Tive Stress Research Articles

The role of oxidative stress in premalignant lesions.

The authors aimed to evaluate serum total oxidant status (TOS), total antioxidant status (TAS), and oxida- tive stress index (OSI) in women with abnormal cervical cytology, to determine the association between serum oxidant and antioxidant status of these women, and the progression of abnormal cervical cytology. A total of 75 women enrolled in the study: 20 women with a determination of atypical squamous cells of undetermined significance (ASCUS), 20 women with low squamous intraepithelial lesions (LSIL), 15 women with high squamous intraepithelial lesions (HSIL) and 20 healthy controls. Serum TOS and TAS were determined and OSI was calculated as the indicator of degree of oxidative stress. Serum TOS levels and OSI were highest in the HSIL group and there was a trend toward increasing serum TOS levels and OSI from ASCUS to HSIL group. The authors demonstrated that increased oxidative stress with altered antioxidant level is associated with abnormal cervical cytology. Serum oxidant and antioxidant status may provide guidance as a simple and cost-effective method for follow-up, treatment, and recommendation in all stages of lesions.

Strain-Related Differences on Response of Liver and Kidney Antioxidant Defense System in Two Rat Strains Following Diazinon Exposure

Background: Diazinon (DZN) is one of the most organophosphates that widely used in agriculture and ectoparasiticide formula- tions. Its extensive use as an eective pesticide was associated with the environmental deleterious eects on biological systems. Objectives: The aim of this study was to investigate the potency of DZN to aect serum biochemical parameters and the antioxidant defense system in the liver and kidney of two rat strains. Materials and Methods: In this experimental study, 30 female Wistar and 30 female Norway rats were randomly divided into con- trol and DZN groups. DZN group was divided into four subgroups: 25, 50, 100 and 200 mg/kg of DZN administered groups by i.p. injection. The parameters were evaluated after 24 hours. Results: At higher doses of DZN, superoxide dismutase, catalase, glutathione S-transferase and lactate dehydrogenase activities and glutathione (GSH) and malondialdehyde levels in liver and kidney of Wistar rats were higher than Norway rats. At these concentra- tions, DZN increased some serum biochemical indices such as liver enzymes activities and levels of urea, uric acid and creatinine in Wistar rat. Conclusions: DZN at higher doses alters the oxidant-antioxidant balance in liver and kidney of both rat strains and induces oxida- tive stress, which is associated with a depletion of GSH and increased lipid peroxidation. However, Wistar rats are found to be more sensitive to the toxicity of DZN compared to Norway rats. In addition, the eect of DZN on liver antioxidant system was more than

The Effect of Selenium and Lycopene on Oxidative Stress in Bone Tissue in Rats Exposed to Cadmium

This study examined the effect of selenium (Se) or lycopene (Lyc) and their combination on oxida- tive stress in bone following cadmium (Cd) exposure in vivo. Cd exposure enhanced accumulation of Cd in femur with subsequent increase in LPO and PC and decreased antioxidative enzyme activ- ities in rat femur, along with significant decreases in body and femur bone weights. Subcutaneous (s.c.) injection of Se or Lyc reduced Cd accumulation in bone and increased body and femur weights, when given individually or concomitantly. Antioxidant enzyme activities maintained and/or in- creased following Se and Lyc supplementation when given individually or concomitantly. However, lycopene dose of 10 mg/kg of body weight alone or selenium alone provided better protection to bone tissues of rats against oxidative stress compared to treatment with their combination. Sele- nium and lycopene could be used as a dietary supplement to protect against bone oxidative stress in areas exposed to Cd pollution.

