Hormonal regulation of superoxide dismutase, catalase, and glutathione peroxidase activities in rat macrophages

Methylprednisolone Does Not Enhance Paraoxonase 1 Activity During Cardiopulmonary Bypass Surgery-A Randomized, Controlled Clinical Trial

OBJECTIVES

Cardiopulmonary bypass (CPB) is linked to systemic inflammatory responses and oxidative stress. Paraoxonase 1 (PON1) is an antioxidant enzyme with a cardioprotective role whose activity is decreased in systemic inflammation and in patients with acute myocardial and global ischemia. Glucocorticoids counteract the effect of oxidative stress by upregulating PON1 gene expression. The authors aimed to determine the effect of methylprednisolone on PON1 activity during cardiac surgery on CPB.

DESIGN

Prospective, randomized, controlled clinical trial.

SETTING

The University Medical Center Ljubljana, Slovenia.

PARTICIPANTS

Forty adult patients who underwent complex cardiac surgery on CPB between February 2016 and December 2017 were randomized into methylprednisolone and control groups (n = 20 each).

INTERVENTIONS

Patients in the methylprednisolone group received 1 g of methylprednisolone in the CPB priming solution, whereas patients in the control group were not given methylprednisolone during CPB.

MEASUREMENTS AND MAIN RESULTS

The effect of methylprednisolone from the CPB priming solution was compared with standard care during CPB on PON1 activity until postoperative day 5. Correlations of PON1 activity with lipid status, mediators of inflammation, and hemodynamics were analyzed also. No significant differences were found between study groups for PON1 activity, high-density lipoprotein, and low-density lipoprotein in any of the measurement intervals (p > 0.016). The methylprednisolone group had significantly lower tumor necrosis factor alpha (p < 0.001) and interleukin-6 (p < 0.001), as well as C-reactive protein and procalcitonin (p < 0.016) after surgery. No significant difference was found between groups for hemodynamic parameters. A positive correlation existed between PON1 and lipid status, whereas a negative correlation was found between PON1 activity and tumor necrosis factor alpha, interleukin-6, and CPB duration.

CONCLUSIONS

Methylprednisolone does not influence PON1 activity during cardiac surgery on CPB.

Markers of elevated oxidative stress in oligodendrocytes captured from the brainstem and occipital cortex in major depressive disorder and suicide

Major depressive disorder (MDD) and suicide have been associated with elevated indices of oxidative damage in the brain, as well as white matter pathology including reduced myelination by oligodendrocytes. Oligodendrocytes highly populate white matter and are inherently susceptible to oxidative damage. Pathology of white matter oligodendrocytes has been reported to occur in brain regions that process behaviors that are disrupted in MDD and that may contribute to suicidal behavior. The present study was designed to determine whether oligodendrocyte pathology related to oxidative damage extends to brain areas outside of those that are traditionally considered to contribute to the psychopathology of MDD and suicide. Relative telomere lengths and the gene expression of five antioxidant-related genes, SOD1, SOD2, GPX1, CAT, and AGPS were measured in oligodendrocytes laser captured from two non-limbic brain areas: occipital cortical white matter and the brainstem locus coeruleus. Postmortem brain tissues were obtained from brain donors that died by suicide and had an active MDD at the time of death, and from psychiatrically normal control donors. Relative telomere lengths were significantly reduced in oligodendrocytes of both brain regions in MDD donors as compared to control donors. Three antioxidant-related genes (SOD1, SOD2, GPX1) were significantly reduced and one was significantly elevated (AGPS) in oligodendrocytes from both brain regions in MDD as compared to control donors. These findings suggest that oligodendrocyte pathology in MDD and suicide is widespread in the brain and not restricted to brain areas commonly associated with depression psychopathology.

The Unity of Redox and Structural Remodeling of Brown Adipose Tissue in Hypothyroidism

Brown adipose tissue (BAT) is important for maintaining whole-body metabolic and energy homeostasis. However, the effects of hypothyroidism, one of the most common diseases worldwide, which increases the risk of several metabolic disorders, on BAT redox and metabolic homeostasis remain mostly unknown. We aimed to investigate the dynamics of protein expression, enzyme activity, and localization of antioxidant defense (AD) enzymes in rat interscapular BAT upon induction of hypothyroidism by antithyroid drug methimazole for 7, 15, and 21 days. Our results showed an increased protein expression of CuZn- and Mn-superoxide dismutase, catalase, glutamyl-cysteine ligase, thioredoxin, total glutathione content, and activity of catalase and thioredoxin reductase in hypothyroid rats, compared to euthyroid control. Concomitant with the increase in AD, newly established nuclear, mitochondrial, and peroxisomal localization of AD enzymes was found. Hypothyroidism also potentiated associations between mitochondria, peroxisomes, and lipid bodies, creating specific structural-functional units. Moreover, hypothyroidism induced protein expression and nuclear translocation of a master regulator of redox-metabolic homeostasis, nuclear factor erythroid 2-related factor 2 (Nrf2), and an increased amount of 4-hydroxynonenal (4-HNE) protein adducts. The results indicate that spatiotemporal overlap in the remodeling of AD is orchestrated by Nrf2, implicating the role of 4-HNE in this process and suggesting the potential mechanism of redox-structural remodeling during BAT adaptation in hypothyroidism.

Oxidative stress in liver cell culture from mullet, Liza klunzingeri, induced by short-term exposure to benzo[a]pyrene and nonylphenol

The present investigation aimed to use primary liver cell culture obtained from mullet, Liza klunzingeri, to evaluate the toxic effects of benzo[a]pyrene (BaP) and nonylphenol (NP) on the antioxidant defense system. Liver samples taken from 20 L. klunzingeri were digested with 0.1% collagenase IV. The digested cells were then moved to Leibovitz L-15 culture medium and incubated at 25 °C for 2 weeks. 10^-5 mol/l of BaP and 10^-4 mol/l of NP were considered as the half maximal inhibitory concentration (IC50). Cells were then incubated with L-15 medium containing BaP (0[control], 10^-6,2 × 10^-6,3 × 10^-6 mol/l) and NP (0[control],10^-5,2 × 10^-5,3 × 10^-5 mol/l), and sampling was performed after 6, 12, and 24 h of incubation for measurement of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), lipid peroxidation (LPO), total antioxidant power, and total protein. The lowest concentration of BaP and NP did not have considerable toxic effects on cultivated hepatocytes. The activities of SOD, CAT, GPx, LPO, total antioxidant power, and total protein changed dose-dependently in cells treated with BaP and NP. In conclusion, based on the results, short-term exposure to BaP and NP induced the oxidative stress in cultivated liver cells of L. klunzingeri. The toxicity of both pollutants is mainly because of the induction of the reactive oxygen species (ROS), which lead to cell membrane disruption, damage of cellular metabolism, and interference with cellular macromolecules.

Moderate physical exercise improves lymphocyte function in melanoma-bearing mice on a high-fat diet

Background

Obesity can lead to a chronic systemic inflammatory state that increases the risk of cancer development. Therefore, this study aimed to evaluate the alterations in tumor non-infiltrated lymphocytes function and melanoma growth in animals maintained on a high-fat diet and/or moderate physical exercise program in a murine model of melanoma.

