Increased advanced oxidation of protein products and enhanced total antioxidant capacity in plasma by action of toxins of Escherichia coli STEC

Shiga toxin (Stx) and hemolysin (Hly) of Escherichia coli O157:H7 produced an increase of reactive oxygen species (ROS) in normal human blood. In vitro assays showed that stimuli of ROS with these toxins oxidized proteins to carbonyls in plasma and raised the degradation of oxidized macromolecules, with the AOPP/carbonyl relationship also increasing. The oxidative stress generated by toxins during the Hemolytic Uremic Syndrome (HUS) produced oxidation of blood proteins with a rise in advanced oxidation protein products (AOPP) in children with HUS. There was a response from the antioxidant system in these patients, evaluated through the determination of the total antioxidant capacity of plasma by the Ferric Reducing Antioxidant Power (FRAP), which reduced the stimuli of ROS during in vitro incubation with Stx or Hly. The application of natural antioxidants was sufficient to reduce in vitro the oxidative stress provoked by both toxins in blood.     

Increased oxidative stress and apoptosis in peripheral blood mononuclear cells of fructose-fed rats

BackgroundMeasuring of oxidative stress in peripheral blood mononuclear cells is a suitable model of dietary induced systemic oxidative stress. Thus, we aimed to evaluate whether a chronic high fructose intake could induce oxidative damage in peripheral blood and bone marrow mononuclear cells of rats.MethodsAnimals were randomly assigned to the following groups: Control group (standard rat chow and tap water n = 8), and Fructose group (standard rat chow and a 10% fructose solution in the drinking water n = 8). Reactive oxygen species and cytokines were measure using flow cytometry in peripheral blood and bone-marrow mononuclear cells. Apoptotic cell death and the advanced oxidation protein products (AOPP) were also determined.ResultsWe observed a significant increase in ROS production in peripheral blood mononuclear cells of fructose group as compared to control rats. Apoptosis and the AOPP were higher in those animals underwent high fructose intake. Serum levels of IL-6 and IL-12 were also increased after 12 weeks of high fructose intake.ConclusionWe concluded that fructose intake leads to systemic oxidative stress and pro-inflammatory condition which affect peripheral blood mononuclear cells and bone-marrow mononuclear cells viability.     

The effect of resveratrol on glycation and oxidation products in plasma and liver of chronic methylglyoxal-treated rats

Background

Methylglyoxal (MG) is a highly reactive dicarbonyl compound. It is produced by processes like glycolysis, glucose autooxidation, lipid peroxidation, and protein glycation. It is a major precursor of advanced glycation end products (AGE). It also exacerbates oxidative stress in the organism. Although there are some in vitro studies investigating the effect of resveratrol (RES) as an antioxidant and antiglycating agent on MG-induced toxicity, in vivo effect of RES is unknown. Therefore, we aimed to investigate the efficiency of RES in chronic MG-treated rats.

Association of Sarcopenia and Gut Microbiota Composition in Older Patients with Advanced Chronic Kidney Disease,Investigation of the Interactions with Uremic Toxins,Inflammation and Oxidative Stress

Sarcopenia is a prevalent condition in chronic kidney disease (CKD). We determined gut microbiota (gMB) composition in CKD patients with or without sarcopenia. Furthermore, we investigated whether in these patients, there was any association between gMB, uremic toxins, inflammation and oxidative stress. We analyzed gMB composition, uremic toxins (indoxyl sulphate and p-cresyl sulphate), inflammatory cytokines (interleukin 10, tumor necrosis factor α, interleukin 6, interleukin 17, interleukin 12 p70, monocyte chemoattractant protein-1 and fetuin-A) and oxidative stress (malondialdehyde) of 64 elderly CKD patients (10 < eGFR < 45 mL/min/1.73 m², not on dialysis) categorized as sarcopenic and not-sarcopenic. Sarcopenia was defined according to European Working Group on Sarcopenia in Older People 2 criteria. Sarcopenic patients had a greater abundance of the Micrococcaceae and Verrucomicrobiaceae families and of Megasphaera, Rothia, Veillonella, Akkermansia and Coprobacillus genera. They had a lower abundance of the Gemellaceae and Veillonellaceae families and of Acidaminococcus and Gemella genera. GMB was associated with uremic toxins, inflammatory cytokines and MDA. However, uremic toxins, inflammatory cytokines and MDA were not different in sarcopenic compared with not-sarcopenic individuals, except for interleukin 10, which was higher in not-sarcopenic patients. In older CKD patients, gMB was different in sarcopenic than in not-sarcopenic ones. Several bacterial families and genera were associated with uremic toxins and inflammatory cytokines, although none of these latter substantially different in sarcopenic versus not-sarcopenic patients.     

