RESUMO
Inducible nitric oxide synthase (iNOS) is an enzyme upregulated in the brain during neuroimmune stimuli which is associated with an oxidative and pro-inflammatory environment in several brain regions, including the hippocampal formation and the prefrontal cortex. The dentate gyrus of the hippocampal formation is the site of a process known as adult hippocampal neurogenesis (AHN). Although many endogenous and extrinsic factors can modulate AHN, the exact participation of specific proinflammatory mediators such as iNOS in these processes remains to be fully elucidated. Here, we investigated how the total genetic ablation of iNOS impacts the hippocampal neurogenic niche and microglial phenotype and if these changes are correlated to the behavioral alterations observed in iNOS knockout (K.O.) mice submitted or not to the chronic unpredictable stress model (CUS - 21 days protocol). Contrary to our initial hypothesis, at control conditions, iNOS K.O. mice displayed no abnormalities on microglial activation in the dentate gyrus. However, they did exhibit impaired newborn cells and immature neuron survival, which was not affected by CUS. The reduction of AHN in iNOS K.O. mice was accompanied by an increased positive coping response in the tail suspension test and facilitation of anxiety-like behaviors in the novelty suppressed feeding. Next, we investigated whether a pro-neurogenic stimulus would rescue the neurogenic capacity of iNOS K.O. mice by administering in control and CUS groups the antidepressant escitalopram (ESC). The chronic treatment with ESC could not rescue the neurogenic capacity or the behavioral changes observed in iNOS K.O. mice. Besides, in the ventromedial prefrontal (vmPFC) cortex there was no change in the expression or the chronic activation of PV neurons (evaluated by double labeling PV with FOSB) in the prelimbic (PrL) or infralimbic subregions. FOSB expression, however, increased in the PrL of iNOS K.O. mice. Our results suggest that iNOS seems essential for the survival of newborn cells and immature neurons in the hippocampus and seem to partially explain the anxiogenic-like behavior observed in iNOS K.O. mice. On the other hand, the iNOS ablation appears to result in increased activity of the PrL which could explain the antidepressant-like behaviors of iNOS K.O mice.
Assuntos
Giro Denteado/citologia , Neurônios/fisiologia , Óxido Nítrico Sintase Tipo II/fisiologia , Animais , Sobrevivência Celular , Citocinas/fisiologia , Escitalopram/farmacologia , Masculino , Camundongos , Camundongos Knockout , Microglia/fisiologia , Neurogênese/efeitos dos fármacos , Óxido Nítrico Sintase Tipo II/genética , Estresse Psicológico/psicologiaRESUMO
We tested the hypothesis that ethanol would aggravate the deleterious effects of sub-lethal cecal ligation and puncture (SL-CLP) sepsis in the cardiorenal system and that inhibition of inducible nitric oxide synthase (iNOS) would prevent such response. Male C57BL/6 mice were treated with ethanol for 12 weeks. One hour before SL-CLP surgery, mice were treated with N6-(1-iminoethyl)-lysine (L-NIL, 5 mg/kg, i.p.), a selective inhibitor of iNOS. A second dose of L-NIL was administered 24 h after SL-CLP surgery. Mice were killed 48 h post surgery and the blood, the renal cortex, and the left ventricle (LV) were collected for biochemical analysis. L-NIL attenuated the increase in serum creatinine levels induced by ethanol, but not by SL-CLP. Ethanol, but not SL-CLP, increased creatine kinase (CK)-MB activity and L-NIL did not prevent this response. In the renal cortex, L-NIL prevented the redox imbalance induced by ethanol and SL-CLP. Inhibition of iNOS also decreased lipoperoxidation induced by ethanol and SL-CLP in the LV. L-NIL prevented the increase of pro-inflammatory cytokines and reactive oxygen species induced by ethanol and (or) SL-CLP in the cardiorenal system, suggesting that iNOS modulated some of the molecular mechanisms that underlie the deleterious effects of both conditions in the cardiorenal system.
