predominant NO sources, as inducible NO synthase inhibition attenuated lipophagic defects and testosterone insufficiency in LCs in a macrophage-LC co-culture system. In scavenging NO (2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (CPTIO)) we effectively restored lipophagy and testosterone levels both in vitro and in vivo, and importantly, spermatogenesis in vivo. Autophagy activation by LYN-1604 also promoted lipid degradation and testosterone synthesis.

Discussion

In summary, we showed that NO-disrupted-lipophagy caused testosterone deficiency following SCI, and NO clearance or autophagy activation could be effective in preventing reproductive dysfunction in males with SCI.

Effect of prenatal perfluoroheptanoic acid exposure on spermatogenesis in offspring mice

BACKGROUND

Perfluoroheptanoic acid (PFHpA), a persistent organic pollutant widespread in the environment, is suspected as an environmental endocrine disruptor for its disturbance effect on hormone homeostasis and reproductive development. Whereas the effect of intrauterine PFHpA exposure during gestation on spermatogenesis of male offspring mice is still unknown.

OBJECTIVE

This study aimed to explore the effect of prenatal PFHpA exposure on the reproductive development of male offspring mice and the role of N⁶-methyladenosine (m⁶A) during the process.

METHODS

Fifty-six C57BL/6 pregnant mice were randomly divided into 4 groups. During the gestation period, the pregnant mice were exposed to 0, 0.0015, 0.015, and 0.15 mg/kg bw/d PFHpA from gestational day 1 (GD1) to GD16 by oral gavage. The male offspring mice were sacrificed by spinal dislocation at 7 weeks old. The body weight, testicular weight, and brain weight were weighed, and the intra-testicular testosterone was detected. The sperm qualities were analyzed with computer-aided sperm analysis (CASA). The testicular tissues were taken to analyze the pathological changes and examine the global m⁶A RNA methylation levels. Quantitative real-time PCR (qRT-PCR) was adopted to figure out the mRNA expression levels of m⁶A-related enzymes in testicular tissues of different PFHpA treated groups. Methylated RNA immunoprecipitation sequencing (MeRIP-seq) was applied to further explore the m⁶A RNA methylation at a whole-genome scale.

RESULTS

Compared with the control group, no significant differences were observed in body weight, testicular weight, testicular coefficient, and the visceral-brain ratio of testicular tissue in the PFHpA treated groups. And no significant change was observed in intra-testicular testosterone among the four groups. CASA results showed a decrease of sperm count, sperm concentration, and total cell count, as well as an increase of sperm progressive cells' head area after prenatal PFHpA exposure (P < 0.05). Hematoxylin and eosin staining of pathological sections showed seminiferous tubules morphological change, disorder arrangement of seminiferous epithelium, and reduction of spermatogenic cells in the PFHpA treated groups. PFHpA significantly decreased global levels of m⁶A RNA methylation in testicular tissue (P < 0.05). Besides, qRT-PCR results showed significant alteration of the mRNA expression levels of seven m⁶A-related enzymes (Mettl3, Mettl5, Mettl14, Pcif1, Wtap, Hnrnpa2b1, and Hnrnpc) in the PFHpA treated groups (P < 0.05). MeRIP-seq results showed a correlation between prenatal PFHpA exposure and activation and binding of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Cnga3 and Mpzl3 showed differential expression in the enrichment subcategories or pathways.

CONCLUSIONS

Exposure to PFHpA during the gestation period would adversely affect the development of seminiferous tubules and testicular m⁶A RNA methylation in offspring mice, which subsequently interferes with spermatogenesis and leads to reproductive toxicity.

Yangjing capsule improves oligoasthenozoospermia by promoting nitric oxide production through PLCγ1/AKT/eNOS pathway

Background: Oligoasthenozoospermia is an important factor leading to male infertility. Yangjing capsule (YC), a traditional Chinese preparation, displays beneficial effects on male infertility. However, whether YC could improve oligoasthenozoospermia remains unclear. Methods: In this study, we aimed to explore the effect of YC in the treatment of oligoasthenozoospermia. Male Sprague-Dawley (SD) rats were treated with 800 mg/kg ornidazole once daily for 30 days to induce in vivo oligoasthenozoospermia; primary Sertoli cells were treated with 400 μg/mL ornidazole for 24 h to induce in vitro oligoasthenozoospermia. Results: We found that YC improved the testicle and epididymis weight, sperm concentration, sperm progressive motility, serum testosterone, fertility rate and testis morphology in ornidazole-exposed rats and enhanced cell survival in ornidazole-stimulated primary Sertoli cells. YC also inhibited the ornidazole-caused decrease in nitric oxide (NO) generation and the phosphorylation of phospholipase C γ1 (PLCγ1), AKT, and eNOS in vivo and in vitro in oligoasthenozoospermia. Furthermore, the knockdown of PLCγ1 blunted the beneficial effects of YC in vitro. Conclusion: Collectively, our data suggested that YC protected against oligoasthenozoospermia by promoting NO levels through the PLCγ1/AKT/eNOS pathway.

