Expression of endothelial nitric oxide synthase in the Sertoli cells of men with infertility of various causes

SP-Max-A herbomineral formulation attenuates busulfan-induced oligospermia in mice by preventing loss of reproductive hormones

SP-Max herbal capsule formulation contains Withania somnifera, Asparagus recemosus, Mucuna pruriens, Chlorophytum arundinaceum, Ipomoea digitata, and Dioscorea bulbifera which are reported in the 'Ayurveda', an Indian Traditional System of medicine as aphrodisiacs. The present study focused on the effect of herbomineral formulation, SP-Max in the treatment of oligospermia. Oligospermia was induced in male Swiss Albino mice by a single intraperitoneal injection of busulfan at a dose of 45 mg/kg. SP-Max herbomineral formulation was given at various doses of 130, 270, and 390 mg/kg for 45 days. Treatment with SP-Max herbomineral formulation at 130, 270 and 390 mg/kg doses significantly improved the sperm count, sperm motility and viability (p < 0.001). SP-Max treatment at a dose of 390 mg/kg significantly prevented the loss of anti-oxidant enzymes in testicular cells. SP-Max prevented the reduction in the level of testosterone, luteinizing hormone, and follicle-stimulating hormone. Histological findings showed that SP-Max treatment prevented degeneration of spermatid, interstitial cells, and Sertoli cells of the testes and also improved epididymal sperm count. High dose of SP-Max treatment i.e 390 mg/kg found to be more effective. Results showed that SP-Max herbomineral formulation is an effective treatment option for oligospermia by decreasing free radical damage to the testes and improving the levels of reproductive hormones.

Polymorphisms in the HSF2, LRRC6, MEIG1 and PTIP genes correlate with sperm motility in idiopathic infertility

The aim of this study was to investigate the association of 24 functionally important single nucleotide polymorphisms (SNPs) with male infertility. In this cross-sectional study, we genotyped 24 functionally important single nucleotide polymorphisms in 24 infertility candidate genes in 500 oligo-/astheno-/oligoastheno-/normo-zoospermic infertile men with idiopathic infertility. Sequenom iPlex gold assay was used for genotyping. Sperm count and motility were compared between prevalent genotypes at each test locus. We did not observe any significant difference in the average sperm count between the alternate genotypes for the loci in the KLK3, LRRC6, MEIG1, HSF2, ESR2 and PTIP genes. However, we observed a significant difference in sperm motility between the alternate genotypes for the loci in the LRRC6, MEIG1, HSF2 and PTIP genes. Polymorphisms in the LRRC6 (rs200321595), MEIG1 (rs150031795), HSF2 (rs143986686) and PTIP (rs61752013) genes show association with sperm motility.

Investigation of the association of endothelial nitric oxide synthase (eNOS)-T786C gene polymorphism with the risk of male infertility in an Iranian population

Recent studies have demonstrated that making the sorts of oxygen reactive, such as nitric oxide, can cause oxidative lipid damage, protein damage, and damage to the DNA of cells. Sperm DNA damage effect on the reduction of sperm mobility and damage of acrosome membrane lead to the inability of sperm to fertilize the oocyte. Increasing expression of endothelial nitric oxide synthase (eNOS) gene is seen in various diseases such as cardiovascular and infertility diseases. This study aimed to assess the association between eNOS gene single nucleotide polymorphism/SNP (rs2070744, T786C) and risk of male infertility and the quality of sperm parameters in an Iranian population. In this case-control study, 100 infertile men were enrolled as a patient group. Control groups consisted of 100 fertile men. T786C genotypes were determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results showed that T786C SNP, contained frequent genotype TC (p = 0.000; OR = 0.000; 95% CI = 0.000-0.015), TC + CC genotypes (p = 0.000; OR = 0.000; 95% CI = 0.000-0.015), and C allele (p = 0.000; OR = 0.00; 95% CI = 0.000-0.007), revealed a significant with male infertility. Based on the findings of this study suggested that although T786C SNP could not be applied as an appropriate genetic risk factor for male infertility, it probably may be considered a protective marker for other researchers. However, more comprehensive studies in different populations are required to confirm our data.

Male Selenoprotein F-Like (SPF-L) Influences Female Reproduction and Population Growth in Nilaparvata lugens (Hemiptera: Delphacidae)

Selenoproteins serve in anti-oxidant and cellular redox functions in almost all organisms. A recent study characterized a selenoprotein F-like (SPF-L) in the brown plant hopper’s (BPH), Nilaparvata lugens, male accessory glands (MAGs), raised the question of whether the SPF-L is associated with female fecundity. In this study, SPF-L mRNA was found to be enriched in the internal reproductive organ (IRO) of virgin males, also expressed relatively stably in virgin males and females, and dietary dsSPF-L-treatments led to reduced MAG protein and Arginine content. Knockdown of NlSPF-L in unmated males did not influence juvenile hormone (JH) III and ecdysteroid titers, however, dsSPF-L-treated mated males had increased JH III titer, and reduced ecdysteroid titer compared to controls. After mating with dsSPF-L-treated males, female partners had reduced fat body and ovary soluble proteins and JH III tier and vitellogenin (Vg) mRNA levels, but no alterations in ecdysteroid titer, body weight or longevity. The experimental females had prolonged pre-oviposition periods and they laid fewer eggs, which suffered reduced hatching rates and population growth index (PGI). Such mating also led to impaired IRO development in males and females, which was confirmed by immunofluorescence staining. We infer that SPF-L affects reproductive success of males and their partners.

