PROTECTION OF ELECTROACUPUNCTURE ON HIPPOCAMPAL INJURY INDUCED BY QUINOLINIC ACID IN RATS

Objective To probe into the protective mechanism of electro-acupuncture （EA） on anti-oxygen stress in dementia-model rats. Methods A total of 30 male SD rats of cleaning grade were randomized into three groups, named sham-operation （n = 10）, model （n = 10）, model＋ EA （n = 10）. The dementia-model rat was made with hippocampal GA1 lesions by quinolinic acid （QA）. On the second day of modeling, in model＋ EA group, EA （3 Hz, 2-4 mA, continuous waves） was applied to ＂Dàzhuī＂ （大椎 GV 14） and ＂Shènshū＂ （肾俞 BL 23） for 10 min. The capability of learning and memory was evaluated by step-down test to observe the changes of nitric oxide （NO）, nitric oxide synthase （NOS） activity, superoxide dismutase （SOD） activity and malondialdehyde （MDA） of the hippocampal tissues in rats separately by biochemical methods. Results EA improved learning and memory of dementia rats with hippocampal CA1 lesions induced by QA at different degrees. It significantly increased SOD activity, reduced MDA content and improved NO level and NOS activity. Conclusion EA improves significantly the learning and memory of the dementia rats due to hippocampal CA1 lesions induced by QA, which is probably relevant with the anti-oxygen stress of EA.

Neurotoxicity of Quinolinic Acid to Spiral Ganglion Cells in Rats

Our study investigated the neurotoxicity of quinolinic acid(QA) to spiral ganglion cells(SGCs),observed the protective effects of N-methyl-D-aspartate(NMDA) receptor antagonist MK-801 and magnesium ions on the QA-induced injury to SGCs,and analyzed the role of QA in otitis media with effusion(OME)-induced sensorineural hearing loss(SNHL).After culture in vitro for 72 h,SGCs were exposed to different media and divided into 4 groups:the blank control group,the QA injury group,the MK-801 treatment group,and the MgCl2 protection group.The apoptosis rate of SGCs was analyzed by Annexin V and PI double staining under the fluorescence microscopy 24 h later.SGCs were cultured in vitro for 72 h and divided into four groups:the low concentration QA group,the high concentration QA group,the MK-801 group,the MgCl2 group.The transient changes of intracellular calcium concentration were observed by the laser scanning confocal microscopy.Apoptosis rate in QA injury group was higher than that in blank control group and MgCl2 protection group(both P0.05).In high concentration QA group,there was an obvious increase of the intracellular calcium concentration in SGCs,which didn’t present in low concentration QA group.In MgCl2 group,the peak values of the intracellular calcium concentration in SGCs were reduced and the duration was shortened,but the intracellular calcium concentration in SGCs had no significant change in MK-801 group.It was concluded that QA could injure SGCs by excessively activating NMDA receptors on the cell membrane,which might be the mechanism by which OME induced SNHL,while Mg2+ could protect the SCGs from the neurotoxicity of QA.

Research progress of quinolinic acid in neuropsychiatric diseases

Quinolinic acid is a neurotoxic substance produced by tryptophan through the kynurenine metabolism pathway.Quinolinic acid is involved in the pathological processes of Alzheimer's disease,Parkinson's disease,Huntington's disease,amyotrophic lateral sclerosis,encephalitis,depression,and schizophrenia.The above process is realized through pathophysiological processes such as excitatory neurotoxicity,metabolic damage,free radical generation and oxidative stress,participation in inflammatory response,induction of neuron and astrocytic apoptosis.This article will explain the metabolic regulation,biological characteristics,and neurotoxicity of quinolinic acid.The research progress of quinolinic acid in Alzheimer's disease,Parkinson's disease,Huntington's disease,depression and subacute sclerosing panencephalitis is also described.