The effects and molecular mechanism of heat stress on spermatogenesis and the mitigation measures

Under normal conditions, to achieve optimal spermatogenesis, the temperature of the testes should be 2-6 °C lower than body temperature. Cryptorchidism is one of the common pathogenic factors of male infertility. The increase of testicular temperature in male cryptorchidism patients leads to the disorder of body regulation and balance, induces the oxidative stress response of germ cells, destroys the integrity of sperm DNA, yields morphologically abnormal sperm, and leads to excessive apoptosis of germ cells. These physiological changes in the body can reduce sperm fertility and lead to male infertility. This paper describes the factors causing testicular heat stress, including lifestyle and behavioral factors, occupational and environmental factors (external factors), and clinical factors caused by pathological conditions (internal factors). Studies have shown that wearing tight pants or an inappropriate posture when sitting for a long time in daily life, and an increase in ambient temperature caused by different seasons or in different areas, can cause an increase in testicular temperature, induces testicular oxidative stress response, and reduce male fertility. The occurrence of cryptorchidism causes pathological changes within the testis and sperm, such as increased germ cell apoptosis, DNA damage in sperm cells, changes in gene expression, increase in chromosome aneuploidy, and changes in Na⁺/K⁺-ATPase activity, etc. At the end of the article, we list some substances that can relieve oxidative stress in tissues, such as trigonelline, melatonin, R. apetalus, and angelica powder. These substances can protect testicular tissue and relieve the damage caused by excessive oxidative stress.

Long-term effects of orchiopexy and orchiectomy on the testes of rats with testicular torsion

INTRODUCTION

Ischemia/reperfusion injury occurs after testicular torsion, levels of free oxygen radicals and inflammatory cytokines are increased in both the torsional and contralateral testis, leading to testicular injury.

OBJECTIVE

The present study investigated whether orchiopexy or orchiectomy after testicular torsion was superior in terms of fertility potential in the long term.

STUDY DESIGN

Following 720°, 4 h left testicular torsion, orchiectomy or orchiopexy was performed on 84 rats, which were then sacrificed and evaluated for testicular function at day 1, at 3 months and 6 months (n = 14 per group). An additional 14 rats were in the control group.

RESULTS

Follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels were significantly lower in the orchiopexy group than the orchiectomy and control groups after 3 months. However, there were no significant differences in hormone parameters among the three groups after 6 months. The hormone levels, Johnsen score, seminiferous tubule diameter, and inducible nitric oxide synthase (iNOS) expression at 3 and 6 months were not significantly different between the orchiectomy group and controls. Histopathological analyses at 3 and 6 months indicated significant decreases in Johnsen score and seminiferous tubule diameter in the ipsilateral testis in the orchiopexy group. At 3 months, the level of iNOS expression in the contralateral testis was significantly lower in the orchiopexy group than in other groups. At 6 months, however, it was not significantly different between the orchiopexy and control groups. There were no significant differences in iNOS expression at 3 or 6 months in the orchiectomy group compared to controls.

DISCUSSION

The ipsilateral testis in the orchiopexy group began to atrophy at 3 months, and the degree of atrophy became more evident at 6 months. The level of iNOS expression was low in the bilateral testis at 3 months in the orchiopexy group, and sperm in the contralateral testis were not yet functionally healthy. The level of iNOS expression in the ipsilateral testis decreased further at 6 months in the orchiopexy group, while that in the contralateral testis returned to the normal level.

CONCLUSION

Testicular functions were restored faster after orchiectomy compared to orchiopexy following testicular torsion. However, follow-up of the rats for 6 months demonstrated that orchiopexy or orchiectomy procedures conducted on the testicular torsion had no effect on future fertility potential after 4 h of torsion.

The Interaction of NO and H2S in Boar Spermatozoa under Oxidative Stress

Various recent studies dedicated to the role of nitric oxide (NO) and hydrogen sulfide (H2S) in somatic cells provide evidence for an interaction of the two gasotransmitters. In the case of male gametes, only the action of a single donor of each gasotransmitter has been investigated up until today. It has been demonstrated that, at low concentrations, both gasotransmitters alone exert a positive effect on sperm quality parameters. Moreover, the activity of gaseous cellular messengers may be affected by the presence of oxidative stress, an underlying condition of several male reproductive disorders. In this study, we explored the effect of the combination of two donors SNP and NaHS (NO and H2S donors, respectively) on boar spermatozoa under oxidative stress. We applied NaHS, SNP, and their combination (DD) at 100 nM concentration in boar spermatozoa samples treated with Fe2+/ascorbate system. After 90 min of incubation at 38 °C, we have observed that progressive motility (PMot) and plasma membrane integrity (PMI) were improved (p < 0.05) in DD treatment compared to the Ctr sample under oxidative stress (CtrOX). Moreover, the PMot of DD treatment was higher (p < 0.05) than that of NaHS. Similar to NaHS, SNP treatment did not overcome the PMot and PMI of CtrOX. In conclusion, for the first time, we provide evidence that the combination of SNP and NaHS surmounts the effect of single-donor application in terms of PMot and PMI in porcine spermatozoa under oxidative stress.

