Sodium Nitroprussiate Research Articles

Availability of antidotes in Moroccan hospitals: a national survey

AimThe lack of availability of antidotes is a challenge for hospitals all over the world. The objective of our study was to investigate the availability of antidotes in Moroccan hospitals.MethodsA...

An experimental XAS and ab initio approach to describe the electronic and local structure of sodium nitroprussiate single crystals

The electronic and local structural properties of single crystals in the ground state (GS) of the photo-switchable compound Na2[Fe(CN)5NO]•2H2O (sodium nitroprussiate, SNP) have been investigated by X-ray Absorption Fine Structure Spectroscopy (XAFS) and FEFF simulations. In SNP, the XANES (X-ray Absorption Near Edge Structure) pre-edge region presents three distinct peaks with different intensities depending on the crystal axis orientation with respect to the polarization direction of the X-ray beam. The peaks correspond to a combination of 1s to 4p and 1s to 3d transitions with possibly mixed dipole and quadrupole character. The EXAFS fitting reveals, as expected, a biased structure according to the relative position of the crystal with respect to the beam polarization and the fittings are in accordance to theoretical values. The best fitted model has a large contribution from multi-scattering paths, which clarifies the interpretation of the actual peak contributions on the Fourier Transformed signal.

Effects of Kynurenic Acid on the Rat Aorta Ischemia-Reperfusion Model: Pharmacological Characterization and Proteomic Profiling.

Kynurenic acid (KYNA) is derived from tryptophan, formed by the kynurenic pathway. KYNA is being widely studied as a biomarker for neurological and cardiovascular diseases, as it is found in ischemic conditions as a protective agent; however, little is known about its effect after ischemia-reperfusion in the vascular system. We induced ischemia for 30 min followed by 5 min reperfusion (I/R) in the rat aorta for KYNA evaluation using functional assays combined with proteomics. KYNA recovered the exacerbated contraction induced by phenylephrine and relaxation induced by acetylcholine or sodium nitroprussiate in the I/R aorta, with vessel responses returning to values observed without I/R. The functional recovery can be related to the antioxidant activity of KYNA, which may be acting on the endothelium-injury prevention, especially during reperfusion, and to proteins that regulate neurotransmission and cell repair/growth, expressed after the KYNA treatment. These proteins interacted in a network, confirming a protein profile expression for endothelium and neuron repair after I/R. Thus, the KYNA treatment had the ability to recover the functionality of injured ischemic-reperfusion aorta, by tissue repairing and control of neurotransmitter release, which reinforces its role in the post-ischemic condition, and can be useful in the treatment of such disease.

Pentacyanoferrate(II) complex of pyridine-4- and pyrazine-2-hydroxamic acid as source of HNO: investigation of anti-tubercular and vasodilation activities.

A pharmacophore design approach, based on the coordination chemistry of an intimate molecular hybrid of active metabolites of pro-drugs, known to release active species upon enzymatic oxidative activation, is devised. This is exemplified by combining two anti-mycobacterial drugs: pyrazinamide (first line) and delamanid (third line) whose active metabolites are pyrazinoic acid (PyzCOOH) and likely nitroxyl (HNO (or NO.)), respectively. Aiming to generate those active species, a hybrid compound was envisaged by coordination of pyrazine-2-hydroxamic acid (PyzCONHOH) witha Na3[FeII(CN)5]moiety. The corresponding pentacyanoferrate(II) complex Na4[FeII(CN)5(PyzCONHO-)] was synthesized and characterized by several spectroscopic techniques, cyclic voltammetry, and DFT calculations. Chemical oxidation of this complex with H2O2 was shown to induce the release of the metabolite PyzCOOH, without the need of the Mycobacterium tuberculosis (Mtb) pyrazinamidase enzyme (PncA). Control experiments show that both H2O2- and N-coordinated pyrazine FeII species are required, ruling out a direct hydrolysis of the hydroxamic acid or an alternative oxidative route through chelation of ametal center by a hydroxamic group. The release of HNO was observed using EPR spectroscopy in the presence of a spin trapping agent. The devised iron metal complex of pyrazine-2-hydroxamic acid wasfound inactive against an actively growing/non-resistant Mtb strain; however, itshowed a strong dose-dependent and reversible vasodilatory activity with mostly lesser toxic effects than the reference drug sodium nitroprussiate, unveiling thus a potential indication for acute or chronic cardiovascular pathology. This is a priori a further indirect evidence of HNO release from this metal complex, standing as a possible pharmacophore model for an alternative vasodilator drug.

