Butyric acid retention in gingival tissue induces oxidative stress in jugular blood mitochondria

Butyric acid (BA) is a major extracellular metabolite produced by anaerobic periodontopathic bacteria and is commonly deposited in the gingival tissue. BA induces mitochondrial oxidative stress in vitro; however, its effects in vivo were never elucidated. Here, we determined the effects of butyric acid retention in the gingival tissues on oxidative stress induction in the jugular blood mitochondria. We established that BA injected in the rat gingival tissue has prolonged retention in gingival tissues. Blood taken at 0, 60, and 180 min after BA injection was used for further analysis. We isolated blood mitochondria, verified its purity, and measured hydrogen peroxide (H₂O₂), heme, superoxide (SOD), and catalase (CAT) to determine BA effects. We found that H₂O₂, heme, SOD, and CAT levels all increased after BA injection. This would insinuate that mitochondrial oxidative stress was induced ascribable to BA.     

Exercise training decreases expression of inflammation-related adipokines through reduction of oxidative stress in rat white adipose tissue

Increased oxidative stress in adipocytes causes dysregulated expression of inflammation-related adipokines. We have examined the effects of exercise training on oxidative stress in rat white adipose tissue (WAT), especially focusing on inflammation-related adipokines. The levels of lipid peroxidation in WAT of exercise-trained (TR) rats were lower than those in control (C) rats. The content of manganese-containing superoxide dismutase in WAT of TR rats was increased as compared with those in C rats. In contrast, the expression of the NADPH oxidase NOX2 protein in WAT was downregulated by exercise training. Moreover, the levels of inflammation-related adipokines, such as tumor necrosis factor-α and monocyte chemoattractant protein-1, in WAT of TR rats were lower than those in C rats. The effects of exercise training were more remarkable in visceral WAT than in subcutaneous. These results suggest that exercise training decreases the expression of inflammation-related adipokines by reducing oxidative stress in WAT.     

The tyrosine phosphatase, SHP-1, is involved in bronchial mucin production during oxidative stress

Mucus hypersecretion is a clinically important manifestation of chronic inflammatory airway diseases, such as asthma and Chronic obstructive pulmonary disease (COPD). Mucin production in airway epithelia is increased under conditions of oxidative stress. Src homology 2 domain-containing protein tyrosine phosphatase (SHP)-1 suppression is related to the development of airway inflammation and increased ROS levels. In this study, we investigated the role of SHP-1 in mucin secretion triggered by oxidative stress. Human lung mucoepidermoid H292 carcinoma cells were transfected with specific siRNA to eliminate SHP-1 gene expression. Cultured cells were treated with hydrogen peroxide (H₂O₂), and Mucin 5AC(MUC5AC) gene expression and mucin production were determined. Activation of p38 mitogen activated protein kinase (MAPK) in association with MUC5AC production was evaluated. N-acetylcysteine (NAC) was employed to determine whether antioxidants could block MUC5AC production. To establish the precise role of p38, mucin expression was observed after pre-treatment of SHP-1-depleted H292 cells with the p38 chemical blocker. We investigated the in vivo effects of oxidative stress on airway mucus production in SHP-1-deficient heterozygous (mev/+) mice. MUC5AC expression was enhanced in SHP-1 knockdown H292 cells exposed to H₂O₂, compared to that in control cells. The ratio between phosphorylated and total p38 was significantly increased in SHP-1-deficient cells under oxidative stress. Pre-treatment with NAC suppressed both MUC5AC production and p38 activation. Blockage of p38 MAPK led to suppression of MUC5AC mRNA expression. Notably, mucin production was enhanced in the airway epithelia of mev/+ mice exposed to oxidative stress. Our results clearly indicate that SHP-1 plays an important role in airway mucin production through regulating oxidative stress.     

