[Show abstract][Hide abstract] ABSTRACT: Nitric oxide donor SNAP induced apoptosis in primary rat cerebral cortical neurons, which was characterized morphologically
by chromatin condensation and the formation of apoptotic bodies. With redox-sensitive fluorescence probes DCFH-DA and DHR123,
the formation of endogenous reactive oxygen species (ROS) inside cells during the apoptosis process was monitored by laser
confocal scanning microscopy (LCSM). SNAP treatment also caused the accumulation of extracellular hydrogen peroxide. Pretreatment
with the nitric oxide scavenger hemoglobin could effectively inhibit the formation of endogenous ROS and protect neurons from
apoptosis. The results suggested that ROS might be involved in NO-induced apoptosis in neuronal cells.
Full-text · Article · Apr 2012 · Research on Chemical Intermediates
[Show abstract][Hide abstract] ABSTRACT: With sodium nitrite NaNO2 as a standard source of nitric oxide, we compared the correlation coefficients obtained by three measuring methods used currently
in the determination of the NOFe2+ (DETC)2 complex (DETC, N,N-diethyldithiocarbamate) with that of the measuring method suggested in this study. The result showed that
measuring the total height of triplet signals was the best linear correlation to the concentration of NO compared with other
methods used in this system. With this method, we observed the effect of chinonin on the NOFe2+ (DETC)2 complex in myocardial ischemic-reperfusion injury in vivo. The hearts of Wistar rats were subjected to 30 min of ischemia
and 10 min of reperfusion in vivo. Different doses of chinonin (5, 10, 25, 50 mg/kg intraperitoneally) were administered to
the ischemic-reperfusion rats. Chinonin increased the signal intensity of the NOFe2+ (DETC)2 complex, inhibited the formation of thiobarbituric acid reaction substance and release of creatine kinase, and mitigated
the incidence of ventricular arrhythmia in a dose-dependent way. Chinonin has cardiovascular protective effects by means of
adjusting the level of NO and inhibiting oxygen free-radical-induced lipid peroxidation in myocardial ischemic-reperfusion
injury in vivo.
No preview · Article · Apr 2012 · Applied Magnetic Resonance
[Show abstract][Hide abstract] ABSTRACT: Protective effects of EPC-K1 (L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyldecyl)-2H-1-benzopyran-6-yl-hydrogen
phosphate] potassium salt, a difunctional derivative of vitamin C and vitamin E) on neuronal cell damage mediated by peroxynitrite
were studied. Primary cultures of cerebellar granule cells were exposed to peroxynitrite by treatment with 3-morpholinosydnonimine-N-ethylcarbamide (SIN-1), which generated nitric oxide and superoxide anion simultaneously upon decomposition. The results
showed that SIN-1 treatment triggered time-dependent cell death, which was accompanied by the decrease in the cellular GSH
level, the increase in the lipid peroxidation level, and the alteration of cell membrane biophysical characteristics. EPC-K1
showed only moderate scavenging effect on peroxynitrite, but could effectively protect neuronal cells from oxidative damage
mediated by peroxynitrite.
Full-text · Article · Apr 2012 · Research on Chemical Intermediates
[Show abstract][Hide abstract] ABSTRACT: The kinetic scavenging effect of chinonin on NO and oxygen free radicals generated from ischemia reperfusion myocardium and
its protective effect on the myocardium were studied by electron spin resonance (ESR) spin trapping technique. It was found
that after 20 minutes ischemia, the first peak of oxygen free radical appeared at about 0.5 minutes after the beginning of
reperfusion, then the release of oxygen free radicals decreased with time. The second peak appeared at about 3 minutes. Similarly,
there were two peaks of creatine kinase (CK) release, which indicated the myocardial damage, the first one appeared concomitantly
with the first oxygen free radical peak but the second one appeared later about 1 minute after appearance of the second peak
of oxygen free radicals. The release of NO free radicals was not significant in the absence of L-arginine. However, it increased
significantly in the presence of L-arginine and it also possesses a biphase profile. It could protect the ischemia-reperfusion
damage in the presence of low concentration of L-arginine (0.1 mM), but in high L-arginine concentration (10 mM) it generated
higher concentrations of NO leading to a more serious ischemia-reperfusion damage. Addition of chinonin could scavenge the
free radicals and protect the ischemia-reperfusion injury, especially in the second phase. The reduction stoichiometry of
chinonin for Fe(III) was measured.
