Elevated Nitric Oxide Levels Research Articles

Nitric oxide levels and endothelial nitric oxide synthase gene polymorphisms in Turkish women with idiopathic recurrent miscarriage

To determine whether endothelial nitric oxide synthase (eNOS) gene polymorphisms are associated with an increased risk for Idiopathic Recurrent Miscarriage (IRM) in the Turkish population and to evaluate the association between Nitric Oxide (NO) levels and eNOS gene polymorphisms in women with IRM. A total of 120 Turkish women were enrolled in this study in four groups. Of these, 30 women were first trimester pregnant who had IRM (Group I). Thirty healthy multipara women were in the first trimester of pregnancy with no history of abortion (Group II). Thirty women were non pregnant with a history of IRM (Group III). The remaining 30 subjects were healthy multipara non-pregnant women with no history of abortion (Group IV). DNA analysis of four groups were performed for the two polymorphisms using the PCR and/or PCR-RFLPs method and NO levels were measured spectrophotometrically. We observed statistically significant decreased NO levels in the pregnant patient group (p=0.001) while elevated NO levels were measured in the non pregnant patient group (p=0.004). We demonstrated that, while there was no significant difference in terms of VNTR 4/eNOS genotype, there was a marginally significant difference in terms of Glu298Asp/eNOS genotype frequency (p=0.055) in patients with IRM in the Turkish population. We observed no association between NO levels and Glu298Asp/eNOS or VNTR 4/eNOS genotypes in any of the groups. The Glu298Asp polymorphism of eNOS could be an intriguing susceptibility factor that modulates an individual's risk of IRM in Turkish population. Further studies to explain the role of the NO pathway in the pathophysiology of IRM are needed.

Oxidative stress and hematological profiles of advanced breast cancer patients subjected to paclitaxel or doxorubicin chemotherapy

Several adverse effects of chemotherapy treatments have been described, and most of these effects are associated with direct interactions between blood cells and indirect effects generated during the oxidative metabolism of antineoplastic drugs. In this study we evaluated the oxidative systemic status and hematological profiles of breast cancer patients with advanced ductal infiltrative carcinoma treated with doxorubicin (DOX) or paclitaxel (PTX) within 1 h after chemotherapy. Blood analyses included evaluation of hemogram, pro-oxidative markers, and antioxidant status. The results showed that advanced breast cancer diseased (AD) patients without previous chemotherapy presented anemia and high oxidative stress status characterized by elevated levels of lipid peroxidation and nitric oxide, and reduced catalase activity when compared with controls. DOX-treated patients exhibited increased anemia and reduced antioxidant status, which was revealed by decreases in reduced glutathione levels and the total antioxidant capacity of plasma; however, these changes did not lead to further increases in lipid peroxidation or carbonyl proteins when compared with the AD group. PTX-treated patients also showed increased anemia, lactate dehydrogenase leakage, and enhanced lipid peroxidation. These data reveal for the first time that patients subjected to chemotherapy with DOX or PTX present immediate systemic oxidative stress and red blood cell oxidative injury with anemia development. These findings provide a new perspective on the systemic redox state of AD and patients subjected to chemotherapy regarding oxidative stress enhancement and its possible involvement in the aggravation of chronic anemia.

Association between serum nitric oxide and hypertension among 1453 women in Suzhou

To investigate the association between serum nitric oxide (NO) and hypertension among women in Suzhou. Blood pressure, height, weight and waist circumference (WC) were measured and factors including smoking, alcohol intake, family history of hypertension were investigated and blood glucose, blood lipid, serum NO were tested among 1453 women aged ≥ 30 years who lived in Jinchang district of Suzhou. Association between serum NO and hypertension was analyzed by univariate and multivariate methods. The mean levels of serum NO in hypertensive and normotensive persons were 28.17 (17.42 - 45.30) µmol/L and 27.56 (17.19 - 44.42) µmol/L, respectively, with no significant difference between the two groups (P > 0.05). from multivariable logistic regression analysis showed that low serum NO was not associated with hypertension, after adjustment for confounders (OR = 0.979, 95%CI: 0.747 - 1.283). The mean levels of systolic blood pressure/diastolic blood pressure were 130.1/83.3, 128.5/82.7, 129.8/83.2 and 129.1/83.3 mm Hg for whose serum NO level were in the first, second, third and fourth quartile, respectively. The risk of hypertension did not change along with the elevated serum NO levels. Compared to the first quartile of serum NO, the risks of hypertension in the second, third and fourth quartile did not change after adjustment for confounders and OR were 0.988 (0.709 - 1.377), 1.001 (0.720 - 1.390) and 1.077 (0.774 - 1.499), respectively. The serum NO level was not associated with hypertension in women in Suzhou.