Assuntos
Inibidores Enzimáticos/farmacologia , Etanol/efeitos adversos , Ventrículos do Coração/metabolismo , Córtex Renal/metabolismo , Lisina/farmacologia , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Sepse/etiologia , Sepse/prevenção & controle , Animais , Creatina Quinase Forma MB/metabolismo , Creatinina/sangue , Citocinas/metabolismo , Inibidores Enzimáticos/administração & dosagem , Mediadores da Inflamação/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Lisina/administração & dosagem , Masculino , Camundongos Endogâmicos C57BL , Óxido Nítrico Sintase Tipo II/fisiologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
Neospora caninum infection is an important cause of neuromuscular disease in dogs and abortion in cattle, leading to significant economic losses in beef and dairy industries. The protective immunity against apicomplexan parasites, specifically Toxoplasma gondii and N. caninum, is typically achieved by inducing an IL-12-driven Th1 immune response. IL-12 stimulates IFN-γ production, which activates Inducible Nitric Oxide Synthase (iNOS) and promotes consequent Nitric Oxide (NO) synthesis, classically described as one of the main effector mechanisms for parasite elimination. Here, we aimed to evaluate the role played by iNOS during N. caninum infection. Our results show that N. caninum infection in C57BL/6 wild type (WT) mice induce NO production in vivo and in vitro. In agreement, iNOS deficient mice, as well as WT mice treated with iNOS inhibitor aminoguanidine, succumbed during acute infection with a dose lethal to 50 % of the WT mice, and presented significant increase in parasite load when submitted to sub-lethal infection protocols. Interestingly, the lack of control of parasite proliferation observed in iNOS-/- mice was associated with notable CNS inflammation and increased production of the main systemic proinflammatory cytokines (IL-12, IFN-γ, IL-6, TNF and IL-17A). Taken together, our findings show that iNOS plays an important role in restricting N. caninum replication, while also modulates the inflammatory process induced by the infection.
Assuntos
Coccidiose/enzimologia , Neospora/imunologia , Óxido Nítrico Sintase Tipo II/fisiologia , Animais , Coccidiose/parasitologia , Coccidiose/patologia , Interferon gama/análise , Subunidade p40 da Interleucina-12/análise , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/deficiênciaRESUMO
The baroreflex is a prominent moment-to-moment mechanism regulating the blood pressure. The hippocampus is a limbic structure in which has been pointed out as part of central network regulating baroreflex. However, the local neurochemical mechanisms involved in control of baroreflex function are not completely understood. Thus, this study aimed to investigate the involvement of nitrergic neurotransmission present in the dorsal hippocampus in baroreflex control of heart rate in conscious rats. For this, we evaluated the effect of bilateral microinjection into the dorsal hippocampus of either the nitric oxide (NO) scavenger carboxy-PTIO, the selective neuronal nitric oxide synthase (nNOS) inhibitor Nω-Propyl-l-arginine (NPLA) or the selective inducible nitric oxide synthase (iNOS) inhibitor 1400â¯W in bradycardia evoked by blood pressure increases in response to intravenous infusion of phenylephrine, and tachycardia caused by blood pressure decreases evoked by intravenous infusion of sodium nitroprusside. Bilateral microinjection of carboxy-PTIO into the dorsal hippocampus decreased the baroreflex tachycardic response without affecting the reflex bradycardia. Hippocampus treatment with NPLA increased the baroreflex bradycardia gain without affecting the reflex tachycardia. Bilateral hippocampal treatment with 1400â¯W decreased the reflex tachycardia and increased the baroreflex bradycardic response. Overall, these findings provide evidence that hippocampal nitrergic mechanisms acting in a NOS isoform-specific manner plays a prominent role in control of baroreflex function. Indeed, the results indicate that nNOS and iNOS exerts an inhibitory influence on reflex bradycardia, whereas iNOS mediates the reflex tachycardia.
Assuntos
Barorreflexo/fisiologia , Hipocampo/fisiologia , Óxido Nítrico Sintase Tipo II/fisiologia , Óxido Nítrico Sintase Tipo I/fisiologia , Animais , Barorreflexo/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Inibidores Enzimáticos/administração & dosagem , Frequência Cardíaca/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Masculino , Óxido Nítrico Sintase Tipo I/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Ratos WistarRESUMO
Orofacial pain is pain perceived in the face and/or oral cavity, generally caused by diseases or disorders of regional structures, by dysfunction of the nervous system, or through referral from distant sources. Treatment of orofacial pain is mainly pharmacological, but it has increased the number of reports demonstrating great clinical results with the use of non-pharmacological therapies, among them electroacupuncture. However, the mechanisms involved in the electroacupuncture are not well elucidated. Thus, the present study investigate the involvement of the nitric oxide synthase (NOS) and ATP sensitive K+ channels (KATP) in the antinociception induced by electroacupuncture (EA) at acupoint St36. Thermal nociception was applied in the vibrissae region of rats, and latency time for face withdrawal was measured. Electrical stimulation of acupoint St36 for 20 minutes reversed the thermal withdrawal latency and this effect was maintained for 150 min. Intraperitoneal administration of specific inhibitors of neuronal nitric oxide synthase (nNOS), inducible nitric oxide synthase (iNOS) and a KATP channels blocker reversed the antinociception induced by EA. Furthermore, nitrite concentration in cerebrospinal fluid (CSF) and plasma, increased 4 and 3-fold higher, respectively, after EA. This study suggests that NO participates of antinociception induced by EA by nNOS, iNOS and ATP-sensitive K+ channels activation.