Hydrogen sulfide reduces oxidative stress in Huntington's disease via Nrf2

The pathophysiology of Huntington's disease involves high levels of the neurotoxin quinolinic acid. Quinolinic acid accumulation results in oxidative stress, which leads to neurotoxicity. However, the molecular and cellular mechanisms by which quinolinic acid contributes to Huntington's disease pathology remain unknown. In this study, we established in vitro and in vivo models of Huntington's disease by administering quinolinic acid to the PC12 neuronal cell line and the striatum of mice, respectively. We observed a decrease in the levels of hydrogen sulfide in both PC12 cells and mouse serum, which was accompanied by down-regulation of cystathionine β-synthase, an enzyme responsible for hydrogen sulfide production. However, treatment with NaHS(a hydrogen sulfide donor) increased hydrogen sulfide levels in the neurons and in mouse serum, as well as cystathionine β-synthase expression in the neurons and the mouse striatum, while also improving oxidative imbalance and mitochondrial dysfunction in PC12 cells and the mouse striatum. These beneficial effects correlated with upregulation of nuclear factor erythroid 2-related factor 2 expression. Finally, treatment with the nuclear factor erythroid 2-related factor 2inhibitor ML385 reversed the beneficial impact of exogenous hydrogen sulfide on quinolinic acid-induced oxidative stress. Taken together, our findings show that hydrogen sulfide reduces oxidative stress in Huntington's disease by activating nuclear factor erythroid 2-related factor 2,suggesting that hydrogen sulfide is a novel neuroprotective drug candidate for treating patients with Huntington's disease.

Preparation of a high-performance synthetic pitch from aromatic hydrocarbons containing N/Cl

The preparation of a synthetic pitch from aromatic monomers could easily regulate structure orientation at the molecu-lar level,which would be useful in fabrication.An isotropic synthetic pitch was prepared by a chlorine-and/or nitrogen-induced sub-stitution polymerization reaction method using aromatic hydrocarbon precursors containing Cl and N,which for this study were chloromethyl naphthalene and quinoline.This method was verified by investigating the structural changes under different synthesis conditions,and the synthesis mechanism induced by aromatics containing Cl was also probed.The result shows that the pyridinic N in quinoline contains a lone pair of electrons,and is an effective active site to induce the polymerization reaction by coupling with aromatic hydrocarbons containing Cl.The reaction between such free radicals causes strong homopolymerization and oligomeriza-tion.A higher reaction temperature and longer reaction time significantly increased the degree of polymerization and thus increased the softening point of the pitch.A linear molecular structure was formed by the Cl substitution reaction,which produced a highly spinnable pitch with a softening point of 258.6℃,and carbon fibers with a tensile strength of 1163.82 MPa were obtained.This study provides a relatively simple and safe method for the preparation of high-quality spinnable pitch.

Removal of Nitrogen Compounds from Fuels by Deep Eutectic Solvent Based on 1-Butyl-3-Methylimidazolium Bromide and Dicarboxylic Acids

1-Butyl-3-methylimidazolium bromide-based ([Bmim]Br-based) deep eutectic solvents (DESs) can be used aseffective extractants for removing nitrogen compounds from fuel oil. Among the DESs studied, the combination of [Bmim]Brand malonic acid (MA) in a 1:1 molar ratio demonstrated good performance for the removal of both basic and non-basic Ncompounds. The DES [Bmim]Br-MA exhibited extraction efficiencies of 98.4% for quinoline and 92.9% for indole after 30min at 30 ℃ with a DES/oil mass ratio of 1/7. Moreover, the extraction efficiencies remained high at 86.4% for quinolineand 85.9% for indole after recycling the DES four times.. In addition, the DES [Bmim]Br-MA could effectively removeN compounds from Fushun shale diesel oil, with extraction efficiencies of 83.5% for total nitrogen and 89.9% for basicnitrogen at a DES/oil mass ratio of 1/1.

