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

Impaired Spermatogenesis in Infertile Patients with Orchitis and Experimental Autoimmune Orchitis in Rats

Experimental autoimmune orchitis (EAO) is a well-established rodent model of organ-specific autoimmunity associated with infertility in which the testis immunohistopathology has been extensively studied. In contrast, analysis of testis biopsies from infertile patients associated with inflammation has been more limited. In this work, testicular biopsies from patients with idiopathic non-obstructive azoospermia diagnosed with hypospermatogenesis (HypoSp) [mild: n = 9, and severe: n = 11], with obstructive azoospermia and complete Sp (spermatogenesis) (control group, C, n = 9), and from Sertoli cell-only syndrome (SCOS, n = 9) were analyzed for the presence of immune cells, spermatogonia and Sertoli cell (SCs) alterations, and reproductive hormones levels. These parameters were compared with those obtained in rats with EAO. The presence of increased CD45+ cells in the seminiferous tubules (STs) wall and lumen in severe HypoSp is associated with increased numbers of apoptotic meiotic germ cells and decreased populations of undifferentiated and differentiated spermatogonia. The SCs showed an immature profile with the highest expression of AMH in patients with SCOS and severe HypoSp. In SCOS patients, the amount of SCs/ST and Ki67+ SCs/ST increased and correlated with high serum FSH levels and CD45+ cells. In the severe phase of EAO, immune cell infiltration and apoptosis of meiotic germ cells increased and the number of undifferentiated and differentiated spermatogonia was lowest, as previously reported. Here, we found that orchitis leads to reduced sperm number, viability, and motility. SCs were mature (AMH-) but increased in number, with Ki67+ observed in severely damaged STs and associated with the highest levels of FSH and inflammatory cells. Our findings demonstrate that in a scenario where a chronic inflammatory process is underway, FSH levels, immune cell infiltration, and immature phenotypes of SCs are associated with severe changes in spermatogenesis, leading to azoospermia. Furthermore, AMH and Ki67 expression in SCs is a distinctive marker of severe alterations of STs in human orchitis.

The Protective effects of Vitamin E against alterations of rat testis structure induced by deltamethrin; histological, ultrastructure, and biochemical study

Deltamethrin is a widely used synthetic pyrethroid pesticide. It causes reproductive toxicity. Aim of the work: it evaluates the impact of vitamin E in restoration of the testicular integrity of albino rats after toxicity induced by Deltamethrin. Thirty-six adult male albino rats were included, and they were further sub-divided into four experimental groups; Group A: six rats served as controls. Group B (Model): 10 rats equally divided into two sub-groups (B1): the rats received deltamethrin dissolved in oil in a dose of 0.6 mg/kg/daily by nasogastric gavage for 2 weeks. (B2): the rats received Deltamethrin in the same dose of group B1 for 1 month. Group C (Protected): 10 rats equally divided into two sub-groups (C1): the rats received deltamethrin orally 0.6 mg/kg/day concomitant with Vitamin E dissolved in 1 ml of corn oil in a dose 200 mg/kg/day by nasogastric gavage for 2 weeks. (C2): the rats received deltamethrin concomitant with Vitamin E in the same dose of group C1 for 1 month. Group D (Treatment): 10 rats received deltamethrin for 1 month followed by Vitamin E for another month in the same previously prescribed doses. Significant decreases in serum testosterone level, GSH, catalase activity, and significant increase in MDA in the deltamethrin-treated group were detected. Moreover, histological and ultrastructural examinations of the testis seminiferous tubules showed detrimental alterations in the deltamethrin group which were duration dependent. Vitamin E administration reversed such alterations. Vitamin E ameliorates the testicular dysfunction caused by Deltamethrin.

Role of serotonin, estrogen, and TNF-α in the paroxetine-impaired steroidogenesis and testicular macrophages polarization

BACKGROUND

Paroxetine, a selective serotonin reuptake inhibitor (SSRI) antidepressant, has caused male sexual dysfunction; however, the paroxetine mechanisms of action in testes are still unclear.

OBJECTIVES

Paroxetine serotonergic effects in testes were evaluated, focusing on steroidogenesis and the correlation between macrophages population and possible TNF-α-derived oxidative stress. We also verified whether the changes are reversible following treatment interruption.