Methods

Female mice were randomly divided into eight groups: 1) normolipidic control (N), 2) normolipidic + melanoma (NM), 3) high-fat control (H), 4) high-fat + melanoma (HM), 5) normolipidic control + physical exercise (NE), 6) normolipidic melanoma + physical exercise (NEM), 7) high-fat control + physical exercise (HE), and 8) high-fat melanoma + physical exercise (HEM). After 8 weeks of diet treatment and/or moderate physical exercise protocol, melanoma was initiated by explanting B16F10 cells into one-half of the animals.

Results

Animals fed a high-fat diet presented high-energy consumption (30%) and body weight gain (H and HE vs N and NE, 37%; HM and HEM vs NM and NEM, 73%, respectively), whether or not they carried melanoma explants. Although the tumor growth rate was higher in animals from the HM group than in animals from any other sedentary group, it was reduced by the addition of a physical exercise regimen. We also observed an increase in stimulated peripheral lymphocyte proliferation and a decrease in the T-helper 1 response in the HEM group.

Conclusions

The results of the present study support the hypothesis that altering function of tumor non-infiltrated lymphocytes via exercise-related mechanisms can slow melanoma progression, indicating that the incorporation of a regular practice of moderate-intensity exercises can be a potential strategy for current therapeutic regimens in treating advanced melanoma.

Exposure of liver cell culture from the orange-spotted grouper, Epinephelus coioides, to benzo[a]pyrene and light results in oxidative damage as measured by antioxidant enzymes

Among the various toxicants discharged into aquatic environments, benzo (a) pyrene (BaP) has been shown to effect on the antioxidant system of fish and the evaluation of its impact on biota is of considerable concern. The aim of the present study was to use the primary hepatocyte culture obtained from the orange-spotted grouper, Epinephelus coioides, to evaluate the adverse effects of benzo (a) pyrene (BaP) on cell viability and liver antioxidant system. BaP was selected for its high ability to produce reactive oxygen species (ROS) and oxidative stress. The liver was minced by a scalpel and digested in the PBS solution with 0.1% collagenase IV at room temperature for 20 min. Then, the cell suspension was transferred to a plate contained an equal amount of Leibovitz's L-15 medium with 20% fetal bovine serum (FBS), 100 IU mL^-1 of penicillin and 100 μg mL^-1 streptomycin. 5 mL of cell suspension were plated into sterile 25 cm² tissue culture flasks at the density of 1.5 × 10⁶ cell/ml L-15 and incubated at 30 °C for two weeks. The medium was renewed after 24-48 h. The number of the liver cells was adjusted to 4 × 10⁶ after two weeks. 10^-4 mol l^-1 was verified by MTT assay as the IC50 of BaP. Then, hepatocytes were exposed to three concentrations of BaP (10^-5, 2 × 10^-5, 3 × 10^-5 mol L^-1) and incubated for 24 h. Samples were collected after 6, 12 and 24 h and the amounts of SOD, CAT, GPx, LPO, LDH, AST, ALT, ALP and total protein were analyzed. The results showed that, 10^-5 mol L^-1 of BaP was not significantly toxic to cultivated hepatocytes, however, the sensitivity of cells to BaP increased in a dose-related pattern. The activity of the antioxidant enzymes (SOD, CAT and GPx) and liver enzymes (ALT, AST, ALP, LDH) significantly increased, though the amount of LPO, total antioxidant power and total protein decreased dose-dependently in BaP-exposed cells. In conclusion, according to the finding of the present study, BaP has a high potential to induce the oxidative stress in primary liver cell culture of E. coioides.

Comparative Effects of Estrogen and Phytoestrogen, Genistein on Testicular Activities of Streptozotocin-Induced Type 2 Diabetic Mice

The aim of this study was to compare the effect of synthetic estrogen (E2) with a phytoestrogen and genistein in ameliorating type 2 diabetes mellitus (T2D)-mediated testicular dysfunction in mice. The streptozotocin (STZ)-induced type 2 diabetic mice were treated exogenously with either E2 or genistein for 2 durations and compared their effects on testicular activities, serum glucose, and insulin level. Type 2 diabetic mice treated with E2 for only short term (14 days) improved regressive changes in the testicular histology by increasing testosterone synthesis and improving insulin sensitivity, whereas those treated for longer duration (28 days) failed to improve testicular dysfunctions. On the other hand, genistein treated for both short- and long term was useful in improving T2D-induced adverse effects on testicular functions. This study further suggests that treatment with genistein improves spermatogenesis in type 2 diabetic mice by increasing insulin-induced formation of lactate and antioxidative enzymes, which contributes to prevent germ cell apoptosis. Thus, genistein can be used to ameliorate T2D-induced testicular dysfunction.

Mangiferin prevents corticosterone-induced behavioural deficits via alleviation of oxido-nitrosative stress and down-regulation of indoleamine 2,3-dioxygenase (IDO) activity

BACKGROUND

In recent years, a substantial amount of experimental studies have demonstrated that exogenous administration of corticosterone causes anxiety and depressive-like behaviour in rodents which involves hypothalamic-pituitary-adrenal axis dysregulation. Our present study aimed to explore the neuroprotective potential of mangiferin against corticosterone-induced anxiety and depressive-like behaviour.

METHODS

Corticosterone (40 mg/kg; subcutaneously) was administered once daily in swiss albino mice for 21 days. Mice were treated simultaneously with mangiferin (40 mg/kg; p.o.), 30 min prior to the corticosterone injection.

RESULTS

Chronic administration of corticosterone caused anxiety and depressive-like behaviour in mice which was significantly alleviated by mangiferin treatment. Biochemical analysis revealed that mangiferin treatment significantly attenuated corticosterone-induced oxido-nitrosative stress and neuroinflammation in the hippocampus region. Furthermore, concomitant treatment with mangiferin significantly enhanced the hippocampal brain-derived neurotrophic factor (BDNF) level and decreased the serum corticosterone level in the corticosterone-treated animals. Western blotting analysis revealed that corticosterone administration significantly up-regulated the indoleamine 2,3-dioxygenase (IDO) protein expression level in the hippocampus which was significantly reduced by mangiferin treatment.

CONCLUSION

Taken together, our results suggest that mangiferin exerts anti-anxiety and antidepressant effect in corticosterone-treated rats, which is probably mediated through up-regulation of BDNF level along with inhibition of oxido-nitrosative stress, neuroinflammation and IDO up-regulation in the hippocampus region.

Elevated DNA Oxidation and DNA Repair Enzyme Expression in Brain White Matter in Major Depressive Disorder

BACKGROUND

Pathology of white matter in brains of patients with major depressive disorder (MDD) is well-documented, but the cellular and molecular basis of this pathology are poorly understood.

METHODS

Levels of DNA oxidation and gene expression of DNA damage repair enzymes were measured in Brodmann area 10 (BA10) and/or amygdala (uncinate fasciculus) white matter tissue from brains of MDD (n=10) and psychiatrically normal control donors (n=13). DNA oxidation was also measured in BA10 white matter of schizophrenia donors (n=10) and in prefrontal cortical white matter from control rats (n=8) and rats with repeated stress-induced anhedonia (n=8).

RESULTS

DNA oxidation in BA10 white matter was robustly elevated in MDD as compared to control donors, with a smaller elevation occurring in schizophrenia donors. DNA oxidation levels in psychiatrically affected donors that died by suicide did not significantly differ from DNA oxidation levels in psychiatrically affected donors dying by other causes (non-suicide). Gene expression levels of two base excision repair enzymes, PARP1 and OGG1, were robustly elevated in oligodendrocytes laser captured from BA10 and amygdala white matter of MDD donors, with smaller but significant elevations of these gene expressions in astrocytes. In rats, repeated stress-induced anhedonia, as measured by a reduction in sucrose preference, was associated with increased DNA oxidation in white, but not gray, matter.