THU0084 TOFACITINIB REVERSED ENDOTHELIAL DYSFUNCTION IN RHEUMATOID ARTHRITIS: MECHANISTIC INSIGHTS FROM THE RAT ADJUVANT-INDUCED ARTHRITIS MODEL.

Background:Tofacitinib, an inhibitor of JAK3 and JAK1, is approved for the treatment of rheumatoid arthritis (RA)1. Cardiovascular (CV) risk2and events3in RA patients treated with Tofacitinib is a matter of debate, but the vascular mechanisms involved are unknown.Objectives:The aim of this study was to investigate whether Tofacitinib improves endothelial dysfunction (ED) and if so to explore the underlying mechanisms in the model of adjuvant-induced arthritis (AIA) in rats.Methods:AIA was induced by injection ofMycobacterium butyricumin the tail of male Lewis rats. A group of rats without arthritis served as controls. At the first signs of arthritis, AIA received Tofacitinib (10 mg/kg twice daily, s.c.) or 33%DMSO/PEG300(Vehicle). Arthritis score was daily evaluated. After 21 days, preconstricted isolated aortic rings were relaxed with acetylcholine (Ach, 10-11-10-4moles/liter) in the presence or not of inhibitor of nitric oxide (NO) synthase (L-NAME), cyclooxygenase-2 (NS398), arginase (nor-NOHA), endothelium-derived hyperpolarizing factor (EDHF) (apamin/charybdotoxin) and superoxide anions production (Tempol). Endothelium-denuded rings were used to determine the vasorelaxant response to the NO-donor sodium nitroprussiate (SNP, 10-11-10-4moles/liter). Blood pressure and heart rate were measured by invasive method. A radiographic score was attributed to hind paws.Results:Compared to AIA-Vehicle, Tofacitinib dramatically reduced arthritis (-76%) and radiographic (-73%) scores (p<0.001), and improved Ach-induced vasorelaxation (p<0.05). Of note, Ach-induced vasorelaxation was not different between Tofacitinib-AIA and control rats. The response to SNP was not different between groups. The effect of Tofacitinib on ED was mediated by decreased cyclooxygenase-2 and arginase activities, decreased superoxide anions production, increased NO synthase activity and EDHF synthesis. As compared to AIA-Vehicle, Tofacitinib changed neither blood pressure nor heart rate.Conclusion:The present results demonstrated that Tofacitinib reversed arthritis-induced ED, through the correction of all the acknowledged impaired endothelial pathways in the AIA model. As ED is theprimum movensof atherogenesis, these data provide a mechanistic explanation to the potential benefits of Tofacitinib on the cardiovascular comorbidities associated to RA.

Maternal Supplementation of Inositols, Fucoxanthin, and Hydroxytyrosol in Pregnant Murine Models of Hypertension.