No preview · Article · Apr 2012 · Research on Chemical Intermediates
[Show abstract][Hide abstract] ABSTRACT: Pistacia weinmannifolia J. Poisson ex Franch (Anacardiaceae) is a shrub or arbor widely found in Yunnan province of China and its leaves are used as traditional Chinese medicine by herbalists. The leaves of P. weinmannifolia are rich in phenolic compounds, among which two novel gallotannins, Pistafolin A and Pistafolin B, are identified. In the present investigation, the antioxidant efficiency of Pistafolin A and Pistafolin B in preventing lipid, protein and DNA from reactive oxygen species-mediated damage was studied. Both Pistafolin A and Pistafolin B inhibited the peroxyl-radical induced lipid peroxidation of l-alpha-phosphatidylcholine liposomes dose-dependently and prevented the bovine serum albumin from peroxyl-induced oxidative damage. Pistafolin A and Pistafolin B also inhibited copper (II)-1,10-phenanthroline complex-induced DNA oxidative damage. Both Pistafolin A and Pistafolin B scavenged the hydrophilic 2,2'-azinobis(3-ethylbenzothiozoline-6-sulphonic acid) diammonium salt-free radicals and the hydrophobic 1,1-dipheny-2-picrylhydrazyl radicals effectively, suggesting they may act as hydrogen donating antioxidants. The protective effects of the two gallotannins against oxidative damage of biomacromolecules were due to their strong free radical scavenging ability. Pistafolin A with three galloyl moieties showed stronger antioxidant ability than Pistafolin B with two galloyl moieties.
[Show abstract][Hide abstract] ABSTRACT: Within the central nervous system uncontrolled production of large amounts of nitric oxide (NO) by activated glial cells might be the common pathogenesis of several neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. In the present investigation, we measured the effect of a novel antioxidant gamma-L-glutamyl-S-[2-[[[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-yl]oxy]carbonyl]-3-[[2-(1H-indol-3-yl)ethyl]amino]-3-oxopropyl]-L-cysteinyl-glycine sodium salt (ESeroS-GS) on NO production in cultured rat astrocytes. Upon stimulation with 1 microg/mL lipopolysaccharide plus 100 U/mL interferon-gamma which induced the expression of inducible nitric oxide synthase, cultured astrocytes generated large amounts of NO as measured by nitrite assay and ESR technique. The endogenous NO caused oxidative damage in astrocytes, which was confirmed by the accumulation of both cytosolic and extracellular peroxides, the decrease in the cellular glutathione level, and the formation of thiobarbituric acid reactive substrates. Production of endogenous NO resulted in cell death finally. Pretreatment with the novel antioxidant ESeroS-GS effectively decreased the expression of iNOS gene, inhibited the formation of endogenous NO, and prevented NO-induced oxidative damage and cell death in astrocytes. The results suggest that ESeroS-GS might be used as a potential agent for the prevention and therapy of diseases associated with the overproduction of NO by activated astrocytes.
Full-text · Article · Aug 2003 · Biochemical Pharmacology
[Show abstract][Hide abstract] ABSTRACT: Tetramethylpyrazine and ferulic acid are two active ingredients of a Chinese herbal medicine Ligusticum wallichi Franchat. In the present investigation, iron-induced oxidative neuronal damage and the protective effects of tetramethylpyrazine and ferulic acid against this induction were studied in primary cultures of rat cerebellar granule cells. When neurons were treated with 200 microM of FeSO(4) for 1 h, lipid peroxidation in neurons increased time dependently, as measured with the thiobarbituric acid assay. Thirty-six hours after iron treatment, the cell viability decreased to 43.6% and the percentage of apoptotic cells increased to 50.6%. Transmission electron microscopic examination showed a disrupted nuclear envelope and condensed chromatin in iron-treated neurons. Analysis of DNA extracted from iron-treated cells by agarose gel electrophoresis showed the typical "ladder pattern", which indicated the formation of mono- and oligonucleosomes. After iron treatment, caspase 3 activity increased significantly, as measured in a fluoregenic assay. The results above suggested that iron treatment triggered oxidative stress and apoptosis in neurons. Western blot revealed that iron treatment up-regulated the apoptosis-related gene p53 as well as its effector gene p21(waf1/cip1). Pretreatment of the cells with 100 microM of tetramethylpyrazine or ferulic acid effectively decreased the activation of caspase 3 as well as the expression of p53 and p21(waf1/cip1), and attenuated iron-induced oxidative damage and apoptosis. The results suggest that tetramethylpyrazine and ferulic acid might be used as preventive agents against neuronal diseases associated with oxidative stress.