Assuntos
Pontos de Acupuntura , Eletroacupuntura , Dor Facial/terapia , Manejo da Dor , Animais , Dor Facial/fisiopatologia , Temperatura Alta/efeitos adversos , Canais KATP/antagonistas & inibidores , Canais KATP/fisiologia , Masculino , Óxido Nítrico Sintase Tipo I/antagonistas & inibidores , Óxido Nítrico Sintase Tipo I/fisiologia , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/fisiologia , Nitritos/sangue , Nitritos/líquido cefalorraquidiano , Ratos WistarRESUMO
Sertoli cell (SC) proliferation in mice occurs until two weeks after birth and is mainly regulated by FSH and thyroid hormones. Previous studies have shown that transient neonatal hypothyroidism in laboratory rodents is able to extend SC mitotic activity, leading ultimately to higher testis size and daily sperm production (DSP) in adult animals. Moreover, we have shown that due to higher SC proliferation and lower germ cell apoptosis, iNOS deficiency in mice also results in higher testis size and DSP. Although the cell size was smaller, the Leydig cells (LCs) number per testis also significantly increased in iNOS-/- mice. Our aims in the present study were to investigate if the combination of neonatal hypothyroidism and iNOS deficiency promotes additive effects in SC number, testis size and DSP. Hypothyroidism was induced in wild-type (WT) and iNOS-/- mice using 6-propyl-2-thiouracil (PTU) through the mother's drinking water from 0 to 20 days of age, and were sacrificed at adulthood. Our results showed that, in contrast to the WT mice in which testis size, DSP and SC numbers increased significantly by 20, 40 and 70% respectively, after PTU treatment, no additive effects were observed for these parameters in treated iNOS-/- mice, as well as for LC. No alterations were observed in spermatogenesis in any group evaluated. Although we still do not have an explanation for these intriguing findings, we are currently investigating whether thyroid hormones influence iNOS levels and/or counterbalance physiological effects of iNOS deficiency in testis function and spermatogenesis.
Assuntos
Animais Recém-Nascidos , Proliferação de Células/fisiologia , Hipotireoidismo/patologia , Óxido Nítrico Sintase Tipo II/deficiência , Células de Sertoli/patologia , Animais , Feminino , Hipotireoidismo/induzido quimicamente , Lactação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/fisiologia , Tamanho do Órgão , Propiltiouracila/administração & dosagem , Túbulos Seminíferos/patologia , Espermatogênese/fisiologia , Testículo/patologiaRESUMO
Silver nanoparticles (AgNPs) are used to manufacture materials with new properties and functions. However, little is known about their toxic or beneficial effects on human health, especially in the respiratory system, where its smooth muscle (ASM) regulates the airway contractility by different mediators, such as acetylcholine (ACh) and nitric oxide (NO). The aim of this study was to evaluate the effects of AgNPs on ASM cells. Exposure to AgNPs induced ACh-independent expression of the inducible nitric oxide synthase (iNOS) at 100 µg/mL, associated with excessive production of NO. AgNPs induced the muscarinic receptor activation, since its blockage with atropine and blockage of its downstream signaling pathway inhibited the NO production. AgNPs at 10 and 100 µg/mL induced ACh-independent prolonged cytotoxicity and decreased cellular proliferation mediated by the muscarinic receptor-iNOS pathway. However, the concentration of 100 µg/mL of AgNPs induced muscarinic receptor-independent apoptosis, suggesting the activation of multiple pathways. These data indicate that AgNPs induce prolonged cytotoxic and anti-proliferative effects on ASM cells, suggesting an activation of the muscarinic receptor-iNOS pathway. Further investigation is required to understand the full mechanisms of action of AgNPs on ASM under specific biological conditions.