Effects of caffeic acid,rofecoxib,and their combination against quinolinic acid-induced behavioral alterations and disruption in glutathione redox status

Objective The neuroprotective roles of cyclooxygenase （COX） and lipooxygenase （LOX） inhibitors have been well documented. Quinolinic acid （QA） is a well-known excitotoxic agent that could induce behavioral, morphological and biochemical alterations similar with symptoms of Huntington’s disease （HD）, by stimulating NMDA receptors. However, the exact roles of COX and LOX inhibitors in HD have not yet been explained. The present study aims to elucidate the effects of caffeic acid （a specific inhibitor for LOX）, rofecoxib （a specific inhibitor for COX-2）, and their combination in ameliorating QA-induced neurotoxicity in rats. Methods QA was injected into the right striatum of rats to induce neurotoxicity. Caffeic acid and rofecoxib were then orally administered separately. In the combination study, caffeic acid and rofecoxib were administered together. After that, a series of behavioral assessments were conducted to determine the effects of caffeic acid and rofecoxib, respectively, and the co-effect of caffeic acid and rofecoxib, against QA-induced neurotoxicity. Results Intrastriatal QA administration （300 nmol） not only induced a significant reduction in body weight and motor incoordination, but also altered the redox status （decreased glutathione and increased oxidized glutathione level） in striatum, as compared to the sham group. Moreover, chronic treatment with caffeic acid （5 mg/kg and 10 mg/kg, respectively, p.o.） or rofecoxib （10 mg/kg, p.o.） could significantly attenuate QA-induced behavioral alterations and restore the redox status in striatum. However, at the dose of 2.5 mg/kg, caffeic acid did not show any significant effects on these parameters in QA-treated rats. Furthermore, the combination of rofecoxib （10 mg/kg） and caffeic acid （5 mg/kg） could significantly protect against QA neurotoxicity. Conclusion The in vivo study indicates that excitotoxic injury to the brain might affect oxidant/antioxidant equilibrium by eliciting changes in glutathione. Moreover, the LOX and the COX pathways may be both involved in quinolinic-induced neurotoxicity, which provides a promising target for HD treatment.

Assessing quinoline removal performances of an aerobic continuous moving bed biofilm reactor(MBBR) bioaugmented with Pseudomonas citronellolis LV1

This study evaluated the bioaugmentation potential of a quinoline-degrading strain Pseudomonas citronellolis LV1 inoculation into activated sludge for treating quinoline wastewater, and results indicated the inoculation of LV1 in aerobic continuous MBBR could substantially improve the quinoline removal performance with an improved removal efficiency of 34% averagely when quinoline was used as the sole carbon and nitrogen source. Additionally, efficient removal of quinoline in enhanced MBBR occurred at the influent p H of 7.0–8.0, hydraulic retention time(HRT) of 24–28 h and influent quinoline concentration of 100–700 mg·L^(-1). High-throughput sequencing analysis indicated that bioaugmentation could increase microbial diversity and shape the microbial community structure. Although the inoculant LV1 did not remain its dominance in stage Ⅲ, bioaugmentation indeed induced the formation of effective microbial community, and the indigenous microbes including Flavobacterium, Pseudoxanthomonas,Pseudomonas, Vermamoeba, Dyadobacter and Sphingomonas might play the key role in quinoline removal.According to the PICRUSt, the enhanced genes encoding aromatic ring-cleavage enzyme, especially for Nheterocyclic ring-cleavage enzymes, could lead to the improved removal performance of quinoline in bioaugmentation stage. Moreover, the enhanced MBBR treated well actual coking wastewater, as indicated by high removal performance of quinoline, phenol and COD.

Eleutheroside B or E enhances learning and memory in experimentally aged rats

Eleutheroside B or E, the main component of Acanthopanax, can relieve fatigue, enhance memory, and improve human cognition. Numerous studies have confirmed that high doses of acetylcholine significantly attenuate clinical symptoms and delay the progression of Alzheimer＇s disease. The present study replicated a rat model of aging induced by injecting quinolinic acid into the hippocampal CA1 region. These rats were intraperitoneally injected with low, medium and high doses of eleutheroside B or E （50, 100, 200 mg/kg）, and rats injected with Huperzine A or PBS were used as controls. At 4 weeks after administration, behavioral tests showed that the escape latencies and errors in searching for the platform in a Morris water maze were dose-dependently reduced in rats treated with medium and high-dose eleutheroside B or E. Hematoxylin-eosin staining showed that the number of surviving hippocampal neurons was greater and pathological injury was milder in three eleutheroside B or E groups compared with model group. Hippocampal homogenates showed enhanced cholinesterase activity, and dose-dependent increases in acetylcholine content and decreases in choline content following eleutheroside B or E treatment, similar to those seen in the Huperzine A group. These findings indicate that eleutheroside B or E improves learning and memory in aged rats. These effects of eleutheroside B or E may be mediated by activation of cholinesterase or enhanced reuse of choline to accelerate the synthesis of acetylcholine in hippocampal neurons.