Myeloid-Derived Suppressor Cell Inhibition of the IFN Response in Tumor-Bearing Mice

Our group and others have determined that immune effector cells from patients with advanced cancers exhibit reduced activation of IFN signaling pathways. We hypothesized that increases in immune regulatory cells termed myeloid-derived suppressor cells (MDSC) could interfere with the host immune response to tumors by inhibiting immune cell responsiveness to IFNs. The C26 murine adenocarcinoma model was employed to study immune function in advanced malignancy. C26-bearing mice had significantly elevated levels of GR1(+)CD11b(+) MDSC as compared with control mice, and splenocytes from tumor-bearing mice exhibited reduced phosphorylation of STAT1 (P-STAT1) on Tyr(701) in response to IFN-α or IFN-γ. This inhibition was seen in splenic CD4(+) and CD8(+) T cells as well as natural killer cells. In vitro coculture experiments revealed that MDSC inhibited the IFN responsiveness of splenocytes from normal mice. Treatment of C26-bearing mice with gemcitabine or an anti-GR1 antibody led to depletion of MDSC and restored splenocyte IFN responsiveness. Spleens from C26-bearing animals displayed elevated levels of iNOS protein and nitric oxide. In vitro treatment of splenocytes with a nitric oxide donor led to a decreased STAT1 IFN response. The elevation in nitric oxide in C26-bearing mice was associated with increased levels of nitration on STAT1. Finally, splenocytes from iNOS knockout mice bearing C26 tumors exhibited a significantly elevated IFN response as compared with control C26 tumor-bearing mice. These data suggest that nitric oxide produced by MDSC can lead to reduced IFN responsiveness in immune cells.

Differential effects of nitric oxide on the responsiveness of tactile hairs

The responses of tactile hairs located on legs of the desert locust Schistocerca gregaria (Forskål) are modulated by nitric oxide (NO). There are two types of tactile hair on the tibia of the hind leg of the locust which differ in their thresholds for mechanical stimulation, their location on the leg and in the effect of NO on their responses to deflection. The spike response rates of mechanosensory neurons of low-threshold hairs decreased when exposed to elevated NO levels caused by perfusion of the leg with saline containing the NO donor PAPANONOate. In contrast, in high-threshold hairs, which show low responsiveness under control conditions, an increase in spike rates was observed during PAPANONOate application. These opposing effects of NO reduce the differences in the spike responses of the two types of tactile hairs to mechanical stimulation and are likely to have an impact on behaviours elicited by mechanical stimulation of the legs.

Nitric Oxide Regulates DELLA Content and PIF Expression to Promote Photomorphogenesis in Arabidopsis