MATERIALS AND METHODS

Adult rats received paroxetine (PG35 and PG65) or tap water (CG) for 35 days. PG65 was maintained without treatment for 30 more days. Intratesticular testosterone (IT), nitrite, and malondialdehyde concentrations were measured. To confirm serotonergic and estrogenic effects, Htr1b and Esr1 expressions were analyzed. The daily sperm production (DSP), frequency of abnormal seminiferous tubules (ST), SC number, ST area, and Leydig cells nuclear area (LCnu) were evaluated. TUNEL+ germ cells, M1 (CD68+ ), and M2 (Perls+ ) macrophages were quantified. 17β-HSD7, CYP19A1, NDRG2, oxytocin, TNF-α, and iNOS were evaluated by immunoreactions. Oxytocin and NDRG2 protein levels as well as Tnfa mRNA expression were also analyzed.

RESULTS

The Htr1b downregulation in testes confirmed the paroxetine serotonergic effect. The testicular sections showed abnormal ST frequency, ST atrophy and reduction of DSP, LCnu, SC number and Perls+ macrophages. TUNEL+ germ cells and LC were associated with strong NDRG2 immunoexpression. Paroxetine reduced IT levels and 17β-HSD7 immunoexpression in parallel to increased CYP19A1, oxytocin, TNF-α and iNOS. Esr1 and Tnfa overexpression and increased number of CD68+ macrophages were also observed together with high nitrite and malondialdehyde levels. Most parameters were not recovered in PG65.

CONCLUSIONS

Paroxetine serotonergic effect impairs LC steroidogenesis, via aromatization, increasing estrogen/testosterone ratio, which in turn upregulate NDRG2, promoting apoptosis, and impairing sperm production. Serotonin-estrogen pathways may be responsible for M2/M1 polarization, Tnfa upregulation, and induction of oxidative stress. The unrecovered testicular changes after treatment discontinuation are due to persistent paroxetine serotonin/estrogen effects.

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 running exercise training on inflammatory mediators and cytokines expression in testicular tissue; effect of exercise intensity

The aim of this study is to investigate the impact of running exercise training protocols (ETPs) with varying intensities on inflammatory responses, with a specific focus on the interactions between inflammatory mediators, cytokines, and Leydig cell steroidogenic activity, as well as testosterone secretion. To this end, 24 Wistar rats were subdivided into sedentary control, low (LICT), moderate (MICT), and high (HICT) intensity continuous running ETP groups. After 8 weeks, the expression levels of Toll-like receptor-4 (TLR-4), nuclear factor-kappa-B (NF-KB), interleukin-6 (IL-6), interleukin-10 (IL-10), Tumor necrosis factor alpha (TNF-α), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and the testicular nitric oxide (NO) content were assessed and compared between groups. Moreover, the mean distributions of Leydig cells/mm2 of interstitial connective tissue, their steroidogenic activity, and serum level of testosterone were assessed. The LICT did not show any significant (p > 0.05) change in the expression levels of all aforementioned biomarkers. In contrast, both the MICT and HICT groups demonstrated a significant (p < 0.05) increase in the expression levels of TLR-4, NFK-B, IL-6, TNF-α, iNOS, and COX-2 at both the mRNA and protein levels. The testicular NO has increased in HICT and MICT groups. Despite a decrease in the distribution of Leydig cells in both the MICT and HICT groups, the HICT group exhibited a significant (p < 0.05) reduction in Leydig cell steroidogenic activity and serum testosterone levels. In conclusion, our findings revealed that ETPs can influence Leydig cell steroidogenic activity and testosterone secretion, contingent on their intensity. These effects are attributed to alterations in the expression levels of pro-inflammatory mediators and cytokines.