Assuntos
Proliferação de Células/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Miócitos de Músculo Liso/efeitos dos fármacos , Óxido Nítrico/fisiologia , Receptores Muscarínicos/fisiologia , Transdução de Sinais/fisiologia , Prata , Traqueia/efeitos dos fármacos , Acetilcolina/farmacologia , Animais , Apoptose/efeitos dos fármacos , Masculino , Miócitos de Músculo Liso/citologia , Óxido Nítrico Sintase Tipo II/fisiologia , Ratos , Ratos Wistar , Traqueia/patologiaRESUMO
PURPOSE: We evaluated the role of inducible nitric oxide synthase and PPARγ as prognostic factors for bladder cancer. MATERIALS AND METHODS: Inducible nitric oxide synthase and PPARγ were evaluated by Western blot and immunohistochemistry in a mouse bladder cancer model of nonmuscle invasive and invasive MB49-I tumor cells, and in human bladder cancer samples. RESULTS: Inducible nitric oxide synthase expression was negative in mouse normal urothelium and higher in invasive than in noninvasive MB49 tumors. In vitro inducible nitric oxide synthase activity, determined as nitrite, was higher in MB49-I than in MB49 cells (p <0.001). In human samples expression was also associated with tumor invasion. Nuclear PPARγ expression was negative in normal mouse urothelium but higher in nonmuscle invasive MB49 than in MB49-I tumors. Similarly in human tumors low PPARγ was associated with poor prognosis factors, such as high histological grade (p = 0.0160) and invasion status (p = 0.0352). A positive correlation was noted between inducible nitric oxide synthase and PPARγ in low histological grade and nonmuscle invasive tumors (Pearson correlation index 0.6368, p = 0.0351, 0.4438 and 0.0168, respectively). As determined by gene reporter assay, PPARγ activity was induced by nitric oxide only in nonmuscle invasive MB49 cells (p <0.001). CONCLUSIONS: Results suggest that increased PPARγ controls inducible nitric oxide synthase expression at early tumor stages. However, regulation is lost at advanced tumor stages, when the increase in inducible nitric oxide synthase and the decrease in PPARγ seem to be associated with bladder cancer progression.
Assuntos
Óxido Nítrico Sintase Tipo II/fisiologia , PPAR gama/fisiologia , Neoplasias da Bexiga Urinária/etiologia , Animais , Progressão da Doença , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Prognóstico , Neoplasias da Bexiga Urinária/patologiaRESUMO
Mechanisms involved in stress-induced asthmatic alterations have been poorly characterised. We assessed whether inducible nitric oxide synthase (iNOS) inhibition modulates the stress-amplified lung parenchyma responsiveness, oxidative stress and extracellular matrix remodelling that was previously increased by chronic lung inflammation. Guinea pigs were subjected to 7 exposures to ovalbumin (1-5 mg/ml) or saline (OVA and SAL groups) over 4 weeks. To induce behavioural stress, animals were subjected to a forced swimming protocol (5 times/week, over 2 weeks; SAL-Stress and OVA-Stress groups) 24 h after the 4th inhalation. 1400W (iNOS-specific inhibitor) was administered intraperitoneally in the last 4 days of the protocol (SAL-1400W, OVA-1400W, SAL-Stress+1400W and OVA-Stress+1400W groups). Seventy-two hours after the last inhalation, animals were anaesthetised and exsanguinated, and adrenal glands were removed. Lung tissue resistance and elastance were evaluated by oscillatory mechanics and submitted for histopathological evaluation. Stressed animals had higher adrenal weights compared to non-stressed groups, which were reduced by 1400W treatment. Behavioural stress in sensitised animals amplified the resistance and elastance responses after antigen challenge, numbers of eosinophils and iNOS+ cells, actin content and 8-iso-PGF2α density in the distal lung compared to the OVA group. 1400W treatment in ovalbumin-exposed and stressed animals reduced lung mechanics, iNOS+ cell numbers and 8-iso-PGF2α density compared to sensitised and stressed animals that received vehicle treatment. We concluded that stress amplifies the distal lung constriction, eosinophilic inflammation, iNOS expression, actin content and oxidative stress previously induced by chronic lung inflammation. iNOS-derived NO contributes to stress-augmented lung tissue functional alterations in this animal model and is at least partially due to activation of the oxidative stress pathway.