Myoinositol (M) and D-chiro-inositol (D) are insulin sensitizer compounds, while fucoxanthin (F) and hydroxytyrosol (H) are antioxidant substances. We aim to investigate if the combination of these compounds, will improve the vascular responses in pregnant mouse models of hypertension: a genetic model, transgenic heterozygous mice lacking endothelial nitric oxide synthase gene (eNOS-/+); and environmental, wild-type (WT) mice. Those mouse models will allow a better understanding of the genetic/environmental contribution to hypertension in pregnancy. eNOS-/+ and WT female were fed high fat diet for 4 weeks, then at 7-8 weeks of age were mated with WT male. On gestational day (GD) 1, they were randomly allocated to receive MDFH treatment or water as control: eNOS-/+ MDFH (n = 13), eNOS-/+ (n = 13), WT-MDFH (n = 14), and WT (n = 20). Systolic blood pressure (SBP) was obtained at GD 18, then dams were sacrificed; fetuses and placentas collected, and 2 mm segments of carotid arteries isolated for vascular responses using the wire-myograph system. Responses to phenylephrine (PE), with/without the NOS inhibitor (N-nitro-l-arginine methyl ester (l-NAME)), and to acetylcholine (Ach) and sodium nitroprussiate (SNP) were performed. SBP decreased in eNOS-/+ and WT dams after MDFH supplementation. In eNOS-/+, MDFH lower the contractile response to PE and l-NAME and improved Ach vasorelaxation. In WT dams, MDFH treatment did not affect PE response; MDFH treatment lowered the vascular PE response after incubation with l-NAME. No differences were seen in SNP relaxation in both models. MDFH decreased SBP in both genetically and environmentally hypertensive dams and improved vascular responses mostly in the eNOS-/+ dams.

Characterization of the cystine/glutamate antiporter in cultured Bergmann glia cells

Glutamate, the major excitatory transmitter in the vertebrate brain is a potent neurotoxin through the over-stimulation of its specific membrane receptors. In accordance, a tight regulation of its extracellular levels by plasma membrane transporters is present. A family of excitatory amino acid transporters is expressed in neurons and glia cells and is responsible of the removal of the neurotransmitter from the synaptic cleft. Glial transporters account for more than 80% of the brain uptake activity. The cystine/glutamate antiporter is another plasma membrane-bound protein critically involved in glutamatergic transmission. Upon oxidative stress, it begins to pump out glutamate in exchange for cystine, mostly needed for glutathione production. Taking into consideration that all of these glutamate transporter proteins are present in glia cells that surround glutamatergic synapses, we reasoned that a functional coupling of them should exist to prevent an excitotoxic insult to the neighboring neuronal cells. To this end, we used the established model of chick cerebellar Bergmann glia cultures. Once we could establish the expression of the cystine/glutamate antiporter in our system, we characterized its kinetic properties and started to gain insight into its regulation and plausible coupling to other transporters. Exposure to glutamate reduces the uptake activity and favors a physical interaction with the excitatory amino acid transporter 1 and the Na+-dependent neutral amino acids transporter 3. In contrast, treatment of the cultured cells with a nitric oxide donor such as sodium nitroprussiate augments the exchanger activity. Longer sodium nitroprussiate exposure periods down-regulates the cystine/glutamate protein levels. These results suggest that a coordinated interplay between glutamate transporters and exchangers takes place in glia cells to prevent excitotoxic insults.

Anti-apoptotic effect of interleukin-22 on fibroblast-like synoviocytes in patients with rheumatoid arthritis is mediated via the signal transducer and activator of transcription 3 signaling pathway.

Inadequate apoptosis of fibroblast-like synoviocytes (FLS) plays a crucial role in the immunopathogenesis of rheumatoid arthritis (RA). Interleukin-22 (IL-22) is a novel member of the cytokine network that has been found to be involved in the immunological process underlying RA. In this study, we investigated the effect of IL-22 on the survival of RA-FLS from RA patients and examined the possible mechanism to determine new therapeutic strategies for RA. FLS obtained from patients with RA were cultured in vitro and treated with sodium nitroprussiate (SNP) to induce apoptosis in the presence or absence of IL-22. RA-FLS viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RA-FLS apoptosis was analyzed by annexin V/propidium iodide staining (AV/PI). The levels of IL-22R1, pSTAT3-Y705, pSTAT3-S727, total STAT3, Bcl-xL and Bcl-2 were detected by Western blot analysis. IL-22R1 was expressed on RA-FLS. IL-22 pretreatment at concentrations ranging from 10 to 100 ng/mL increased RA-FLS viability and prevented SNP-induced apoptosis. Treatment with the STAT3 inhibitors, HO3867 or STA21, reversed the protective effect of IL-22 on SNP-induced apoptosis of RA-FLS. IL-22-induced phosphorylation of STAT3 (pSTAT3-Y705 and pSTAT3-S727) was increased in RA-FLS. Also IL-22 increased Bcl-2 expression in SNP-treated RA-FLS, and the effect was reversed by treatment with HO3867 or STA21. IL-22 protects against SNP-induced apoptosis in RA-FLS by activating the STAT3 pathway and the downstream target gene, Bcl-2. Therefore, therapeutic strategies that target the IL-22/STAT3 pathway are implicated as candidates for RA treatment.