New Insight into Molecular and Hormonal Connection in Andrology

Hormones and cytokines are known to regulate cellular functions in the testes. These biomolecules induce a broad spectrum of effects on various level of spermatogenesis, and among them is the modulation of cell junction restructuring between Sertoli cells and germ cells in the seminiferous epithelium. Cytokines and androgens are closely related, and both correct testicular development and the maintenance of spermatogenesis depend on their function. Cytokines also play a crucial role in the immune testicular system, activating and directing leucocytes across the endothelial barrier to the inflammatory site, as well as in increasing their adhesion to the vascular wall. The purpose of this review is to revise the most recent findings on molecular mechanisms that play a key role in male sexual function, focusing on three specific molecular patterns, namely, cytokines, miRNAs, and endothelial progenitor cells. Numerous reports on the interactions between the immune and endocrine systems can be found in the literature. However, there is not yet a multi-approach review of the literature underlying the role between molecular patterns and testicular and sexual function.

PPP2R1B is modulated by ubiquitination and is essential for spermatogenesis

The serine-threonine protein phosphatase 2A (PP2A) is a heterotrimeric enzyme complex that regulates many fundamental cellular processes. PP2A is involved in tumorigenesis because mutations in the scaffold subunit, PPP2R1B, were found in several types of cancers. However, the biological function of PPP2R1B remains largely unknown. We report here that homozygous deletion of Ppp2r1b in Mus musculus impairs meiotic recombination and causes meiotic arrest in spermatocytes. Consistently, male mice lacking Ppp2r1b are characterized with infertility. Furthermore, heterozygous missense mutations in the Homo sapiens PPP2R1B gene, which encodes PPP2R1B, are identified in azoospermia patients with meiotic arrest. We found that PPP2R1B mutants are susceptible to degradation by an E3 ligase CRL4A^DCAF6 , and resistant to de-polyubiquitylation by ubiquitin-specific protease 5 (USP5). In addition, heterozygous mutations in PPP2R1B reduce stability of the wild-type PPP2R1B. Our results demonstrate an essential role of PPP2R1B in spermatogenesis and identify upstream regulators of PPP2R1B.

Protective effects of Astragalin on spermatogenesis in streptozotocin-induced diabetes in male mice by improving antioxidant activity and inhibiting inflammation

Spermatogenic dysfunction is a common complication in men with diabetes and is the most important manifestation of diabetes-related male reproduction damage. Astragalin (AG) is one of the main flavonoids from Cuscuta chinensis, which has rich pharmacological activities. This study aimed to establish whether AG may contribute to the recovery from spermatogenic dysfunction. AG (3.3, 10 and 30 mg/kg) and Clomiphene (5 mg/kg) were orally administered to streptozotocin-induced diabetic male mice for 8 weeks. After the experiments performed, reproductive organs, sperm parameters and histomorphological changes were analysed. Antioxidant and anti-inflammatory capacity were estimated in testicular tissues. The results revealed that AG significantly improved the reproductive organs, sperm parameters and testicular morphology to different degrees in diabetic mice. Nitric oxide (NO) and malondialdehyde (MDA) levels were significantly reduced, and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), markedly increased in the testicular tissue after AG was administered. Interestingly, AG also downregulated the protein expressions of tumour necrosis factor-α (TNF-α) and inducible nitric oxide synthase (iNOS) in testes. In conclusion, AG is a potential beneficial agent to protect diabetic-induced spermatogenic dysfunction in male mice by increasing antioxidant enzymes activities and inhibiting inflammation.

Effects of short- and long-term regular exercise on reproductive tissue in streptozotocin-induced diabetic male Wistar rats

OBJECTIVE

Reproductive disorders are one of the complications of diabetes mellitus. Since conflicting results have been obtained from different studies, which examined serum levels of cytokines in patients with diabetes, and considering the fact that the origin of cytokines cannot be accurately determined from their serum changes, attempts were made in the present study to study histological changes and testicular tissue levels of TNF-α and IL-1 in rats treated with exercise. Considering the effects of exercise in reducing blood sugar level and its complications, two types of short-term and long-term regular exercises were also considered to evaluate their effects on male reproductive tissues.

METHODS

In this study, 60 male rats with the weight range of 250±50 g were used and were randomly divided into six groups (10 rats each). Healthy groups included sedentary control group, and groups treated with two and eight weeks of exercise. Rats with type 1 diabetes (induced by streptozotocin) included sedentary control group, groups treated with two and eight weeks of exercise (six groups). All groups were evaluated in terms of testicular tissue levels of TNF-α and IL-1 using ELISA and the histometry of spermatogonia, primary spermatocytes, Sertoli cells, epithelial thickness, diameter of veins, and thickness of the seminiferous tubule.