Impact of tannic acid on blood pressure,oxidative stress and urinary parameters in L-NNA-induced hypertensive rats

Hypertension is a major health problem with increasing prevalence around the world. Tannic acid is water-soluble polyphenol that is present in tea, green tea, coffee, red wine, nuts, fruits and many plant foods. It has been reported to serve as an antioxidant or a pro-oxidant depending on the type of cells and its concentration. The purpose of our study was to evaluate the effect of tannic acid on systolic blood pressure, oxidative stress and some urinary parameters in the rat model of essential hypertension. Blood pressures of all rats were measured using the tail-cuff method. The nitric oxide synthase inhibitor N (omega)-nitro-L-arginine was administered orally at a dose of 0.5 g/l/day for 15 days to rats in order to create an animal model of hypertension. Tannic acid was intraperitoneally injected at a dose of 50 mg/kg for 15 days. Superoxide dismutase, catalase activity and the concentration of malondialdehyde (MDA) were determined in blood plasma and homogenates of heart, liver and kidney. In order to evaluate renal functions, urine pH, urine volume, urine creatine, uric acid, and urea nitrogen values were measured. Compared with the hypertension group, a decrease in MDA concentrations of heart tissue (p < 0.01), urea nitrogen values (p < 0.01) and urine volumes (p < 0.001) were established in hypertension + tannic acid group. There was also a decrease in blood pressure values (20th and 30th days) of this group, but there was no a statistical difference according to hypertension group. The findings of our research show the effect of tannic acid in lowering blood pressure in hypertensive rats.     

High butyric acid amounts induce oxidative stress,alter calcium homeostasis,and cause neurite retraction in nerve growth factor-treated PC12 cells

Butyric acid (BA) is a common secondary metabolite by-product produced by oral pathogenic bacteria and is detected in high amounts in the gingival tissue of patients with periodontal disease. Previous works have demonstrated that BA can cause oxidative stress in various cell types; however, this was never explored using neuronal cells. Here, we exposed nerve growth factor (NGF)-treated PC12 cells to varying BA concentrations (0.5, 1.0, 5.0 mM). We measured total heme, H₂O₂, catalase, and calcium levels through biochemical assays and visualized the neurite outgrowth after BA treatment. Similarly, we determined the effects of other common periodontal short-chain fatty acids (SCFAs) on neurite outgrowth for comparison. We found that high (1.0 and 5.0 mM) BA concentrations induced oxidative stress and altered calcium homeostasis, whereas low (0.5 mM) BA concentration had no significant effect. Moreover, compared to other SCFAs, we established that only BA was able to induce neurite retraction.     

Influence of static magnetic field on cadmium toxicity: Study of oxidative stress and DNA damage in rat tissues

In the present study, we investigated the effect of co-exposure to static magnetic field (SMF) and cadmium (Cd) on the biochemical parameters, antioxidant enzymes activity and DNA damage in rat tissues. Animals were treated with cadmium (CdCl₂, 40 mg/L, per os) in drinking water during 4 weeks. Cd treatment induced an increase of plasma lactate dehydrogenase (LDH) and transaminases levels. Moreover, Cd treatment increased malondialdehyde (MDA) and 8-oxodGuo levels in rat tissues. However, the antioxidant enzymes activity such as the glutathione peroxidase (GPx), catalase (CAT) and the superoxide dismutase (SOD) were decreased in liver and kidney, while we noted a huge increase of hepatic and renal cadmium content. Interestingly, the combined effect of SMF (128mT, 1 h/day during 30 consecutive days) and Cd (40 mg/L, per os) decreased the GPx and CAT activities in liver compared to cadmium treated group. However, the association between SMF and Cd failed to alter transaminases, MDA and 8-oxodGuo concentration.

Cd treatment altered antioxidant enzymes and DNA in liver and kidney of rats. Moreover, SMF associated to Cd disrupt this antioxidant response in liver compared to Cd-treated rats.     