Evidences of antihypertensive potential of extract from Solanum capsicoides All. in spontaneously hypertensive rats

BackgroundSolanum capsicoides All. is morphologically similar to Solanum sisymbriifolium Lam. which is used in folk medicine in South America for antihypertensive and diuretics purposes. This similarity has led to species identification errors, which therefore may result in errors by patients. PurposeTo evaluate the antihypertensive and diuretics potential of the methanol extract from Solanum capsicoides All. (MeOH–Sc), in vitro and in vivo, in spontaneously hypertensive rats (SHR). MethodsInitial experiments were performed in rat mesenteric artery to evaluate the in vitro vascular effect of MeOH–Sc and its fractions, in addition to the mechanisms involved during the observed effect. Mean arterial pressure (MAP) and heart rate (HR) were recorded in non-anesthetised hypertensive and normotensive rats. In another set of experiments, MeOH–Sc was administered for 21 consecutive days. Daily body weight measurements were conducted and MAP, HR and urinary volume were measured every 5 days. The mesenteric artery from treated animals was tested for phenylephrine and sodium nitroprussiate (SNP) sensitivity. ResultsInitially, MeOH–Sc and fractions relaxed phenylephrine-induced contractions in mesenteric artery rings. The vasorelaxant effect was not changed in the presence of a blocker of eNOS (L-NAME) in rings with an intact endothelium. In denuded-endothelium rings, the vasorelaxant response was significantly reduced in the presence of a cAMP inhibitor (SQ 22536 10µM) in SHR but not in Wistar Kyoto rats (WKY). However, in the presence of a cGMP inhibitor (ODQ 10µM), a curve shift to the right was observed in WKY animals, but not in SHR. Intravenous bolus injections of MeOH–Sc into non-anesthetised SHR and WKY, induced hypotension that was associated with an increase in HR. A significant antihypertensive effect was observed in animals that received MeOH–Sc orally for 21 days, which also prevented the development of cardiac hypertrophy. Urine volume from animals treated with MeOH–Sc significantly increased. Finally, MeOH–Sc induced beneficial changes in vascular responsiveness. ConclusionMeOH–Sc has a potential antihypertensive effect in SHR.

Disclosing caffeine action on insulin sensitivity: Effects on rat skeletal muscle

Caffeine, a non-selective adenosine antagonist, has distinct effects on insulin sensitivity when applied acutely or chronically. Herein, we investigated the involvement of adenosine receptors on insulin resistance induced by single-dose caffeine administration. Additionally, the mechanism behind adenosine receptor-mediated caffeine effects in skeletal muscle was assessed.The effect of the administration of caffeine, 8-cycle-1,3-dipropylxanthine (DPCPX, A1 antagonist), 2-(2-Furanyl)-7-(2-phenylethyl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine (SCH58261, A2A antagonist) and 8-(4-{[(4-cyanophenyl)carbamoylmethyl]-oxy}phenyl)-1,3-di(n-propyl)xanthine (MRS1754, A2B antagonist) on whole-body insulin sensitivity was tested. Skeletal muscle Glut4,5′-AMP activated protein kinase (AMPK) and adenosine receptor protein expression were also assessed. The effect of A1 and A2B adenosine agonists on skeletal muscle glucose uptake was evaluated in vitro. Sodium nitroprussiate (SNP, 10nM), a nitric oxide (NO) donor, was used to evaluate the effect of NO on insulin resistance induced by adenosine antagonists.Acute caffeine decreased insulin sensitivity in a concentration dependent manner (Emax=55.54±5.37%, IC50=11.61nM), an effect that was mediated by A1 and A2B adenosine receptors. Additionally, acute caffeine administration significantly decreased Glut4, but not AMPK expression, in skeletal muscle. We found that A1, but not A2B agonists increased glucose uptake in skeletal muscle. SNP partially reversed DPCPX and MRS1754 induced-insulin resistance.Our results suggest that insulin resistance induced by acute caffeine administration is mediated by A1 and A2B adenosine receptors. Both Glut4 and NO seem to be downstream effectors involved in insulin resistance induced by acute caffeine.