CONCLUSIONS

Cellular residents of brain white matter demonstrate markers of oxidative damage in MDD. Medications that interfere with oxidative damage or pathways activated by oxidative damage have potential to improve treatment for MDD.

A Mechanistic Basis for the Beneficial Effects of Caloric Restriction On Longevity and Disease: Consequences for the Interpretation of Rodent Toxicity Studies

Caloric restriction in rodents has been repeatedly shown to increase life span while reducing the severity and retarding the onset of both spontaneous and chemically induced neoplasms. These effects of caloric restriction are associated with a spectrum of biochemical and physiological changes that characterize the organism's adaptation to reduced caloric intake and provide the mechanistic basis for caloric restriction's effect on longevity. Here, we review evidence suggesting that the primary adaptation appears to be a rhythmic hypercorticism in the absence of elevated adrenocorticotropin (ACTH) levels. This characteristic hypercorticism evokes a spectrum of responses, including reduced body temperature and increased metabolic efficiency, decreased mitogenic response coupled with increased rates of apoptosis, reduced inflammatory response, reduced oxidative damage to proteins and DNA, reduced reproductive capacity, and altered drug-metabolizing enzyme expression. The net effect of these changes is to (1) decrease growth and metabolism in peripheral tissues to spare energy for central functions, and (2) increase the organism's capacity to withstand stress and chemical toxicity. Thus, caloric restriction research has uncovered an evolutionary mechanism that provides rodents with an adaptive advantage in conditions of fluctuating food supply. During periods of abundance, body growth and fecundity are favored over endurance and longevity. Conversely, during periods of famine, reproductive performance and growth are sacrificed to ensure survival of individuals to breed in better times. This phenomena can be observed in rodent populations that are used in toxicity testing. Improvements over the last 30 years in animal husbandry and nutrition, coupled with selective breeding for growth and fecundity, have resulted in several strains now exhibiting larger animals with reduced survival and increased incidence of background lesions. The mechanistic data from caloric restriction studies suggest that these large animals will also be more susceptible to chemically induced toxicity. This creates a problem in comparing tests performed on animals of different weights and comparing data generated today with the historical database. The rational use of caloric restriction to control body weight to within preset guidelines is a possible way of alleviating this problem.

Evidence for protective effect of lipoic acid and desvenlafaxine on oxidative stress in a model depression in mice

Oxidative stress is implicated in the neurobiology of depression. Here we investigated oxidative alterations in brain areas of animals submitted to the model of depression induced by corticosterone (CORT) and the effects of the antioxidant compound alpha-lipoic acid (ALA) alone or associated with the antidepressant desvenlafaxine (DVS) in these alterations. Female mice received vehicle or CORT (20 mg/kg) during 14 days. From the 15th to 21st days different animals received further administrations of: vehicle, DVS (10 or 20 mg/kg), ALA (100 or 200 mg/kg), or the combinations of DVS10+ALA100, DVS20+ALA100, DVS10+ALA200, or DVS20+ALA200. Twenty-four hours after the last drug administration prefrontal cortex (PFC), hippocampus (HC) and striatum (ST) were dissected for the determination of the activity of superoxide dismutase (SOD), reduced glutathione (GSH) and lipid peroxidation (LP) levels. CORT significantly increased SOD activity in the PFC and HC, decreased GSH levels in the HC and increased LP in all brain areas studied when compared to saline-treated animals. Decrements of SOD activity were observed in all groups and brain areas studied when compared to controls and CORT. The hippocampal decrease in GSH was reversed by ALA100, DVS10+ALA100, DVS20+ALA100 and DVS20+ALA200. The same DVS+ALA combination groups presented increased levels of GSH in the PFC and ST. The greater GSH levels were observed in the PFC, HC and ST of DVS20+ALA200 mice. LP was reversed in the groups ALA200 (PFC), DVS10+ALA100, DVS20+ALA100 (PFC, HC and ST), and DVS20+ALA200 (PFC, HC). Our findings contribute to the previous preclinical evidences implicating ALA as a promising agent for augmentation therapy in depression.

Shortened telomere length in white matter oligodendrocytes in major depression: potential role of oxidative stress

Telomere shortening is observed in peripheral mononuclear cells from patients with major depressive disorder (MDD). Whether this finding and its biological causes impact the health of the brain in MDD is unknown. Brain cells have differing vulnerabilities to biological mechanisms known to play a role in accelerating telomere shortening. Here, two glia cell populations (oligodendrocytes and astrocytes) known to have different vulnerabilities to a key mediator of telomere shortening, oxidative stress, were studied. The two cell populations were separately collected by laser capture micro-dissection of two white matter regions shown previously to demonstrate pathology in MDD patients. Cells were collected from brain donors with MDD at the time of death and age-matched psychiatrically normal control donors (N = 12 donor pairs). Relative telomere lengths in white matter oligodendrocytes, but not astrocytes, from both brain regions were significantly shorter for MDD donors as compared to matched control donors. Gene expression levels of telomerase reverse transcriptase were significantly lower in white matter oligodendrocytes from MDD as compared to control donors. Likewise, the gene expression of oxidative defence enzymes superoxide dismutases (SOD1 and SOD2), catalase (CAT) and glutathione peroxidase (GPX1) were significantly lower in oligodendrocytes from MDD as compared to control donors. No such gene expression changes were observed in astrocytes from MDD donors. These findings suggest that attenuated oxidative stress defence and deficient telomerase contribute to telomere shortening in oligodendrocytes in MDD, and suggest an aetiological link between telomere shortening and white matter abnormalities previously described in MDD.

The effect of certain steroid hormones on the expression of genes involved in the metabolism of free radicals

Steroid hormones influence the antioxidant processes of cells. However, the molecular mechanism of this effect is not fully clear. Our aim was to examine how steroid hormones affect the expression of certain genes that play a role in antioxidant processes. Blood was taken from ten healthy volunteers. Neutrophil granulocytes were separated and treated either with 17-β-estradiol, progesterone, testosterone, or cortisol. Whole RNA was isolated and reverse transcription was carried out in treated and control groups. Relative quantification was performed with SYBR Green assay and gene-specific oligonucleotides. We found that the expression of Mn-superoxide dismutase was significantly increased by 17-β-estradiol and testosterone, myeloperoxidase expression was significantly elevated by cortisol and progesterone, and the expression of NADPH oxidase was significantly decreased by progesterone. We conclude that the antioxidant effect of steroid hormones is in part carried out through transcriptional regulation of certain enzymes. Subsequent studies are required in order to examine the non-genomic, membrane receptor mediated effect of steroids on antioxidant processes.