Insights into Canine Infertility: Apoptosis in Chronic Asymptomatic Orchitis

Chronic asymptomatic orchitis (CAO) is a common cause of acquired non-obstructive azoospermia in dogs. To understand the impact and mode of action of apoptosis, we investigated TUNEL, Bax, Bcl-2, Fas/Fas ligand, and caspase 3/8/9 in testicular biopsies of CAO-affected dogs and compared the results to undisturbed spermatogenesis in healthy males (CG). TUNEL⁺ cells were significantly increased in CAO, correlating with the disturbance of spermatogenesis. Bcl-2, Bax (p < 0.01 each), caspase 9 (p < 0.05), Fas, caspase 8 (p < 0.01 each), and caspase 3 (p < 0.05) were significantly increased at the mRNA level, whereas FasL expression was downregulated. Cleaved caspase 3 staining was sporadic in CAO but not in CG. Sertoli cells, some peritubular (CAO/CG) and interstitial immune cells (CAO) stained Bcl-2⁺, with significantly more immunopositive cells in both compartments in CAO compared to CG. Bcl-2 and CD20 co-expressing B lymphocytes were encountered interstitially and in CAO occasionally also found intratubally, underlining their contribution to the maintenance of CAO. Our results support the crucial role of the intrinsic and extrinsic apoptotic pathways in the pathophysiology of canine CAO. Autoprotective Bcl-2 expression in Sertoli cells and B lymphocytes seems to be functional, however, thereby also maintaining and promoting the disease by immune cell activation.

Unraveling the effect of the inflammatory microenvironment in spermatogenesis progression

Experimental autoimmune orchitis (EAO) is a chronic inflammatory disorder that causes progressive spermatogenic impairment. EAO is characterized by high intratesticular levels of nitric oxide (NO) and tumor necrosis factor alpha (TNFα) causing germ cell apoptosis and Sertoli cell dysfunction. However, the impact of this inflammatory milieu on the spermatogenic wave is unknown. Therefore, we studied the effect of inflammation on spermatogonia and preleptotene spermatocyte cell cycle progression in an EAO context and through the intratesticular DETA-NO and TNFα injection in the normal rat testes. In EAO, premeiotic germ cell proliferation is limited as a consequence of the undifferentiated spermatogonia (CD9⁺) cell cycle arrest in G2/M and the reduced number of differentiated spermatogonia (c-kit⁺) and preleptotene spermatocytes that enter in the meiotic S-phase. Although inflammation disrupts spermatogenesis in EAO, it is maintained in some seminiferous tubules at XIV and VII-VIII stages of the epithelial cell cycle, thereby guaranteeing sperm production. We found that DETA-NO (2 mM) injected in normal testes arrests spermatogonia and preleptotene spermatocyte cell cycle; this effect reduces the number of proliferative spermatogonia and the number of preleptotene spermatocytes in meiosis S-phase (36 h after). The temporal inhibition of spermatogonia clonal amplification delayed progression of the spermatogenic wave (5 days after) finally altering spermatogenesis. TNFα (0.5 and 1 µg) exposure did not affect premeiotic germ cell cycle or spermatogenic wave. Our results show that in EAO the inflammatory microenvironment altered spermatogenesis kinetics through premeiotic germ cell cycle arrest and that NO is a sufficient factor contributing to this phenomenon.

High Throughput scRNA-Seq Provides Insights Into Leydig Cell Senescence Induced by Experimental Autoimmune Orchitis: A Prominent Role of Interstitial Fibrosis and Complement Activation

Leydig cells (Lc), located in the interstitial space of the testis between seminiferous tubules, produce 95% of testosterone in male individuals, which is pivotal for male sexual differentiation, spermatogenesis, and maintenance of the male secondary sex characteristics. Lc are prone to senescence in aging testes, resulting in compromised androgen synthesis capability upon aging. However, little is known about whether Lc undergo senescence in a chronic inflammatory environment. To investigate this question, mouse models of experimental autoimmune orchitis (EAO) were used, and Lc were analyzed by high throughput scRNA-Seq. Data were screened and analyzed by correlating signaling pathways with senescence, apoptosis, androgen synthesis, and cytokine/chemokine signaling pathways. EAO did induce Lc senescence, and Lc senescence in turn antagonized androgen synthesis. Based on the correlation screening of pathways inducing Lc senescence, a plethora of pathways were found to play potential roles in triggering Lc senescence during EAO, among which the Arf6 and angiopoietin receptor pathways were highly correlated with senescence signature. Notably, complement and interstitial fibrosis activated by EAO worsened Lc senescence and strongly antagonized androgen synthesis. Furthermore, most proinflammatory cytokines enhanced both senescence and apoptosis in Lc and spermatogonia (Sg) during EAO, and proinflammatory cytokine antagonism of the glutathione metabolism pathway may be key in inducing cellular senescence during EAO.