Soluble semicarbazide-sensitive amine oxidase (SSAO) activity is related to oxidative stress and subchronic inflammation in streptozotocin-induced diabetic rats

Diabetes is known to increase the risk of Alzheimer's disease (AD) and vascular dementia via oxidative stress and inflammation. There are speculations that SSAO activity might be related to the development of AD. Our aim was to investigate whether changes of soluble SSAO activity, oxidative stress and inflammation markers are related to each other in diabetes. Soluble and tissue-bound SSAO activities (from serum and aorta, respectively) were determined in streptozotocin (STZ)-induced diabetic rats without insulin treatment, receiving insulin once, or twice daily compared to control animals. After three weeks of treatment soluble and tissue-bound SSAO activities (seSSAO and aoSSAO, respectively), serum total antioxidant status (TAS), high sensitivity C-reactive protein (hsCRP), fructose amine levels and routine laboratory parameters were determined. SeSSAO activity significantly increased in the diabetic groups without treatment and receiving insulin once daily, and a marked decrease in aoSSAO activity was seen in all diabetic groups. Increased oxidative stress was correlated with hsCRP elevation, while hsCRP and seSSAO activity were also significantly correlated. In all groups seSSAO and aoSSAO activities were in negative correlation with each other. Our results support the view that poor metabolic control leads to increased oxidative stress, which in turn may cause the elevation of hsCRP levels. Soluble SSAO on the one hand acts as an adhesion molecule - thus possibly being a factor responsible for the late complications of diabetes - and on the other hand, it may contribute to oxidative stress. Our parsimonious conclusion is that there is a relation between the risk factors of AD and vascular dementia (diabetes, oxidative stress and chronic inflammation) and SSAO activity, which may originate from the vessel wall.     

CCN1 protects cardiac myocytes from oxidative stress via beta1 integrin-Akt pathway

CCN1 (Cyr61) is a secreted matricellular protein, mediating angiogenesis and cell survival through interaction with integrins. Although CCN1 expression is induced in the heart during ischemia and pressure overload, its function in cardiac myocytes remains to be elucidated. We hypothesized that CCN1 may not only induce angiogenesis but may also have a direct effect on cardiac myocytes during ischemia. In this study, we investigated the effect of CCN1 on survival of cardiac myocytes under oxidative stress and examined a signal transduction pathway downstream of CCN1. A solid-phase binding assay demonstrated that CCN1 was bound to cardiac myocytes in a dose-dependent, saturable manner. Inactivation of beta1 integrin in cardiac myocytes inhibited binding with CCN1, indicating that CCN1 was bound to cardiac myocytes via beta1 integrin. Knockdown of endogenous CCN1 decreased the number of surviving cells under oxidative stress, while pretreatment of cardiac myocytes with recombinant CCN1 significantly increased the number of surviving cells. Moreover, TUNEL staining showed that CCN1 significantly decreased apoptotic cells. Furthermore, treatment of cardiac myocytes with CCN1 induced phosphorylation of Akt and extracellular signal-regulated kinase (ERK). Inactivation of beta1 integrin inhibited CCN1-induced phosphorylation of these kinases and abolished the protective effect of CCN1. Moreover, pretreatment of cells with wortmannin completely blocked the protective effect of CCN1 on cardiac myocytes under oxidative stress, indicating that the protective effect of CCN1 was mainly mediated by activation of Akt. The antiapoptotic effect of CCN1 on cardiac myocytes together with its proangiogenic property could be beneficial in the treatment of ischemic heart disease.     

Poly(ADP-ribose) polymerase-1 protects from oxidative stress induced endothelial dysfunction

Background

Generation of reactive oxygen species (ROS) is a key feature of vascular disease. Activation of the nuclear enzyme poly (adenosine diphosphate [ADP]-ribose) polymerase-1 (PARP-1) is a downstream effector of oxidative stress.

Methods

PARP-1(−/−) and PARP-1(+/+) mice were injected with paraquat (PQ; 10 mg/kg i.p.) to induce intracellular oxidative stress. Aortic rings were suspended in organ chambers for isometric tension recording to analyze vascular function.