Ameliorative potential of S-allyl cysteine on oxidative stress in STZ induced diabetic rats

Increased oxidative stress and impaired antioxidant defense mechanism are important factors in the pathogenesis and progression of diabetes mellitus and other oxidant-related diseases. The present study was undertaken to evaluate the possible protective effects of S-allyl cysteine (SAC) against oxidative stress in streptozotocin (STZ) induced diabetic rats. SAC was administered orally for 45 days to control and STZ induced diabetic rats. The effects of SAC on glucose, plasma insulin, thiobarbituric acid reactive substances (TBARS), hydroperoxide, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), oxidized glutathione (GSSG) and GSH/GSSG ratio were studied. The levels of glucose, TBARS, hydroperoxide, and GSSG were increased significantly whereas the levels of plasma insulin, reduced glutathione, GSH/GSSG ratio, superoxide dismutase, catalase and GPx were decreased in STZ induced diabetic rats. Administration of SAC to diabetic rats showed a decrease in plasma glucose, TBARS, hydroperoxide and GSSG. In addition, the levels of plasma insulin, superoxide dismutase, catalase, GPx and reduced glutathione (GSH) were increased in SAC treated diabetic rats. The above findings were supported by histological observations of the liver and kidney. The antioxidant effect of SAC was compared with glyclazide, a well-known antioxidant and antihyperglycemic drug. The present study indicates that the SAC possesses a significant favorable effect on antioxidant defense system in addition to its antidiabetic effect.

The role of oxidative stress in the pathogenesis and treatment of asthma

The role of oxidative stress in asthma is gaining increasing scientific attention. The hallmark of asthma is airway inflammation. Oxidative stress may initiate and augment inflammation, and may also result from inflammation. Exposure to tobacco smoke, ozone, diesel exhaust, and a variety of other pollutants generates reactive oxygen species and other oxidative stressors. Some studies suggest that asthmatics have a decreased ability to respond to oxidative stress, while others find upregulated antioxidative function. Oxidative stress may alter the Th(1)/Th(2) immune response and result in activation of NF-kbeta, a powerful inducer of pro-inflammatory genes. Genetic polymorphisms may play an important role in determining susceptibility to oxidative stress. Many therapeutic strategies to decrease oxidative stress in asthma have been suggested. Dietary changes, antioxidant vitamins, other antioxidant drugs, Ayurvedic supplements, and even radon exposure in a hot bathroom have been studied. Minimizing exposure of young children to environmental tobacco smoke remains paramount.

Effect of aqueous Enicostemma littorale Blume extract on key carbohydrate metabolic enzymes, lipid peroxides and antioxidants in alloxan-induced diabetic rats

The present study investigates the effect of oral administration of an aqueous Enicostemma littorale whole plant extract on some key carbohydrate metabolic enzymes and antioxidant defence in alloxan-induced diabetes in rats. Rats were rendered diabetic by alloxan (150 mg kg−1 body weight) administration. Oral administration of E. littorale extract for 45 days increased the activity of hexokinase and decreased the activities of glucose 6-phosphatase and fructose 1,6-bisphosphatase significantly in the serum, liver and kidney of diabetic rats. The extract lowered the concentration of thiobarbituric acid reactive substances and lipid hydroperoxides significantly in brain and increased it significantly in heart in diabetic rats. E. littorale administration increased the concentration of reduced glutathione and the activity of glutathione peroxidase in diabetic rats. The activities of superoxide dismutase and catalase were increased significantly by E. littorale treatment in diabetic rats. The effect of a 2 g kg−1 dose was greater than that of a 1 g kg−1 dose. Insulin (6 units kg−1) normalized all the parameters in diabetic rats. Our study has provided evidence for the antidiabetic activity of E. littorale aqueous extract. This study can also be extrapolated to clinical studies in future.

Hypothalamic-pituitary-adrenal system and enzymes of the glutathione-dependent antioxidant system during stress and aging

Activity of glutathione-dependent antioxidant enzymes (glutathione peroxidase, glutathione reductase, and glutathione transferase) in blood erythrocytes from female Macaca mulatta (6-8 and 20-26 years) was measured during activation of the hypothalamic-pituitary-adrenal system under conditions of acute psychoemotional stress (2-h restraint stress). Glutathione reductase activity increased during stress, depended on the time of day, and strongly correlated with blood corticosteroid level. Circadian variations in stress reactivity of glutathione reductase during aging were accompanied by similar changes in stress reactivity of the hypothalamic-pituitary-adrenal system.

Efeitos da suplementação de fibras solúveis sobre as células do sistema imune após exercício exaustivo em ratos treinados

A intensidade, volume, modalidade de exercício, assim como o nível de aptidão e fatores nutricionais podem alterar a reposta imunológica. O objetivo deste estudo foi avaliar o efeito da suplementação crônica de farelo de aveia (fonte de fibras solúveis) sobre as células do sistema imunológico em ratos treinados, frente a um teste de exaustão. Foram utilizados ratos Wistar, ± dois meses, peso ± 200g, divididos em três grupos (n = 9, cada um): 1) controle sedentário (C); 2) treinado oito semanas submetido ao teste de exaustão (EX); e 3) treinado oito semanas submetido ao teste de exaustão com suplementação de 30% de farelo de aveia (EXA). O treinamento consistiu de 60 minutos de natação diários, cinco dias por semana durante oito semanas. As análises realizadas foram: contagem total de leucócitos, linfócitos dos linfonodos mesentéricos, macrófagos peritoneais e capacidade fagocitária de macrófagos peritoneais. Aplicou-se o teste estatístico ANOVA two way, seguido do post hoc de Tukey com p < 0,05. O grupo EX apresentou leucocitose quando comparado com o controle, o que não ocorreu no grupo EXA, porém, na comparação entre os grupos exercitados EXA, mostrou menor leucocitose em relação a EX. Não houve alteração significativa nos linfócitos teciduais em nenhum dos grupos exercitados. Tanto o número de macrófagos peritoneais como a capacidade fagocitária desta célula foram maiores nos grupos exercitados. Porém, no grupo suplementado a capacidade fagocitária foi maior em relação ao grupo exaustão sem farelo de aveia. A suplementação de fibras solúveis demonstrou resultados benéficos com relação às alterações imunológicas induzidas pelo exercício extenuante, além de aumentar a capacidade fagocitária de macrófagos peritoniais em ratos treinados durante oito semanas submetidos ao teste de exaustão.

Oral sulforaphane increases Phase II antioxidant enzymes in the human upper airway

BACKGROUND

Cellular oxidative stress is an important factor in asthma and is thought to be the principle mechanism by which oxidant pollutants such as ozone and particulates mediate their pro-inflammatory effects. Endogenous Phase II enzymes abrogate oxidative stress through the scavenging of reactive oxygen species and metabolism of reactive chemicals.

OBJECTIVE

We conducted a placebo-controlled dose escalation trial to investigate the in vivo effects of sulforaphane, a naturally occurring potent inducer of Phase II enzymes, on the expression of glutathione-s-transferase M1 (GSTM1), glutathione-s-transferase P1 (GSTP1), NADPH quinone oxidoreductase (NQO1), and hemoxygenase-1 (HO-1) in the upper airway of human subjects.

METHODS

Study subjects consumed oral sulforaphane doses contained in a standardized broccoli sprout homogenate (BSH). RNA expression for selected Phase II enzymes was measured in nasal lavage cells by RT-PCR before and after sulforaphane dosing.

RESULTS

All subjects tolerated oral sulforaphane dosing without significant adverse events. Increased Phase II enzyme expression in nasal lavage cells occurred in a dose-dependent manner with maximal enzyme induction observed at the highest dose of 200 g broccoli sprouts prepared as BSH. Significant increases were seen in all sentinel Phase II enzymes RNA expression compared to baseline. Phase II enzyme induction was not seen with ingestion of non-sulforaphane containing alfalfa sprouts.

CONCLUSION

Oral sulforaphane safely and effectively induces mucosal Phase II enzyme expression in the upper airway of human subjects. This study demonstrates the potential of antioxidant Phase II enzymes induction in the human airway as a strategy to reduce the inflammatory effects of oxidative stress.