RESULTS

Histological changes resulting from diabetes, particularly in the diameter of testicular veins and a number of cells, including Sertoli, highlights the important fact that tissue perfusion in patients with diabetes is especially crucial, in a way that exercise proved useful for tissue structures by offsetting this complication. Measurement of the cytokines IL-1 and TNF-α in the current study showed that perfusion problems are more important in diabetic complications than inflammatory factors.

CONCLUSIONS

The main result of this research is recommendation of investigating the tissue of interest for diagnosis of diabetes complications, measuring inflammatory mediators of tissue rather than evaluating their serum concentrations, and focusing on vascular complications as a major complication of diabetes. Furthermore, regular exercise could help improve the function of reproductive organs in healthy groups and prevent diabetes infertility complications to an acceptable degree in diabetic groups.

Can exercise training counteract doxorubicin-induced oxidative damage of testis proteome?

The use of the chemotherapeutic drug doxorubicin (DOX) is limited by its toxicity in several organs such as testes. So, we analyzed the effect of endurance treadmill exercise training (EX) performed before sub-chronic DOX treatment on sperm count and motility, testes markers of oxidative damage and apoptosis. Tissue profiling of proteins more susceptible to oxidation was made to identify the molecular pathways regulated by oxidative modifications, as nitration and carbonylation. Twenty-four adult male rats were divided into four groups (n=6/group): sedentary saline (SED+SAL), sedentary sub-chronically injected with DOX (2mg-kg-1 per week, during 7 weeks; SED+DOX), 12 weeks trained saline (EX+SAL) and trained treated with DOX (EX+DOX). DOX treatment started 5 weeks after the beginning of the exercise program. Testes caspase-3, -8 and -9, as well as aconitase activities, the content of malondialdehyde (MDA), sulfhydryl groups (-SH), carbonyl and nitrotyrosine derivatives were determined. Modified proteins were identified by 2D-Western blot followed by MALDI-TOF/TOF mass spectrometry, and bioinformatic analysis was performed to assess the biological processes regulated by these chemical modifications. The decreased sperm motility induced by DOX was not modified by exercise. Significant increases in MDA content in SED+DOX and in caspase-3 and -9 activities in EX+DOX were found. Despite no significant differences in the levels of carbonylated and nitrated proteins, exercise modulated testis proteome susceptibility to oxidation in DOX-treated group, with less modified proteins identified. Zinc finger Ran-binding domain-containing protein 2 (ZRAB2) and AN1-type zinc finger protein 3 (ZFAN3) were among the proteins found oxidativelly modified. Although no marked alterations in testes oxidative damage were noticed, proteomic analysis of oxidativelly modified proteins highlighted the protective role of exercise against oxidative damage of some proteins involved in metabolism and stress response against DOX.

Oxidative DNA Damage to Sperm Cells and Peripheral Blood Leukocytes in Infertile Men

BACKGROUND Oxidative DNA damage is associated with male infertility. The aim of this study was to evaluate the oxidative DNA damage of sperm cells and blood leukocytes and to determine the levels of MDA and NO levels in seminal and blood plasma of idiopathic infertile men. MATERIAL AND METHODS The study enrolled 52 patients, including 30 infertile and 22 fertile men. MDA, NO, and 8-OHdG/106dG were estimated using spectrophotometry and high-pressure liquid chromatography (HPLC)-based methods in seminal and blood plasma. The association with the sperm parameters was assessed, particularly sperm counts and motility. RESULTS The mean sperm concentration and sperm motility of the fertile men were significantly higher than that of the infertile men. The mean MDA and NO concentration in the seminal and blood samples of the infertile men were higher than that of fertile men. Also, the mean numbers of sperm cells and leukocytes 8-OHdG/106dG of the infertile men were significantly higher than that of fertile men (p=0.04 and p<0.001, respectively). Sperm motility and sperm count were negatively correlated with leukocyte and sperm cell 8-OHdG/106dG ratio. However, progressive motility was significantly negatively correlated with sperm cell and leukocyte 8-OHdG/106dG ratio (R=-0.357, p=0.026; R=-0.388, p=0.024, respectively). CONCLUSIONS Oxidative stress is an important factor in male infertility. Therefore, biochemical detection of 8-OHdG/106dG in sperm cells and blood leukocytes may be an additional tool in the diagnosis of male infertility.

Genetics of male infertility: from research to clinic

Male infertility is a multifactorial complex disease with highly heterogeneous phenotypic representation and in at least 15% of cases, this condition is related to known genetic disorders, including both chromosomal and single-gene alterations. In about 40% of primary testicular failure, the etiology remains unknown and a portion of them is likely to be caused by not yet identified genetic anomalies. During the last 10 years, the search for 'hidden' genetic factors was largely unsuccessful in identifying recurrent genetic factors with potential clinical application. The armamentarium of diagnostic tests has been implemented only by the screening for Y chromosome-linked gr/gr deletion in those populations for which consistent data with risk estimate are available. On the other hand, it is clearly demonstrated by both single nucleotide polymorphisms and comparative genomic hybridization arrays, that there is a rare variant burden (especially relevant concerning deletions) in men with impaired spermatogenesis. In the era of next generation sequencing (NGS), we expect to expand our diagnostic skills, since mutations in several hundred genes can potentially lead to infertility and each of them is likely responsible for only a small fraction of cases. In this regard, system biology, which allows revealing possible gene interactions and common biological pathways, will provide an informative tool for NGS data interpretation. Although these novel approaches will certainly help in discovering 'hidden' genetic factors, a more comprehensive picture of the etiopathogenesis of idiopathic male infertility will only be achieved by a parallel investigation of the complex world of gene environmental interaction and epigenetics.