The transition from etiolated to green seedlings involves a shift from hypocotyl growth-promoting conditions to growth restraint. These changes occur through a complex light-driven process involving multiple and tightly coordinated hormonal signaling pathways. Nitric oxide (NO) has been lately characterized as a regulator of plant development interacting with hormone signaling. Here, we show that Arabidopsis (Arabidopsis thaliana) NO-deficient mutant hypocotyls are longer than those from wild-type seedlings under red light but not under blue or far-red light. Accordingly, exogenous treatment with the NO donor sodium nitroprusside and mutant plants with increased endogenous NO levels resulted in reduced hypocotyl length. In addition to increased hypocotyl elongation, NO deficiency led to increased anthocyanin levels and reduced PHYB content under red light, all processes governed by phytochrome-interacting factors (PIFs). NO-deficient plants accordingly showed an enhanced expression of PIF3, PIF1, and PIF4. Moreover, exogenous NO increased the levels of the gibberellin (GA)-regulated DELLA proteins and shortened hypocotyls, likely through the negative regulation of the GA Insensitive Dwarf1 (GID1)-Sleepy1 (SLY1) module. Consequently, NO-deficient seedlings displayed up-regulation of SLY1, defective DELLA accumulation, and altered GA sensitivity, thus resulting in defective deetiolation under red light. Accumulation of NO in wild-type seedlings undergoing red light-triggered deetiolation and elevated levels of NO in the GA-deficient ga1-3 mutant in darkness suggest a mutual NO-GA antagonism in controlling photomorphogenesis. PHYB-dependent NO production promotes photomorphogenesis by a GID1-GA-SLY1-mediated mechanism based on the coordinated repression of growth-promoting PIF genes and the increase in the content of DELLA proteins.

The Involvement of Nitric Oxide and Endothelin-1 in Exercise-Induced Bronchospasm in Young Soccer Players

To investigate the levels of nitric oxide (NO) and endothelin-1 (ET-1) in soccer players with exercise-induced bronchospasm (EIB), to test whether these endogenous vasoactive molecules are involved in the development of EIB, and to examine the possible participation of reactive oxygen metabolites in these alterations. Observational study. Football club. Forty-three soccer players (N = 43) aged 16 to 22 years performed maximal exercise test on a treadmill by using Bruce protocol. Respiratory function tests were evaluated before and after exercise tests. Participants were grouped as control (n = 35) or EIB (n = 8) groups according to the respiratory function test results. Endothelin-1 (ET-1), nitric oxide (NO), carbonyl, malondialdehyde, and glutathione levels were determined from the blood samples taken before and after exercise tests. In the control group, significant decreases in plasma ET-1 and serum NO levels were determined after exercise. On the other hand, plasma malondialdehyde and carbonyl levels were significantly decreased, whereas glutathione levels were significantly increased after exercise. In the EIB group, blood levels of NO, ET-1, carbonyl, and malondialdehyde after exercise were found to be significantly increased compared with pre-exercise levels. These findings demonstrate that in young soccer players, EIB is associated with elevated serum NO and plasma ET-1 levels. Moreover, significant increases in lipid peroxidation and protein oxidation and decreases in antioxidant sulfhydryl (RSH) content indicate a significant compromise in the blood antioxidant status and the presence of systemic oxidative stress in young athletes with EIB.

Neurotrophins induce nitric oxide generation in human pulmonary artery endothelial cells

Members of the growth factor family of neurotrophins [NTs; e.g. brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT3)] and their high-affinity receptors (tropomyosin-related kinase; Trk) and low-affinity receptors p75 neurotrophin receptor (p75NTR) have been localized to pulmonary artery (PA) in humans. However, their role is unclear. Based on previous findings of NTs and their receptors within the pulmonary endothelium, we tested the hypothesis that NTs induce nitric oxide (NO) production in pulmonary endothelial cells (ECs), thus contributing to vasodilation. In human pulmonary artery ECs loaded with the NO-sensitive fluorescent dye diaminofluorescein-2, both BDNF and NT3 (100 pM, 1 nM, and 10 nM) acutely (<10 min) and substantially increased fluorescence levels in a concentration-dependent fashion (to levels comparable to that induced by 1 μM acetylcholine). NT-induced elevation of NO levels was blunted by the tyrosine kinase inhibitor K252a, the nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester, the Ca(2+) chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, and the NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide. Suppression of TrkB or TrkC expression via siRNA as well as functional blockade of p75NTR prevented NT-induced NO elevation. Both BDNF and NT3 increased phosphorylation of Akt and endothelial NO synthase (eNOS). In endothelium-intact porcine PA rings, NTs increased cGMP and induced vasodilation in pre-contracted arteries. These results indicate that NTs acutely modulate pulmonary endothelial NO production and contribute to relaxation of the pulmonary vasculature.