Changes in serum carbonyl and malondialdehyde levels following colchicine and vitamin E treatment in Behcet's disease

Behcet's disease (BD) is an inflammatory disorder of an unknown cause, but growing evidence indicates that the oxidative stress is increased in BD, owing to the overproduction of reactive oxygen species (ROS) and decreased efficiency of antioxidant defenses. ROS affect proteins and lipids and cause their oxidation, therefore, contributing to the formation of oxidation products: carbonyl, a marker of protein oxidation, and malondialdehyde (MDA), a marker of lipid peroxidation. The investigation was undertaken to evaluate protein oxidation (carbonyl group) levels and lipid peroxidation (MDA) levels, and the role of colchicine and vitamin E therapy on protein carbonyl group and MDA levels in serum samples of patients with BD. In this study, subjects were classified as control group, colchicine therapy group alone and colchicine and vitamin E therapy group. Protein carbonyl and MDA levels at the beginning of the study were significantly (p < 0.05) higher in both therapy groups compared with those of the control group. We found that the protein carbonyl and MDA levels at the end of the study showed no significant (p > 0.05) differences between the therapy groups and control group. These results provide some evidence for a potential effect of colchicine and vitamin E therapies on increased protein oxidation and lipid peroxidation in BD.     

Mitigating effects of antioxidant properties of Artemisia campestris leaf extract on hyperlipidemia,advanced glycation end products and oxidative stress in alloxan-induced diabetic rats

Artemisia campestris is used as antivenom and anti-inflammatory Tunisian folk medicine. Recently, increased oxidative stress was shown to play an important role in the etiology and pathogenesis of diabetes mellitus and its complications. This study was designed to examine the effects of A. campestris leaf aqueous extract (Ac) on alloxan-induced diabetic rats by measuring glycemia, lipid profile, lipid peroxidation (MDA), protein carbonyl content (PCO), advanced oxidation protein products (AOPP), activities of both non-enzymatic and enzymatic antioxidants. Results of our study showed an increase in blood glucose levels, total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-c), a decrease in high-density lipoprotein cholesterol (HDL-c) level and disturbed antioxidant enzyme activities (CAT, SOD, GPx) in the pancreatic tissue of diabetic rats. Furthermore, MDA, PCO and AOPP were elevated in the pancreas of the diabetic rats. The administration of Ac to diabetic rats at a dose of 200 mg kg⁻¹ bw resulted in a significant reduction in glycemia, TC, TG, LDL-c, pancreas LPO, PCO and AOPP levels, CAT and GPx activities associated with an elevation of GSH content and SOD activity in comparison with diabetic group. We conclude that A. campestris aqueous extract may be effective for correcting hyperglycemia and preventing diabetic complications.     

Protective effect of MOTILIPERM in varicocele-induced oxidative injury in rat testis by activating phosphorylated inositol requiring kinase 1α (p-IRE1α) and phosphorylated c-Jun N-terminal kinase (p-JNK) pathways

Context: MOTILIPERM was prepared as a mixture of extracts of three medicinal herbs [roots of Morinda officinalis How (Rubiaceae), outer scales of Allium cepa L. (Liliaceae) and seeds of Cuscuta chinensis Lamark (Convolvulaceae)].

Objective: To investigate the role of reactive oxygen species (ROS)-based endoplasmic reticulum (ER) stress in a rat model of varicocele and the therapeutic efficacy of MOTILIPERM in this model.