Assuntos
Óxido Nítrico Sintase Tipo II/administração & dosagem , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/fisiologia , Estresse Oxidativo , Pneumonia/enzimologia , Estresse Fisiológico , Actinas/metabolismo , Glândulas Suprarrenais/patologia , Animais , Colágeno , Dinoprosta/análogos & derivados , Dinoprosta/metabolismo , Eosinófilos/patologia , Cobaias , Hidrocortisona/sangue , Pulmão/enzimologia , Pulmão/imunologia , Pulmão/patologia , Masculino , Tamanho do Órgão , Pneumonia/patologia , Pneumonia/fisiopatologiaRESUMO
AIM: To investigate the effects of exogenous antioxidant copper zinc superoxide dismutase (Cu/Zn SOD) on oxidative stress in the experimental model of diabetes mellitus (DM). METHODS: Twenty eight male Wistar rats divided in four groups were used: control (CO), controls treated with SOD (CO + SOD), diabetics (DM), and diabetics treated with SOD (DM + SOD). SOD (orgotein, 13 mg/Kg body weight was administered. DM was induced by a single streptozotocin injection (i.p., 70 mg/kg), and 60 days later, we evaluated liver oxidative stress. RESULTS: Liver lipoperoxidation was increased in the DM group and significantly decreased in the DM + SOD group. Nitrite and nitrate measures were reduced in the DM and increased in the DM + SOD group, while iNOS expression in the DM group was 32% greater than in the CO and 53% greater in the DM + SOD group than in the DM group (P < .01). P65 expression was 37% higher in the DM (P < .05), and there was no significant difference between the DM and DM + SOD groups. CONCLUSION: SOD treatment reduced liver oxidative stress in diabetic animals, even though it did not change NFκB. SOD also increased NO, probably by the increased dismutation of the superoxide radical. The iNOS expression increase, which became even more evident after SOD administration.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Fígado/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Superóxido Dismutase/farmacologia , Animais , Fígado/metabolismo , Masculino , Óxido Nítrico/fisiologia , Óxido Nítrico Sintase Tipo II/fisiologia , Ratos , Ratos Wistar , EstreptozocinaRESUMO
Nitric oxide (NO) and reactive oxygen species (ROS) are key molecules in resistance to pathogens. Little is known about their role in pathogenesis of periapical lesions. To address this issue, we induced periapical lesions in mice lacking nitric oxide synthase (iNOS(-/-)) or phagocyte oxidase (PHOX(-/-)). iNOS(-/-) mice expressed higher levels of IL-1ß, TNF-α, RANK, RANKL, and MCP-1 than C57BL/6 and PHOX(-/-). Apical thickening of the periodontal ligament was also greater in iNOS(-/-) compared with other groups. Interestingly, ROS production did not interfere in periapical lesion progression, but seemed to be essential for the appearance of multinucleated TRAP-positive cells. Thus, periapical lesion progression in iNOS(-/-) was associated with an imbalance of pro-inflammatory cytokines (IL-1ß and TNF-α), bone-resorptive modulators (RANK and RANKL), and MCP-1. We conclude that NO, but not ROS, controls progression of bone resorption in a murine experimental model of apical periodontitis.
Assuntos
Perda do Osso Alveolar/enzimologia , NADPH Oxidases/fisiologia , Óxido Nítrico Sintase Tipo II/fisiologia , Periodontite Periapical/enzimologia , Fagócitos/enzimologia , Fosfatase Ácida/análise , Perda do Osso Alveolar/metabolismo , Perda do Osso Alveolar/patologia , Animais , Biomarcadores/análise , Quimiocina CCL2/análise , Citocinas/análise , Modelos Animais de Doenças , Progressão da Doença , Mediadores da Inflamação/análise , Interleucina-1beta/análise , Isoenzimas/análise , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Camundongos Knockout , Óxido Nítrico/fisiologia , Periodontite Periapical/patologia , Ligamento Periodontal/enzimologia , Ligamento Periodontal/patologia , Ligante RANK/análise , Espécies Reativas de Oxigênio/farmacologia , Receptor Ativador de Fator Nuclear kappa-B/análise , Fosfatase Ácida Resistente a Tartarato , Fator de Necrose Tumoral alfa/análiseRESUMO
The Aß(25-35) fraction mimics the toxic effects of the complete peptide Aß(1-42) because this decapeptide is able to cause memory impairment and neurodegenerative events. Recent evidence has shown that the injection of Aß(25-35) into the temporal cortex (TCx) of the rat increases the nitric oxide (NO) pathways with several consequences, such as neuronal loss in rats. Our aim was to investigate the effects of each NOS isoform by the prior injection of NOS inhibitors before the injection of the Aß(25-35). One month after the treatment, the animals were tested for their spatial memory in the radial maze. The hippocampus (Hp) and TCx were assessed for NO production, nitration of proteins (3-NT), astrocytosis (GFAP), and neuronal loss. Our findings show a significant impairment in the memory caused by Aß25-35 injection. In contrast NOS inhibitors plus Aß25-35 cause a protection yielding a high performance in the memory test and reduction of cell damage in the TCx and the Hp. Particularly, iNOS is the major source of NO and related to the inflammatory response leading to the memory deficits. The inhibition of iNOS is an important target for neuronal protection against the toxicity of the Aß25-35 over the long term.