PHF7, a novel male gene influences female fecundity and population growth in Nilaparvata lugens Stål (Hemiptera: Delphacidae)

PHF7 exhibits male-specific expression in early germ cells, germline stem cells and spermatogonia in insects, and its expression promotes spermatogenesis in germ cells when they are present in a male soma. However, the influence of male-specific PHF7 on female reproductive biology via mating remains unclear. Thus, we investigated the potential impacts of male PHF7, existed in seminal fluid of Nilaparvata lugens (NlPHF7), on fecundity and population growth via mating. Our results revealed that suppressing male NlPHF7 expression by RNAi led to decreases in body weight, soluble accessory gland protein content, arginine content, and reproductive organ development in males, resulting in significant reduction of oviposition periods and fecundity in females, and significant decrease in body weight, fat body and ovarian protein content, yeast-like symbionts abundance, ovarian development and vitellogenin gene expression in their female mating partners. Similarly, suppression of NlPHF7 expression in males mated with the control female reduced population growth and egg hatching rate, but did not influence gender ratio. We infer that NlPHF7 play a role important in stimulating female fecundity via mating. This study provides valuable information by identifying a potentially effective target gene for managing BPH population through RNAi.

TiO2 Nanoparticle Exposure Decreases Spermatogenesis via Biochemical Dysfunctions in the Testis of Male Mice

TiO2 nanoparticles (NPs) have been demonstrated to suppress spermatogenesis in animals, while there is little data related to the biochemical dysfunctions during spermatogenesis due to exposure to TiO2 NPs. In this study, male mice have been exposed to TiO2 NPs via intragastric administration for 60 consecutive days. The findings showed that TiO2 NP exposure resulted in lesions of testis and epididymis, deductions in sperm concentration and sperm motility, and an increase of the number of abnormal sperm in mice. Furthermore, TiO2 NP exposure with 2.5, 5, or 10 mg/kgbw decreased activities of lactate dehydrogenase (-11.59% to -39.84%), sorbitol dehydrogenase (-23.56% to -57.33%), succinate dehydrogenase (-27.04% to -57.85%), glucose-6-phosphate dehydrogenase (-28.3% to -56.42%), Na(+)/K(+)-ATPase (-15.59% to -53.11%), Ca(2+)-ATPase (-12.44% to -55.41%), and Ca(2+)/Mg(2+)-ATPase (-28.25% to -65.72%), and elevated activities of acid phosphatase (+10.48% to +40.0%), alkaline phosphatase (+20.65% to +64.07%), and total nitric oxide synthase (+0.68- to +2.3-fold) in the testes of mice, respectively. In addition, TiO2 NP exposure caused excessive production of reactive oxygen species (+16.15% to +110.62%), and increased malondialdehyde of lipid peroxidation product (+38.96% to +118.07%), carbonyl of protein oxidative product (+20.98% to +108.1%), and 8-hydroxydeoxyguanosine of DNA oxidative product (+0.9- to +1.83-fold) in the testes, respectively. It implied that spermatogenesis suppression caused by TiO2 NP exposure may be associated with alterations of testicular marked enzymes and oxidative stress in the testes.

Inhibition of NOS-NO System Prevents Autoimmune Orchitis Development in Rats: Relevance of NO Released by Testicular Macrophages in Germ Cell Apoptosis and Testosterone Secretion

Background

Although the testis is considered an immunoprivileged organ it can orchestrate immune responses against pathological insults such as infection and trauma. Experimental autoimmune orchitis (EAO) is a model of chronic inflammation whose main histopathological features it shares with human orchitis. In EAO an increased number of macrophages infiltrate the interstitium concomitantly with progressive germ cell degeneration and impaired steroidogenesis. Up-regulation of nitric oxide (NO)-NO synthase (NOS) system occurs, macrophages being the main producers of NO.

Objective

The aim of our study was to evaluate the role of NO-NOS system in orchitis development and determine the involvement of NO released by testicular macrophages on germ cell apoptosis and testosterone secretion.

Method and Results

EAO was induced in rats by immunization with testicular homogenate and adjuvants (E group) and a group of untreated normal rats (N) was also studied. Blockage of NOS by i.p. injection of E rats with a competitive inhibitor of NOS, L-NAME (8mg/kg), significantly reduced the incidence and severity of orchitis and lowered testicular nitrite content. L-NAME reduced germ cell apoptosis and restored intratesticular testosterone levels, without variations in serum LH. Co-culture of N testicular fragments with testicular macrophages obtained from EAO rats significantly increased germ cell apoptosis and testosterone secretion, whereas addition of L-NAME lowered both effects and reduced nitrite content. Incubation of testicular fragments from N rats with a NO donor DETA-NOnoate (DETA-NO) induced germ cell apoptosis through external and internal apoptotic pathways, an effect prevented by N-acetyl-L-cysteine (NAC). DETA-NO inhibited testosterone released from Leydig cells, whereas NAC (from 2.5 to 15 mM) did not prevent this effect.

Conclusions

We demonstrated that NO-NOS system is involved in the impairment of testicular function in orchitis. NO secreted mainly by testicular macrophages could promote oxidative stress inducing ST damage and interfering in Leydig cell function.

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.