Arginine promotes testicular development in boars through nitric oxide and putrescine

The present work aimed to explore the influence and underlying mechanisms involving arginine in testicular development in boars. To this end, thirty 30-day-old male Duroc piglets (7.00 ± 0.30 kg) were randomly sorted into two groups, maintained on either a basal diet (CON, n = 15) or a diet supplemented with 0.8% arginine (ARG, n = 15). Blood and testicular samples were collected during the experimental period to analyse amino acid composition and arginine metabolite levels. The results showed that dietary supplementation with arginine increased number of spermatogonia and height of the seminiferous epithelium (p < 0.05). Sperm density, total number and effective number of sperm of the boars in the ARG group increased significantly compared with those in the CON group (p < 0.05). Although arginine supplementation did not affect plasma amino acid levels, testicular arginine levels in 150-day-old boars exhibited a significant increase (p < 0.05). The level of serum nitric oxide (NO) and activity of nitric oxide synthase (NOS) also increased in 150-day-old boars in the ARG group (p < 0.05). Interestingly, dietary supplementation with arginine increased testicular levels of putrescine in 150-day-old boars (p < 0.05). These results indicated that arginine supplementation increased serum NO levels and testicular arginine and putrescine abundance, thereby improving testicular development and semen quality in boars.

NO● Represses the Oxygenation of Arachidonoyl PE by 15LOX/PEBP1: Mechanism and Role in Ferroptosis

We recently discovered an anti-ferroptotic mechanism inherent to M1 macrophages whereby high levels of NO^● suppressed ferroptosis via inhibition of hydroperoxy-eicosatetraenoyl-phosphatidylethanolamine (HpETE-PE) production by 15-lipoxygenase (15LOX) complexed with PE-binding protein 1 (PEBP1). However, the mechanism of NO^● interference with 15LOX/PEBP1 activity remained unclear. Here, we use a biochemical model of recombinant 15LOX-2 complexed with PEBP1, LC-MS redox lipidomics, and structure-based modeling and simulations to uncover the mechanism through which NO^● suppresses ETE-PE oxidation. Our study reveals that O₂ and NO^● use the same entry pores and channels connecting to 15LOX-2 catalytic site, resulting in a competition for the catalytic site. We identified residues that direct O₂ and NO^● to the catalytic site, as well as those stabilizing the esterified ETE-PE phospholipid tail. The functional significance of these residues is supported by in silico saturation mutagenesis. We detected nitrosylated PE species in a biochemical system consisting of 15LOX-2/PEBP1 and NO^● donor and in RAW264.7 M2 macrophages treated with ferroptosis-inducer RSL3 in the presence of NO^●, in further support of the ability of NO^● to diffuse to, and react at, the 15LOX-2 catalytic site. The results provide first insights into the molecular mechanism of repression of the ferroptotic Hp-ETE-PE production by NO^●.

N-acetyl cysteine co-treatment abates perfluorooctanoic acid-induced reproductive toxicity in male rats

Perfluorooctanoic acid is a synthetic perfluoroalkyl-persistent in the environment and toxic to humans. N-acetylcysteine is a pro-drug of both amino acid l-cysteine and glutathione-a non-enzymatic antioxidant. N-acetylcysteine serves as an antidote for paracetamol poisoning and alleviates cellular oxidative and inflammatory stressors. We investigated N-acetylcysteine role against reproductive toxicity in male Wistar rats (weight: 140-220 g; 10 weeks old) posed by perfluorooctanoic acid exposure. Randomised rat cohorts were dosed both with perfluorooctanoic acid (5 mg/kg; p.o) or co-dosed with N-acetylcysteine (25 and 50 mg/kg p.o) for 28 days. Sperm physiognomies, biomarkers of testicular function and reproductive hormones, oxidative stress and inflammation were evaluated. Co-treatment with N-acetylcysteine significantly (p < .05) reversed perfluorooctanoic acid-mediated decreases in reproductive enzyme activities, and adverse effect on testosterone, luteinising and follicle-stimulating hormone concentrations. N-acetylcysteine treatment alone, improved sperm motility, count and viability, and reduced total sperm abnormalities. Co-treatment with N-acetylcysteine mitigated perfluorooctanoic acid-induced alterations in sperm function parameters. N-acetylcysteine abated (p < .05) perfluorooctanoic acid-induced oxidative stress in experimental rats testes and epididymis, and generally improved antioxidant enzyme activities and cellular thiol levels. Furthermore, N-acetylcysteine suppressed inflammatory responses and remedied perfluorooctanoic acid-mediated histological injuries in rat. Cooperatively, N-acetylcysteine enhanced reproductive function in perfluorooctanoic acid dosed rats, by lessening oxidative and nitrative stressors and mitigated inflammatory responses in the examined organ.