Assuntos
Peptídeos beta-Amiloides/toxicidade , Memória/efeitos dos fármacos , Memória/fisiologia , Óxido Nítrico Sintase/fisiologia , Fragmentos de Peptídeos/toxicidade , Lobo Temporal/efeitos dos fármacos , Lobo Temporal/enzimologia , Peptídeos beta-Amiloides/administração & dosagem , Animais , Inibidores Enzimáticos/farmacologia , Proteína Glial Fibrilar Ácida/metabolismo , Guanidinas/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Indazóis/farmacologia , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Transtornos da Memória/induzido quimicamente , Transtornos da Memória/enzimologia , Transtornos da Memória/patologia , NG-Nitroarginina Metil Éster/farmacologia , Nitratos/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/fisiologia , Fragmentos de Peptídeos/administração & dosagem , Ratos , Ratos Wistar , Lobo Temporal/patologia , Tirosina/análogos & derivados , Tirosina/metabolismoRESUMO
Sepsis develops when the initial host response is unable to contain the primary infection, resulting in widespread inflammation and multiple organ dysfunction. The impairment of neutrophil migration into the infection site, also termed neutrophil paralysis, is a critical hallmark of sepsis, which is directly related to the severity of the disease. Although the precise mechanism of this phenomenon is not fully understood, there has been much advancement in the understanding of this field. In this review, we highlight the recent insights into the molecular mechanisms of neutrophil paralysis during sepsis.
Assuntos
Quimiotaxia de Leucócito , Neutrófilos/fisiologia , Sepse/fisiopatologia , Animais , Quimiotaxia de Leucócito/fisiologia , Citocinas/fisiologia , Humanos , Infecções/imunologia , Infecções/fisiopatologia , Mediadores da Inflamação/fisiologia , Insuficiência de Múltiplos Órgãos/etiologia , Insuficiência de Múltiplos Órgãos/fisiopatologia , Óxido Nítrico Sintase Tipo II/fisiologia , Especificidade de Órgãos , PPAR gama/fisiologia , Sepse/complicações , Sepse/imunologia , Sepse/terapia , Síndrome de Resposta Inflamatória Sistêmica/etiologia , Síndrome de Resposta Inflamatória Sistêmica/fisiopatologia , Receptores Toll-Like/fisiologiaRESUMO
Our aim was to investigate the effect of central NOS inhibition on hypothalamic arginine vasopressin (AVP) gene expression, hormone release and on the cardiovascular response during experimental sepsis. Male Wistar rats were intracerebroventricularly injected with the non-selective NO synthase (NOS) inhibitor (L-NAME) or aminoguanidine, a selective inhibitor of the inducible isoform (iNOS). After 30 min, sepsis was induced by cecal ligation and puncture (CLP) causing an increase in heart rate (HR), as well as a reduction in median arterial pressure (MAP) and AVP expression ratio (AVP(R)), mainly in the supraoptic nucleus. AVP plasma levels (AVPp) increased in the early but not in the late phase of sepsis. L-NAME pretreatment increased MAP but did not change HR. It also resulted in an increase in AVPp at all time points, except 24h, when it returned to basal levels. AVP(R), however remained reduced in both nuclei. Aminoguanidine pretreatment resulted in increased MAP in the early phase and higher AVP(R) in the supraoptic, but not in the paraventricular nucleus, while AVPp remained elevated at all time points. We suggest that increased central NO production, mainly inducible NOS-derived, reduces AVP gene expression differentially in supraoptic and paraventricular nuclei, and that this may contribute to low AVP plasma levels and hypotension in the late phase of sepsis.
Assuntos
Arginina Vasopressina/biossíntese , Arginina Vasopressina/genética , Regulação da Expressão Gênica , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/fisiologia , Núcleo Hipotalâmico Paraventricular/enzimologia , Sepse/imunologia , Núcleo Supraóptico/enzimologia , Animais , Regulação da Expressão Gênica/imunologia , Injeções Intraventriculares , Masculino , NG-Nitroarginina Metil Éster/administração & dosagem , Óxido Nítrico/antagonistas & inibidores , Óxido Nítrico/metabolismo , Núcleo Hipotalâmico Paraventricular/imunologia , Núcleo Hipotalâmico Paraventricular/patologia , Ratos , Ratos Wistar , Sepse/enzimologia , Sepse/patologia , Núcleo Supraóptico/imunologia , Núcleo Supraóptico/patologiaRESUMO
RATIONALE: The mechanism of action of diethylcarbamazine (DEC), an antifilarial drug effective against tropical pulmonary eosinophilia, remains controversial. DEC effects on microfilariae depend on inducible NO synthase (iNOS). In eosinophilic pulmonary inflammation, its therapeutic mechanism has not been established. We previously described the rapid up-regulation of bone marrow eosinophilopoiesis in ovalbumin (OVA)-sensitized mice by airway allergen challenge, and further evidenced the down-regulation of eosinophilopoiesis by iNOS- and CD95L-dependent mechanisms. OBJECTIVES: We investigated whether: (1) DEC can prevent the effects of airway challenge of sensitized mice on lungs and bone marrow, and (2) its effectiveness depends on iNOS/CD95L. METHODS: OVA-sensitized BALB/c mice were intranasally challenged for 3 consecutive days, with DEC administered over a 12-, 3-, or 2-day period, ending at the day of the last challenge. We evaluated: (1) airway resistance, cytokine (IFN-gamma, IL-4, IL-5, and eotaxin) production, and pulmonary eosinophil accumulation; and (2) bone marrow eosinophil numbers in vivo and eosinophil differentiation ex vivo. MEASUREMENTS AND MAIN RESULTS: DEC effectively prevented the effects of subsequent challenges on: (1) airway resistance, Th1/Th2 cytokine production, and pulmonary eosinophil accumulation; and (2) eosinophilopoiesis in vivo and ex vivo. Recovery from unprotected challenges included full responses to DEC during renewed challenges. DEC directly suppressed IL-5-dependent eosinophilopoiesis in naive bone marrow. DEC was ineffective in CD95L-deficient gld mice and in mice lacking iNOS activity because of gene targeting or pharmacological blockade. CONCLUSIONS: DEC has a strong impact on pulmonary eosinophilic inflammation in allergic mice, as well as on the underlying hemopoietic response, suppressing the eosinophil lineage by an iNOS/CD95L-dependent mechanism.