Inhibition of NADPH oxidase alleviates experimental diabetes-induced myocardial contractile dysfunction

O(2) (-) production is implicated in cardiac dysfunction for a number of diseases including diabetes. Activation of the O(2) (-)-producing enzyme NADPH oxidase is seen in diabetes, although its role in diabetic cardiomyopathy is unclear. This study was designed to evaluate the effect of NADPH oxidase inhibition on cardiac function in diabetes. Experimental diabetes was induced in adult C57 mice using streptozotocin (STZ, 150 mg/kg, i.p.) prior to the administration of the NADPH oxidase inhibitor apocynin (4 mg/kg/day) for 2 weeks. Left ventricular (LV) and myocyte contractile functions were evaluated using echocardiography and edge-detection, respectively. STZ elicited hyperglycaemia and reduced body weight gain, which was unaffected by apocynin. STZ significantly reduced fractional shortening, LV wall thickness, peak shortening, maximal velocity and duration of shortening or relengthening, the effects of which - with the exception of wall thickness - were significantly attenuated or ablated by apocynin. Western blot analysis revealed that the effects of comparable Akt phosphorylation, reduced AMPK phosphorylation, downregulation of sarco(endo)plasmic reticulum Ca(2+)-ATPase and lessened phosphorylation of phospholamban in diabetic myocardium were unaffected by apocynin. Both apocynin and the nitric oxide synthase (NOS) inhibitor l-arginine methyl ester (L-NAME) inhibited elevated O(2) (-) production in diabetes without any additive effect between the two, indicating the presence of endothelial nitric oxide synthase (eNOS) uncoupling. However, neither diabetes nor apocynin altered the expression of heat shock protein 90 and eNOS phosphorylation (Ser(1177)). In addition, apocynin mitigated elevated levels of nitrotyrosine and nitric oxide in diabetes. Taken together, these data indicate the beneficial role of NADPH oxidase inhibition in diabetes-induced myocardial contractile dysfunction.

Elevated levels of NO are localized to distal airways in asthma

The contribution of nitric oxide (NO) to the pathophysiology of asthma remains incompletely defined despite its established pro- and anti-inflammatory effects. Induction of the inducible nitric oxide synthase (iNOS), arginase, and superoxide pathways is correlated with increased airway hyperresponsiveness in asthmatic subjects. To determine the contributions of these pathways in proximal and distal airways, we compared bronchial wash (BW) to traditional bronchoalveolar lavage (BAL) for measurements of reactive nitrogen/oxygen species, arginase activation, and cytokine/chemokine levels in asthmatic and normal subjects. Levels of NO were preferentially elevated in the BAL, demonstrating higher level NOS activation in the distal airway compartment of asthmatic subjects. In contrast, DHE+ cells, which have the potential to generate reactive oxygen species, were increased in both proximal and distal airway compartments of asthmatics compared to controls. Different patterns of cytokines and chemokines were observed, with a predominance of epithelial cell-associated mediators in the BW compared to macrophage/monocyte-derived mediators in the BAL of asthmatic subjects. Our study demonstrates differential production of reactive species and soluble mediators within the distal airways compared to the proximal airways in asthma. These results indicate that cellular mechanisms are activated in the distal airways of asthmatics and must be considered in the development of therapeutic strategies for this chronic inflammatory disorder.