Inhibiting the kynurenine pathway in spinal cord injury: multiple therapeutic potentials?

Chronic induction of the kynurenine pathway（KP） contributes to neuroinflammation by producing the excitotoxin quinolinic acid（QUIN）. This has led to significant interest in the development of inhibitors of this pathway, particularly in the context of neurodegenerative disease. However, acute spinal cord injury（SCI） also results in deleterious increases in QUIN, as secondary inflammatory processes mediated largely by infiltrating macrophages, become predominant. QUIN mediates significant neurotoxicity primarily by excitotoxic stimulation of the N-methyl-D-aspartate receptor, but other mechanisms of QUIN toxicity are known. More recent focus has assessed the contribution that neuroinflammation and modulations in the KP make in mood and psychiatric disorders with recent studies linking inflammation and modulations in the KP, to impaired cognitive performance and depressed mood in SCI patients. We hypothesize that these findings suggest that in SCI, inhibition of QUIN production and other metabolites, may have multiple therapeutic modalities and further studies investigating this are warranted. However, for central nervous system-based conditions, achieving good blood-brain-barrier permeability continues to be a limitation of current KP inhibitors.

Alpha-7 nicotinic acetylcholine receptor agonist treatment in a rat model of Huntington's disease and involvement of heme oxygenase-1

Neuroinflammation is a common element involved in the pathophysiology of neurodegenerative diseases.We recently reported that repeated alpha-7 nicotinic acetylcholine receptor（α7 n ACh R） activations by a potent agonist such as PHA 543613 in quinolinic acid-injured rats exhibited protective effects on neurons.To further investigate the underlying mechanism,we established rat models of early-stage Huntington＇s disease by injection of quinolinic acid into the right striatum and then intraperitoneally injected 12 mg/kg PHA 543613 or sterile water,twice a day during 4 days.Western blot assay results showed that the expression of heme oxygenase-1（HO-1）,the key component of the cholinergic anti-inflammatory pathway,in the right striatum of rat models of Huntington＇s disease subjected to intraperitoneal injection of PHA 543613 for 4 days was significantly increased compared to the control rats receiving intraperitoneal injection of sterile water,and that the increase in HO-1 expression was independent of change in α7 n ACh R expression.These findings suggest that HO-1 expression is unrelated to α7 n ACh R density and the increase in HO-1 expression likely contributes to α7 n ACh R activation-related neuroprotective effect in early-stage Huntington＇s disease.

Research progress of kynurenine pathway in Alzheimer's disease

The kynurenine pathway(KP)has been shown to be involved in the pathophysiology of dementia diseases.Among the dementia diseases,the neurodegenerative diseases Alzheimer's disease and cerebrovascular diseases are vascular.The highest incidence of dementia.KP activation results in the production of neuroactive metabolites,which may interfere with normal neuronal function,leading to the appearance of symptoms of cognitive impairment.This review investigated KP's involvement in the neurological diseases Alzheimer's disease and vascular dementia,suggesting that KP is a potential therapeutic target for both diseases.