Assuntos
Doenças da Medula Óssea/tratamento farmacológico , Dietilcarbamazina/farmacologia , Eosinofilia/tratamento farmacológico , Proteína Ligante Fas/fisiologia , Filaricidas/farmacologia , Óxido Nítrico Sintase Tipo II/fisiologia , Eosinofilia Pulmonar/tratamento farmacológico , Resistência das Vias Respiratórias/efeitos dos fármacos , Animais , Broncoconstritores/farmacologia , Eosinófilos/efeitos dos fármacos , Hematopoese/efeitos dos fármacos , Interferon gama/biossíntese , Interleucina-4/biossíntese , Interleucina-5/biossíntese , Contagem de Linfócitos , Cloreto de Metacolina/farmacologia , Camundongos , Camundongos Endogâmicos BALB CRESUMO
Ovarian carcinoma is the most important cause of gynaecological cancer-related mortality in Western societies. The age at diagnosis, extent of disease (as expressed by FIGO state), success of primary surgery and the histopathological features of the tumour are important prognostic markers. The majority of patients with ovarian cancer present with advanced disease (FIGO stage III/IV) and in this group of patients the median survival is only three years. New treatment approaches are therefore required to improve outcome in this disease. Angiogenesis, the development of a neovascular blood supply, is a critical step in the propagation of malignant tumour growth and metastasis and represents a promising target. This review will focus on angiogenesis, VEGF biology and the potential value of angiogenic factors with prognostic value in ovarian cancer.
Assuntos
Carcinoma/irrigação sanguínea , Neovascularização Patológica/fisiopatologia , Neoplasias Ovarianas/irrigação sanguínea , Carcinoma/diagnóstico , Carcinoma/genética , Carcinoma/patologia , Feminino , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/fisiologia , Modelos Biológicos , Neovascularização Patológica/genética , Neovascularização Patológica/patologia , Neovascularização Fisiológica/genética , Neovascularização Fisiológica/fisiologia , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/fisiologia , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Ovário/irrigação sanguínea , Prognóstico , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/fisiologiaRESUMO
In order to examine the role of IFN-gamma, TNFRp55 and iNOS in inflammatory reaction during toxoplasmosis, IFN-gamma(-/-), TNFRp55(-/-) and iNOS(-/-) mice were experimentally infected with Toxoplasma gondii ME-49 strain. The organs of the mice were evaluated for histology and immunohistochemistry in detection of tissue parasitism and iNOS positive cells. IFN-gamma(-/-) mice presented mild inflammation in peripheral organs associated with a high parasitism and mortality in the acute phase of infection. In contrast, the peripheral organs of WT, TNFRp55(-/-) and iNOS(-/-) mice, presented a significant inflammatory reaction and low tissue parasitism in the same period of infection. The inflammatory lesions and tissue parasitism were increased and more severe in the Central Nervous System (CNS) of TNFRp55(-/-) and iNOS(-/-) with a progression of infection, when compared to WT mice. In these knockout animals, the inflammatory changes were associated with low levels or no expression of iNOS in TNFRp55(-/-) and iNOS(-/-) mice, respectively.