CLINICAL IMPLICATIONS

This study demonstrates the potential of enhancement of Phase II enzyme expression as a novel therapeutic strategy for oxidant induced airway disease.

CAPSULE SUMMARY

A placebo-controlled dose escalation trial demonstrated that naturally occurring sulforaphane from broccoli sprouts can induce a potent increase in antioxidant Phase II enzymes in airway cells.

Oral sulforaphane increases Phase II antioxidant enzymes in the human upper airway

BACKGROUND

Cellular oxidative stress is an important factor in asthma and is thought to be the principle mechanism by which oxidant pollutants such as ozone and particulates mediate their pro-inflammatory effects. Endogenous Phase II enzymes abrogate oxidative stress through the scavenging of reactive oxygen species and metabolism of reactive chemicals.

OBJECTIVE

We conducted a placebo-controlled dose escalation trial to investigate the in vivo effects of sulforaphane, a naturally occurring potent inducer of Phase II enzymes, on the expression of glutathione-s-transferase M1 (GSTM1), glutathione-s-transferase P1 (GSTP1), NADPH quinone oxidoreductase (NQO1), and hemoxygenase-1 (HO-1) in the upper airway of human subjects.

METHODS

Study subjects consumed oral sulforaphane doses contained in a standardized broccoli sprout homogenate (BSH). RNA expression for selected Phase II enzymes was measured in nasal lavage cells by RT-PCR before and after sulforaphane dosing.

RESULTS

All subjects tolerated oral sulforaphane dosing without significant adverse events. Increased Phase II enzyme expression in nasal lavage cells occurred in a dose-dependent manner with maximal enzyme induction observed at the highest dose of 200 g broccoli sprouts prepared as BSH. Significant increases were seen in all sentinel Phase II enzymes RNA expression compared to baseline. Phase II enzyme induction was not seen with ingestion of non-sulforaphane containing alfalfa sprouts.

CONCLUSION

Oral sulforaphane safely and effectively induces mucosal Phase II enzyme expression in the upper airway of human subjects. This study demonstrates the potential of antioxidant Phase II enzymes induction in the human airway as a strategy to reduce the inflammatory effects of oxidative stress.

CLINICAL IMPLICATIONS

This study demonstrates the potential of enhancement of Phase II enzyme expression as a novel therapeutic strategy for oxidant induced airway disease.

CAPSULE SUMMARY

A placebo-controlled dose escalation trial demonstrated that naturally occurring sulforaphane from broccoli sprouts can induce a potent increase in antioxidant Phase II enzymes in airway cells.

The effect of different treatment modalities on oxidative stress in COPD

INTRODUCTION

Oxidant/antioxidant interactions are known to be important processes in the pathogenesis of chronic obstructive pulmonary disease (COPD). We aimed to evaluate the effects of corticosteroids (CS), and N-acetylcysteine (NAC) on plasma oxidant/antioxidant levels in patients with COPD.

METHODS

This study utilised a single-blind, randomised, placebo-controlled, parallel-group methodology. We enrolled 58 patients with stable COPD and 30 healthy controls with similar demographic profiles. The patients with COPD were randomly divided into three treatment groups. Group 1 received basal treatment (regular ipratropium bromide and beta-2 agonist as needed), placebo CS and placebo NAC. In addition to basal treatment, group 2 received oral CS (methylprednisolone 40 mg/day) and placebo NAC. Group 3 received basal treatment plus NAC (600 mg/day) and placebo CS. Each group received treatment for 15 days. We measured plasma malondialdehyde (MDA) and superoxide dismutase (SOD) at the start and the end of study.

RESULTS

Post-treatment plasma MDA levels were significantly lowered only in group 2 (P=0.004). No significant differences were found with respect to erythrocyte SOD levels.

CONCLUSION

This study demonstrates that oral CS, by aiding the oxidant/antioxidant system, may offer a new therapeutic option in COPD treatment.

Superoxide dismutase activity as a measure of hepatic oxidative stress in cattle following ethionine administration

The goal of this study was to assess if oxidative stress, as measured by alterations in the concentrations of antioxidant enzymes in the liver and erythrocytes of cattle, could be induced following dl-ethionine administration. Whole blood, serum and liver biopsy samples were collected 0, 4, 7 and 10 days after intra-peritoneal ethionine administration to five cows. The activities of the antioxidant enzymes copper zinc superoxide dismutase (Cu, Zn SOD) and catalase were assessed in the liver biopsies which were also examined histopathologically. Significant increases in hepatic Cu, Zn SOD concentrations (P<0.01) were noted on days 7 and 10 post-treatment. Hepatic catalase activity decreased significantly (P<0.01) on days 4, 7 and 10 post-treatment and erythrocyte Cu, Zn SOD activity was significantly increased on day 10. Serum biochemical analysis revealed a significant increase (P<0.01) in non-esterified fatty acid concentrations on day 4 and significant decreases in total cholesterol and phospholipid levels on days 4 (P<0.05), 7 (P<0.01) and 10 (P<0.01). In this model system, dl-ethionine administration was effective in inducing oxidative stress particularly reflected in the liver.

Importance of oxidative stress in the pathogenesis and treatment of asthma

PURPOSE OF REVIEW

The purpose of the current review is to summarize recent evidence demonstrating the important role of oxidative stress in asthma pathogenesis. The therapeutic implications of these findings will be presented.

RECENT FINDINGS

Mechanistically, the effect of oxidative stress on dendritic cells has been demonstrated to have a potent effect on Th1/Th2 skewing of the immune response. Investigations of gene-environment interactions have identified genetic polymorphisms associated with individual susceptibility to pollutant-induced respiratory oxidative stress. The effects of current asthma therapy on oxidative stress are currently unclear, but previous trials using conventional antioxidant therapy in asthma have been largely ineffective. Recent investigations have identified two promising broad-based therapeutic approaches: Nrf2 pathway activation and the use of thiol precursors. Preliminary data suggest that fullerene nanomaterials and dietary interventions may also have potential benefits in asthma.

SUMMARY

Our current understanding of the role of oxidative stress in asthma suggests that antioxidant therapy may be important in optimizing asthma treatment and prevention. The future success of antioxidant asthma therapy will require strategies with broad effects on airway redox equilibrium and the selection of appropriate target populations.

The relationship between serum level of thyroid hormones, trace elements and antioxidant enzymes in dromedary camel (Camelus dromedarius)

Thyroid hormones might be able to regulate the activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPX). The role of thyroid hormones in metabolic pathways and antioxidant enzyme activities are well known in many species. Nevertheless, there is no report describing probable relationship between thyroid hormones status, erythrocyte antioxidant enzymes and serum profiles of trace elements. This study was undertaken to investigate the relationship between these parameters in Iranian dromedary camels. Blood samples were taken from the jugular vein of 30 clinically healthy Iranian dromedary camels under aseptic conditions during 6 consecutive days of summer. The serum was analyzed for serum profile of thyroid hormones, trace elements, SOD and GPX activity. There were no significant differences in serum thyroid hormones, serum level of zinc (Zn), copper (Cu), manganese (Mn), iron (Fe), selenium and antioxidant enzymes in different days (P > 0.05). There was a significant negative correlation between SOD and Fe (P < 0.01, r = -493). There was no significant correlation between other parameters. In case of copper deficiency likewise the present study, the copper was used to produce more SOD, so there was a decrease in Fe transportation, and it might be a cause of decrease in Fe amount. On the other hand, a relatively small quantity of Fe is present in tissue myoglobin, catalase, peroxidases, and cytochromes. So it might be another cause of decrease in Fe amount. The explanation for these finding is not possible at this moment and further investigations are needed to interpret these changes.