In vivo antioxidant and antigenotoxic evaluation of an enaminone derivative BDHQ combined with praziquantel in uninfected and Schistosoma mansoni infected mice

tive stress may occur after short-term treatment and participate in side effects. The aim of this study was to evaluate the antioxidant and antigenotoxic effects of the novel antischistosomal enaminone derivative, 4–hydroxyquinoline (BDHQ), alone or combined with PZQ, in hepatic tissues of uninfected and

QUERCETIN AMELIORATES DIABETIC NEPHROPATHY IN RATS VIA MODULATION OF RENAL NA<sup>+</sup>, K<sup>+</sup>-ATPASE EXPRESSION AND OXIDATIVE STRESS

Diabetic Nephropathy (DN) is one of most prevalent complications of Diabetes Mellitus (DM), therefore prevention of its development is a important field for researches. Quercetin is a plant flavenoid with hypoglycemic and antioxidant properties that is cla imed to have a reno-protective effect in diabetes. This study was designed to investigate the reno-preventi ve role of Quercetin treatment in terms of biochemi cal and pathological changes in diabetic rats and to de termine whether the effect is mediated through modulation of oxidative stress and Na + , K + ATPase expression and activity. Sixty male Sprague-Dawley rats were distributed equally among 6 groups: (i) Contro l group (C), (ii) Quercetin treated Control group ( CQ), (iii) Diabetic group (D), (iv) Diabetic Insulin tre ated group (DI), (v) Diabetic Quercetin treated gro up (DQ) and (vi) Diabetic Insulin and Quercetin treated gro up (DIQ). Systolic blood pressure was measured at t he end of the experiments (8 weeks). Retro-orbital blo od samples were used to determine the serum levels of glucose, HbA1c, urea, creatinine, Na + and K + . Renal homogenate levels of Na + , K + ATPase activity, Malondialdehyde (MDA0, Superoxide Dismutase (SOD) and Glutathione Peroxidase (GPx) were measured. Semiquantitative reverse transcriptase-PCR Na + , K + ATPase expression assays and kidney histopathological examination were conducted. Treatment with either insulin or Quercetin alone resulted in partial rever sal of the biochemical and histopathological signs of neph ropathy in diabetic rats. This was associated with partial but significant amelioration of indicators of oxida tive stress and Na + , K + ATPase gene expression and activity. However only combined treatment by both insulin and Quercetin significantly improved all of the aforementioned parameters up to the control levels. These results suggested that combined therapy with insulin and Quercetin might be a useful preventive tool aga inst development of DN.

EFFECTS OF EXTRACTS OF HYPODAPHNIS ZENKERI AND XYLOPIA AETHIOPICA ON BLOOD LIPIDS, GLYCEMIA AND BODY WEIGHT OF TRITON WR1339 AND INSULINO RESISTANT RATS

Obesity is a complicated multifaceted problem generally accompanied by disturbances in carbohydrate and fat meta bolism, insulin resistance as well as an increase in oxida tive stress. The bark of Hypodaphnis zenkeri (HZ) and dry fruits of Xylopia aet hiopica (XA) commonly used as spices in Cameroonian cuisine also have applications in traditional medicine. This study evaluates their effects on some biological parameters of acute hyperlipidemic rats and on rats fed with High Fat High Sucrose (HFHS) diet. The spices were extrac ted in water, water/ethanol (50/50) and ethanol. The first part of the work was the in vitro st udy where, the partial phytochemical composition as well as the antioxidant potential of extracts w ere studied, using folin Ciocalteu’s phenol method and ABTS (3 - ethyl - benzothiazoline - 6 - sulfonic acid) assay. The best extract for each spice was selected and used for the “ in vivo ” study which consisted in studying their effect on weight and biochemical parameters in acute hyperlipidemic r ats and insulin resistant rats. The extracts contained phenols like flavonoids. They also showed free radical scavenging pr operties in vitro . Total phenolic content were higher particularly for the hydroethanolic extract ( HEE ) of Hypodaphnis zenkeri (413.87 ± 13.19 mg Eq catechin/g of extrac t), but lowest for the water extract ( WE ) of Xylopia aet hiopica (63.07 ± 1.60 mg Eq cat echin/g of extract). At a concentration of 400 mg/kg, t he HEE extract of Hypodaphnis zenkeri showed a hypotriglyceridemic activity on rats with hypertriglyceridemia induced by triton WR - 1339 unlike the EE of Xylopia aet hiopica . But these two ext racts inhib ited weight gain and reduced postprandial glycemia in insulin resistant rats. T he bark of H y podaphnis zenkeri , and dry fruits of Xylopia aethiopica cont ained bioactive ingr edients; they ameliorated the glucose uptake and the evolution of weight impaired by the chronic consumption of HF HS diet i n rats.