Acute heat stress induces differential gene expressions in the testes of a broiler-type strain of Taiwan country chickens

The expression of testicular genes following acute heat stress has been reported in layer-type roosters, but few similar studies have been conducted on broilers. This study investigated the effect of acute heat stress on the gene expression in the testes of a broiler-type strain of Taiwan country chickens. Roosters were subjected to acute heat stress (38°C) for 4 h, and then exposed to 25°C, with testes collected 0, 2, and 6 h after the cessation of heat stress, using non-heat-stressed roosters as controls (n = 3 roosters per group). The body temperature and respiratory rate increased significantly (p<0.05) during the heat stress. The numbers of apoptotic cells increased 2 h after the acute heat stress (79 ± 7 vs. 322 ± 192, control vs. heat stress; p<0.05), which was earlier than the time of increase in layer-type roosters. Based on a chicken 44 K oligo microarray, 163 genes were found to be expressed significantly different in the testes of the heat-stressed chickens from those of the controls, including genes involved in the response to stimulus, protein metabolism, signal transduction, cell adhesion, transcription, and apoptosis. The mRNA expressions of upregulated genes, including HSP25, HSP90AA1, HSPA2, and LPAR2, and of downregulated genes, including CDH5, CTNNA3, EHF, CIRBP, SLA, and NTF3, were confirmed through quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, numerous transcripts in the testes exhibited distinct expressions between the heat-stressed broiler-type and layer-type chickens. We concluded that the transcriptional responses of testes to acute heat stress may differ between the broiler-type and layer-type roosters. Whether the differential expression patterns associate with the heat-tolerance in the strains require a further exploration.

eNOS-JNK1-AR signaling pathway mediates deltamethrin-induced germ cells apoptosis in testes of adult rats

The purpose of this study is to examine germ cells apoptosis and reduction of spermatogenesis which might be induced by deltamethrin (DM). Furthermore, the study is performed to determine if the apoptosis is mediated by the signaling proteins: eNOS, JNK1 and androgen receptor (AR). Fifty-four male SD rats were divided into nine groups (six rats each): blank control group; corn oil treated group; DM treated group; saline treated group; DM+saline treated group; DM+histamine (eNOS specific agonist) treated group; 50% ethanol treated group; DM+50% ethanol group and DM+quercetagetin (JNK1 specific inhibitor) treated group. The experiment was conducted for 15 days. Apoptosis was evaluated by TUNEL; S-nitrosylation of JNK1 was examined by the biotin switch assay; eNOS expression and Ser650 phosphorylation of AR were assessed by immunoblotting and immunohistochemical analysis, respectively. DM treated group showed notable apoptotic cells and reduced production of sperm, while DM plus histamine group and DM plus quercetagetin group showed remarkably decreased apoptosis and improved production of sperm. Administration of DM inhibited spermatogenesis, the activity of eNOS and S-nitrosylation of JNK1. Meanwhile, phosphorylation of AR was shown to be elevated. Histamine and quercetagetin were also examined to have a further confirmation. It is suggested DM-induced germ cells apoptosis and reduction of sperm production were mediated by eNOS-JNK1-AR signaling pathway.

Protective effects of Big-leaf mulberry and physiological roles of nitric oxide synthases in the testis of mice following water immersion and restraint stress

Big-leaf mulberry is a new hybrid plant from the application of cell engineering technology, but its effect in stress-induced testicular dysfunction is unknown. Nitric oxide (NO) is a tiny, highly reactive lipophilic molecule produced by nitric oxide synthases (NOS). Three isoforms of NOS (neuronal NOS, inducible NOS and endothelial NOS) have been identified. Our aim was to investigate the effect of water immersion and restraint stress (WIRS) on NOS in the testis, and the effect of Big-leaf mulberry to protect against WIRS. The activity and expression of NOS, and total antioxidant capacity (T-AOC) in the mouse testis of different treatment groups (non-WIRS, 3 h-WIRS, WIRS-recovery) were examined. Histological analysis of WIRS-induced testicular damage and immunohistochemical staining of NOS were also analyzed. Results demonstrated that WIRS-exposed mice produced several injuries and showed an increased iNOS and eNOS mRNA expression in testes, whereas pretreatment with Big-leaf mulberry down-regulated iNOS and eNOS mRNA expressions and up-regulated T-AOC activities. Immunohistochemical studies showed that both iNOS and eNOS were localized in germ cells, spermatozoa and blood vessels in addition to Leydig cells and Sertoli cells, but nNOS was not present in these areas. In conclusion, our results suggested that Big-leaf mulberry exerted a protective effect on WIRS-induced testicular dysfunction, and iNOS and eNOS appeared to exert an important action in mouse testes exposed to WIRS.