Circadian and age-related changes in stress responsiveness of the adrenal cortex and erythrocyte antioxidant enzymes in female rhesus monkeys

BACKGROUND

The objective of this study was to evaluate the role of the adrenal cortex in the regulation of antioxidant enzyme defense and to characterize this regulation in different age periods.

METHODS

Five young and five old female rhesus monkeys were subjected to 2 hours squeeze cage restraint stress at 0900 or 1500 hours. Plasma levels of corticosteroids and activities of erythrocyte antioxidant enzymes were measured before the stress and 30, 60, 120, 240 minutes after beginning of the stress.

RESULTS

Young monkeys showed a circadian rhythm in stress responsiveness as measured by corticosteroids and glutathione reductase. The rhythm was attenuated in old animals. Age-related changes in the overall level of response to the afternoon stress were also seen in the corticosteroid and glutathione reductase measures.

CONCLUSIONS

The study demonstrated that corticosteroids play an essential role in the regulation of antioxidant enzyme defense in stress conditions and that the reliability of their regulation decreases with age.

Annona squamosa seed extract in the regulation of hyperthyroidism and lipid-peroxidation in mice: possible involvement of quercetin

Annona squamosa (Custard apple) seeds are generally thrown away as waste materials. The extract of these seeds was evaluated for its possible ameliorative effect in the regulation of hyperthyroidism in mouse model. Serum triiodothyronine (T(3)), thyroxine (T(4)) concentrations, hepatic glucose-6-phospatase (G-6-Pase) and 5'-mono-deiodinase (5'DI) activity were considered as the end parameters of thyroid function. Simultaneously hepatic lipid peroxidation (LPO), superoxide dismutase (SOD) and catalase (CAT) activities were investigated to observe its hepatotoxic effect, if any. L-T(4) administration (0.5 mg/kg/d for 12 days, i.p.) increased the levels of serum T(3) and T(4), activity of hepatic G-6-Pase, 5'DI and LPO with a parallel decrease in SOD and CAT activities. However, simultaneous administration of the Annona seed extract (200 mg/kg) or quercetin (10 mg/kg) to T(4)-induced hyperthyroid animals for 10 days, reversed all these effects indicating their potential in the regulation of hyperthyroidism. Further, the seed extract did not increase, but decreased the hepatic LPO suggesting its safe and antiperoxidative nature. Quercetin also decreased hepatic LPO. When relative efficacy was compared with that of propyl thiouracil (PTU), a standard antithyroidic drug, experimental seed extract appeared to be more effective. Phytochemical analyses including HPLC revealed the presence of quercetin in the seed extract and the results on the effects of quercetin suggested the involvement of this phytochemical in the mediation of antithyroidal activity of Annona squamosa seed extract.

The macrophage at the crossroads of insulin resistance and atherosclerosis

The macrophage has emerged as an important player in the pathogenesis of both atherosclerosis and insulin resistance. Cross-talk between inflammatory macrophages and adipocytes may be involved in insulin resistance in peripheral tissues. Defective insulin signaling in cells of the arterial wall including macrophages may promote the development of atherosclerosis. Insulin resistant macrophages are more susceptible to endoplasmic reticulum stress and apoptosis in response to various stimuli such as nutrient deprivation, free cholesterol loading, and oxidized LDL. Increased apoptosis of insulin resistant macrophages and impaired phagocytic clearance of apoptotic cells by insulin resistant macrophages in atherosclerotic lesions may lead to enhanced postapoptotic necrosis, larger lipid-rich cores, increased inflammation, and more complex vulnerable plaques.

Effect of fish or soybean oil-rich diets on bradykinin, kallikrein, nitric oxide, leptin, corticosterone and macrophages in carrageenan stimulated rats

We have previously demonstrated that both n-3 and n-6 polyunsaturated fatty acids (PUFA)-rich diets decrease the acute inflammatory response partially explained by the high corticosterone basal levels. The present study aimed to determine the effect of hyperlipidic diets (PUFA n-3 or n-6) on phagocytosis, hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) release by macrophages, bradykinin (BK) and NO release in the paw inflammatory perfusate and Kallikrein (KK), corticosterone and leptin blood levels. Hyperlipidic diets decreased H(2)O(2) release from macrophages stimulated by carrageenan or phorbol-miristate-acetate (PMA), NO release from macrophage stimulated by carrageenan, BK and NO release in the edema perfusate, KK plasma levels and the increase of serum leptin after carrageenan stimulus. These data show that both fish and soybean oil-rich diets promote similar alterations on inflammatory mediators of carrageenan edema and a causal association with the anti-inflammatory effect of these diets.

Oxidative status of DBA/1J mice with type II collagen-induced arthritis

The present study was undertaken to compare the oxidant statuses of mice with collagen-induced arthritis (CIA) and those of healthy mice. For this purpose, serum oxidant products and arthritic profiles were measured in DBA/1J mice with CIA. In addition, the levels of oxidation products and the activities of antioxidant enzymes were determined in liver, heart, spleen, kidney, lung and brain. The induction of arthritis significantly increased anti-collagen antibody, rheumatoid factor, interleukin (IL)-1beta, IL-6, protein carbonyl (PCO), advanced glycation end-products (AGE), malondialdehyde (MDA) and low density lipoprotein (LDL)-cholesterol levels in serum (P < 0.05). CIA in DBA/1J mice was associated with significantly lower activities of superoxide dismutase, glutathione peroxidase and glutathione reductase in spleen but higher levels of oxidation products in spleen, kidney and liver than healthy normal mice (P < 0.05). However, lower concentrations of oxidized protein and higher activities of antioxidant enzymes were observed in CIA mouse lung and brain than in healthy normal mice. Dexamethasone treated CIA mice had decreased arthritis-related indices and showed: reduced PCO and AGE in spleen and brain, and increased PCO and AGE in heart, kidney and lung; increased MDA in heart, spleen, lung and brain; reduced SOD and GR activities in lung and brain; increased GPx activity in spleen and brain; and increased GR activity heart and spleen. These data suggest that mice with CIA were more susceptible to oxidative damage in the spleen and liver under the chronic inflammatory conditions.

Glucocorticosteroids as antioxidants in treatment of asthma and COPD. New application for an old medication?

Inhaled corticosteroids (ICS) are the standard of care in asthma and are widely used in the treatment of patients with COPD. The influence of steroids on inflammatory processes has long been established since glucocorticoids and their receptor belong to the regulatory network involved in inhibition of several inflammatory pathways. Inflammatory processes are usually accompanied by an increased oxidative burden followed by a depletion of antioxidants. Therefore, the effects of steroids on antioxidant status have been investigated revealing possible positive effects on the reduced antioxidant enzyme activity. Nevertheless, the mechanisms of this modulation have not been fully elucidated yet. It is possible that antioxidant enzyme activity is regulated at the level of transcription. Additionally, because of the fact that antioxidant enzymes are trace element dependent, steroids may affect their activity through influence on trace element accumulation. This review summarizes the effects of steroids on the antioxidant enzymes activity in vitro and in vivo in relation to asthma and COPD.