Reconstruction of Fe-S protein clusters in Escherichia coli and biofilm formation

27 Biogenesis of Fe-S clusters in E. coli is a multistep process controlled by the iscRSUA-hscBA-fdx gene ensemble. The products of these genes—ironsulfur proteins IscA, SufA, and IscS—accumulate iron and sulfur and transport them to the IscU platform, the main assemble structure, and the protein IscR (2Fe- 2S) is a repressor of the cluster reconstruction system. The function of IscR in the activation of the type I protein in E. coli fimbriae, forming the connection of the bacterial film to the substrate, is no less important. The regulatory mechanism of biofilm formation has not yet been established. We performed the search for the compounds that can regulate the level of biofilm formation by E. coli cells, with the study of the func� tions of iron, which provides the relationship of film formation with the reconstruction of clusters in iron- sulfur proteins in normal state and in stress. It was found that, in stress, the SufA pathway of iron trans� port during the reconstruction of Fe-S clusters in E. coli dominates compared to the IscA pathway. The Fe 2+ chelating agent ferene selectively inhibited bio� film formation by cells with a normal system of Fe-S� cluster assembly. This is the first study to demonstrate the strong destructive effect of the NO donor GSNO on mature biofilms, comparable in terms of activity to the effect of the antibiotic ciprofloxacin. A combined treatment of bacteria with NOcompounds and bacte� ricidal agents is a promising new strategy to control infections induced by filmforming pathogens. Biofilms are a relatively new biological and medical problem. Under stress conditions, especially in oxida� tive stress, they are formed on various substrates, including the human body leading to recurrent and chronic infections due to bacterial resistance to antibi� otics. Biofilms are a community of microorganisms with a complex architecture, strongly associated with the secreted polymer matrix (1, 2). External signals regulate the structure of biofilms; they may undergo

Progress in pathogenesis of glutaric aciduria type I

Glutaric aciduria type I is an autosomal recessive disorder resulting from glutaryl-CoA de- hydrogenase（GCDH） deficiency. Untreated patients commonly present with severe striatal degeneration and ex- trapyramidal sequelae during encephalopathic crises. GCDH deficiency leads to accumulation of glutaric acid and 3-hydroxyglutaric acid in tissues and body fluids （especially in brain）, which are neurotoxic. There is no correla- tion between residual enzyme activity caused by mutations in GCDH and phenotype. The pathogenesis of glutaric aciduria type I is complicated. Previous studies have demonstrated that glutaric and 3-hydroxyglutaric acids are synthesized in central nervous system and trapped because of limiting transport across the blood-brain barrier. The studies on metabolite-mediated neurotoxicity mainly focus on excitotoxicity,impairment of energy metabo- lism and oxidative stress. In addition, activation of astrocyte, vascular derangements,inflammatory processes may be a synergism of neurotoxicity. Key words: Glutaric aciduria; Neurotoxicity; Excitotoxicity; Impairment of energy metabolism; Oxida- tive stress

Protective Effects of Mangifera indica L. Extract Against Lipofundininduced Oxidative Stress in Rats

Lipofundin is a lipid rich emulsion used in parenteral nutrition. It is known that Lipofundin induces an oxida- tive stress state characterized by an increase of lipid peroxidation and a dramatic depletion of antioxidants. The aim of the present study was to evaluate the effects of an aqueous extract of Mangifera indica L., on Lipofundin-induced oxidative stress. Male Sprague Dawley rats were treated orally with 200 mg/kg of Vimang®, followed by an intravenous dose of 2 mL/kg Lipofundin, daily, for 8 days. Selected oxidative stress biomarkers were then measured spectrophotometrically. The results showed that Vimang® produced significant (p<0.05) reduction of malondialdehyde, total hydroperoxides and advanced oxidation protein products, while the activities of superoxide dismutase and catalase were positively modulated. A significant (p<0.05) reduction of peroxidation potential and a preservation of glutathione and total antioxidant status was also observed. Our data demonstrated that Vimang® protects against Lipofundin-induced oxidative stress, which is an important finding that further reinforces the antioxidant properties of this natural product.