Study of the effects of oral zinc supplementation on peroxynitrite levels, arginase activity and NO synthase activity in seminal plasma of Iraqi asthenospermic patients

BACKGROUND

Low concentrations of nitric oxide (NO) are necessary for the biology and physiology of spermatozoa, but high levels of NO are toxic and have negative effects on sperm functions. Although several studies have considered the relationship between infertility and semen NO concentrations, no study on the effects of asthenospermia treatments such as oral zinc supplementation on concentrations of NO, which are important in fertility, has been reported. Studies have shown that oral zinc supplementation develops sperm count, motility and the physical characteristics of sperm in animals and in some groups of infertile men. The present study was conducted to study the effect of zinc supplementation on the quantitative and qualitative characteristics of semen, along with enzymes of the NO pathway in the seminal plasma of asthenospermic patients.

METHODS

Semen samples were obtained from 60 fertile and 60 asthenozoospermic infertile men of matched age. The subfertile group was treated with zinc sulfate; each participant took two capsules (220 mg per capsule) per day for 3 months. Semen samples were obtained (before and after zinc sulfate supplementation). After liquefaction of the seminal fluid at room temperature, routine semen analyses were performed. The stable metabolites of NO (nitrite) in seminal plasma were measured by nitrophenol assay. Arginase activity and NO synthase activity were measured spectrophotometrically.

RESULTS

Peroxynitrite levels, arginase activity, NO synthase activity and various sperm parameters were compared among fertile controls and infertile patients (before and after treatment with zinc sulfate). Peroxynitrite levels and NO synthase activity were significantly higher in the infertile patients compared to the fertile group. Conversely, arginase activity was significantly higher in the fertile group than the infertile patients. Peroxynitrite levels, arginase activity and NO synthase activity of the infertile patient were restored to normal values after treatment with zinc sulfate. Volume of semen, progressive sperm motility percentage and total normal sperm count were increased after zinc supplementation.

CONCLUSIONS

Treatment of asthenospermic patients with zinc supplementation leads to restored peroxynitrite levels, arginase activity and NO synthase activity to normal values and gives a statistically significant improvement of semen parameters compared with controls.

Genetic variants of eNOS gene may modify the susceptibility to idiopathic male infertility

In testis, eNOS is responsible for synthesis of nitric oxide (NO) which is an essential gas message regulator in spermatogenesis, suggesting that eNOS gene plays a role in normal spermatogenesis and the genetic variants of eNOS gene may be potential genetic risk factors of spermatogenesis impairment. In this study, the polymorphic distributions of three common polymorphism loci including T-786C, 4A4B and G894T in eNOS gene were investigated in 355 Chinese infertile patients with azoospermia or oligozoospermia and 246 healthy fertile men and a meta-analysis was carried in order to explore the possible relationship between the three loci of eNOS gene and male infertility with spermatogenesis impairment. As a result, allele -786C of T-786C (11.4% versus 6.5%, p = 0.004) and 4A of 4A4B (11.0% versus 6.3%, p = 0.005) as well as genotype TC of T-786C (22.8% versus 13.0%, p = 0.002) and AB of 4A4B (18% versus 11%, p = 0.015) were significantly associated with idiopathic male infertility. The haplotypes T-4A-G (7.4% versus 4.1%, p = 0.015) and C-4B-G (7.6% versus 4.4%, p = 0.028) could increase the susceptibility to male infertility, whereas haplotype T-4B-G (67.0% versus 75.2%, p = 0.002) might be a protective factor for male infertility. The results of meta-analysis revealed that the polymorphism of T-786C was associated with male infertility. These findings suggested that the variants of eNOS gene may modify the susceptibility to male infertility with impaired spermatogenesis.

Loss of occludin expression and impairment of blood-testis barrier permeability in rats with autoimmune orchitis: effect of interleukin 6 on Sertoli cell tight junctions

Inflammation of the male reproductive tract is accepted as being an important etiological factor of infertility. Experimental autoimmune orchitis (EAO) is characterized by interstitial lymphomononuclear cell infiltration and severe damage of seminiferous tubules with germ cells that undergo apoptosis and sloughing. Because the blood-testis barrier (BTB) is relevant for the protection of haploid germ cells against immune attack, the aim of this study was to analyze BTB permeability and the expression of tight junction proteins (occludin, claudin 11, and tight junction protein 1 [TJP1]) in rats during development of autoimmune orchitis. The role of IL6 as modulator of tight junction dynamics was also evaluated because intratesticular content of this cytokine is increased in EAO rats. Orchitis was induced in Sprague-Dawley adult rats by active immunization with testicular homogenate and adjuvants. Control rats (C) were injected with saline solution and adjuvants. Untreated (N) rats were also studied. Concomitant with early signs of germ cell sloughing, a reduced expression of occludin and delocalization of claudin 11 and TJP1 were detected in the testes of rats with EAO compared to C and N groups. The use of tracers showed increased BTB permeability in EAO rats. Intratesticular injection of IL6 induced focal testicular inflammation, which is associated with damaged seminiferous tubules. Rat Sertoli cells cultured in the presence of IL6 exhibited a redistribution of tight junction proteins and reduced transepithelial electrical resistance. These data indicate the possibility that IL6 might be involved in the downregulation of occludin expression and in the modulation of BTB permeability that occur in rats undergoing autoimmune orchitis.