Relevance of angiogenesis in autoimmune testis inflammation

Experimental autoimmune orchitis (EAO) is a useful model to study organ-specific autoimmunity and chronic testicular inflammation. This model reflects testicular pathological changes reported in immunological infertility in men. Progression of EAO in rodents is associated with a significantly increased percentage of testicular endothelial cells and interstitial testicular blood vessels, indicating an ongoing angiogenic process. Vascular endothelial growth factor A (VEGFA), the main regulator of physiological and pathological angiogenesis, can stimulate endothelial cell proliferation, chemotaxis and vascular permeability. The aim of this study was to explore the role of VEGFA in the pathogenesis of testicular inflammation. Our results found VEGFA expression in Leydig cells, endothelial cells and macrophages in testis of rats with autoimmune orchitis. VEGFA level was significantly higher in testicular fluid and serum of rats at the end of the immunization period, preceding testicular damage. VEGF receptor (VEGFR) 1 is expressed mainly in testicular endothelial cells, whereas VEGFR2 was detected in germ cells and vascular smooth muscle cells. Both receptors were expressed in testicular interstitial cells. VEGFR2 increased after the immunization period in the testicular interstitium and VEGFR1 was downregulated in EAO testis. In-vivo-specific VEGFA inhibition by Bevacizumab prevented the increase in blood vessel number and reduced EAO incidence and severity. Our results unveil relevance of VEGFA-VEGFR axis during orchitis development, suggesting that VEGFA might be an early marker of testicular inflammation and Bevacizumab a therapeutic tool for treatment of testicular inflammation associated with subfertility and infertility.

Effect of ketotifen fumarate on experimental autoimmune orchitis and torsion of the spermatic cord

The aim of this work was to study effects of ketotifen fumarate (KF) on prevention of tissue damage in testes of rats with experimental autoimmune orchitis (EAO) and on the contralateral testis in a model of prolonged testicular cord torsion (TCT). Rats with EAO or TCT were injected intraperitoneally once daily with KF or saline solution (vehicle group). Incidence and severity of testicular damage were evaluated by histopathology using an EAO score or a Johnsen score. Mast cells (MC) were identified by histochemistry and quantified. In EAO model, KF significantly reduced severity of histopathological testicular damage compared to rats in the vehicle group. KF also reduced the number of testicular MC compared to vehicle group. Similarly, in TCT model, multifocal damage of the contralateral testis was observed 30 days after testicular torsion characterized by sloughing of the germinal epithelium, seminiferous tubule atrophy, and interstitial edema. Focal signs of inflammation and fibrosis of seminiferous tubular walls were also observed. In contrast, sections of contralateral testis of rats injected with KF and killed 30 days after surgery showed normal histological features. A significant decrease in the number of MC was observed in rats treated with KF compared to untreated animals. In conclusion, we demonstrated that treatment with KF reduced testicular inflammatory process and MC infiltrates in both EAO and TCT models. The results suggest a promising treatment for infertile male patients with testicular pathologies associated with inflammation and germ cell loss.

Pathomechanisms of Autoimmune Based Testicular Inflammation

Infection and inflammation of the male reproductive tract are relevant causes of infertility. Inflammatory damage occurs in the special immunosuppressive microenvironment of the testis, a hallmark termed testicular immune privilege, which allows tolerance to neo-antigens from developing germ cells appearing at puberty, long after the establishment of systemic immune tolerance. Experimental autoimmune orchitis (EAO) is a well-established rodent model of chronic testicular inflammation and organ specific autoimmunity that offers a valuable in vivo tool to investigate the pathological and molecular mechanisms leading to the breakdown of the testicular immune privilege. The disease is characterized by the infiltration of the interstitium by immune cells (mainly macrophages, dendritic cells, and T cells), formation of autoantibodies against testicular antigens, production of pro-inflammatory mediators such as NO, MCP1, TNFα, IL6, or activins and dysregulation of steroidogenesis with reduced levels of serum testosterone. EAO leads to sloughing of germ cells, atrophic seminiferous tubules and fibrotic remodeling, parameters all found similarly to changes in human biopsies from infertile patients with inflammatory infiltrates. Interestingly, testosterone supplementation during the course of EAO leads to expansion of the regulatory T cell population and inhibition of disease development. Knowledge of EAO pathogenesis aims to contribute to a better understanding of human testicular autoimmune disease as an essential prerequisite for improved diagnosis and treatment.