Microbial Degradation of Quinoline: Kinetics Study With Burkholderia picekttii

Objective To investigate the kinetics of quinoline biodegradation by Burkholderia pickttii, a Gram negative rod-shaped aerobe, isolated in our laboratory. Methods HPLC (Hewlett-Packard model 5050 with an UV detector) was used for the analysis of quinoline concentration. GC/MS method was used to identify the intermediate metabolites of quinoline degradation. Results The biodegradation of quinoline was inhibited by quinoline at a high concentration, and the degradation process could be described by the Haldane model. The kinetic parameters based on Haldane substrate inhibition were evaluated. The values were v = 0.44 h-1,Ks=166.7 mg/L, Ki= 650 mg/L, respectively. The quinoline concentration to avoid substrate inhibition was inferred theoretically and determined to be 329 mg/L. Conclusion The biodegradation of quinoline conforms to the Haldane inhibition model and the main intermediate metabolite of quinoline biodegradation is 2-hydroxy-quinoline.

Effective adsorptive denitrogenation from model fuels over yttrium ion-exchanged Y zeolite

The adsorption removal of indole and quinoline in octane with and without toluene over zeolites NaY and Yttrium Ion-exchanged Y(YY)using batch adsorption experiments was studied at 25℃and 0.1 MPa.YY was prepared by treating NaY with Y(NO3)3 solution twice via liquid ion-exchange method.NaY and YY were both characterized by XRD,SEM,N2 adsorption,XRF,NH3-TPD,and pyridine-FTIR techniques.Adsorption isotherms of indole,quinoline and toluene in octane were conducted at 25.0℃to explain the influence of toluene on nitrogen removal over NaY and YY.The partial destruct of the crystalline structure of NaY was observed after the introduction of yttrium ion,which led to an evident decline in BET surface area and pore volume of YY.Strong Br?nsted acidity and medium Lewis acidity were introduced by yttrium ion-exchange.Though the specific surface area and pore volume of YY were much lower than those of NaY,YY exhibited equivalent adsorption capacities for indole and quinoline as NaY in model fuels without toluene.In the presence of 20 vol%toluene,however,YY exhibited much higher adsorption capacities for indole and quinoline than NaY,especially in the case of quinoline.The improved toluene-tolerant of YY was ascribed to the strong acid–base interaction between YY and quinoline and the decreased adsorption strength between YY and toluene.

Pyrolysis Mechanisms of Quinoline and Isoquinoline with Density Functional Theory

The pyrolysis mechanisms of quinoline and isoquinoline were investigated using the density functional theory of quantum chemistry,including eight reaction paths and a common tautomeric intermediate 1-indene imine.It is concluded that the conformational tautomerism of the intermediate decides the pyrolysis products(C6H6,HC≡C—C≡N,C6H5C≡N and HC≡CH)to be the same,and also decides the total disappearance rates of the reactants to be the same,for both original reactants quinoline and isoquinoline during the pyrolysis reaction.The results indicate that the intramolecular hydrogen migration is an important reaction step,which often appears in the paths of the pyrolysis mechanism.The activation energies of the rate determining steps are obtained.The calculated results are in good agreement with the experimental results.

Anti-hepatitis C virus potency of a new autophagy inhibitor using human liver slices model

AIM: To evaluate the antiviral potency of a new antihepatitis C virus(HCV) antiviral agent targeting the cellular autophagy machinery. METHODS: Non-infected liver slices, obtained from human liver resection and cut in 350 μm-thick slices(2.7 × 106 cells per slice) were infected with cell culture-grown HCV Con1b/C3 supernatant(multiplicity of infection = 0.1) cultivated for up to ten days. HCV infected slices were treated at day 4 post-infection with GNS-396 for 6 d at different concentrations. HCV replication was evaluated by strand-specific real-time quantitative reverse transcription- polymerase chain reaction. The infectivity titers of supernatants were evaluated by foci formation upon inoculation into naive Huh-7.5.1 cells. The cytotoxic effect of the drugs was evaluated by lactate dehydrogenase leakage assays. RESULTS: The antiviral efficacy of a new antiviral drug, GNS-396, an autophagy inhibitor, on HCV infection of adult human liver slices was evidenced in a dosedependent manner. At day 6 post-treatment, GNS-396 EC50 was 158 nmol/L without cytotoxic effect(compared to hydroxychloroquine EC50 = 1.17 μmol/L).CONCLUSION: Our results demonstrated that our ex vivo model is efficient for evaluation the potency of autophagy inhibitors, in particular a new quinoline derivative GNS-396 as antiviral could inhibit HCV infection in a dosedependent manner without cytotoxic effect.