Overexpression of Endothelial Nitric Oxide Synthase in Transgenic Mice Accelerates Testicular Germ Cell Apoptosis Induced by Experimental Cryptorchidism

Surgical induction of cryptorchidism in experimental animals causes testicular germ cell apoptosis and infertility. The mechanisms of germ cell apoptosis have been associated with oxidative stress or testicular exposure to elevated temperature. Nitric oxide (NO) has been associated with apoptosis in a number of cell types. The objective of this study was to investigate whether overexpression of endothelial NO synthase (eNOS) could accelerate apoptosis of germ cells in the testes of transgenic mice. There are 3 NOS isoforms, and we restricted the analysis to eNOS at this time. For the colocalization of eNOS, staining in degenerating germ cells that were apoptotic cells suggested that eNOS may be related to germ cell apoptosis. eNOS overexpression in the testes of eNOS transgenic (eNOS-Tg) mice was examined using Western blot analysis. Unilateral cryptorchidism was surgically induced in both eNOS-Tg and wild-type (WT) adult mice. The testes were evaluated 1, 3, 5, 7, and 14 days after the operation by weighing the testes and examining histopathologic features and cell apoptosis using in situ microscopic analysis of DNA fragmentation. Immunoblotting for eNOS protein demonstrated increases in eNOS protein expression in testes, as well as the lung and aorta. In eNOS-Tg mice, weight reduction of cryptorchid testis was significantly increased on days 3, 5, and 7 (P = .02, .02, and .04, respectively). The numbers of spermatocytes and spermatids of eNOS-Tg cryptorchid testis significantly decreased compared with those of WT cryptorchid testis from day 3 (spermatocytes: P = .04; spermatids: P = .02). Moreover, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling demonstrated that eNOS-Tg mice significantly accelerate germ cell apoptotic changes induced by experimental cryptorchidism compared with WT mice from day 3 (P = .03). We have provided evidence that eNOS plays a functional role in mouse spermatogenesis in cryptorchidism-induced apoptosis.

Up regulation of nitric oxide synthase-nitric oxide system in the testis of rats undergoing autoimmune orchitis

BACKGROUND

Male reproductive tract infection and inflammation are important aetiological factors of infertility. Experimental Autoimmune Orchitis (EAO) is a model of chronic inflammation useful to study mechanisms of inflammatory reactions leading to testicular impairment. EAO is characterised by interstitial cell infiltrate of lymphomonocytes, producers of pro-inflammatory cytokines involved in germ cell apoptosis. Nitric oxide (NO), a free radical promoting immune cell activation and apoptosis, is synthesised by conversion of l-arginine to l-citrulline catalysed by NO synthase (NOS). The NOS isoforms are: constitutively endothelial (e) and neuronal (n) NOS and inducible (i) NOS.

OBJECTIVES

Although the NO-NOS system was found to be up-regulated by pro-inflammatory mediators in immune and non immune testicular cells, data on its regulation in chronic inflammatory states is lacking.

METHODS AND RESULTS

EAO was induced in rats by active immunisation with spermatic antigens and adjuvants; control (C) rats were injected with adjuvants. Untreated normal (N) rats were also studied. We demonstrated that iNOS, eNOS and nNOS was mainly expressed by interstitial cells in N and C rats and that in EAO NOS was up-regulated and also expressed by tubular cells. Constitutive and inducible NOS content (Western blot) as well as NO production and activity increased in the testis of rats with EAO. iNOS content and activity were selectively up-regulated in the testis of rats with orchitis. Flow cytometric analysis of NOS isoforms in testicular macrophages (M) showed that the percentage of ED1(+)ED2(-) and ED1(+)ED2(+) M subsets, expressing constitutive and iNOS isoforms was significantly higher in EAO, but no change in the percentage of ED1(-)ED2(+) resident M was observed compared to C rats. M from EAO rats also released more NO than C and N rats.

CONCLUSIONS

In testis of rats with EAO, NO-NOS system was up-regulated and both testicular M and cells from seminiferous tubules contributed to NO increase. NO over production in orchitis was generated mainly by increased iNOS content and activity.

Proteomic analysis of insecticide triazophos-induced mating-responsive proteins of Nilaparvata lugens Stål (Hemiptera: Delphacidae)

The brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), is a classic example of a resurgent pest induced by insecticides. It has been demonstrated that triazophos treatment causes an increase in the content of male accessory gland proteins (Acps) that can be transferred to females via mating, influencing female reproduction. However, the mechanism of this type of insecticide-induced Acps in males and the subsequent stimulation of reproduction in females are not well understood. To identify changes in the types of Acps and reproductive proteins in mated females, we conducted a comparative proteomic analysis. Six samples were categorized into four different groups: (1) untreated unmated males compared to treated unmated males (UUM vs TUM); (2) treated unmated males compared to treated mated males (TUM vs TMM); (3) untreated unmated females compared to treated unmated females (UUF vs TUF); (4) treated unmated females compared to treated mated females (TUF vs TMF). Protein expression changes among the four different groups were examined by two-dimensional gel electrophoresis (2-DE) and liquid chromatography tandem mass spectrometry (LC-MS/MS). Of the 500-600 reproducibly detected protein spots on each gel, 107 protein spots were differentially expressed between the four different groups. Of the 63 proteins identified by LC-MS/MS analysis, 38 were up-regulated and 25 were down-regulated in the four different groups. Some novel proteins related to fecundity were observed including spermatogenesis-associated protein 5, testis development protein NYD-SP6, arginine kinase, actin-5C, vitellogenin, and ovarian serine protease nudel. The elevated expression of novel fecundity proteins in six samples of N. lugens females and males due to exposure to triazophos was confirmed by quantitative real-time PCR (qRT-PCR). The results suggest that these proteins may participate in the reproductive process of N. lugens adult females and males. Our findings fill a gap in understanding the relationship between insecticide-treated males and the stimulated reproduction of N. lugens females.