Phenolic Compounds as Stress Markers in Plants from Gypsum Habitats

Gypsum habitats represent a stressful environment for plants, combining aridity, limited nutrients and salt toxicity in the soil. Si nce different abiotic stress conditions cause oxida tive stress by generation of 'reactive oxygen species' ( ROS), the activation of antioxidant systems is considered as one of the general mechanisms of resp onse to stress in plants. The levels of total phenolic compounds and total flavonoids, well-known antioxidants, were determined in several species from a gypsum area in Valencia, SE Spain, t o study their possible role as biochemical markers of stress responses. Plant samples were collected f rom three selected experimental plots, located on a hill slope and showing different levels of environm ental stress, regarding dryness and gypsum content in the soil. Samplings were repeated three times al ong the year 2009, in spring, summer and autumn. The measured levels of total phenolics and flavonoi ds were very variable among taxa, precluding a direct comparison of different species, but in gene ral most of them showed higher contents of these compounds in summer, which is the most stressful period in the Mediterranean climate, with higher temperatures and practically no rainfall. The patte rns of phenolics and flavonoids accumulation in plants, according to spatial gradients in the exper imental area, also suggested a correlation with wat er stress, but not so much with the toxicity of the su bstrate.

Role of Environmental and Inflammatory Toxicity in Neuronal Cell Death

Neuronal cells are exclusively dependent on oxidative phosphorylation for energy and are under constant threat of oxidative damage due to mitochondrial production of reactive oxygen species by partial reduction of molecular oxygen. These cells also have a multitude of antioxidative defense mechanisms, but there is a slow decline of antioxidative de- fence capacity with aging. The result is the increased vulnerability of cells to oxidative stress, particularly neuronal cells. Any environmental, inflammatory or psychological stress that can topple the redox balance will eventually lead to oxida- tive stress and neuronal cell death. Indeed, cell death induced by oxidative stress has been implicated in age-related loss of neurons during normal aging and several neurodegenerative disorders. It is critical to understand the mechanisms by which different risk factors lead to neuronal cell death in order to identify pathways involved in neurodegenerative dis- eases. In this review we focus on the implications of various factors such as environmental toxins, drugs and psychologi- cal stress in neurodegenerative diseases with specific focus on Parkinson's disease and Alzheimer's disease. Here we highlight the recent progress that supports the role of molecular mechanisms of oxidative stress, neuroinflammation and mitochondrial dysfunction as contributors to neurotoxicity and research on developing therapeutics that could potentially slow down the progression of neurodegeneration.

Brain Senescence and Neuroprotective Dietary Components

Senescence is an ageing process characterized by progressive and irreversible dysfunction of various physio- logical systems. Physiological senescence with advancing age is not a disease, but it affects the life-span and life-quality of elderly people. Brain functions such as cognition and motor skills, as with other organ systems, are impaired in almost all elderly people. Neuroprotective dietary components can play a key role in ensuring healthy ageing of the brain. Al- though the causative mechanisms of senescence are complex and not yet fully elucidated, enhanced oxidative stress is thought to be an important contributor. Dietary antioxidants from fruits and vegetables have preventative effects on oxida- tive stress. Catechin, a polyphenol found in green tea, has a potent antioxidative effect. Recently, catechin has been re- ported to protect against reduced ageing-related cognitive functions such as those associated with learning and memory, and ischemic brain damage. Catechin may act as a neuroprotective agent in progressive neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. The neuroprotective effects and putative mechanisms of action of catechin and other antioxidants are examined and discussed in this review.

Oxidative Stress and the Pathogenesis of Atrial Fibrillation

There is growing evidence that oxidative stress is involved in the pathogenesis of atrial fibrillation. Many known triggers of oxidative stress, such as age, diabetes, smoking, inflammation, and renin angiotensin system activation are linked with an increased risk of the arrhythmia. Blockers of angiotensin II signaling and other drugs with anti-oxidant properties can reduce the incidence of atrial fibrillation. Now, studies in animal models and human tissue have shown di- rectly that atrial fibrillation is associated with increased atrial oxidative stress. We review the evidence for a role of oxida- tive stress in causing atrial fibrillation and propose a unifying hypothesis that multiple triggers elicit oxidative stress which acts to enhance the risk of atrial fibrillation through ion channel dysregulation.