Full-text · Article · May 2003 · European Journal of Pharmacology
[Show abstract][Hide abstract] ABSTRACT: Tetramethylpyrazine is one of the active ingredients of the Chinese herb Ligusticum wallichii Franchat. By electron spin resonance spin trapping methods, effects of tetramethylpyrazine on superoxide anion and nitric oxide generated by human polymorphonuclear leukocytes were studied. During the respiratory burst of polymorphonuclear leukocytes induced by N-formylmethionyl-leucyl-phenylalanine, tetramethylpyrazine scavenges superoxide anion dose-dependently, and decreases the production of nitric oxide significantly, but shows no influence on oxygen consumption. These results suggest that the effective protection of tetramethylpyrazine against ischemic brain injury might be due to its scavenging of reactive oxygen species and regulation on nitric oxide production, and consequent prevention of peroxynitrite formation.
[Show abstract][Hide abstract] ABSTRACT: In this paper, an electron transfer reaction mediated by sodium tanshinone IIA sulfonate (STS) was studied in rat heart mitochondria. It was found that STS could stimulate mitochondrial NADH oxidation dose-dependently and partly restore NADH oxidation in the presence of respiratory inhibitor (rotenone or antimycin A or KCN). It was likely that STS could accept electrons from complex I similar to ferricyanide and could be converted to its semiquinone form that could then reduce oxygen molecule. The data also showed that cytochrome c (Cyt c) could be reduced by STS in the presence of KCN, or STS could transfer the electron to oxygen directly. Free radicals were involved in the process. The results suggest that STS may protect ischemia-reperfusion injury through an electron transfer reaction in mitochondria against forming reactive oxygen radicals.
Full-text · Article · Feb 2003 · Biochemical Pharmacology
[Show abstract][Hide abstract] ABSTRACT: Neonatal rat cardiomyocytes were subjected to 24 h of hypoxia 95%N2/5%CO2 and 24 h of hypoxia plus 4 h of reoxygenation 95%O2/5%CO2. 24 h of hypoxia increased the levels of NO, NO2-/NO3-, TBARS and LDH. 24 h of hypoxia plus 4 h of reoxygenation decreased the levels of NO, NO2-/NO3-, but further increased TBARS and LDH. The hypoxia up-regulated the expression of bcl-2, p53 and p21/waf1/cip1 but the reoxygenation down-regulated the expression of bcl-2, and further up-regulated p53 and p21/waf1/cip1. The hypoxia increased cell apoptosis and reoxygenation further increased both apoptotic and necrotic cell death. NO, NO2-/NO3- TBARS, DNA fragmentation and cell apoptosis were enhanced by SNP and inhibited by L-NAME respectively. In addition, SOD/catalase down-regulated the expression of p53, p21/wafl/cipl and TBARS but up-regulated bcl-2 and increased indirectly the level of NO, NO2-/NO3-, and inhibited DNA fragmentation. The results suggest that hypoxia-induced cell death is associated with the activation of NO, bcl-2 and p53 pathway, while hypoxia-reoxygenation induced cell death via the generation of reactive oxygen species and activation of p53 pathway. The present study clarified that NO may be an initiative signal to apoptotic cell death and the activation of bcl-2, p53 and p21/waf1/cip1 pathway in hypoxic and hypoxia-reoxygenated cardiomyocytes.
No preview · Article · Feb 2003 · Science in China Series C Life Sciences
[Show abstract][Hide abstract] ABSTRACT: Adriamycin (ADR) is a powerful and widely used antitumor drug, but its dose dependent cardiotoxicity limits its application. This side effect is believed to be caused by the adriamycin semiquinone free radical (ASFR). The primary focus of this work is to test effects of sodium tanshinone IIA sulfonate (STS) on ASFR and adriamycin–induced lipid peroxidation. It was found that ADR, whether in the system of heart homogenate, heart mitochondria or heart submitochondria, with NADH as the substrate or in xanthine/xanthine oxidase under anaerobic conditions, all produced ASFR rapidly. STS was shown to effectively scavenge ASFR in all these systems and postpone the appearance of ASFR. The delayed time was proportional to the amount of STS. Under aerobic conditions, ASFR could be oxidized to generate oxygen free radicals. STS could not scavenge these oxygen free radicals, but it could effectively scavenge lipid free radicals generated from membrane lipid peroxidation of heart mitochondria. STS could significantly reduce mitochondrial swelling and lipid peroxidation induced by ADR. Animal experiments show that treatment of STS could inhibit endogenous lipid peroxidation caused by ADR. Here, a protective mechanism of STS is suggested that STS can rapidly and univalently oxidize ASFR, causing the cycle of adriamycin between its quinone form and semiquinone form and inhibiting the accumulation of ASFR. Under aerobic condition, STS can protect heart mitochondria by scavenging lipid free radicals generated from adriamycin-induced mitochondrial lipid peroxidation. This investigation shows that STS may be a physiological drug to antagonize the cardiotoxicity of ADR.