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.

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

Spermatogenesis is a highly complicated process in which functional spermatozoa (haploid, 1n) are generated from primitive mitotic spermatogonia (diploid, 2n). This process involves the differentiation and transformation of several types of germ cells as spermatocytes and spermatids undergo meiosis and differentiation. Due to its sophistication and complexity, testis possesses intrinsic mechanisms to modulate and regulate different stages of germ cell development under the intimate and indirect cooperation with Sertoli and Leydig cells, respectively. Furthermore, developing germ cells must translocate from the basal to the apical (adluminal) compartment of the seminiferous epithelium. Thus, extensive junction restructuring must occur to assist germ cell movement. Within the seminiferous tubules, three principal types of junctions are found namely anchoring junctions, tight junctions, and gap junctions. Other less studied junctions are desmosome-like junctions and hemidesmosome junctions. With these varieties of junction types, testes are using different regulators to monitor junction turnover. Among the uncountable junction modulators, nitric oxide (NO) is a prominent candidate due to its versatility and extensive downstream network. NO is synthesized by nitric oxide synthase (NOS). Three traditional NOS, specified as endothelial NOS (eNOS), inducible NOS (iNOS), and neuronal NOS (nNOS), and one testis-specific nNOS (TnNOS) are found in the testis. For these, eNOS and iNOS were recently shown to have putative junction regulation properties. More important, these two NOSs likely rely on the downstream soluble guanylyl cyclase/cGMP/protein kinase G signaling pathway to regulate the structural components at the tight junctions and adherens junctions in the testes. Apart from the involvement in junction regulation, NOS/NO also participates in controlling the levels of cytokines and hormones in the testes. On the other hand, NO is playing a unique role in modulating germ cell viability and development, and indirectly acting on some aspects of male infertility and testicular pathological conditions. Thus, NOS/NO bears an irreplaceable role in maintaining the homeostasis of the microenvironment in the seminiferous epithelium via its different downstream signaling pathways.

Determination of nitric oxide synthase activity and apoptosis of germ cells in different obstruction models

We aimed to determine the changes of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) immunoreactivity and apoptosis after proximal and distal obstruction models on ipsilateral and contralateral testicular tissues. Male albino Wistar rats were randomly divided into three groups (n=30): a control group which underwent sham operations (n=10), a unilateral vasal ligation (n=10) and a unilateral epididymal ligation group (n=10). iNOS and eNOS distribution and apoptosis were studied in both ipsilateral and contralateral testes using quantitative immunohistochemistry. Nitric oxide synthase activity was significantly affected in ipsilateral and contralateral testes cells after vasal and epididymal ligation. eNOS immunoreactivity increased markedly after ipsilateral vasal ligation (ILVL). Degeneration-related changes were also associated with changes in apoptotic rate. Analysis using the terminal dUTP nick end-labeling TUNEL method revealed that apoptotic cell numbers significantly increased after ILVL. p53 and bcl-2 immunoreactivity increased in both experimental groups compared with the sham-operated group. Changes in iNOS and eNOS immunolocalisation were strongly associated with cell damage, because germ cell degeneration was more prominent in the ILVL group. Altered p53 immunolocalisation was also associated with cell degeneration, and a rise in bcl-2 immunoreactivity might be considered to reflect a protective mechanism in the testis. These cellular changes could enlighten understanding of the interaction between testicular functioning and damage.

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

Spermatogenesis is a highly complicated process in which functional spermatozoa (haploid, 1n) are generated from primitive mitotic spermatogonia (diploid, 2n). This process involves the differentiation and transformation of several types of germ cells as spermatocytes and spermatids undergo meiosis and differentiation. Due to its sophistication and complexity, testis possesses intrinsic mechanisms to modulate and regulate different stages of germ cell development under the intimate and indirect cooperation with Sertoli and Leydig cells, respectively. Furthermore, developing germ cells must translocate from the basal to the apical (adluminal) compartment of the seminiferous epithelium. Thus, extensive junction restructuring must occur to assist germ cell movement. Within the seminiferous tubules, three principal types of junctions are found namely anchoring junctions, tight junctions, and gap junctions. Other less studied junctions are desmosome-like junctions and hemidesmosome junctions. With these varieties of junction types, testes are using different regulators to monitor junction turnover. Among the uncountable junction modulators, nitric oxide (NO) is a prominent candidate due to its versatility and extensive downstream network. NO is synthesized by nitric oxide synthase (NOS). Three traditional NOS, specified as endothelial NOS (eNOS), inducible NOS (iNOS), and neuronal NOS (nNOS), and one testis-specific nNOS (TnNOS) are found in the testis. For these, eNOS and iNOS were recently shown to have putative junction regulation properties. More important, these two NOSs likely rely on the downstream soluble guanylyl cyclase/cGMP/protein kinase G signaling pathway to regulate the structural components at the tight junctions and adherens junctions in the testes. Apart from the involvement in junction regulation, NOS/NO also participates in controlling the levels of cytokines and hormones in the testes. On the other hand, NO is playing a unique role in modulating germ cell viability and development, and indirectly acting on some aspects of male infertility and testicular pathological conditions. Thus, NOS/NO bears an irreplaceable role in maintaining the homeostasis of the microenvironment in the seminiferous epithelium via its different downstream signaling pathways.