Plasma Thioredoxin Level and Its Correlation to Myocardial Damage in Patients with Acute Myocardial Infarction who Underwent Successful Primary Angioplasty

Backgroud and Objectives:Oxidative stress is thought to play important role in cardiovascular disease. Thiore- doxin is an important biomarker for determining the degree of oxidative stress. However, the relationship between the plasma thioredoxin levels and myocardial damage has not been investigated. Subjects and Methods:We measured the plasma thioredoxin levels in the patients suffering with acute myocardial infarction and who also underwent successful primary angioplasty. We then compared the plasma thioredoxin levels and the clinical parameters in acute myocardial infarction patients (n=37) in order to examine the relationship between oxida- tive stress and myocardial damage. Results:The plasma thioredoxin level was significantly related with the initial WBC count (r=0.349, p<0.05) and the myocardial damage, the peak CK level (r=0.489, p<0.01), the CK in- crement (r=0.452, p<0.05), the peak MB level (r=0.417, p<0.05), and the MB increment (r=0.364, p<0.05). We divided the patients into two groups according to the plasma thioredoxin levels. There was a significant diffe- rence in myocardial damage between the low and high plasma thoiredoxin levels at the initial WBC count (10174.2±3380.4/uL vs 13500±3740.7/uL, respectively; p<0.01) and the cardiac enzyme, the peak CK level (2565.2±1389.9 IU/L vs 4045.9±1978.9 IU/L, respectively; p=0.02), the CK increment (2309.6±1351.8 IU/L vs 3762.8±2079.7 IU/L, respectively; p=0.03), the peak MB level (208.7±127.5 IU/L vs 322.7±146.3 IU/L, respectively; p=0.02), and the MB increment (173.8±128.4 IU/L vs 277.7±158.9 IU/L, respectively; p=0.05). Conclusion:High thioredoxin levels were associated with the degree of oxidative stress and the extent of myocardial damage. Thioredoxin levels may be used as a new surrogate biomarker for the severity of oxidative stress and the extent of myocardial damage in the patients suffering with acute myocardial infarction. (Korean Circulation J 2006;36:39-45)

Differentiation and Hydrogen Peroxide Production in Sclerotium rolfsii Are Induced by the Oxidizing Growth Factors, Light and Iron

Hydrogen peroxide is produced by Sclero- tium rolfsii during sclerotial differentiation, in re- sponse to oxidative growth conditions of light and Fe. An additive effect of (? light ? Fe)-induced oxida- tive stress is observed on H202 production levels and on sclerotia numbers during fungal development. High H202 production rates are correlated with high oxidative stress and are observed in less lipid-perox- idized young mycelia and sclerotia (sclerotia initials and early developing sclerotia) and not in differen- tiated, highly lipid-peroxidized older mycelia and sclerotia (developed and mature sclerotia). H202 production by undifferentiated mycelia and their ex- posure to exogenous H202 show a rate/dose-depen- dent correlation with degree of sclerotial differenti- ation (sclerotia numbers). Hydrogen peroxide and lipid peroxide concentration gradients are observed in fungal colonies during their transition from un- differentiated (mycelial) to differentiated (sclerotial) stage. Growth-stage-dependent changes in H202 pro- duction rates during development are not due to changes in glucose concentration and pH of the growth medium. Light/Fe-induced H202 production and its effect on S. rolfsii differentiation, are dis- cussed in the context of our hypothesis of oxidative stress-induced sclerotial differentiation.

Acculturative Stress and Acculturation A ttitudes Among Indian Immigran ts to the United Sta tes

The paper investigates the relationship between acculturation experience and accultura tive stress among a group of 76 Asian Indian immigrants living in mid-western United States using Berry et al. 's(1987) model. The most preferred acculturation attitude was found to be one of Integration. Acculturative stress had significant positive relationships with attitudes of Separation and Marginalisation but negative relation ship with Integration. Assimilation was found predictive of psychological stress, Separation of psychosomatic stress and Integration of overall stress. Results generally supported the postulated model.