Nitric oxide induces specific isoforms of antioxidant enzymes in soybean leaves subjected to enhanced ultraviolet-B radiation

Antioxidant enzymes play a key role in plant tolerance to different types of stress, including ultraviolet-B (UV-B) radiation. Here we report that nitric oxide (NO) enhances antioxidant enzymes gene expression and increases the activity of specific isoforms protecting against UV-B radiation. Pre-treatments with sodium nitroprussiate (SNP), a NO-donor, prevented lipid peroxidation, ion leakage and H2O2 and superoxide anion accumulation in leaves of UV-B-treated soybean plants. Transcripts levels of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were significantly induced by SNP. These data correlated with the enhancement of particular antioxidant enzyme isoforms, such as one CAT isoform and two APX isoforms. Moreover, SNP induced the expression of three new isoforms of SOD, identified as Mn-SOD subclass. Further results showed that total activities of SOD, CAT and APX significantly increased by 2.2-, 1.8- and 2.1-fold in SNP-treated plants compared to controls, respectively. The protective effect of SNP against UV-B radiation was negated by addition of the specific NO scavenger cPTIO, indicating that NO released by SNP mediates the enhancement of antioxidant enzymes activities. In conclusion, NO is involved in the signaling pathway that up-regulates specific isoforms of antioxidant enzymes protecting against UV-B-induced oxidative stress.

Duhuo Jisheng decoction treatment inhibits the sodium nitroprussiate‑induced apoptosis of chondrocytes through the mitochondrial‑dependent signaling pathway.

Chondrocyte apoptosis activated by the mitochondrial-dependent signaling pathway plays a crucial role in the cartilage degeneration of osteoarthritis. Duhuo Jisheng decoction (DHJSD), a herbal formula from traditional Chinese medicine, has been widely used for treating osteoarthritis (OA). However, the molecular mechanisms behind the therapeutic effect of DHJSD remain to be elucidated. In the present study, the effects of DHJSD on the mitochondrial-dependent signaling pathway in sodium nitroprussiate (SNP)-induced chondrocyte apoptosis were investigated. Chondrocytes, from the knee articular cartilage of Sprague Dawley rats, were identified by type II collagen immunohistochemistry. The chondrocytes, stimulated with or without SNP to induce apoptosis, were treated by DHJSD for various concentrations and times. The viability of SNP-induced chondrocytes treated with DHJSD was enhanced compared to SNP-induced chondrocytes in a dose- and time-dependent manner, as assessed by the MTT assay. The apoptosis of SNP-induced chondrocytes treated by DHJSD was significantly decreased compared to SNP-induced chondrocyte, as shown by 4',6-diamidino-2-phenylindole and Annexin V/propidium iodide staining. The mitochondrial membrane potential (∆Ψm) of SNP-induced chondrocytes treated by DHJSD was significantly decreased compared to SNP-induced chondrocyte, as shown by JC-1 staining. To understand the mechanism, the mRNA and protein levels of Bax, B-cell lymphoma 2 (Bcl-2), caspase-9 and caspase-3 were detected by reverse transcription‑polymerase chain reaction and western blot analysis, respectively. In SNP-induced chondrocyte treated by DHJSD, the Bcl-2 expression was increased, whereas the expression of Bax, caspase-9 and caspase-3 was decreased compared to SNP-induced chondrocyte. Taken together, these results indicated that DHJSD inhibits the apoptosis of SNP-induced chondrocyte by the mitochondrial-dependent apoptotic pathway, and this may partly explain its therapeutic efficacy for OA.