Results

PQ treatment markedly impaired endothelium-dependent relaxations to acetylcholine in PARP-1(−/−), but not PARP-1(+/+) mice (p < 0.0001). Maximal relaxation was 45% in PQ treated PARP-1(−/−) mice compared to 79% in PARP-1(+/+) mice. In contrast, endothelium-independent relaxations to sodium nitroprusside (SNP) were not altered. After PQ treatment, l-NAME enhanced contractions to norepinephrine by 2.0-fold in PARP-1(−/−) mice, and those to acetylcholine by 3.3-fold, respectively, as compared to PARP-1(+/+) mice. PEG-superoxide dismutase (SOD) and PEG-catalase prevented the effect of PQ on endothelium-dependent relaxations to acetylcholine in PARP-1(−/−) mice (p < 0.001 vs. PQ treated PARP-1(+/+) mice. Indomethacin restored endothelium-dependent relaxations to acetylcholine in PQ treated PARP-1(−/−) mice (p < 0.05 vs. PQ treated PARP-1(+/+).

Conclusion

PARP-1 protects from acute intracellular oxidative stress induced endothelial dysfunction by inhibiting ROS induced production of vasoconstrictor prostanoids.     

Both oxidative and nitrosative stress are associated with muscle wasting in tumour-bearing rats

Reactive oxygen and nitrogen species (ROS and RNS) have been proposed as mechanisms of cancer-induced cachexia. In this study, we assessed using Western blot analysis the levels of total protein carbonylation (2,4-dinitrophenylhydrazine assay), both malondialdehyde- (MDA-) and 2-hydroxy-4-nonenal- (HNE-) protein adducts, Mn-superoxide dismutase (Mn-SOD), catalase, heme oxygenase-1 (HO-1) and 3-nitrotyrosine formation in gastrocnemius muscles of rats bearing the Yoshida AH-130 hepatoma. In the muscles of the tumour-bearing animals, protein carbonylation as measured by total levels of carbonyl group formation and both HNE and MDA-protein adducts, and protein tyrosine nitration were significantly greater than in control muscles. Protein levels of the antioxidant enzymes Mn-SOD, catalase, and HO-1 were not significantly modified in the rat cachectic muscles compared to controls. The inefficiency of the antioxidant enzymes in neutralizing excessive ROS production may account for elevated markers of protein oxidation and be responsible for the development of both oxidative and nitrosative stress in cancer-induced cachexia.     

Chemiluminescence associated with the oxidative metabolism of salicylic acid in rat liver microsomes

Rat liver microsomal suspension (1 mg protein per ml) was incubated at 37 degrees C with 5 mM salicylic acid and 0.2 mM NADPH. The amounts of thiobarbituric acid reactive substances (TBARS) and 2,5-dihydroxybenzoic acid (2,5-DHB), an oxidative metabolite of salicylic acid increased with the incubation time. Simultaneously spontaneous chemiluminescence (CL) was found to be generated there. The addition of SKF-525A, an inhibitor of cytochrome P450 (P450), to the reaction mixture inhibited the CL generation together with the inhibition of the oxidative metabolism. The anti-oxidants and singlet oxygen scavengers like N,N-diphenylphenylenediamine (DPPD) and histidine suppressed the CL generation. The addition of 1,4-diazabicyclo [2.2.2] octane (DABCO), a singlet oxygen quencher, to the reaction mixture generating CL enhanced CL transiently and then CL decreased markedly. Thus CL observed here may possibly originate from the singlet oxygen. The CL generation was suggested to be closely related with salicylic acid-induced lipid peroxidation, and to be coupled with the oxidative metabolism mediated by P450 in rat liver microsomes.     

Aluminum-induced oxidative stress in rat brain: response to combined administration of citric acid and HEDTA