The inflammatory mediators TNFα and nitric oxide arrest spermatogonia GC-1 cell cycle

During an inflammatory process of the testis, the network of somatic, immune, and germ cell interactions is altered leading to organ dysfunction. In testicular biopsies of infertile men, spermatogenesis impairment is associated with reduced spermatogonia proliferation, increased number of immune cells, and content of pro-inflammatory cytokines. TNFα-TNFR and nitric oxide (NO)-NO synthase systems are up-regulated in models of testicular damage and in human testis with maturation arrest. The purpose of this study was to test the hypothesis that TNFα-TNFR system and NO alter the function of spermatogonia in the inflamed testis. We studied the effect of TNFα and NO on GC-1 spermatogonia cell cycle progression and death by flow cytometry. GC-1 cells expressed TNFR1 and TNFR2 (immunofluorescence). TNFα (10 and 50 ng/ml) and DETA-Nonoate (0.5 and 2 mM), a NO releaser, increased the percentage of cells in S-phase of the cell cycle and reduced the percentage in G1, inducing also cell apoptosis. TNFα effect was not mediated by oxidative stress unlike NO, since the presence of N-acetyl-l-cysteine (2.5 and 5.0 mM) prevented NO induced cell cycle arrest and death. GC-1 spermatogonia overpass NO induced cell cycle arrest but no TNFα, since after removal of NO, spermatogonia progressed through the cell cycle. We propose TNFα and NO might contribute to impairment of spermatogenesis by preventing adequate functioning of the spermatogonia population. Our results showed that TNFα and NO impaired spermatogonia cell cycle, inducing GC-1 arrest in the S phase.

Role of indoleamine 2,3-dioxygenase in testicular immune-privilege

Male meiotic germ cell including the spermatozoa represent a great challenge to the immune system, as they appear long after the establishment of normal immune tolerance mechanisms. The capacity of the testes to tolerate autoantigenic germ cells as well as survival of allogeneic organ engrafted in the testicular interstitium have led to consider the testis an immunologically privileged site. Disruption of this immune privilege following trauma, tumor, or autoimmune orchitis often results in male infertility. Strong evidence indicates that indoleamine 2,3-dioxygenase (IDO) has been implicated in fetal and allograft tolerance, tumor immune resistance, and regulation of autoimmune diseases. IDO and tryptophan 2,3-dioxygenase (TDO) catalyze the same rate-limiting step of tryptophan metabolism along a common pathway, which leads to tryptophan starvation and generation of catabolites collectively known as kynurenines. However, the relevance of tryptophan metabolism in testis pathophysiology has not yet been explored. Here we assessed the in vivo role of IDO/TDO in experimental autoimmune orchitis (EAO), a model of autoimmune testicular inflammation and immunologically impaired spermatogenesis. EAO was induced in adult Wistar rats with testicular homogenate and adjuvants. Control (C) rats injected with saline and adjuvants and normal untreated rats (N) were also studied. mRNA expression of IDO decreased in whole testes and in isolated Sertoli cells during EAO. TDO and IDO localization and level of expression in the testis were analyzed by immunostaining and Western blot. TDO is expressed in granulomas from EAO rats, and similar protein levels were observed in N, C, and EAO groups. IDO was detected in mononuclear and endothelial cells and reduced IDO expression was detected in EAO group compared to N and C rats. This phenomenon was concomitant with a significant reduction of IDO activity in EAO testis measured by tryptophan and kynurenine concentrations (HPLC). Finally, in vivo inhibition of IDO with 1-methyl-tryptophan increased severity of the disease, demonstrating down regulation of IDO-based tolerance when testicular immune regulation was disrupted. We present evidence that an IDO-based mechanism is involved in testicular immune privilege.