Role of smooth muscle cell mineralocorticoid receptor in vascular tone.

Identification of the mineralocorticoid receptor (MR) in the vasculature (i.e., endothelial and smooth muscle cells) raised the question of its role in vascular function and blood pressure control. Using a mouse model with conditional inactivation of MR in vascular smooth muscle cell (VSMC) (MR(SMKO)), we have recently shown that the VSMC MR is crucial for aldosterone-salt-induced carotid stiffening. In the present study, we have investigated the specific contribution of the VSMC MR in the regulation of vascular tone in large vessels. In MR(SMKO) mice, contractions induced by potassium chloride and calcium (Ca(2+)) are decreased in the aorta, whereas contraction is normal in response to phenylephrine and caffeine. The difference in response to Ca(2+) suggests that the VSMC-specific deficiency of the MR modifies VSM Ca(2+) signaling but without altering the intracellular Ca(2+) store handling. The relaxation induced by acetylcholine is not affected by the absence of MR. However, the relaxation induced by Ach in the presence of indomethacin and the relaxation induced by sodium nitroprussiate are significantly reduced in MR(SMKO) mice compared to controls. Since endothelial nitric oxide synthase (eNOS) activity is increased in mutant mice, their altered relaxation reflects impairment of the nitric oxide (NO) signaling pathway. In addition to altered NO and Ca(2+) signaling, the activity of myosin light chain and its regulators, myosin light chain kinase (MLCK) and myosin phosphatase (MLCP), is reduced. In conclusion, MR expressed in VSMC is required for NO and Ca(2+) signaling pathways and contractile protein activity leading to an altered contraction/relaxation coupling.

AB0138 Time-Course of Microvascular versus Macrovascular Endothelial Dysfunction in Rat Adjuvant-Induced Arthritis

BackgroundRheumatoid arthritis (RA) is associated with increased risk for cardiovascular disease (CVD). Whereas ample evidence demonstrated the presence of endothelial dysfunction (ED) in RA, it is still unclear how early...

Interaction of nitric oxide and polyamines involves antioxidants and physiological strategies against chilling-induced oxidative damage in Zingiber officinale Roscoe

Nitric oxide (NO) and polyamines (PAs) are two kinds of important signal in plant tolerance to abiotic stress. In the present study, it was observed that both sodium nitroprussiate (SNP; a NO donor) and spermidine (Spd), increased ginger seedlings tolerance to chilling stress, which depend on their roles in protecting photosystem II (PSII), keeping high level of unsaturated fatty acids, regulating reactive oxygen species (ROS) detoxification. Further investigation indicated that co-application of SNP and Spd had more powerful effects on improving chilling stress tolerance of ginger by enhancing above physiological strategies. This provides a possible cross-talk between NO and PAs to overcome chilling stress in plants. Further study indicated that NO and PAs can stimulate accumulation each other to synergistically enhance chilling tolerance. For practicality, co-application of SNP and Spd could be an effective approach for the survival of plants under chilling stress through ROS detoxification.

Abstract 69: Role of Neutrophil Gelatinase Associated Lipocalin in Cardiovascular Remodeling Induced by Aldosterone