Direct evidence that (−)-epicatechin increases nitric oxide levels in human endothelial cells

The dietary flavanol (-)-epicatechin has been suggested to mediate its vasodilatory effect by increasing nitric oxide levels in endothelial cells. To directly prove the formation of nitric oxide (NO) in human endothelial cells (HUVEC) in vitro by trapping NO to yield a fluorescent nitrosamine. HUVEC were treated with (-)-epicatechin; nitrite and NO formation were determined by reductive chemiluminescence detection and the NO-sensitive fluorophore 5-methoxy-2-(1H-naphthol[2,3-d]imidazol-2-yl)-phenol copper complex (MNIP-Cu), respectively. MNIP was synthesized in a rapid and convenient one-step microwave reaction. Endothelial nitric oxide synthase (eNOS) mRNA levels and mRNA stability were measured. Incubation with (-)-epicatechin (0.3-10 μM) led to elevated NO levels in HUVEC measured via reductive chemiluminescence detection and visualized as the fluorescent NO derivative of MNIP. Expression of eNOS mRNA and mRNA stability were not affected by (-)-epicatechin treatment within the time frame studied. (-)-Epicatechin augments the level of NO in endothelial cells, a process suggested to be responsible for the vasodilatory properties of the compound.

Different challenge terms determine disease patterns of antigen‐induced pulmonary inflammation in E3 rats

Antigen induced pulmonary inflammation (AIPI) in rats, a classic animal model for asthma, has greatly contributed to the understanding of the disease pathogenesis, especially for the inflammation process. E3 rats are recently used to induce AIPI model for its susceptibility to pulmonary inflammation, but the features of AIPI with different antigen challenge terms on E3 rats require to be elucidated systemically. The aim of this study was to compare AIPI disease patterns in E3 rats with different challenge terms. E3 rats were immunized and challenged with ovalbumin (OVA) for 1, 4, and 8 weeks. Histological methods were used to determine morphological changes in lungs and cell types in bronchoalveolar lavage fluid. Nitric oxide (NO) concentration was assayed by Griess method. IL-4 and TGF-β expression were detected by real-time PCR. ELISA was used for the determination of serum IgE and OVA-specific IgG1. The results showed that all the sensitized E3 rats had a strong influx of eosinophils into the airway. In 1-week challenge group, the rats showed stronger inflammation, such as elevated levels of NO, delayed type hypersensitivity, IL-4 expression, and inflammatory cell infiltration; while in 8-week challenge group, rats manifested significant tissue destruction, accumulation of collagen and mucus production, and higher levels of antibody production, and TGF-β expression. Hence, the detail characterizations of AIPI model challenged for different terms demonstrated that E3 rats challenged with antigen for 1 week are suitable for studying acute pulmonary inflammation; meanwhile, the model established in the rats challenged for 8 weeks is appropriate for understanding pathogenesis of lung remodelling in chronic inflammation.

Glutamate antagonism fails to reverse mitochondrial dysfunction in late phase of experimental neonatal asphyxia in rats

Neonatal asphyxia is a primary contributor to neonatal mortality and neuro-developmental disorders. It progresses in two distinct phases, as initial primary process and latter as the secondary process. A dynamic relationship exists between excitotoxicity and mitochondrial dysfunction during the progression of asphyxic injury. Study of status of glutamate and mitochondrial function in tandem during primary and secondary processes may give new leads to the treatment of asphyxia. Neonatal asphyxia was induced in rat pups on the day of birth by subjecting them to two episodes (10 min each) of anoxia, 24 h apart by passing 100% N 2 into an enclosed chamber. The NMDA antagonist ketamine (20 mg/kg/day) was administered either for 1 day or 7 days after anoxic exposure. Tissue glutamate and nitric oxide were estimated in the cerebral cortex, extra-cortex and cerebellum. The mitochondria from the above brain regions were used for the estimation of malondialdehyde, and activities of superoxide dismutase and succinate dehydrogenase. Mitochondrial membrane potential was evaluated by using Rhodamine dye. Anoxia during the primary process increased glutamate and nitric oxide levels; however the mitochondrial function was unaltered in terms of succinate dehydrogenase and membrane potential. Acute ketamine treatment reversed the increase in both glutamate and nitric oxide levels and partially attenuated mitochondrial function in terms of succinate dehydrogenase activity. The elevated glutamate and nitric oxide levels were maintained during the secondary process but however with concomitant loss of mitochondrial function. Repeated ketamine administration reversed glutamate levels only in the cerebral cortex, where as nitric oxide was decreased in all the brain regions. However, repeated ketamine administration was unable to reverse anoxia-induced mitochondrial dysfunction. The failure of glutamate antagonism in the treatment of asphyxia may be due to persistence of mitochondrial dysfunction. Therefore, additionally targeting mitochondrial function may prove to be therapeutically beneficial in the treatment of asphyxia.