Pharmacological and biochemical studies on protective effects of mangiferin and its interaction with nitric oxide (NO) modulators in adjuvant-induced changes in arthritic parameters, inflammatory, and oxidative biomarkers in rats

Current study was designed to evaluate protective effect of mangiferin and its interaction with low dose of nitric oxide (NO) modulators in complete Freund's adjuvant (CFA) inoculated rats. Male wistar rats (200-300 g, n = 8 per group) were used in the study. On day ''0'' of study arthritis was induced in rats by injecting 0.2 ml CFA in sub-planter region of right hind paw of animals. Treatment with methotrexate (5 mg/kg), mangiferin (10-30 mg/kg) alone and in combination with NO modulators was given (i.p.) from days 14 to 28. After 28 days, blood and joint synovial fluid was collected for biochemical analysis and rat paws were excised to estimate MDA and SOD in tissue (paw) homogenates. CFA inoculation significantly increases (1) arthritic index, (2) ankle diameter, (3) paw volume, and (4) serum TNF-α, IL-6, IL-1β, and synovial TNF-α levels (p < 0.001). The serum Th1 (IFN-γ) and Th2 (IL-4) cytokine levels, MDA levels in rat paw tissue homogenates and serum NF-κB levels were also found significantly increased. Significant decrease in serum IL-10 levels and SOD activity was found after CFA inoculation. These CFA-induced arthritic changes, cytokine profile, and oxidative stress markers were significantly reversed by mangiferin (10-30 mg/kg) treatment alone and in combination with L-arginine and L-NAME nitric oxide modulators (p < 0.05). Treatment with methotrexate (5 mg/kg) also significantly reversed these adjuvant changes (p < 0.05). However, effect of methotrexate was less marked as compared to mangiferin (30 mg/kg) alone and in combination with L-NAME (10 mg/kg), but was comparable or slightly better than mangiferin (10 and 20 mg/kg). Thus, on the basis of our findings, we can suggest that interaction of mangiferin with nitric oxide modulators may have therapeutic value for chronic inflammatory disease such as RA.

MEHP-induced rat testicular inflammation does not exacerbate germ cell apoptosis

The testis is an organ that maintains an immune suppressive environment. We previously revealed that exposure of pre-pubertal rats to an acute dose of a well-described Sertoli cell toxicant, mono-(2-ethylhexyl) phthalate (MEHP), leads to an accumulation of CD11b+ immune cells in the testicular interstitial space that closely correlates with a robust incidence of germ cell (GC) apoptosis. Here, we test the hypothesis that the infiltrating immune cells contribute to GC apoptosis. Postnatal day 28 Fischer rats that received an oral dose of 700 mg/kg MEHP showed a significant infiltration of both CD11bc+/CD68+/CD163- macrophages and neutrophils. The infiltration peaked at 12 h, but had reduced by 48 h. Testicular macrophages from MEHP-treated rats showed significantly upregulated expression of Tnfa and Il6, and the Arg1/Nos2 ratio was reduced compared to controls. However, small increases in anti-inflammatory genes Il10 and Tgfb1 were also observed. Depletion of circulating monocytes with clodronate liposomes prior to MEHP treatment reduced the macrophage influx into the testis, but did not lower GC apoptosis. Additionally, depletion of neutrophils using an anti-polymorphonuclear cell antibody prevented both macrophage and neutrophil infiltration into the testis, and also did not affect GC apoptosis. Together, these results show that exposure to MEHP leads to a rapid and temporary influx of pro-inflammatory monocytes and neutrophils in the interstitium of the testis. However, with this acute dosing paradigm, these infiltrating leukocytes do not appear to contribute to MEHP-induced testicular GC apoptosis leaving the functional significance of these infiltrating cells in the pathogenesis of MEHP-induced testicular injury unresolved.