Neutrophil Gelatinase Associated Lipocalin (NGAL) is a circulating protein, member of the lipocalin family, which binds MMP9 and modulates its stability and activity. We have recently shown that NGAL is a primary target of aldosterone/mineralocorticoid receptor (MR) in endothelial cells, vascular smooth muscle cells and cardiomyocytes. We hypothesized that NGAL could be a mediator of aldosterone/MR profibrotic and proinflammatory effects in the cardiovascular system. Wild type (WT) and NGAL Knock Out (KO) mice were subjected to an uni-nephrectomy aldosterone salt challenge (NAS, 200μg/kg/day of aldo, 1% NaCl in tap water) for 4 weeks. Blood pressure (SBP) was measured by tail cuff method. Vascular reactivity was assessed by wire myograph. Cardiovascular fibrosis and inflammation were analyzed by RT-PCR, western blot, immunohistochemistry and ELISA. There was no difference in SBP between NGAL KO mice compared to WT mice in basal condition. With NAS challenge, SBP was increased only in WT (SBP; CT 107±3, CT NAS 133±5, KO 109±3, KO NAS 115±3 mmHg). Ex vivo aortic contraction induced by phenylephrine (Phe) and potassium chloride (KCl) were increased by NAS challenge in WT and KO (Emax Phe; CT 2.28±0.8, CT NAS 10.65±1.3, KO 1.45±0.3, KO NAS 9.32±0.9 mN). Responses to vasodilators (acetylcholine and sodium nitroprussiate) were altered in NAS condition in both groups. Quantification of pro collagen I N-terminal peptide (PINP) in plasma showed an increase of PINP due to NAS treatment in WT that was prevented by NGAL inactivation (CT 83±15, CT NAS 129±10, KO 70±19, KO NAS 59±12 μg/l). In myocardium, NAS treatment increased collagen type I and perivascular fibrosis in WT whereas KO were resistant to fibrosis (Collagen Volume Fraction; CT 19±3, CT NAS 28±2, KO 20±3, KO NAS 20±3 %). In aorta, collagen type I, vascular fibrosis and osteopontin were also increased by NAS in WT. These increases were prevented by NGAL inactivation (CVF; CT 24±4, CT NAS 34±5, KO 21±2, KO NAS 28±2 %). Our results show that NGAL plays a role in aldosterone/MR-mediated hypertension, vascular and cardiac peri-vascular fibrosis and inflammation, but not in vascular dysfunction.

Alleviating CTAC and Flu combined pollution damage in Chlorella vulgaris by exogenous nitric oxide

This study investigates the effect of sodium nitroprussiate (SNP), an exogenous NO-donor, on the joint toxicity of binary mixtures of cetyltrimethylammonium chloride (CTAC) and fluoranthene (Flu) (CTAC/Flu), which are representatives for surfactants and polycyclic aromatic hydrocarbons (PAHs) respectively, in a unicellular green alga Chlorella vulgaris (C. vulgaris). The results showed that the addition of low SNP (20μM) alleviated the CTAC/Flu combined pollution damage in C. vulgaris. Supplement of low SNP significantly increased the algae biomass, chlorophyll content, soluble protein content and the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) as compared to CTAC/Flu treatment alone. SNP also reduced the content of malondialdehyde (MDA) and the reactive oxygen species (ROS), as compared with CTAC/Flu treated alone. On the contrary, the above phenomena were reversed when high concentration of SNP (100μM) was added. Our study indicated that the damage of the joint action of surfactants and PAHs on hydrobios can be alleviated through protecting against oxidant substances and increasing the activity of antioxidant enzymes with an exogenous supply of NO in certain concentration range.

Effect of skin temperature on skin endothelial function assessment

PurposeMicrocirculatory dysfunction plays a key role in the development of sepsis during which core temperature is often disturbed. Skin microvascular assessment using laser techniques has been suggested to evaluate microvascular dysfunction during sepsis, but skin microcirculation is also a major effector of human thermoregulation. Therefore we aimed to study the effect of skin temperature on endothelial- and non-endothelial microvascular responses. MethodsFifteen healthy participants were studied at different randomized ambient temperatures leading to low (28.0+/−2.0°C), intermediate (31.6+/−2.1°C), and high (34.1+/−1.3°C) skin temperatures. We measured skin blood flow using laser speckle contrast imaging on the forearm in response to vasodilator microvascular tests: acetylcholine (ACh) iontophoresis, sodium nitroprussiate (SNP) iontophoresis, and post-occlusive reactive hyperemia (PORH). The results are expressed as absolute (laser speckle perfusion units, LSPU) or normalized values (cutaneous vascular conductance, CVC in LSPU/mmHg and multiple of baseline). ResultsMaximal vasodilation induced by these tests is modified by skin temperature. A low skin temperature induced a significant lower vasodilation for all microvascular tests when results are expressed either in absolute values or in CVC. For example, ACh peak was 57.6+/−19.6LSPU, 66.8+/−22.2LSPU and 88.5+/−13.0LSPU for low, intermediate and high skin temperature respectively (p<0.05). When results are expressed in multiple of baseline, statistical difference disappeared. ConclusionsThese results suggest that skin temperature has to be well controlled when performing microvascular assessments in order to avoid any bias. The effect of skin temperature can be corrected by expressing the results in multiple of baseline.