Novel indole and quinoline alkaloids from Melodinus yunnanensis

6/7-Seco rearranged spiro-indolone alkaloids,meloyunines A(1)and B(2)and a monoterpenoid quinoline alkaloid meloyunine C(3)together with its possible intermediate 14,15-dehydromelohenine B(4),and their precursorΔ14-vincamenine(5)were isolated from Melodinus yunnanensis.All structures were elucidated based on NMR,FTIR,UV,and MS spectroscopic data.The isolation of monoterpenoid indole,quinoline,and its immediate from the same plant chemically supported the biosynthesis of quinoline from indole.Compound 2 was cytotoxic against several human cancer cell lines.

Synthesis and Crystal Structure of N-methyl-N-((2-(p-tolyl)quinolin-4-yl)methyl)aniline

Compound 1, N-methyl-N-（（2-（p-tolyl）quinolin-4-yl）methyl）aniline （C24H22N2）, as a potential drug for the treatment of acid-related diseases has been synthesized via palladium- catalyzed intramolecular hydroarylation. The compound was characterized by MS and NMR spectra. Meanwhile, the crystal of I was obtained and determined by X-ray single-crystal diffrac- tion. Crystal data： triclinic system, space group P1, a = 5.548（5）, b = 11.545（10）, c = 14.546（12）A, a = 90.427（15）, β = 90.727（14）, γ = 101.099（16）°, V= 914.1（13） A3, Z = 2, F（000） = 360, Dc = 1.230 g/cm3,μ = 0.072 mm-1, R = 0.0564 and wR = 0.1616 for 9768 independent reflections （Rint = 0.0447） and 3003 observed ones （I 〉 2σ（I））.

Measurable surface d charge of Pd as a descriptor for the selective hydrogenation activity of quinoline

Au Pd nanoalloys with tunable Pd concentrations have been synthesized and used as model catalysts. They have been directly imaged by high-angle annular dark-field scanning transmission electron microscopy and investigated by thorough analyses of their extended X-ray absorption fine structure, X-ray absorption near-edge structure, X-ray diffraction and X-ray photoelectron spectroscopy measurements. The bimetallic nanoparticles are embedded in a carbonaceous matrix and have almost an identical structure at the atomic level and the same electronic properties as Au Pd bulk alloys with the same compositions. The d-electron increase at surface Pd sites is determined by the Pd concentration of the alloy. Similarly, their activation entropy and catalytic activity for the hydrogenation of quinoline is related to the Pd concentration, with Au50 Pd50 the most active of the alloys investigated. An almost 11 times higher activity was achieved compared to a pure Pd catalyst. The experimentally measurable surface d charge at the Pd sites in the Au Pd was found to linearly correlate with the activation entropy and catalytic activity for the hydrogenation of quinoline. The alloy structure is stable, showing negligible metal segregation, dissolution-redeposition and aggregation during the hydrogenation process which involves strong adsorption.

Preparation of Copper Phthalocyanine Crystals Using Solvothermal Synthesis

A novel solvothermal synthesis method for the direct growth of B-form crystals of copper phthalocyanine（CuPc） is presented in this article. With quinoline as solvent, crystals were grown after cooling the reaction mixture of 1,3-diiminoisoindoline and copper oxide, heated for 9 h at 270 ℃, to room temperature in an autoclave. These high quality crystals were suitable for characterization measurements. The single-crystal diffraction data show a monoclinic system unit cell： a=1.4668（3） nm, b=0.48109（10） nm, c=1.9515（7） nm, a=90°, B=121.04（2）°, r=90°, where the corresponding cell volume is 1.17991 nm^3. Needle-like single crystals of CuPc up to 10.5 mm in length were obtained. The influences of different temperatures, reaction time and solvent volume on the crystal yields were also discussed. Optimum reaction conditions were 10 mL of quinoline, at 270 ℃ for 8 h.