No preview · Article · May 2002 · Research on Chemical Intermediates
[Show abstract][Hide abstract] ABSTRACT: Pistafolia A is a novel gallotannin isolated from the leaf extract of Pistacia weinmannifolia. In the present investigation, the ability of Pistafolia A to scavenge reactive oxygen species including hydroxyl radicals and superoxide anion was measured by ESR spin trapping technique. The inhibition effect on iron-induced lipid peroxidaiton in liposomes was studied. The protective effects of Pistafolia A against oxidative neuronal cell damage and apoptosis induced by peroxynitrite were also assessed. The results showed that Pistafolia A could scavenge both hydroxyl radicals and superoxide anion dose-dependently and inhibit lipid peroxidation effectively. In cerebellar granule cells pretreated with Pistafolia A, peroxynitrite-induced oxidative neuronal damage and apoptosis were prevented markedly. The antioxidant capacity of Pistafolia A was much more potent then that of the water-soluble analog of vitamin E, Trolox. The results suggested that Pistafolia A might be used as an effective natural antioxidant for the prevention and cure of neuronal diseases associated with the production of peroxynitrite and related reactive oxygen species.
[Show abstract][Hide abstract] ABSTRACT: Lysophosphatidic acid (LPA) induced apoptosis in primary rat cerebellar granule cells, which was characterized morphologically by chromatin condensation and the formation of apoptotic bodies. With redox-sensitive fluorescence probes DCFH-DA and DHR123, the formation of endogenous reactive oxygen species (ROS) inside cells during the apoptosis process was monitored by laser confocal scanning microscopy (LCSM). Pretreatment with the antioxidant tetramethylpyrazine (TMP) could effectively inhibit the formation of endogenous ROS and protect neurons from apoptosis. The results suggest that ROS might be involved in LPA-induced apoptosis in neurons.
Full-text · Article · Feb 2002 · Research on Chemical Intermediates
[Show abstract][Hide abstract] ABSTRACT: Within the central nervous system and under normal conditions, nitric oxide (NO) is an important physiological signaling molecule. When produced in large excess, NO also displays neurotoxicity. In our previous report, we have demonstrated that the exposure of neuronal cells to NO donors induced apoptotic cell death, while pretreatment with free radical scavengers L-ascorbic acid 2-[3, 4-dihydro-2,5,7,8-tetramethyl-2-(4,8, 12-trimethyltridecyl)-2H-1-benzopyran-6-yl-hydrogen phosphate] potassium salt (EPC-K1) or superoxide dismutase attenuated apoptosis effectively, suggesting that reactive oxygen species (ROS) may be involved in the cascade of events leading to apoptosis. In the present investigation, we directly studied the kinetic generation of ROS in NO-treated neuronal cells by flow cytometry using 2', 7'-dichloro-fluorescein diacetate and dihydrorhodamine 123 as redox-sensitive fluorescence probes. The results indicated that exposure of cerebellar granule cells to the NO donor S-nitroso-N-acetylpenicillamine (SNAP) induced oxidative stress, which was characterized by the accumulation of cytosolic and mitochondrial ROS, the increase in the extracellular hydrogen peroxide level, and the formation of lipid peroxidation products. SNAP treatment also induced apoptotic cell death as confirmed by the formation of cytosolic mono- and oligonucleosomes. Pretreating cells with the novel antioxidant EPC-K1 effectively prevented oxidative stress induced by SNAP, and attenuated cells from apoptosis.