Nitric oxide boosts TLR‐4 mediated lipocalin 2 expression in chondrocytes

Lipocalin 2 (LCN2) has recently emerged as a novel adipokine involved in different processes including arthritis and chondrocyte inflammatory response. However, little is known about its activity on chondrocyte homeostasis and its regulation by nitric oxide (NO) Hence, we performed a set of experiments aimed to achieve a better understanding of this relationship. Cell vitality was tested in the ATDC5 cell line by the MTT colorimetric assay. Protein expression and gene expression was evaluated by Western blot and real time RT-PCR, respectively. NO production (determined as nitrite accumulation) was assayed by the Griess reaction. First, we demonstrated that LCN2 decreased murine chondrocytes vitality. Next, LCN2 co-stimulation with LPS enhanced NOS2 protein expression by murine chondrocytes. In addition, inhibition of LPS-induced nitric oxide production by aminoguanidine, a selective NOS2 inhibitor, significantly reduced LPS-mediated LCN2 expression. In contrast, treatment of murine chondrocytes with sodium nitroprussiate (SNP), a classic NO donor, scarcely induced LCN2 expression. Intriguingly, SNP addition to LPS-challenged chondrocytes, treated with aminoguanidine, provoked a strong induction of LCN2 expression. Finally, murine ATDC5 cells, co-cultured with LPS pre-challenged macrophages, had higher LCN2 expression in comparison with murine chondrocytes co-cultured with non pre-challenged macrophages. In this work we have described for the first time that NO is able to exert a control on LCN2 expression, suggesting the existence of a feedback loop regulating its expression.

Exogenous nitric oxide effect on fructan accumulation and FBEs expression in chilling-sensitive and chilling-resistant wheat

This study was to investigate the effect of exogenous nitric oxide (NO) on fructan accumulation and fructan biosynthesic enzymes (FBEs) expression in seedlings leaves of two wheat (Triticum aestivum L.) cultivars, winter wheat (Zhoumai18, ZM) and spring wheat (Yanzhan4110, YZ), under 4°C. The seedlings of two wheat cultivars were subjected to different concentrations of sodium nitroprussiate (SNP) for 0, 24, 48, and 96h. Relative water content (RWC) was increased by exogenous NO in YZ, but decreased in ZM. Except for glucose, fructose and fructans of degree of polymerization (DP) 3 in YZ, other soluble carbohydrates contents in the two wheat cultivars all increased to different degrees. The activities of FS (including sucrose: sucrose 1-fructosyltransferase (1-SST, EC: 2.4.1.99) and sucrose: fructan 6-fructosyltransferase (6-SFT, EC: 2.4.1.10)) were significantly higher than fructan: fructan 1-fructosyltransferase (1-FFT, EC: 2.4.1.100) in the seedlings of two wheat cultivars. The same phenomenon occurred to FBEs expression. In addition, sucrose content decreased while fructans content increased under low temperature, which was in accordance with the improved 1-FFT activity in ZM. Moreover, fructans content increased to a high level under high concentration of NO in ZM while kept at a constant low level in YZ. The expression levels of FBEs were universally higher in ZM than in YZ, which identified with the high frost resistance of the winter cultivar. It is concluded that exogenous NO treatment on wheat may be a good option to reduce chilling injury by regulating fructan accumulation in leaves. This is the first report owing that exogenous NO alleviated the negative effects of chilling stress by accumulating fructans in wheat.