The Benefits of Exogenous NO: Enhancing &amp;lt;i&amp;gt;Arabidopsis&amp;lt;/i&amp;gt; to Resist &amp;lt;i&amp;gt;Botrytis cinerea&amp;lt;/i&amp;gt;

Botrytis cinerea is a necrotrophic fungal pathogen that impacts a wide range of hosts, including Arabidopsis. Pretreatment with nitric oxide (NO) donor sodium nitroprusside (SNP) on Arabidopsis leaves suppressed Botrytis cinerea infection development. Additionally, in this study the dosage levels of SNP applied to the leaves had no direct, toxic impact on the development of the pathogen. The relationship between NO and reactive oxidant species (ROS) was studied by using both spectrophotometrical methods and staining leaf material with fluorescent dyes, nitro blue tetrazolium (NBT), and with 3,3-diaminobenzidine (DAB). The results showed that exogenous NO restrained the generation of ROS, especially H2O2, as the pathogen interacted with the Arabidopsis plant. And this inhibition of reactive oxidant burst coincided with delay infection development in NO-supplied leaves. The influence of elevated level of NO on antioxidant enzymes was investigated in this study. The activities of catalase (CAT) and guaiacol peroxidase (POD) were increased to different degrees in both: 1) SNP treated only leaves, and 2) SNP pretreated leaves that were subsequently inoculateted with pathogens. However, the activity of superoxide dismutase (SOD) was unchanged in the leaves studied. The decrease in H2O2 content probably resulted from the increase in activities of POD and CAT. Our study suggests that NO might trigger some metabolic reactions, i.e. enhanced enzyme activity that restrains H2O2 which ultimately results in resistance to B. cinerea infection.

Different expressions of AQP1, AQP4, eNOS, and VEGF proteins in ischemic versus non-ischemic cerebropathy in rats: potential roles of AQP1 and eNOS in hydrocephalic and vasogenic edema formation

In this study, expressions of aquaporin (AQP) 1, AQP4, endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor in blood-cerebrospinal fluid (CSF) barrier and blood-brain barrier (BBB) are examined in rat choroid plexus and peri-infarcted hippocampal formation (HF) following systemic hyponatremia (SH) and permanent middle cerebral artery occlusion (pMCAO). These events are thought to cause the development of hydrocephalic and vasogenic edemas. The importance of CSF overproduction and intact blood-CSF barrier during hydrocephalic edema formation is demonstrated by the high expression of AQP1 (329.86±10.2%, n=4 , P<0.01) and trapped plasma immunoglobulin G (IgG) in choroid plexus epithelium after 24 hours of SH. However, the increased eNOS expression in peri-infarcted HF (130±3%, n=4, P<0.01) and extravasation of plasma IgG into the extravascular compartment after 24 hours of pMCAO suggest that increased microvascular permeability, probably due to elevated levels of nitric oxide, leads to development of vasogenic brain edema via BBB breakdown. Based on these findings, the authors suggest that modulation of different protein expression, dependent on the type of brain edema, is required for primary (pMCAO) and secondary (SH) brain injuries to attenuate brain edema and neuronal degeneration.