Materials and methods: Sixty male rats were divided into five experimental groups: a normal control group (CTR?+?vehicle), a control group administered MOTILIPERM 200?mg/kg (CTR?+?M 200), a varicocele-induced control group (VC?+?vehicle) and two varicocele-induced groups administered MOTILIPERM 100 (VC?+?M 100) or 200 (VC?+?M 200) mg/kg for 4 weeks. Testis weights were recorded and serums were assayed for hormone concentrations. Tissues were subjected to semen analysis, histopathology, analyses of ER response protein expression levels and oxidative stress were assessed by measuring ROS, reactive nitrogen species (RNS), malondialdehyde (MDA) level and ratios of total glutathione (GSH)/oxidized GSH (GSSG).

Results: MOTILIPERM treatment of varicocele-induced groups significantly increased left testis weight, testosterone level, sperm motility, count and spermatogenic cell density. ER-response protein expression levels were dose-dependently decreased in VC?+?M 200 group compared with VC?+?vehicle group. MOTILIPERM treatment also decreased MDA and ROS/RNS level but increased GSH/GSSG ratio.

Discussion and conclusions: This study suggests that ROS-related ER stress may play a major role in varicocele-induced infertility and MOTILIPERM, a novel compound targeting ROS-based ER stress, may be therapeutically useful in treatment of varicocele, or as a supplement for the treatment of infertility.     

Differential Effects of Indoxyl Sulfate and Inorganic Phosphate in a Murine Cerebral Endothelial Cell Line (bEnd.3)

Endothelial dysfunction plays a key role in stroke in chronic kidney disease patients. To explore the underlying mechanisms, we evaluated the effects of two uremic toxins on cerebral endothelium function. bEnd.3 cells were exposed to indoxyl sulfate (IS) and inorganic phosphate (Pi). Nitric oxide (NO), reactive oxygen species (ROS) and O₂•^– were measured using specific fluorophores. Peroxynitrite and eNOS uncoupling were evaluated using ebselen, a peroxide scavenger, and tetrahydrobiopterin (BH₄), respectively. Cell viability decreased after IS or Pi treatment (p < 0.01). Both toxins reduced NO production (IS, p < 0.05; Pi, p < 0.001) and induced ROS production (p < 0.001). IS and 2 mM Pi reduced O₂•^– production (p < 0.001). Antioxidant pretreatment reduced ROS levels in both IS- and Pi-treated cells, but a more marked reduction of O₂•^– production was observed in Pi-treated cells (p < 0.001). Ebselen reduced the ROS production induced by the two toxins (p < 0.001); suggesting a role of peroxynitrite in this process. BH₄ addition significantly reduced O₂•^– and increased NO production in Pi-treated cells (p < 0.001), suggesting eNOS uncoupling, but had no effect in IS-treated cells. This study shows, for the first time, that IS and Pi induce cerebral endothelial dysfunction by decreasing NO levels due to enhanced oxidative stress. However, Pi appears to be more deleterious, as it also induces eNOS uncoupling.     

Different Roles of N-Terminal and C-Terminal Domains in Calmodulin for Activation of Bacillus anthracis Edema Factor

Bacillus anthracis adenylyl cyclase toxin edema factor (EF) is one component of the anthrax toxin and is essential for establishing anthrax disease. EF activation by the eukaryotic Ca²⁺-sensor calmodulin (CaM) leads to massive cAMP production resulting in edema. cAMP also inhibits the nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase, thus reducing production of reactive oxygen species (ROS) used for host defense in activated neutrophils and thereby facilitating bacterial growth. Methionine (Met) residues in CaM, important for interactions between CaM and its binding partners, can be oxidized by ROS. We investigated the impact of site-specific oxidation of Met in CaM on EF activation using thirteen CaM-mutants (CaM-mut) with Met to leucine (Leu) substitutions. EF activation shows high resistance to oxidative modifications in CaM. An intact structure in the C-terminal region of oxidized CaM is sufficient for major EF activation despite altered secondary structure in the N-terminal region associated with Met oxidation. The secondary structures of CaM-mut were determined and described in previous studies from our group. Thus, excess cAMP production and the associated impairment of host defence may be afforded even under oxidative conditions in activated neutrophils.     