Correlation between activity of antioxidant enzymes and circadian rhythms of corticosteroids in Macaca mulatta monkeys of different age

Young rhesus monkey females (Macaca mulatta) demonstrate the well-defined circadian rhythm in activity of erythrocyte SOD with maximum at 10.00 h and minimum at 22.00 h. However, neither GSH-Px nor GR demonstrated any significant circadian changes, contrastingly to SOD. The diurnal changes in the SOD activity tightly correlate with the diurnal changes in the levels of cortisol and DHEAS in the animals' blood plasma. With aging, these circadian rhythms of SOD, cortisol and DHEAS are smoothed out although the correlation between the diurnal changes in cortisol and SOD still maintains even for old animals. These results suggest that corticosteroids play an essential role in regulation of the SOD activity and that the reliability of the hormonal regulation decreases with aging.

Aging affects oxidative state in hippocampus, hypothalamus and adrenal glands of Wistar rats

The aging process is associated with cognitive impairment and dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, as well as with oxidative stress. We determined some parameters of oxidative stress in homogenates of hippocampus, hypothalamus and adrenal glands from male 2-, 6- and 24-months-old Wistar rats. A significant age-dependent increase in the generation of free radicals was observed in hippocampus, hypothalamus and adrenal glands, as well as on lipid peroxidation in hippocampus and hypothalamus. The glutathione peroxidase (GPx) activity was significantly reduced in hypothalamus and hippocampus from 6-months-old rats; a decline on GPx and catalase activities in adrenal glands of 24-months-old animals was also present. Interestingly, a great decrease in total antioxidant capacity was found in all tissues tested. Reported findings support the idea that oxidative events participate on multiple neuroendocrine-metabolic impairments and suggest that the oxidative stress found in hippocampus, hypothalamus and adrenals might be associated with age-related physiological deficits.

Effects of steroid hormones on catalase activity in neuronal and glial cell systems

The aim of the present study was to determine short- (1 and 3 h) and long-term (24 h) effects of glucocorticoids [GCs; corticosterone (CORT), dexamethasone (DEX) and 6-methylprednisolone (6-MP)] and gonadal steroids [GSs; 17beta-estradiol (E2), progesterone (PROG) and testosterone (TEST)] on the activity of the hydrogen-peroxide-detoxifying enzyme catalase (CAT) in neural hippocampal HT22 cells and glial C6 cells because such effects have been described in peripheral organ systems. In HT22 cells, only long-term treatment with glucocorticoids (10(-5) M) induced effects on catalase activity, whereas gonadal steroids (10(-5) M) affected catalase activity after both short- and long-term incubations. At a lower concentration of 10(-7) M, glucocorticoids exerted only short-term treatment effects on catalase activity, while gonadal steroids (10(-7) M) affected the enzyme activity after short- and long-term treatments. In C6 glial cells, both glucocorticoids (10(-7) M) and gonadal steroids (10(-7) M) induced short- and long-term treatment effects. Thereby, our data show that steroid hormones differentially regulate catalase activity in models of the central nervous system (CNS) in a time- and steroid-dependent manner.

Inducible Nitric Oxide Synthase Activity and Expression in Liver and Hepatocytes of Diabetic Rats

Inducible nitric oxide synthase (iNOS) is expressed by the liver in a number of physiological and pathophysiological conditions. The aim of this study was to investigate the relationship between the diabetic state, iNOS and oxidative stress in the rat liver and isolated hepatocytes. Hepatic iNOS expression and activity was measured in both healthy and streptozotocin-induced diabetic rats and determined in hepatocytes in the presence and absence of insulin. Cu/Zn superoxide dismutase (SOD) and phosphatidylinositol-3-kinase (PI3K) were also measured. In a separate experiment lasting 3 weeks, diabetic rats received either no treatment, two daily injections of insulin or aminoguanidine in the drinking water. Diabetes led to increased activity (45%) and expression (70%) of liver iNOS, an effect that was attenuated by insulin treatment both in vitro and in whole animals. Hepatocyte iNOS expression increased by 56%. Hepatic SOD expression was elevated in the diabetic state, but activity levels were similar to healthy controls. Insulin treatment in vivo led to increased enzyme activity but expression was not modified. Levels of PI3K protein were significantly lower in diabetic rats while insulin treatment markedly increased expression. Aminoguanidine did not inhibit hepatic iNOS in this study. Glycemic control via insulin administration was able to downregulate enhanced hepatic iNOS activity and expression in the liver observed in the diabetic state and improve SOD activity, responses that can potentially reduce the free radical damage associated with diabetes.

L-gamma-Glutamyl-L-cysteinyl-glycine (glutathione; GSH) and GSH-related enzymes in the regulation of pro- and anti-inflammatory cytokines: a signaling transcriptional scenario for redox(y) immunologic sensor(s)?

Of the antioxidant/prooxidant mechanisms mediating the regulation of inflammatory mediators, particularly cytokines, oxidative stress-related pathways remain a cornerstone. It is conspicuous that there is a strong association between free radical accumulation (ROS/RNS; oxidative stress) and the evolution of inflammation and inflammatory-related responses. The scenario that upholds a consensus on the aforementioned is still evolving to unravel, from an immunologic perspective, the molecular mechanisms associated with ROS/RNS-dependent inflammation. Cytokines are keynote players when it comes to defining an intimate relationship among reduction-oxidation (redox) signals, oxidative stress and inflammation. How close we are to identifying the molecular basis of this intricate association should be weighed against the involvement of specific signaling molecules and, potentially, transcription factors. L-gamma-Glutamyl-L-cysteinyl-glycine, or glutathione (GSH), an antioxidant thiol, has shaped, and still is refining, the face of oxidative signaling in terms of regulating the milieu of inflammatory mediators, ostensibly via the modulation (expression/repression) of oxygen- and redox-responsive transcription factors, hence termed redox(y)-sensitive cofactors. When it comes to the arena of oxygen sensing, oxidative stress and inflammation, nuclear factor-kappaB (NF-kappaB) and hypoxia-inducible factor-1alpha (HIF-1alpha) are key players that determine antioxidant/prooxidant responses with oxidative challenge. It is the theme therein to underlie current understanding of the molecular association hanging between oxidative stress and the evolution of inflammation, walked through an elaborate discussion on the role of transcription factors and cofactors. Would that classify glutathione and other redox signaling cofactors as potential anti-inflammatory molecules emphatically remains of particular interest, especially in the light of identifying upstream and downstream molecular pathways for conceiving therapeutic, alleviating strategy for oxidant-mediated, inflammatory-related disease conditions.

Daily rhythm of gene expression in rat superoxide dismutases

Antioxidant enzymes are a mainstay of the defense system of any organism to fight oxidative stress caused by physiological and non-physiological production of free radicals. The oxidative status of the tissues is known to regulate these enzymes, together with other factors such as hormones and cytokines. In the present work, we show the daily rhythmicity in the expression of genes for copper-zinc and manganese superoxide dismutases (Cu-Zn and Mn SODs) as observed in several tissues of normal male rats. Intestine, lung, and cerebellum showed significant daily variations. Liver, brain cortex, and mesencephalon also have daily changes although statistically not significant. A possible relation with the oxidative status and the metabolic activity of the organism is discussed.