Assuntos
Interferon gama/fisiologia , Óxido Nítrico Sintase Tipo II/fisiologia , Receptores Tipo I de Fatores de Necrose Tumoral/fisiologia , Toxoplasma/fisiologia , Toxoplasmose Animal/imunologia , Receptores Chamariz do Fator de Necrose Tumoral/fisiologia , Animais , Encéfalo/parasitologia , Coração/parasitologia , Imuno-Histoquímica , Inflamação/imunologia , Fígado/parasitologia , Pulmão/parasitologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Medula Espinal/parasitologia , Baço/parasitologia , Toxoplasmose Animal/patologiaRESUMO
The goal of this study was to investigate whether sub-chronic anti-oxidant treatment with ascorbic acid (Vit C) is able to protect the heart against myocardial infarction. The effects of Vit C treatment on the histopatological changes and immunohistochemistry for p53, COX-2 and iNOS were evaluated in rats submitted to acute myocardial infarction induced by isoproterenol (ISO). Male Wistar rats (n = 32) were divided into four groups: group 1, control; group 2, ISO treated; group 3, Vit C treated; group 4, ISO + Vit C treated. An amount of 150 mg/kg of isoproterenol was administered for two consecutive days. The rats were treated with Vit C once a day (150 mg/kg, orally) for seven consecutive days. In the day 5 and 6 the rats from group ISO + Vit C were submitted to acute administration of ISO third minutes after Vit C treatment. The results pointed out that treatment with Vit C showed mild degenerative changes of myocardial tissue in ISO group. Also, the antioxidant was able to decrease the iNOS expression in rats treated with Vit C. Taken together, our results suggest that chronic Vit C administration was able to prevent the myocardial infarction induced by ISO as a result of iNOS downregulation. Certainly, this finding offers new insights into the mechanisms underlying the relation between oxidative stress and cardiac mortality after myocardial infarction.
Assuntos
Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Isoproterenol/farmacologia , Infarto do Miocárdio/induzido quimicamente , Infarto do Miocárdio/prevenção & controle , Óxido Nítrico Sintase Tipo II/fisiologia , Animais , Ciclo-Oxigenase 2/metabolismo , Imuno-Histoquímica , Masculino , Óxido Nítrico Sintase Tipo II/metabolismo , Ratos , Ratos Wistar , Proteína Supressora de Tumor p53/metabolismoRESUMO
The skin is the largest organ in the body and one of its main functions is to protect the body from environmental and endogenous noxious conditions, such as injury, infection and inflammation. The inducible nitric oxide synthase (iNOS) has been implicated as a key component in the inflammatory response. In the present study, we assessed the role of iNOS in the skin inflammation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Mice deficient in iNOS had reduced edema and cellular infiltration in the skin following topical TPA application. Moreover, the genetic blockage of iNOS signaling inhibited the TPA-induced ERK and p38 activation resulting in reduced COX-2 upregulation. Finally, immunohistochemical studies revealed that iNOS knockout mice exhibited marked inhibition of AP-1, CREB and NF-kappaB transcriptional factors activation. Together, these results indicate that TPA induces the activation of several iNOS-dependent intracellular signaling pathways that have a key role in the control of inflammatory response in the skin. Therefore, selective iNOS inhibitors may be potentially relevant tools for cutaneous skin disease drug development.
Assuntos
Ciclo-Oxigenase 2/metabolismo , Dermatite/etiologia , Óxido Nítrico Sintase Tipo II/fisiologia , Otite/induzido quimicamente , Acetato de Tetradecanoilforbol/toxicidade , Animais , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Dermatite/metabolismo , Regulação Enzimológica da Expressão Gênica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NF-kappa B/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/deficiência , Óxido Nítrico Sintase Tipo II/metabolismo , Fator de Transcrição AP-1/metabolismo , Fatores de Transcrição/metabolismoRESUMO
We earlier demonstrated that nitric oxide (NO) is a fungicidal molecule against Sporothrix schenckii in vitro. In the present study we used mice deficient in inducible nitric oxide synthase (iNOS-/-) and C57BL/6 wild-type (WT) mice treated with Nomega-nitro-arginine (Nitro-Arg-treated mice), an NOS inhibitor, both defective in the production of reactive nitrogen intermediates, to investigate the role of endogenous NO during systemic sporotrichosis. When inoculated with yeast cells of S. schenckii, WT mice presented T-cell suppression and high tissue fungal dissemination, succumbing to infection. Furthermore, susceptibility of mice seems to be related to apoptosis and high interleukin-10 and tumour necrosis factor-alpha production by spleen cells. In addition, fungicidal activity and NO production by interferon-gamma (IFN-gamma) and lipopolysaccharide-activated macrophages from WT mice were abolished after fungal infection. Strikingly, iNOS-/- and Nitro-Arg-treated mice presented fungal resistance, controlling fungal load in tissues and restoring T-cell activity, as well as producing high amounts of IFN-gamma Interestingly, macrophages from these groups of mice presented fungicidal activity after in vitro stimulation with higher doses of IFN-gamma. Herein, these results suggest that although NO was an essential mediator to the in vitro killing of S. schenckii by macrophages, the activation of NO system in vivo contributes to the immunosuppression and cytokine balance during early phases of infection with S. schenckii.