甘露醇对维持性血液透析高血压患者氧化应激相关指标的影响

目的:探讨甘露醇对维持性血液透析(MHD)高血压患者氧化应激相关指标的影响。方法:将40例MHD高血压患者随机分为常规透析组和透析+甘露醇组。透析+甘露醇组在常规透析组基础上加用20%甘露醇注射液。于试验前后应用硫代巴比妥酸法检测丙二醛(MDA)、硝酸还原酶法检测一氧化氮(NO)、酶联免疫法检测氧化蛋白产物(AOPP)。结果:治疗后透析+甘露醇组血清中MDA及AOPP浓度较治疗前明显下降(P<0.05),NO浓度较治疗前明显上升(P<0.05);常规透析组血清中MDA、AOPP及NO浓度治疗前后无显著差异(P>0.05)。治疗后,与常规透析组各项指标比较,透析+甘露醇组治疗效果更为显著(P<0.05)。2组均未见严重不良反应发生。结论:甘露醇具有干预MHD高血压患者体内氧化应激水平的作用。     

Comparison of the antioxidant activities of nonfumigated and sulphur-fumigated Chrysanthemum morifolium cv. Hang-ju induced by oxidative stress

Context The traditional drying method, sun drying, for Chrysanthemum morifolium Ramat. cv. Hang-ju (Compositae) (HJ) is widely replaced by sulphur fumigation (SF), which has an unknown effect on its efficacy.Objective To investigate protective effects of nonfumigated HJ (NHJ) and sulphur-fumigated HJ (SHJ) water extracts against oxidative stress and lipid peroxidation.Materials and methods Sprague-Dawley rats were administered high-fat diet to induce hyperlipidaemia and randomly divided into eight groups (n = 6): control, fenofibrate, NHJ and SHJ extracts (1, 2 or 4 g crude drugs/kg/d; intragastric administration for 8 weeks). Serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), superoxide dismutase (SOD) and malondialdehyde (MDA) levels were detected. Human umbilical vein endothelial cells (HUVECs) were treated with NHJ and SHJ extracts (50, 100 or 200 μg/mL) for 24 h, followed by oxidized low-density lipoprotein (ox-LDL, 20 μg/mL) for 2 h in vitro. Cellular reactive oxygen species (ROS), SOD and MDA levels and apoptosis were evaluated.Results NHJ was more effective than SHJ in decreasing serum TG, TC, LDL-C, LDL/HDL and MDA while increasing serum HDL-C and SOD levels at high doses. SHJ (IC₅₀=19.9 mg/mL) suppressed HUVEC growth stronger than NHJ (IC₅₀=186.7 mg/mL). At 200 μg/mL, NHJ was more effective than SHJ in downregulating ROS and MDA levels, reducing HUVECs apoptosis rate and elevating SOD activity in ox-LDL-treated HUVECs.Conclusions SF causes oxidative damage and attenuates antioxidative activity in ox-LDL-treated HUVECs, which promotes lipid peroxidation. SF is not recommended for processing HJ.     

The role of reactive oxygen species in adriamycin and menadione-induced glomerular toxicity

Redox cycling leading to oxidative stress has been proposed as the mechanism by which adriamycin induces glomerular toxicity in rats. The present study compares the extent of the oxidative stress and cytotoxicity induced by adriamycin to menadione (a model redox cycling quinone) in freshly isolated rat glomeruli. Adriamycin and menadione (25 μM) decreased de novo protein synthesis (measured by ³H-proline incorporation into acid-precipitable glomerular protein) by 50 and 85%, respectively, in 2 h. By contrast, menadione at 25 μM reduce glomerular membrane integrity (as assessed by lactate dehydrogenase leakage), adriamycin reduced membrane integrity at 500 μM adriamycin. Reactive oxygen species (ROS) were measured by the oxidation of dihydrodichlorofluorescein. Menadione (25 μM) and adriamycin (25 μM) increased ROS formation to 260 and 156% of controls after 30 min incubation, respectively. Oxidative stress was assessed by measuring the intracellular level of reduced glutathione (GSH) and the decrease of the NADPH/NADP⁺ ratio which stimulates the pentose phosphate pathway (PPP): (a) menadione (25–100 μM) reduced glomerular GSH to 10–20% of controls, adriamycin (25–100 μM) had no effect; (b) menadione (10 μM) increased PPP activity 6-fold, while adriamycin (125 μM) had only a 2-fold effect. Although adriamycin and menadione generate extensive ROS and decrease protein synthesis, there was no correlation between the extent of oxidative stress and cytotoxicity in glomeruli exposed to adriamycin. These results suggest that oxidative stress may not be the primary mechanisms by which adriamycin induces selective glomerular toxicity.     