Induction of experimental autoimmune orchitis in mice: responses to elevated circulating levels of the activin-binding protein, follistatin

Experimental autoimmune orchitis (EAO) is a rodent model of chronic testicular inflammation that mimics the pathology observed in some types of human infertility. In a previous study, testicular expression of the inflammatory/immunoregulatory cytokine, activin A, was elevated in adult mice during the onset of EAO, indicating a potential role in the regulation of the disease. Consequently, we examined the development of EAO in mice with elevated levels of follistatin, an endogenous activin antagonist, as a potential therapeutic approach to testicular inflammation. Prior to EAO induction, mice received a single intramuscular injection of a non-replicative recombinant adeno-associated viral vector carrying a gene cassette of the circulating form of follistatin, FST315 (FST group). Serum follistatin levels were increased 5-fold in the FST group compared with the control empty vector (EV) group at 30 and 50 days of EAO, but intra-testicular levels of follistatin or activin A were not significantly altered. Induction of EAO was reduced, but not prevented, with mild-to-severe damage in 75% of the EV group and 40% of the FST group, at 50 days following immunisation with testicular homogenate. However, the EAO damage score (based on disruption of the blood-testis barrier, apoptosis, testicular damage and fibrosis) and extent of intratesticular inflammation (expression of inflammatory mediators) were directly proportional to the levels of activin A measured in the testis at 50 days. These data implicate activin A in the progression of EAO, thereby providing a potential therapeutic target; however, elevating circulating follistatin levels were not sufficient to prevent EAO development.

Impacts of dose and time of boldenone and stanazolol exposure in inflammatory markers, oxidative and nitrosative stress and histopathological changes in the rat testes

The present study was conducted to analyze the adverse effects of the anabolic steroids boldenone (BOL) and stanazolol (ST) in the reproductive function of male rats. These molecules were administered using three different protocols. In Protocol I, BOL and ST were administered in a higher dose than what is recommended but for a short period. In Protocol II, a moderate dose of these compounds was applied for an intermediate period, whereas in Protocol III a reduced dose was administered but for an extended period. Notably, Protocol I and III resulted in increased levels of reactive oxygen specimens (ROS [I, p < 0.01] [III, p < 0.001)]) and nitrite plus nitrate (NOx [I, p < 0.01] [II, p < 0.01] [III,p < 0.05]), respectively, whereas non-protein thiols (NPSH) levels were decreased only after Protocol III (p < 0.01). Myeloperoxidase activity was significantly increased after treatment with BOL in protocol II (p < 0.01) and III (p < 0.05) than with ST in protocol III (p < 0.05). Boldenone and ST also caused a significant up-regulation in the levels of serum testosterone when protocols I (p < 0.01) and II (p < 0.05) were performed. There were also visible histopathological alterations in the testes induced by treatment with BOL, namely degenerative changes primarily characterized by a decrease in the germinal epithelium. Together, these results suggest that the administration of BOL or ST exerts a significantly harmful effect in the testes of male rats. Moreover, all the treatment protocols used in this study induced deleterious effects on the testes, as indicated by the different biochemical parameters investigated. However, only the protocols of longer exposure time (II and III) induced morphological changes compatible with infertility.

Pharmacological studies on the anti-inflammatory and immunomodulatory role of pentoxifylline and its interaction with nitric oxide (NO) in experimental arthritis in rats

AIM

Present study was designed to evaluate protective effects of pentoxifylline and its potentiation with low dose of nitric oxide (NO) modulators in adjuvant-induced experimental arthritis in rats.

METHOD

Wistar rats (200-300 g, n = 8 per group) of both sexes were used in the study. On day "0" experimental arthritis was induced by injecting 0.2 ml of Complete Freund's adjuvant (CFA) in sub-planter region of right hind paw of animals. Pentoxifylline treatment alone and in combination with NO modulators was given (i.p.) from day 14 to 28. Various arthritic parameters were recorded and blood and joint synovial fluid was collected for biochemical analysis.

RESULTS

CFA inoculation significantly increases (1) arthritic index (2) ankle diameter (3) paw volume (4) histopathology score (5) serum TNF-α, IL-6, IL-1β and synovial TNF-α levels (p < 0.001) (6) serum Th₁ and Th₂ cytokine levels g) MDA levels in rat paw tissue homogenates (7) serum NF-κB levels. Significant decrease in serum IL-10 levels and SOD activity was observed in rats after CFA inoculation. Decrease in body weight and suppressed general quality of life of CFA inoculated rats was also observed. These CFA-induced arthritic changes were significantly reversed by pentoxifylline alone and in combination with low dose of NO modulators (p < 0.05).

CONCLUSION

These results are suggestive of protective effects of pentoxifylline and its potentiation in combination with low dose of NO modulators. These results may provide new pharmacological therapy for management of rheumatoid arthritis (RA).