Full-text · Article · Nov 2000 · Biochimica et Biophysica Acta
[Show abstract][Hide abstract] ABSTRACT: A photoelectric method for analyzing NO-induced apoptosis in cultured neuronal cells is presented. By integrating ITO (a transparent electrode of indium-tin oxide coated with borosilicate) with a layer of primary rat cerebellar granule cells and a photoelectric-current-measuring system, a cytosensor for measuring photoelectric current of neuronal cells was formed. The cells generated an anode photoelectric current under white light (200–800 nm). The amplitude of the photoelectric current was related to the cell number, the light intensity and the cell viability. During neuronal apoptosis, the decrease of the photoelectric current was in accordance with the decrease of the cell viability, the loss of mitochondrial transmembrane potential, and the fragmentation of DNA. This photoelectric method may provide a simple and sensitive way to study electron-transfer mechanism during NO-induced neuronal apoptosis.
[Show abstract][Hide abstract] ABSTRACT: In this study investigation is made on whether oxidative stress produced by treatment with hydroxyl radicals can induce apoptosis in rat cerebellar granule cells. The protective effects of Ginkgo biloba extract (EGb761) and its active constituents against apoptosis are also examined. The results show that hydroxyl radicals generated by the Fenton reaction induced apoptosis in cerebellar granule cells, which was associated with the decrease in the Bcl-2 mRNA level and the increase in the protein levels of the transcription factors Fos and Jun. Moreover, hydroxyl radicals induced time-dependent lipid peroxidation in cells and caused the changes in the sulfhydryl group binding sites on the membrane proteins. Hydroxyl radicals may induce apoptosis via different signaling pathways. EGb761 attenuated these changes and its different constituents showed different effects. The total flavonoid component of EGb761 and a mixture of flavonoids and terpenes protected cerebellar granule cells from oxidative damage and apoptosis induced by hydroxyl radicals. Total terpenes of EGb761 did not protect against apoptosis. Flavonoids and terpenes did not show a synergistic effect in this regard.
[Show abstract][Hide abstract] ABSTRACT: The ability of oxidative stress to induce apoptosis and the protective effects of Ginkgo biloba extract (EGb761) against this induction were studied in cultures of rat cerebellar granule cells. Cells were exposed to oxidative stress by treatment with 50 microm hydrogen peroxide+100 microm ferrous sulphate which generates hydroxyl radicals by Fenton reaction. Both morphological observation and biochemical analysis revealed that H(2)O(2)/FeSO(4)treatment induced apoptotic cell death in cerebellar granule cells, which was characterized by chromatin condensation and DNA fragmentation. During this process, the fluidity of the cell membrane decreased markedly, and the conformation of membrane proteins altered significantly. Pretreating cerebellar granule cells with the antioxidant EGb761 (Ginkgo biloba extract) effectively attenuated oxidative damage induced by H(2)O(2)/FeSO(4), and prevented cells from apoptotic cell death. The results suggested that EGb761 might be used as a potential drug for neuronal diseases associated with the excessive production of reactive oxygen species.
Full-text · Article · May 2000 · Pharmacological Research
[Show abstract][Hide abstract] ABSTRACT: The cytotoxic effect of nitric oxide on primarily cultured rat cerebellar granule cells was studied, and the mechanisms were
discussed. The results showed that nitric oxide donor S-nitroso-N-acetyl-penicillamine (SNAP; 500 μmol/L) could induce apoptosis
in immature cultures of cerebellar granule cells. Flow cytometry and HPLC analyses revealed that after treatment with SNAP,
the mitochondrial transmembrane potential and the cellular ATP content decreased significantly. Nitric oxide scavenger hemoglobin
could effectively prevent the neuronal mitochondria from dysfunction and attenuate apoptosis. The results suggested that nitric
oxide activated the apoptotic program by inhibiting the activity of mitochondrial respiratory chain and thus decreasing the
cellular ATP content.
Full-text · Article · Feb 2000 · Chinese Science Bulletin
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to investigate the protective effect of the antioxidant Ginkgo biloba extract (EGb761) on peroxynitrite-induced neuronal injury. Upon exposure to 25 μM peroxynitrite for 30 min, primary rat cortical neurons in culture underwent apoptosis, which was accompanied by the formation of cytosolic DNA fragments, an increase in the lipid peroxidation level, and an alteration in cell membrane fluidity. Pre-treatment with EGb761 at a dose of 50 μg/ml attenuated oxidative stress induced by peroxynitrite, and prevented neurons from undergoing apoptosis. The results suggest that EGb761 might be used as an effective drug for the treatment of neuronal diseases associated with the production of peroxynitrite.