Antioxidant effects of a dietary supplement: Reduction of indices of oxidative stress in normal subjects by water-soluble chitosan

The effect of water-soluble chitosan, a natural polymer derived from chitin, on indices of oxidative stress was investigated in normal volunteers. Treatment with chitosan for 4 weeks produced a significant decrease in levels of plasma glucose, atherogenic index and led to increase in high density lipoprotein cholesterol (HDL). Chitosan treatment also lowered the ratio of oxidized to reduced albumin and increased total plasma antioxidant activity (TPA). There was good correlation between TPA and oxidized albumin ratio. The results indicate that oxidized albumin ratio represents a potentially useful marker of oxidative stress. In in vitro studies, albumin carbonyls and hydroperoxides were significantly decreased in a time-dependent manner in the presence of chitosan, compared with controls (p < 0.05). Chitosan also reduced two stable radicals in a dose- and time-dependent manner. The results suggest that chitosan has a direct antioxidant activity in systemic circulation by lowering the indices of oxidative stress in both in vitro and in vivo studies. This may confer benefits additional to the reduction in plasma carbohydrate and increase in HDL levels. It may also inhibit oxidation of serum albumin commonly observed in patients undergoing hemodialysis, resulting in reduction of oxidative stress associated with uremia.     

Effects of atorvastatin on fine particle-induced inflammatory response, oxidative stress and endothelial function in human umbilical vein endothelial cells

The study is to explore the toxicity of organic extracts and water-soluble fraction of fine particles on human umbilical vein endothelial cells (HUVECs). The exposure doses were 100, 200 and 400 μg/ml, respectively, for two kinds of fractions. Moreover, atorvastatin was used for intervention study. HUVECs were stimulated by 400 μg/ml organic and water soluble extracts, respectively, immediately followed by treatment with atorvastatin in concentrations of 0.1 μmol/L, 1 μmol/L and 10 μmol/L, respectively. Cell viability, malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), reactive oxygen species (ROS) and the expression of interleukin-6 beta (IL-6), tumor necrosis factor-α (TNF-α), endothelin-1 and P-selectin were determined in cells. The results showed that MDA and ROS increased in HUVECs after exposed to organic extracts and water-soluble fraction, whereas cell viability, NO and SOD decreased. The mRNA expression of IL-6, TNF-α, endothelin-1 (ET-1) and P-selectin increased after exposed to different fractions. Meanwhile, at the same exposure dose, water-soluble fraction caused more significant increase of MDA, IL-6, TNF-α and P-selectin and decrease of cell viability and NO when compared to organic extracts. Compared to no atorvastatin group, the levels of MDA, ROS and the expression of IL-6, TNF-α, ET-1 and P-selectin decreased in HUVECs in adding atorvastatin group, but cell viability, NO and SOD increased, which indicated that atorvastatin attenuated fine particle-induced inflammatory response, oxidative stress and endothelial damage. The results hinted that the inflammatory response, oxidative stress and endothelial dysfunction might be the mechanisms of cardiovascular injury induced by different fractions of ambient fine particles.     