Oxidant-mediated mitochondrial injury in eosinophil apoptosis: enhancement by glucocorticoids and inhibition by granulocyte-macrophage colony-stimulating factor

The mainstay of asthma therapy, glucocorticosteroids (GCs) have among their therapeutic effects the inhibition of inflammatory cytokine production and induction of eosinophil apoptosis. In the absence of prosurvival cytokines (e.g., GM-CSF), eosinophils appear to be short-lived, undergoing apoptosis over 96 h in vitro. In a dose-dependent manner, GC further enhances apoptosis, while prosurvival cytokines inhibit apoptosis and antagonize the effect of GC. The mechanisms of eosinophil apoptosis, its enhancement by GC, and antagonism of GC by GM-CSF are not well-understood. As demonstrated in this study, baseline apoptosis of eosinophils resulted from oxidant-mediated mitochondrial injury that was significantly enhanced by GC. Mitochondrial injury was detected by early and progressive loss of mitochondrial membrane potential and the antioxidant protein, Mn superoxide dismutase (SOD). Also observed was the activation/translocation of the proapoptotic protein, Bax, to mitochondria. Underscoring the role of oxidants was the inhibition of mitochondrial changes and apoptosis with culture in hypoxia, or pretreatment with a flavoprotein inhibitor or a SOD mimic. GCs demonstrated early (40 min) and late (16 h) activation of proapoptotic c-Jun NH2-terminal kinase (JNK) and decreased the antiapoptotic protein X-linked inhibitor of apoptosis, a recently demonstrated inhibitor of JNK activation. Similarly, inhibition of JNK prevented GC-enhanced mitochondrial injury and apoptosis. Importantly, GM-CSF prevented GC-induced loss of X-linked inhibitor of apoptosis protein, late activation of JNK, and mitochondrial injury even in the face of unchanged oxidant production, loss of MnSOD, and early JNK activation. These data demonstrate that oxidant-induced mitochondrial injury is pivotal in eosinophil apoptosis, and is enhanced by GC-induced prolonged JNK activation that is in turn inhibited by GM-CSF.

The use of xenobiotic-mediated methaemoglobin formation to assess the effects of thyroid hormones on diabetic and non-diabetic human erythrocytic oxidant defence mechanisms in vitro

Diabetes is associated with an abnormal incidence of hypothyroidism, which exacerbates hyperglycaemia, so further damaging already compromised erythrocytic defence mechanisms. Methaemoglobin formation is a useful measure of the health of these mechanisms, as it determines the resistance of diabetic erythrocytes to sustained oxidative stress. The effect of l-tri-iodothyronine (T(3)) was, therefore, studied on nitrite and monoacetyldapsone hydroxylamine (MADDS-NHOH) mediated methaemoglobin formation in diabetic and non-diabetic human erythrocytes. Diabetic erythrocytes showed less sensitivity compared with non-diabetics to methaemoglobin formation mediated by both compounds. A 30 min pre-incubation with T(3) at 3 and 30 nM did not affect nitrite-mediated methaemoglobin formation compared with control observations in both cell types. In diabetic erythrocytes incubated with T(3) at 30 nM, there were significant increases in MADDS-NHOH-mediated methaemoglobin formation compared with control in both diabetic and non-diabetic cells. Studies comparing blood isolated from diabetic patients stabilised on thyroxine (T(4); 50 μG/day), T(4)-free diabetics and non-diabetics, showed that T(4) supplementation significantly increased MADDS-NHOH-mediated methaemoglobin formation compared with T(4)-free diabetic cells so that for two time points, T(4)-treated diabetic erythrocytic methaemoglobin formation was indistinguishable from that of non-diabetics. These studies indicate that T(4) supplementation improves some erythrocytic oxidant defence mechanisms in a time dependent manner.

Review article: oxidative stress as a pathogenic factor in inflammatory bowel disease--radicals or ridiculous?

Virtually all inflammatory mediators investigated to date seem to be dysregulated in the inflamed intestinal mucosa of patients with inflammatory bowel disease. However, which of these are actually involved in the initiation and perpetuation of intestinal tissue damage is still not fully understood. Amongst these mediators are the reactive oxygen metabolites, produced in large amounts by the massively infiltrating leucocytes. These reactive oxygen metabolites are believed to constitute a major tissue-destructive force and may contribute significantly to the pathogenesis of inflammatory bowel disease. This paper provides a concise overview of reactive oxygen metabolite biochemistry, the types of cell and tissue damage potentially inflicted by them, and the endogenous antioxidants which should prevent these harmful effects. An up-to-date summary of the available human experimental data suggests that reactive oxygen metabolite-mediated injury is important in both the primary and downstream secondary pathophysiological mechanisms underlying intestinal inflammation. Nonetheless, how the individual components of the mucosal antioxidant enzymatic cascade respond to inflammatory conditions is a neglected area of research. This particular aspect of intestinal mucosal oxidative stress therefore merits further study, in order to provide a sound, scientific basis for the design of antioxidant-directed treatment strategies for inflammatory bowel disease patients.

Influências do exercício na resposta imune

RESUMO O estudo da relação entre o exercício e a resposta imune teve grande impulso a partir da metade da década de 70, tendo como principais áreas de interesse o estudo da infecção de vias aéreas superiores em atletas submetidos a grandes esforços, o exercício como modelo de estresse e a resposta do treinamento como resposta adaptativa frente a situações de estresse. A descrição da interação entre os sistemas imune e neuroendócrino foi de importância capital no desenvolvimento desses estudos. O exercício gerando um desvio da homeostase orgânica leva à reorganização das respostas de diversos sistemas, entre eles o sistema imune. É adequado dividir a resposta ao exercício em resposta aguda, resposta transitória ao estresse e resposta de adaptação crônica, na qual o treinamento capacita o organismo a lidar com o estímulo estressante de maneira mais adequada. Ambas as respostas afetam os diversos componentes do sistema imune, tanto a resposta inata em seu componente celular compreendendo neutrófilos, macrófagos e células natural killer, como em seu componente humoral, proteínas de fase aguda, sistema do complemento e enzimas, como o sistema imune adaptativo, em seu componente celular (linfócitos T e B), como no componente humoral (anticorpos e citocinas). Apesar das incorreções que cometemos quando das generalizações, podemos dizer que, de modo geral, o exercício de intensidade moderada, praticado com regularidade, melhora a capacidade de resposta do sistema imune, enquanto o exercício de alta intensidade praticado sob condições estressantes provoca um estado transitório de imunodepressão.

High glucose concentrations abolish the superoxide dismutase response of leukocytes to ascorbic acid or troglitazone in type 2 diabetes mellitus

The hypoglycemic drug, troglitazone (TGZ) has antioxidant activity. Superoxide dismutase (SOD) removes superoxide produced by cells. We measured the response of SOD-like activity (deltaSOD) to ascorbic acid (AA) or TGZ using electron spin resonance at various glucose concentrations in polymorphonuclear leukocytes from 18 type 2 diabetic patients and 18 healthy controls. In control and diabetic subjects, ASOD in response to AA was dose-dependent (maximal effect at 100 ng/ml). Maximal response occurred 2 min after AA addition (50 ng/ml). In cells from diabetic patients, ASOD with 25 ng/ml AA was significantly less than for healthy controls. The deltaSOD with AA changed little at glucose concentration from 0 to 200 mg/dl. In patient and control cells, higher glucose concentrations (400 to 800 mg/dl) reduced ASOD with AA. Response patterns with TGZ resembled those with AA. deltaSOD with AA correlated positively with glycosylated hemoglobin A1c.

CONCLUSIONS

The present data suggest that an amerioration of blood glucose on high levels in diabetic patients plays an important role in an antioxidant efficacy of TGZ and AA on leukocytes in patients.