Aluminum, a known neurotoxic substance, has been suggested as a contributing factor in the pathogenesis of Alzheimer's disease. Therapeutic efficacy of combined administration of citric acid (CA) and N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA) was evaluated in decreasing blood and brain aluminum concentration and parameters indicative of hematological disorders and brain oxidative stress. Adult male wistar rats were exposed to drinking water containing 0.2% aluminum nitrate for 8 months and treated once daily for 5 consecutive days with CA (50 mg/kg, orally) or HEDTA (50 mg/kg, intraperitoneally) either individually or in combination. Aluminum exposure significantly inhibited blood delta-aminolevulinic acid dehydratase while increased zinc protoporphyrin confirming changed heme biosynthesis. Significant decrease in the level of glutathione S-transferase in various brain regions and an increase in whole brain thiobarbituric acid reactive substance, and oxidized glutathione (GSSG) levels were also observed. Glutathione peroxidase activity showed a significant increase in cerebellum of aluminum exposed rats. Most of the above parameters responded moderately to the individual treatment with CA and HEDTA, but significantly reduced blood and brain aluminum burden. However, more pronounced beneficial effects on some of the above described parameters were observed when CA and HEDTA were administered concomitantly. Blood and brain aluminum concentration however, showed no further decline on combined treatment over the individual effect with HEDTA or CA. We conclude that in order to achieve an optimum effect of chelation, combined administration of CA and HEDTA might be preferred. However, further work is needed before a final recommendation could be made.     

缺氧诱导因子1及下游NADPH氧化酶在酒精性肝病大鼠肝组织中的表达及意义

目的探讨缺氧诱导因子-1(HIF-1)及NADPH氧化酶(NOX)在酒精性肝病(ALD)发病过程中的表达及意义。方法 Wistar大鼠正常饲养1周后随机分为正常对照组和模型组,模型组大鼠采用逐渐增加酒精浓度和剂量(30%-60%,5-9g/kg/d)的方法酒精灌胃,分别于4周、8周、12周和16周末随机分批处死,留取肝组织标本并制备10%的肝匀浆。应用比色法检测肝匀浆肝组织甘油三酯(TG)、氧自由基(OFR)、丙二醛(MDA)和超氧化物歧化酶(SOD)的含量,免疫组织化学染色和Western blot方法观察肝组织HIF-1α蛋白表达,RT-PCR方法分别检测HIF-1α及P47phox NOX mRNA的表达。结果成功制备酒精性肝病大鼠模型,随着造模时间的延长肝组织HIF-1α蛋白表达量及HIF-1α和P47phox NOX mRNA逐渐增强,至16周时达高峰,HIF-1α与P47phox NOX mRNA相对表达量间呈正相关(r=0.73,P0.01),P47phox NOX mRNA相对表达量与TG、OFR和MDA的含量呈正相关,相关系数分别为0.63、0.68和0.65,P值均0.01,与SOD呈负相关,相关系数为-0.65,P0.01。结论 ALD模型大鼠肝组织HIF-α及下游NOX表达增强,与肝脏氧化应激密切相关,参与酒精性肝病的发病过程。     

Cellular accumulation of Cys326-OGG1 protein complexes under conditions of oxidative stress

The common Ser326Cys polymorphism in the base excision repair protein 8-oxoguanine glycosylase 1 is associated with a reduced capacity to repair oxidative DNA damage particularly under conditions of intracellular oxidative stress and there is evidence that Cys326-OGG1 homozygous individuals have increased susceptibility to specific cancer types. Indirect biochemical studies have shown that reduced repair capacity is related to OGG1 redox modification and also possibly OGG1 dimer formation. In the current study we have used bimolecular fluorescence complementation to study for the first time a component of the base excision repair pathway and applied it to visualise accumulation of Cys326-OGG1 protein complexes in the native cellular environment. Fluorescence was observed both within and around the cell nucleus, was shown to be specific to cells expressing Cys326-OGG1 and only occurred in cells under conditions of cellular oxidative stress following depletion of intracellular glutathione levels by treatment with buthionine sulphoximine. Furthermore, OGG1 complex formation was inhibited by incubation of cells with the thiol reducing agents β-mercaptoethanol and dithiothreitol and the antioxidant dimethylsulfoxide indicating a causative role for oxidative stress in the formation of OGG1 cellular complexes.     