Suppression of oxidative stress and pro-inflammatory mediators by Cymbopogon citratus D. Stapf extract in lipopolysaccharide stimulated murine alveolar macrophages

Exploration of antioxidants of plant origin and their scientific validation for their immense pharmacological potential is emerging as an issue of intense research now-a-days.The effect of Cymbopogon citratus extract was seen on cell viability, oxidative stress markers i.e. ROS production, SOD activity, lipid peroxidation and GSH content of murine alveolar macrophages stressed with lipopolysaccharide. Modulation in release of NO and pro-inflammatory cytokine TNF-α along with alterations in mitochondrial membrane potential under stress were compared with known plant derived antioxidant quercetin. The extract was not found to be cytotoxic at any of the selected doses. At 5 and 10 μg the extract showed significant increase in SOD activity, GSH content (p < 0.001), decrease in ROS production as seen by fluorescent dye DCFH-DA and also MDA formation (lipid peroxidation marker) significantly. The extract also showed reduction in the release of pro-inflammatory mediators TNF-α and NO significantly indicating an anti-inflammatory effect. The extract was able to restore mitochondrial membrane potential as estimated by spectrofluorimetry using the fluorescent dye Rhodamine 123. The results suggest potential use of the cytoprotective, antioxidant and anti-inflammatory property of C. citratus in the form of dietary component and also in formulations against lung inflammatory diseases where oxidative stress plays an important role.     

Effect of atorvastatin on paraoxonase1 (PON1) and oxidative status

It has been proposed that paraoxonase1 (PON1), a high density lipoprotein (HDL)-associated esterase/lactonase, has antiatherosclerotic properties. The activity of PON1 is influenced by PON1 polymorphisms. However, the influence of PON1 polymorphisms on PON1 activity and oxidative stress in response to lipid-lowering drugs remains poorly understood. The objective of the present study was to investigate the effects of atorvastatin on PON1 activity and oxidative status. The influence of PON1 polymorphisms on PON1 activity and oxidative status in response to atorvastatin treatment was also evaluated. In total, 22 hypercholesterolemic patients were treated with atorvastatin at a dose of 10 mg/day for 3 months. Lipid profile, lipid oxidation markers (malondialdehyde (MDA), conjugated diene (CD), total peroxides (TP)), total antioxidant substance (TAS), oxidative stress index (OSI), and paraoxonase1 activity were determined before and after treatment. L55M, Q192R, and T(-107)C PON1 polymorphisms were also determined. Atorvastatin treatment significantly reduced the levels of total cholesterol (24.5%), low density lipoprotein (LDL) cholesterol (25.4%), triglycerides (24.4%), CD (4.4%), MDA (15.2%), TP (13.0%) and OSI (24.0%), and significantly increased the levels of TAS (27.3%), and PON1 activity (14.0%). Interestingly, the increase in PON1 activity and the reduction in oxidative stress in response to atorvastatin were influenced only by the PON1 T-107C polymorphism. Atorvastatin treatment improved the lipid profile, lipid oxidation, and oxidative/antioxidative status markers including the activity of PON1 towards paraoxon. These beneficial effects may be attributed to the antioxidant properties of statins and the increase in PON1 activity. The increase in PON1 activity was enhanced by the PON1 T-107C polymorphism.     

Protective activity of the Uncaria tomentosa extracts on human erythrocytes in oxidative stress induced by 2,4-dichlorophenol (2,4-DCP) and catechol

The purpose of this study was to evaluate the effect of the ethanolic and aqueous extracts of Uncaria tomentosa on human erythrocytes and additionally the assessment of protective effect of these extracts on hemolysis induction, hemoglobin oxidation, and changes in the level of reactive oxygen species (ROS) and lipid peroxidation, which were provoked by selected xenobiotics, i.e. 2,4-dichlorophenol (2,4-DCP) and catechol.All tested extracts, even at a very high concentration of 500 μg/ml were not toxic to the erythrocytes because they did not cause lipid peroxidation, increase methemoglobin and ROS levels nor provoked hemolysis. The results of this study also revealed protective effect of extracts of U. tomentosa. The extracts studied depleted the extent of hemoglobin oxidation and lipid peroxidation as well as decreased the level of ROS and hemolysis, which was provoked by 2,4-DCP. No protective activity of the extracts against catechol action, which is a precursor of semiquinones in cell was found.A difference in the effect of the extracts studied was observed. Ethanol-based extracts revealed more pronounced ability to inhibit oxidation processes in human erythrocytes.     