Aspirin inhibits the production of reactive oxygen species by downregulating Nox4 and inducible nitric oxide synthase in human endothelial cells exposed to oxidized low-density lipoprotein

Aspirin has antithrombotic activity and is commonly used to protect patients from cardiovascular disease attacks. The present study investigated whether aspirin reduces reactive oxygen species and proinflammatory proteins in oxidized low-density lipoprotein (ox-LDL)-stimulated human umbilical vein endothelial cells. The results showed that aspirin attenuated reactive oxygen species generation induced by ox-LDL and downregulated Nox4 and inducible nitric oxide synthase expression. Redox-sensitive transcription factor nuclear factor kappa B was inactivated by aspirin, significantly preventing nuclear factor kappa B p65 subunit translocation into the nucleus. The expression of the monocyte/macrophage chemotactic protein 1 also decreased, but endothelial nitric oxide synthase expression increased in aspirin-treated cells. Aspirin ameliorated oxidative stress by downregulating Nox4 and inducible nitric oxide synthase and improved endothelial cell function by increasing endothelial nitric oxide synthase expression. Thus, aspirin may possess protective effects against ox-LDL-induced endothelial cell injury.

Staphylococcus aureus Infection Induced Oxidative Imbalance in Neutrophils: Possible Protective Role of Nanoconjugated Vancomycin

Staphylococcus aureus infection causes oxidative stress in neutrophils. The immune cells use reactive oxygen species (ROS) for carrying out their normal functions while an excess amount of ROS can attack cellular components that lead to cell damage. The present study was aimed to test the protective role of nanoconjugated vancomycin against vancomycin-sensitive Staphylococcus aureus (VSSA) and vancomycin-resistant Staphylococcus aureus (VRSA) infection induced oxidative stress in neutrophils. VSSA- and VRSA-infection were developed in Swiss mice by intraperitoneal injection of 5 × 10(6) CFU/mL bacterial solutions. Nanoconjugated vancomycin was treated to VSSA- and VRSA-infected mice at its effective dose for 10 days. Vancomycin was treated to VSSA and VRSA infected mice at similar dose, respectively, for 10 days. The result reveals that in vivo VSSA and VRSA infection significantly increases the level of lipid peroxidation, protein oxidation, oxidized glutathione level, and nitrite generation and decreases the level of reduced glutathione, antioxidant enzyme status, and glutathione-dependent enzymes as compared to control group; which were increased or decreased significantly near to normal in nanoconjugated vancomycin-treated group. These finding suggests the potential use and beneficial protective role of nanoconjugated vancomycin against VSSA and VRSA infection induced oxidative imbalance in neutrophils.

Êxpression of inducible nitric oxide synthase (iNOS) in the azoospermic human testis

Azoospermia, which is the absence of spermatozoa in the ejaculate, is not a rare cause of male infertility. Inducible nitric oxide synthase (iNOS) is a calcium-independent NOS, which is present in the testis and involved in spermatogenesis, and apoptosis of Sertoli and germ cells. Twenty idiopathic infertile men presenting nonobstructive azoospermia were enrolled in this study, and testicular sperm extraction procedures were performed. Tissue extracts were dissected, and the fluid samples were investigated to determine the presence of spermatozoa. Histologic evaluation of the spermatozoa-present samples revealed that seminiferous tubules were normal and were lined by Sertoli cells and spermatogenic cells. However, in the spermatozoa-absent samples, the diameter of the seminiferous tubules was small, and Sertoli-cell-only syndrome was determined in most of the tubules. iNOS expression was very weak in Sertoli cells, germ cells, and in Leydig cells in the spermatozoa-present group. In the spermatozoa-absent group, the immunostaining was very intense in Sertoli and Leydig cells. Electron microscopy findings were supported the histologic results. In conclusion, complete germ cell loss and intense expression of iNOS in the Sertoli and Leydig cells in the spermatozoa-absent groups of azoospermic human testis suggest an essential role of iNOS in spermatogenesis.