Exogenous markers for the characterization of human diseases associated with oxidative stress

Many human conditions, including neurological diseases, atherosclerosis, cancer, diabetic complications and aging, are thought to be associated with oxidative stress (OS). The development of reliable and informative markers for the characterization of OS in humans is thus highly important. Various endogenous markers are known, but their accumulation with increasing OS and with time is not certain, and most of them do not provide information on the type or source of the stress, or on the kinetics of their formation. The aim of the present overview is to present exogenous markers, designed and synthesized by our group, which are sensitive to OS and can identify its presence, the type of reactive oxygen and nitrogen species involved ex vivo, and potential damage incurred by bio-macromolecules, in real time. A microdialysis technique is used in animals for evaluation of OS in vivo. The designed probes are composed of several endogenous subunits, attached together covalently to form molecules that do not exist as such in humans. The subunits include an amino acid (tyrosine), an unsaturated fatty acid (linoleic acid), a nucleic acid (2′-deoxyribose guanosine) and cholesterol, representing the major macromolecules of the body, i.e. proteins, lipids, DNA and sterols, respectively. Incubation of these markers in a biological sample ex vivo, such as blood/serum, urine, saliva, cells or tissues under OS, alters their subunits, which are then analyzed and identified by LC/MS. This review demonstrates the potential of these markers to identify OS in samples taken from humans and animals suffering from, for example, atherosclerosis, hypertension, or Alzheimer's or Parkinson's disease.     

Protection of cells from oxidative stress by microsomal glutathione transferase 1

Rat liver microsomal glutathione transferase 1 (MGST1) is a membrane-bound enzyme that displays both glutathione transferase and glutathione peroxidase activities. We hypothesized that physiologically relevant levels of MGST1 is able to protect cells from oxidative damage by lowering intracellular hydroperoxide levels. Such a role of MGST1 was studied in human MCF7 cell line transfected with rat liver mgst1 (sense cell) and with antisense mgst1 (antisense cell). Cytotoxicities of two hydroperoxides (cumene hydroperoxide (CuOOH) and hydrogen peroxide) were determined in both cell types using short-term and long-term cytotoxicity assays. MGST1 significantly protected against CuOOH and against hydrogen peroxide (although less pronounced and only in short-term tests). These results demonstrate that MGST1 can protect cells from both lipophilic and hydrophilic hydroperoxides, of which only the former is a substrate. After CuOOH exposure MGST1 significantly lowered intracellular ROS as determined by FACS analysis.     

Caffeic acid phenethyl ester (CAPE) protects brain against oxidative stress and inflammation induced by diabetes in rats

Diabetic patients reveal significant disorders, such as nephropathy, cardiomyopathy, and neuropathy. As oxidative stress and inflammation seem to be implicated in the pathogenesis of diabetic brain, we aimed to investigate the effects of caffeic acid phenethyl ester (CAPE) on oxidative stress and inflammation in diabetic rat brain. Diabetes was induced by a single dose of streptozotocin (45 mg kg⁻¹, i.p.) injection into rats. Two days after streptozotocin treatment 10 μM kg⁻¹ day⁻¹ CAPE was administrated and continued for 60 days. Here, we demonstrate that CAPE significantly decreased the levels of nitric oxide and malondialdehyde induced by diabetes, and the activities of catalase, glutathione peroxidase, and xanthine oxidase in the brain. However, glutathione levels were increased by CAPE. The mRNA expressions of tumor necrosis factor (TNF)-α and interferon (IFN)-γ, and inducible nitric oxide synthase (iNOS) were remarkably enhanced in brain by diabetes. CAPE treatments significantly suppressed these inflammatory cytokines (about 70% for TNF-α, 26% for IFN-γ) and NOS (completely). Anti-inflammatory cytokine IL-10 mRNA expression was not affected by either diabetes or CAPE treatments. In conclusion, diabetes induces oxidative stress and inflammation in the brain, and these may be contributory mechanisms involved in this disorder. CAPE treatment may reverse the diabetic-induced oxidative stress in rat brains. Moreover, CAPE reduces the mRNA expressions of TNF-α and IFN-γ in diabetic brain; suggesting CAPE suppresses inflammation as well as oxidative stress occurred in the brain of diabetic patients.