Melatonin and its metabolites as anti-nitrosating and anti-nitrating agents

Although basal and moderately elevated levels of nitric oxide are physiologically necessary and beneficial, excessive upregulations of this signaling molecule can be a cause of damage and cellular dysfunctions. In the presence of increased amounts of superoxide anions (•O2–) and carbon dioxide, peroxynitrite (ONOO–) and the peroxynitrite-CO2 adduct (ONOOCO2–) generate hydroxyl (•OH), nitrogen dioxide (•NO2) and carbonate (•CO3–) radicals, which damage biomolecules by oxidation/peroxidation, nitration and nitrosation reactions. Nitrosation also occurs with all three NO congeners (NO+, •NO, and HNO = protonated NO–), with •NO especially in combination with electron/hydrogen-abstracting compounds, or with N2O3. 3-Nitrotyrosine, found in low-density lipoprotein particles (LDL), atherosclerotic plaques, ion channels, receptors, transporters, enzymes and respirasomal subunits, is associated with numerous dysfunctions. Damage to the mitochondrial electron transport chain (ETC) is of particular significance and involves nitration, nitrosation and oxidation of proteins, cardiolipin peroxidation, and binding of •NO to ETC irons. Resulting bottlenecks of electron flux cause enhanced electron leakage which leads to elevated •O2–. In combination with high •NO, •O2– initiates a vicious cycle by generating more peroxynitrite that leads to further blockades and electron dissipation. Mitochondrial dysfunction, as induced via the •NO/peroxynitrite pathway, is of utmost importance in inflammatory diseases, especially sepsis, but also relevant to neurodegenerative and various other disorders. It may contribute to processes of aging. Melatonin, hormone of the pineal gland and product of other organs, interacts directly with reactive nitrogen species, but, more importantly, has antiinflammatory properties and downregulates inducible and neuronal NO synthases (iNOS, nNOS). It does not block moderately elevated •NO formation, but rather blunts excessive rises as occurring in sepsis and breaks the vicious cycle of mitochondrial electron leakage. The melatonin metabolite N1-acetyl-5-methoxykynuramine (AMK) forms stable nitrosation products and efficiently inhibits iNOS and nNOS, in conjunction with other antiinflammatory properties.

THYMOQUINONE AND PROANTHOCYANIDIN ATTENUATION OF DIABETIC NEPHROPATHY IN RATS

Diabetic nephropathy (DN) is a major cause of morbidity and mortality in diabetic patients. To prevent the development of this disease and to improve advanced kidney injury, effective therapies directed toward the key molecular target are required. Proanthocyanidin (PA) and thymoquinone (TQ) have been reported to be effective in treating DN, while little is known about their mechanism of action and their combination. Aim: This study was designed to investigate the possible beneficial effects of (TQ), (PA) and their combination to attenuate DN in rats. Materials and Methods: Rats were divided into five groups: group 1 (control), group 2 (diabetic untreated), group 3 (diabetic treated with PA), group 4 (diabetic treated with TQ) and group 5 (diabetic treated with PA+TQ). Diabetes was induced in groups 2-5 by a single dose of 65 mg/kg streptozotocin (STZ) in citrate buffer pH 4.5. Two days after STZ treatment, development of diabetes in the experimental groups was confirmed by measuring blood glucose. Rats in group 3 were given PA (250 mg/kg), rats in group 4 were given TQ (50 mg/kg) and rats in group 5 were given PA+TQ (250+50 mg/kg respectively) once a day orally for 12 weeks starting 2 days after STZ injection. Results: In this work, novel data correlate the relation between reactive oxygen species; advanced glycation end products; IL-6 and DN were obtained. Treatment of rats in groups 3-5 with PA, TQ and PA+TQ was significantly increased- the reduced body weight, the reduced glutathione concentration and activity of superoxide dismutase. The elevated levels of urea, creatinine, nitric oxide, malondialdehyde and IL-6 in group 2 were significantly reduced as a result of the treatment. Conclusion: These findings suggest that PA and TQ treatment exerts a therapeutic protective effect in diabetes by decreasing oxidative stress and attenuating DN. Consequently, TQ and PA may be clinically useful for protecting diabetic kidney against oxidative stress.