Oral administration of tetrahydrobiopterin attenuates testicular damage by reducing nitric oxide synthase activity in a cryptorchid mouse model

Experimental cryptorchidism has been shown to induce germ cell apoptosis. Nitric oxide (NO), a ubiquitous free radical produced by NO synthases (NOSs), has been associated with apoptosis in a number of cell types. However, the regulation of NOSs in experimental cryptorchid testes remains unknown. Tetrahydrobiopterin (BH4), an essential cofactor of NOS, plays an important role in the generation of NO. It has been reported that activation of the immune system stimulates an increase in endogenous BH4 rate-limiting enzyme GTP cyclohydrolase I (GTPCH I) activity, resulting in an increase in intracellular BH4 levels and BH4-dependent NO synthesis in various cells. We examined the effect of dietary treatment with BH4 on GTPCH I, BH4 synthesis, NO production, and testicular damage in cryptorchid model mice. Male mice were treated with oral BH4 starting from age 4 weeks or received standard diet only, and right cryptorchid testes were created surgically at age 10 weeks. The testes were evaluated 0, 3, 5, 7, and 10 days after surgery by assays of testicular weight, BH4 and dihydrobiopterin (oxidized BH4) levels, GTPCH I mRNA levels, NOS protein expression levels, NO concentration, and nitrotyrosine (product of ONOO(-); determinant of NO-dependent damage) levels. In untreated mice, GTPCH I mRNA and BH4 levels increased and eNOS protein expression, NO concentration, and nitrotyrosine levels increased gradually. BH4 treatment decreased GTPCH I mRNA and BH4 levels, with concomitant reduction of eNOS protein levels, nitrotyrosine levels, and NO concentration, resulting in reduced testicular damage. Our findings demonstrate that supplementation with BH4 could provide a new therapeutic intervention for heat stress-based testicular dysfunction.

CB2 receptors in reproduction

Cannabinoids have been always identified as harmful drugs because of their negative effects on male and female reproduction. The discovery of the 'endocannabinoid system (ECS)', composed of bioactive lipids (endocannabinoids), their receptors and their metabolic enzymes, and the generation of mouse models missing cannabinoid receptors or other elements of the ECS, has enabled a wealth of information on the significance of endocannabinoid signalling in multiple reproductive events: Sertoli cell survival, spermatogenesis, placentation, fertilization, preimplantation embryo development, implantation and postimplantation embryonic growth. These studies have also opened new perspectives in clinical applications, pointing to the ECS as a new target for correcting infertility and for improving reproductive health in humans. This review will focus on the involvement of type-2 cannabinoid (CB2) receptors in reproductive biology, covering both the male and female sides. It will also discuss the potential relevance of the immunological activity of CB2 at the maternal/foetal interface, as well as the distinctiveness of CB2 versus type-1 cannabinoid (CB1) receptors that might be exploited for a receptor subtype-specific regulation of fertility. In this context, the different signalling pathways triggered by CB1 and CB2 (especially those controlling the intracellular tone of nitric oxide), the different activation of CB1 and CB2 by endogenous agonists (like anandamide and 2-arachidonoylglycerol) and the different localization of CB1 and CB2 within membrane subdomains, termed 'lipid rafts', will be discussed. It is hoped that CB2-dependent endocannabinoid signalling might become a useful target for correcting infertility, in both men and women.

Effects of surgery, medical therapy and combined therapeutical approach on spermatogenesis in patients suffering from varicocele: a prospective and comparative analysis

The definite mechanisms through which varicocele affects spermatogenesis are still not completely understood, and consequently the exact role of the various approaches available for its treatment is still under debate.

In this study a comparison of medical treatment, surgery and combined approach is reported.

Material and Methods.

The study was conducted as a prospective evaluation of 189 patients suffering from varicocele and oligoasthenospermia. Patients were randomized in three groups on the basis of the different therapeutic approach: group A, treated only with varicocelectomy; group B, treated with varicocelectomy associated with hormonal therapy; group C, treated only with hormonal therapy. Randomization criteria were based on patient's preference. Spermiogram tests were carried out at baseline and after 3, 6 and 12 months from therapy.

Results.

Our results show that patients undergoing a combined therapeutical approach (surgery associated with hormonal therapy) and medical therapy alone achieve a greater improvement of seminal parameters than patients treated by surgery only.

Conclusion.

Data reported in this study are in accordance with Literature review. Furthermore, the association between varicocelectomy and early use of hormonal therapy seems to improve testis functional rehabilitation with a early evidence of sperm parameters improvement. In the light of these results of ours, we should conclude that surgical treatment is not effective for the spermatogenesis improvement.