Oxidative stress generation of silver nanoparticles in three bacterial genera and its relationship with the antimicrobial activity

Oxidative stress is a condition caused by the high intracellular concentrations of reactive oxygen species (ROS) that includes superoxide anion radicals, hydroxyl radicals and hydrogen peroxide. Nanoparticles could cause rapid generation of free radicals by redox reactions. ROS can react directly with membrane lipids, proteins and DNA and are normally scavenged by antioxidants that are capable of neutralizing; however, elevated concentrations of ROS in bacterial cells can result in oxidative stress. The aim of this work was contribute to the knowledge of action mechanism of silver nanoparticles (Ag-NPs) and their relation to the generation of oxidative stress in bacteria. We demonstrated that Ag-NPs generated oxidative stress in Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa mediated by the increment of ROS and this increase correlated with a better antimicrobial activity. On the other hand, we showed that the oxidative stress caused by the Ag-NPs biosynthesized was associated to a variation in the level of reactive nitrogen intermediates (RNI). Oxidative stress in bacteria can result from disruption of the electronic transport chain due to the high affinity of Ag-NPs for the cell membrane. This imbalance in the oxidative stress was evidentiated by a macromolecular oxidation at level of DNA, lipids and proteins in E. coli exposed to Ag-NPs. The formation of ROS and RNI by Ag-NPs may also be considered to explain the bacterial death.     

Modulation of Bax/Bcl-2 and caspases by probiotics during acetaminophen induced apoptosis in primary hepatocytes

Oxidative stress is an important factor in drug induced hepatotoxicity and antioxidants from natural sources have potential to ameliorate it. The present study was aimed to investigate cyto-protective potential of probiotic Enterococcus lactis IITRHR1 (El_SN) and Lactobacillus acidophilus MTCC447 (La_SN) lysate against acetaminophen (APAP) induced hepatotoxicity. Cultured rat hepatocytes pretreated with El_SN/La_SN showed higher cell viability under APAP stress. Pre-treatment with El_SN, restored glutathione level and reduced ROS generation significantly which are major biomarkers of oxidative stress. It also reduced NO level, MDA formation and enhanced SOD activity. Pre-treatment with probiotic lysates significantly inhibited the translocation of pro-apoptotic protein (Bax), enhanced anti-apoptotic (Bcl-2) protein levels and prevented release of cyt c to cytosol; suggesting involvement of mitochondrial proteins in protection against APAP induced oxidative cellular damage. Loss in mitochondrial membrane potential due to APAP treatment was prevented in the presence of probiotic lysates. Protective action of El_SN/La_SN pretreatment was further supported by prevention of procaspase-3 activation, DNA fragmentation and chromatin condensation, in turn inhibiting APAP induced apoptotic cell death. The results indicate that probiotic preparations modulate crucial end points of oxidative stress induced apoptosis and may be used for management of drug induced liver injury.     

Toxicity and oxidative stress induced by T-2 toxin and HT-2 toxin in broilers and broiler hepatocytes

T-2 and HT-2 toxins belong to mycotoxins which are found in human foods and animal chow. We investigated the toxicity and oxidative stress induced by T-2/HT-2 in broilers and chicken hepatocytes. Maize cultures of Fusarium poae was fed to broilers for 42 d, and the physiological index, biochemical index and expression of mRNAs related to oxidative stress were analyzed. Chicken hepatocytes were treated with different levels of T-2/HT-2, and the following parameters were detected: cell viability, GSH and MDA concentration, LDH leakage, activities of ALT/AST, ROS, GSH-PX, SOD and CAT, and expression of mRNA related to oxidative stress. In vivo, high levels of mycotoxins (4 mg/kg T-2 and 0.667 mg/kg HT-2) in feed caused significant reductions in body weight, weight gain, and serum total protein, and significant increases in feed conversion ratio, ALP, ALT/AST activities, and expression of mRNA related to oxidative stress. In vitro, cells treated with T-2/HT-2 showed reductions of GSH concentration and significant increases in LDH leakage, ALT/AST ROS, GSH-PX, SOD and CAT activities, MDA concentration, and expression of mRNA related to oxidative stress. Consequently, F. poae culture material and T-2/HT-2 induced toxicity and oxidative stress in vivo and in vitro, respectively.