Le monoxyde d’azote, bio-marqueur de l’uvéite auto-immune expérimentale induite par l’antigène S

uveitis is an intraocular inflammation and one of the most severe and frequent manifestations of Behçet disease. S antigen (S Ag) is a highly conserved retinal protein implicated in the mechanism of the physiopathology in Behçet disease. This autoantigen is used in different animal models for experimental autoimmune uveitis (EAU) development, particularly in Behçet uveitis. Nitric oxide (NO) production has been reported in this disease by several groups and mainly by our team. in this study, we investigated the development of Behçet uveitis in an experimental model using the Wistar rat after treatment with S antigen. This antigen was isolated and purified from bovine retina by gel filtration chromatography using Sephadex G-200. The rats were immunized with 10μg of S Ag. We evaluated the changes in nitric oxide metabolite production in plasma using the Griess reaction, during the 7th, 14th, and 21st days post-immunization. Furthermore, deleterious effects by S antigen on retinal tissue were assessed in a histological study. the results showed a significant increase in NO production in Wistar rats treated with S Ag in comparison with controls. We noted with interest that the clinical stages of EAU correlated with NO production. Furthermore, S Ag had several deleterious effects on Wistar rat retina. this study indicated in vivo elevation of NO levels, which was observed before retinal tissue damage. Nitric oxide appears to be a good marker for a poor prognosis in this experimental model. Moreover, oxidative stress can be considered the primary step in pathogenesis inducing the destruction of retinal photoreceptors. Collectively, our data could be helpful in the development of strategies for diagnosing patients with Behçet uveitis.

Nitric oxide delivery system for biological media

Developing an understanding of how chronically elevated levels of nitric oxide at sites of inflammation or infection can lead to cancer and other diseases requires ways to expose cells and biomolecules to controlled concentrations of NO for hours to days. To achieve this, a small (65 ml) stirred reactor was fabricated that included a flat, porous poly(tetrafluoroethylene) membrane and a loop of poly(dimethylsiloxane) tubing for NO and O 2 delivery, respectively. It was equipped with probes for continuous monitoring of NO and O 2 concentrations. Transport through the membrane and tubing was characterized using separate O 2 depletion experiments. In experiments using only a 10% NO mixture and a buffer that was initially air-equilibrated, constant rates of accumulation were observed for NO 2 − (53 ± 2 μM/h; n = 8), the end product of NO oxidation, as expected. Simultaneous delivery of NO and O 2 yielded steady NO concentrations of 0.7–2.3 μM, depending on the tubing length and gas compositions. A model was developed that allows the steady NO and O 2 concentrations and the duration of the transients to be predicted to within a few percent. This system should be useful for exposing cells and biomolecules to concentrations of NO that mimic those in vivo.

ORIGINAL ARTICLE: Effects of dietary supplementation of synbiotics and phytobiotics on performance, caecal coliform population and some oxidant/antioxidant parameters of broilers

The current study was conducted to evaluate the effects of dietary supplementation of synbiotics and phytobiotics on performance, small intestine weight, pH and caecal coliform counts of broilers. The influences of synbiotics and phytobiotics on oxidant/antioxidant status in the blood of broilers were also assessed. A total of 200 broiler chicks were randomly allotted to four dietary treatments, either fed a basal diet or the same diet supplemented with 1 g/kg synbiotic, 1 g/kg phytobiotic or 1 g/kg synbiotic plus 1 g/kg phytobiotic. The diet supplemented with both synbiotic and phytobiotic had no effect on body weight, body weight gain, feed intake and feed efficiency of broilers at the end of the study (p > 0.05). Neither small intestine weight nor pH was affected by any of the treatments. Supplementation of both synbiotic and phytobiotic to diet decreased the caecal coliform count (p < 0.01). Addition of synbiotics and phytobiotics in combination significantly increased plasma malondialdehyde (MDA) levels (p ≤ 0.05), whereasphytobiotic addition alone showed only a slight increase. Similarly, elevated nitric oxide (NO) level was recorded in the synbiotic- and phytobiotic-fed group and in the phytobiotic-fed group (p ≤ 0.001). Superoxide dismutase (SOD) activities did not differ between the groups. In conclusion, dietary supplementation of synbiotic and phytobiotic improved the gut health by decreasing the caecal total coliform count, but growth performance was not affected by the supplementations. Further investigations are needed to determine the effects of phytobiotics on oxidative/antioxidative metabolism as regards their compositional analysis.