Jekyll and hyde: two faces of cannabinoid signaling in male and female fertility

Mammalian reproduction is a complicated process designed to diversify and strengthen the genetic complement of the offspring and to safeguard regulatory systems at various steps for propagating procreation. An emerging concept in mammalian reproduction is the role of endocannabinoids, a group of endogenously produced lipid mediators, that bind to and activate cannabinoid receptors. Although adverse effects of cannabinoids on fertility have been implicated for years, the mechanisms by which they exert these effects were not clearly understood. With the identification of cannabinoid receptors, endocannabinoid ligands, their key synthetic and hydrolytic pathways, and the generation of mouse models missing cannabinoid receptors, a wealth of information on the significance of cannabinoid/endocannabinoid signaling in spermatogenesis, fertilization, preimplantation embryo development, implantation, and postimplantation embryonic growth has been generated. This review focuses on various aspects of the endocannabinoid system in male and female fertility. It is hoped that a deeper insight would lead to potential clinical applications of the endocannabinoid signaling as a target for correcting infertility and improving reproductive health in humans.

Immunoexpression of aquaporin-1 in adolescent varicocele testes: Possible significance for fluid reabsorption

OBJECTIVES

To investigate the immunoexpression of aquaporin-1 (AQP-1), a major transmembrane water channel, in high-grade varicocele testes, which are known to imply an unbalanced transmembrane water flow, in both tubular and extratubular compartments.

METHODS

Light microscopy and AQP-1 immunohistologic examination were carried out on incisional testicular biopsies from 20 adolescent boys, aged 13 to 18 years, with grade 2 or 3 idiopathic varicocele. Testicular tissue from 4 autopsied subjects of matched age were also investigated as parallel controls.

RESULTS

At microscopic examination, the tubular lumina and extracellular matrix were expanded and venular profiles dilated. Cytoplasmic vacuoles were frequent in the Sertoli cells, spermatogonia, and spermatocytes, together with premature sloughing of germ cells and residual cytoplasmic droplets inside the spermatozoa, if present. Diffuse AQP-1 positivity occurred at venular endothelial cell membranes and, unexpectedly, at the cell membranes of the Sertoli cells, diploid germ cells, and haploid cells. In the control testes, focal AQP-1 immunolabeling was confined to the microvessel endothelial cells, without any positive reaction in the tubular or extratubular compartments.

CONCLUSIONS

This is the first report showing AQP-1 cell expression in adolescent varicocele testes in both tubular and extratubular compartments. It was associated with the main histologic features of unbalanced water flow in the tubular and interstitial compartments of the testis. Immunocytochemical patterns revealed AQP-1 as a possible critical reabsorption factor, acting to reduce abnormal fluid retention in endotubular cells and the extracellular matrix and, to a lesser extent, in Leydig cells.

Increased nitric oxide is accompanied by lipid oxidation in adolescent varicocele

Summary One of the mechanisms of injury in varicocele has been proposed to be elevated nitric oxide (NO). We aimed to determine the association between the elevation of NO and lipid oxidation in varicocele compared with peripheral venous levels of these two substances as it has not been studied before. The study group consisted of 13 adolescents with left idiopathic varicocele of grades II-III. Blood specimens were obtained from dilated spermatic and peripheral veins simultaneously. Peripheral samples were also collected from 13 healthy children as controls. Nitrite/nitrate levels (NO(x)) and levels of malonedialdehyde (MDA) were determined using Griess reaction and thiobarbituric acid test, respectively. Results were compared with Kruskal-Wallis and Mann-Whitney tests. Peripheral NO(x) and MDA were the same in the study and control groups (p = 0.069 and p = 0.27, respectively). Spermatic vein NO(x) and MDA levels were elevated significantly compared with the peripheral levels in the study group (p = 0.005 and p = 0.048, respectively). Increased NO(x) levels with lipid oxidation occur locally in adolescent varicocele, implying that these events could be reversed by early treatment.

Luminal flow induces eNOS activation and translocation in the rat thick ascending limb. II. Role of PI3-kinase and Hsp90

Endothelial nitric oxide synthase (eNOS) regulates NaCl absorption by the thick ascending limb of the loop of Henle (THAL). We found that augmenting luminal flow induces eNOS activation and translocation to the apical membrane of THALs (Ortiz PA, Hong NJ, and Garvin JL. Am J Physiol Renal Physiol 287: F274-F280, 2004). In other cells, eNOS activation by shear stress is mediated by phosphatidylinositol 3-OH kinase (PI3)-kinase. We hypothesized that luminal flow induces eNOS activation via PI3-kinase. Pretreatment of THALs with wortmannin, a PI3-kinase inhibitor, significantly reduced flow-induced nitric oxide (NO) release by 75% (from 53.6 +/- 6 to 13.2 +/- 5.7 pA/mm). Increasing luminal flow from 0 to 20 nl/min induced eNOS translocation to the apical membrane, whereas in the presence of wortmannin eNOS translocation was prevented (basolateral = 32 +/- 2%, middle = 38 +/- 1%, apical = 30 +/- 1%, n = 5, not significant vs. no flow). We next studied which PI3-kinase product mediates eNOS translocation. Addition of PI(3,4,5)P(3) (5 microM) in the absence of flow increased NO levels (P < 0.05) and induced eNOS translocation to the apical membrane (from 40 +/- 4 to 60 +/- 2% of total eNOS, n = 6, P < 0.05). Incubation with PI(3,4)P(2) or PI(4,5)P(2) did not change eNOS localization. We next tested whether heat shock protein (Hsp)90 is involved in eNOS translocation. The Hsp90 inhibitor geldanamycin blocked flow-induced eNOS translocation to the apical membrane (n = 6). Flow also induced translocation of Hsp90 to the apical membrane (from 35 +/- 2 to 57 +/- 2%; P < 0.05) in a PI3-kinase-dependent manner. We conclude that luminal flow induces eNOS translocation and activation in the THAL via PI3-kinase and that Hsp90 is involved in eNOS translocation to the apical membrane.