Internalization of Staphylococcus aureus in lymphocytes induces oxidative stress and DNA fragmentation: possible ameliorative role of nanoconjugated vancomycin

Staphylococcus aureus is the most frequently isolated pathogen causing bloodstream infections, skin and soft tissue infections and pneumonia. Lymphocyte is an important immune cell. The aim of the present paper was to test the ameliorative role of nanoconjugated vancomycin against Vancomycin-sensitive Staphylococcus aureus (VSSA) and vancomycin-resistant Staphylococcus aureus (VRSA) infection-induced oxidative stress in lymphocytes. VSSA and VRSA infections were developed in Swiss mice by intraperitoneal injection of 5 × 10⁶ CFU/mL bacterial solutions. Nanoconjugated vancomycin was adminstrated to VSSA- and VRSA-infected mice at its effective dose for 10 days. Vancomycin was adminstrated to VSSA- and VRSA-infected mice at a similar dose, respectively, for 10 days. Vancomycin and nanoconjugated vancomycin were adminstrated to normal mice at their effective doses for 10 days. The result of this study reveals that in vivo VSSA and VRSA infection significantly increases the level of lipid peroxidation, protein oxidation, oxidized glutathione level, nitrite generation, nitrite release, and DNA damage and decreases the level of reduced glutathione, antioxidant enzyme status, and glutathione-dependent enzymes as compared to control group, which were increased or decreased significantly near to normal in nanoconjugated vancomycin-treated group. These findings suggest the potential use and beneficial role of nanoconjugated vancomycin against VSSA and VRSA infection-induced oxidative stress in lymphocytes.

Sertoli cell numbers and spermatogenic efficiency are increased in inducible nitric oxide synthase mutant mice

Nitric oxide (NO) is produced via oxidation of l-arginine by nitric oxide synthases (NOSs), and is known as inducible (iNOS), neuronal, endothelial or testis-specific. Suggesting important functions for NOS in the normal rat and mouse testis, iNOS is reported to be constitutively expressed in Leydig cells (LC), Sertoli cells (SC) and germ cells. In our study, we sought to provide further insights into the roles of iNOS in the adult mouse testis using iNOS(-/-) mice. Perfusion-fixed testes from wild type (WT) and iNOS(-/-) mice were used for histological and stereological evaluations. Some of the mice had been injected with (3) H-thymidine to label proliferating cells and to determine the duration of spermatogenesis that was unaffected in iNOS(-/-) mice. Both LC nuclear volume and individual cell size were significantly decreased in iNOS(-/-) mice, but the total number of LC per testis was increased (p < 0.05) by approximately 16%. The number of SC per testis was strikingly increased (approximately twofold) in iNOS(-/-) mice, and testis weight and DSP per gram of testis (spermatogenic efficiency) were similarly increased. The anogenital distance was also significantly increased in iNOS(-/-) mice, and this key endpoint suggests that the augmentation observed for the SC number may be related to increased foetal T-exposure during the masculinization programming window. Compared with WT testes, the numbers of spermatocytes and spermatids and SC per tubule cross sections were significantly increased in iNOS(-/-) mice. Except for stages V-VI and VII-VIII, iNOS(-/-) mice exhibited approximately 3.5-fold fewer apoptotic germ cells than in WT mice. Taken together, our results provide new evidence that iNOS plays an important role in numerical and functional regulation of key somatic cells in the testis, which in turn impacts on germ cells and their survival and thus on daily sperm production.

Amelioratory Effect of Nanoconjugated Vancomycin on Spleen during VRSA-Induced Oxidative Stress

Objective. The aim of the present study was to evaluate the possible antioxidant effects of nanoconjugated vancomycin against VRSA infection on select makers of oxidative damage and antioxidant status in spleen. Methods. A coagulase-positive VRSA strain was used for this study. VRSA infection was developed in Swiss mice by intraperitoneal injection of 5 × 10(6) CFU/mL bacterial solutions. VRSA-infected mice were treated with nanoconjugated vancomycin at its effective dose for 10 days. After decapitation, blood was used for determination of viable bacteria count and spleen was excised from control and experimental groups, homogenized and used for different biochemical estimations. Results. Nitrate level, myeloperoxidase activity, lipid peroxidation, protein oxidation, oxidized glutathione, and DNA fragmentation level were increased significantly (P < 0.05) in spleen of VRSA-infected group as compared to control group, and reduced glutathione level, activity of SOD, CAT, GPx, GR, and GST were decreased significantly (P < 0.05); which were increased or decreased significantly (P < 0.05) near to normal in nanoconjugated vancomycin-treated group. Conclusion. These findings suggest the potential use and beneficial role of nanoconjugated vancomycin against VRSA-infection-induced oxidative stress and DNA damage in spleen.

Ca(2+)-modulated membrane guanylate cyclase in the testes

To date, the calcium-regulated membrane guanylate cyclase Rod Outer Segment Guanylate Cyclase type 1 (ROS-GC1) transduction system in addition to photoreceptors is known to be expressed in three other types of neuronal cells: in the pinealocytes, mitral cells of the olfactory bulb and the gustatory epithelium of tongue. Very recent studies from our laboratory show that expression of ROS-GC1 is not restricted to the neuronal cells; the male gonads and the spermatozoa also express ROS-GC1. In this presentation, the authors review the existing information on the localization and function of guanylate cyclase with special emphasis on Ca(2+)-modulated membrane guanylate cyclase, ROS-GC1, in the testes. The role of ROS-GC1 and its Ca(2+)-sensing modulators in the processes of spermatogenesis and fertilization are discussed.