Nitric Oxide/Nitric Oxide Synthase, Spermatogenesis, and Tight Junction Dynamics1

During spermatogenesis, preleptotene and leptotene spermatocytes, residing in the basal compartment of the seminiferous epithelium, must traverse the blood-testis barrier (BTB) to gain entry to the adluminal compartment for further development at late stage VIII and early stage IX of the epithelial cycle. As such, the timely opening and closing of the BTB is crucial to spermatogenesis. A compromise in this process can lead to infertility. Moreover, the BTB is unique in its relative localization in the seminiferous epithelium compared to the tight junctions (TJs) found in other epithelia. Sertoli cell TJs are situated near the basal lamina in the testis, closest to the basement membrane (a modified form of extracellular matrix [ECM]), unlike TJs found in other epithelia, which are found nearest the apical portion of an epithelium, farthest away from ECM. Needless to say, BTB function in the testis is maintained by intricate regulatory mechanisms. In addition to hormones and cytokines, nitric oxide (NO) was recently shown to be a putative TJ regulator in the testis. Perhaps equally important, TJ dynamics in the testis were shown to be regulated, at least in part, by occludin, a TJ-integral membrane protein, via the NO/soluble guanylate cyclase/cGMP/protein kinase G signaling pathway. This minireview summarizes recent advances in the field regarding the role of NO in testicular function, with special emphasis regarding its role in TJ dynamics and the likely implications of these studies for male contraceptive development.

The potential role of advanced glycation end product and iNOS in chronic renal failure-related testicular dysfunction. An experimental study

OBJECTIVES

To investigate the impact of advanced glycation end products (AGEs) and inducible nitric oxide synthase (iNOS) in chronic renal failure (CRF)-associated testicular dysfunction in an experimental model. In additionally, we examined whether different peritoneal dialysis (PD) fluids could contribute to the elevation in AGE level and iNOS expression in the testes.

METHODS

Adult male Wistar rats, 10 and 12 weeks of age and weighing 200-330 g, were divided into 5 groups. Group 1 served as the control group. In group 2, CRF was induced and a peritoneal catheter was implanted, but the dialysis procedure was not performed until the end of the study. In group 3, CRF was induced and PD was performed with dialysis fluids containing 1.36% glucose and icodextrin. In group 4, CRF rats received dialysis fluids containing 3.86% glucose and icodextrin. Finally, an indwelling catheter was implanted and the dialysis procedure was performed using dialysis fluids containing 3.86% glucose and icodextrin (group 5). Chronic PD began 4 weeks after insertion of the catheter. Each morning, this fluid was drained and 20 ml dialysis fluid, containing either 1.36 or 3.86% glucose, was given intraperitoneally for 4 h in unanesthetized animals. Each evening, 20 ml icodextrin was given for 10 h. The dialysis procedure was performed for 8 weeks. The AGE level was determined from the 5-hydroxymethyl-2-furaldehyde (5-HMF) content of penis samples and iNOS expression was assessed by immunohistochemistry.

RESULTS

The elevation of 5-HMF was significant in the testes from groups 2, 3, 4, and 5 when compared with group 1. Furthermore, the differences between groups 2 and 4, 3 and 4, and 4 and 5 were also significant (p < 0.05). Immunohistochemical analysis revealed the presence of iNOS predominantly in the Leydig cells. While iNOS staining was significantly lower in group 1 than in other groups, there were also significant differences between groups 2 and 3, 2 and 4, 2 and 5, 3 and 5, and 4 and 5 (p < 0.05). Finally, a significant statistical correlation was found between the 5-HMF and iNOS levels (r = 0.698, p = 0.001).

CONCLUSIONS

The present study identifies, for the first time, a potential role of AGE and iNOS in experimental CRF-associated testicular dysfunction. In addition, we found that PD fluids containing glucose contribute to this effect. These results may lead to a better understanding of the pathophysiological pathway in CRF-related testicular dysfunction.

Anandamide activity and degradation are regulated by early postnatal aging and follicle-stimulating hormone in mouse Sertoli cells

Anandamide (AEA), a prominent member of the endogenous ligands of cannabinoid receptors (endocannabinoids), is known to adversely affect female fertility. However, a potential role of AEA in male reproductive functions is unknown. Here we report evidence that immature mouse Sertoli cells have the biochemical tools to bind and inactivate AEA, i.e. a functional type-2 cannabinoid receptor (CB2R), a selective AEA membrane transporter, and an AEA-degrading enzyme fatty acid amide hydrolase. We show that, unlike CB2R, the activity of AEA membrane transporter and the activity and expression of FAAH decrease, whereas the apoptosis-inducing activity of AEA increases with age during the neonatal period. We also show that FSH reduces the apoptotic potential of AEA, but not that of its nonhydrolyzable analog methanandamide. Concomitantly, FSH enhances FAAH activity in a manner dependent on mRNA transcription and protein synthesis and apparently involving cAMP. These data demonstrate that Sertoli cells partake in the peripheral endocannabinoid system, and that FSH reduces the apoptotic potential of AEA by activating FAAH. Taken together, it can be suggested that the endocannabinoid network plays a role in the hormonal regulation of male fertility.

Preliminary report on nitric oxide-mediated oxidative damage in adolescent varicocele

BACKGROUND

The current study was designed to characterize the process of nitric oxide (NO) and peroxynitrite generation through the determination of nitrotyrosine concentration in the dilated veins of varicoceles in adolescents.

METHODS

Ten adolescents with a median age of 13 years (range 12-17) affected by a left idiopathic varicocele (grade II and III) were studied. Whole blood samples were withdrawn from a peripheral vein at time of induction of anaesthesia, and from a dilated spermatic vein before ligation. Peripheral blood samples from five adolescents undergoing minor surgical procedures were used as controls. The nitrotyrosine concentration was evaluated by a sandwich enzyme-linked immunosorbent assay (ELISA), using a monoclonal anti-nitrotyrosine antibody and Western blot analysis.

RESULTS

Plasma nitrotyrosine concentrations were significantly greater in the spermatic vein when compared with the peripheral vein (P = 0.031). Nitrotyrosine in plasma of controls did not show any significant difference in comparison with peripheral samples from varicocele patients. Western blot analysis confirmed the above data.

CONCLUSIONS

In adolescents with a varicocele, there is an increase in nitrotyrosine concentration within the spermatic vein that can cause protein nitration and cytotoxicity via its reaction with various molecular targets. This could have repercussions on both sperm and testis function. We conclude that an oxidative stress status is present and should be considered as an indication for varicocele treatment in the adolescent.

Physiological mechanisms regulating the expression of endothelial-type NO synthase

Although endothelial nitric oxide synthase (eNOS) is a constitutively expressed enzyme, its expression is regulated by a number of biophysical, biochemical, and hormonal stimuli, both under physiological conditions and in pathology. This review summarizes the recent findings in this field. Shear stress, growth factors (such as transforming growth factor-beta, fibroblast growth factor, vascular endothelial growth factor, and platelet-derived growth factor), hormones (such as estrogens, insulin, angiotensin II, and endothelin 1), and other compounds (such as lysophosphatidylcholine) upregulate eNOS expression. On the other hand, the cytokine tumor necrosis factor-alpha and bacterial lipopolysaccharide downregulate the expression of this enzyme. The growth status of cells, the actin cytoskeleton, and NO itself are also important regulators of eNOS expression. Both transcriptional and posttranscriptional mechanisms are involved in the expressional regulation of eNOS. Different signaling pathways are involved in the regulation of eNOS promoter activity and eNOS mRNA stability. Changes in eNOS expression and activity under pathophysiological conditions and the pharmacological modulation of eNOS expression are subject of a subsequent brief review (part 2) to be published in the next issue of this journal.

Guanylate cyclase activity and sperm function

In species with external fertilization, the guanylate cyclase family is responsible for the long-distance interaction between gametes, as its activation allows sperm chemotaxis toward egg-derived substances, gamete encounter, and fertilization. In species with internal fertilization, guanylate cyclase-activating substances, which are secreted by several tissues in the genital tracts of both sexes, deeply affect sperm motility, capacitation, and acrosomal reactivity, stimulating sperm metabolism and promoting the ability of the sperm to approach the oocyte, interact with it, and finally fertilize it. A complex system of intracellular pathways is activated by guanylate cyclase agonists in spermatozoa. Sperm motility appears to be affected mainly through an increase in intracellular cAMP, whereas the acrosome reaction depends more directly on cyclic GMP synthesis. Both cyclic nucleotides activate specific kinases and ion signals. A complex cross-talk between cAMP- and cyclic GMP-generating systems occurs, resulting in an upward shift in sperm function. Excessive amounts of certain guanylate cyclase activators might exert opposite, antireproductive effects, increasing the oxidative stress on sperm membranes. In view of the marked influence exerted by guanylate cyclase-activating substances on sperm function, it seems likely that guanylate cyclase activation or inhibition may represent a new approach for the diagnosis and treatment of male and/or female infertility.

Nitric oxide synthase patterns in normal and varicocele testis in adolescents

OBJECTIVE

To determine if the testes of normal adolescents can produce nitric oxide (NO), by assessing NO synthase (NOS) activity, and whether this activity changes in adolescents with left idiopathic varicocele.

PATIENTS AND METHODS

After obtaining informed consent, testicular biopsies were obtained from eight adolescents (mean age 16.4 years; controls) who underwent surgery for inguinal hernia or hydrocele, and from 20 adolescents (mean age 16.2 years) operated for left idiopathic varicocele. Inducible and endothelial NOS (iNOS and eNOS) isoforms were investigated in the biopsy specimens by immunohistochemical localization and Western blot analysis using specific fluorescein-conjugated antibodies.

RESULTS

Both normal and pathological samples expressed eNOS at the level of vessels and Leydig cells. The iNOS was expressed in Leydig cells of normal testes and over-expressed in Leydig cells of varicocele testes.

CONCLUSION

Leydig cells of adolescent testes constitutively express iNOS. Under pathological conditions, e.g. varicocele, iNOS is up-regulated and is a possible source of NO overproduction. These results could be useful in explaining the pathogenesis of both testis and sperm dysfunction in varicocele.