GSH Peroxidase Activity Research Articles

MicroRNA-144 modulates oxidative stress tolerance in SH-SY5Y cells by regulating nuclear factor erythroid 2-related factor 2-glutathione axis.

Genome-wide analysis of miRNA expression has revealed increased levels of miR-144 in the brains of Alzheimer's disease (AD) patients. Nuclear factor erythroid 2-related factor 2 (NRF2), a potential target of miR-144, is a central regulator of antioxidant response, and plays an important role in glutathione (GSH) biosynthesis and recycling. In this study, miR-144 mimic was used to over express miR-144. Aβ (1-42) was used to induce oxidative stress in SH-SY5Y cells. Cell viability and intracellular reactive oxygen species (ROS) were assessed to identify the effects of miR-144 on oxidative stress status. GSH and glutathion peroxidase (GPX) activities were detected to reveal the effect of miR-144 on GSH accumulation. To understand the effects of miR-144 on GSH biosynthesis and recycling, intracellular GPX1, glutamate-cysteine ligase catalytic subunit (GCLC), glutamate-cysteine ligase modifier subunit (GCLM), glutathione reductase (GR), and NRF2 expression were detected by western blot and Real-time PCR. In oxidative stress conditions, miR-144 increased the intracellular accumulation of ROS, reduced cell viability, reduced the activities of GSH and antioxidant enzymes, GPX1, and decreased the expression of GCLC, GCLM, GR and NRF2. In conclusion, miR-144 modulates oxidative stress tolerance by regulating NRF2 expression and GSH generation, which may contribute to the pathogenesis of AD.

Glutathione biosynthesis and activity of dependent enzymes in food-grade lactic acid bacteria harbouring multidomain bifunctional fusion gene (gshF).

To assess glutathione (GSH) biosynthesis ability and activity of dependent enzymes in food-grade lactic acid bacteria (LAB) and correlating with genomic information on GSH system in LAB. Whole-genome sequences of 26 food-grade LAB were screened for the presence/absence of a set of genes involved in de novo GSH system. Multiple strains of Streptococcus thermophilus (37), Lactobacillus casei (37), Lactobacillus rhamnosus (4), Lactobacillus paracasei (8) Lactobacillus plantarum (23) and Lactobacillus fermentum (22) were screened for biochemical evidence of the GSH system. Multiple sequence analysis of GshF sequences was carried out for comparing the genomic signatures between GSH-producing and nonproducing species. Streptococcus thermophilus was found to have de novo GSH biosynthesis as well as import ability. Lactobacillus sp. were negative for GSH synthesis but could import it from the medium. All the species exhibited prolific GSH reductase and peroxidase activity. Sequence analysis revealed the absence of key amino acid residues as well as a truncated N-terminal region in lactobacilli. The study provides a comprehensive view on the status of an important antioxidative system (the GSH system) in LAB and is expected to serve as a primer for future work on the mechanistic role of GSH in the group.

SA19. N-Acetyl-Cysteine in a Double-Blind Randomized Placebo-Controlled Trial: Toward Biomarker-Guided Treatment in Early Psychosis

Background: Biomarker-guided treatments are needed in psychiatry and previous data suggest redox dysregulation / oxidative stress may be a target in schizophrenia (1,2). A previous add-on trial with the antioxidant N-Acetyl-Cysteine (NAC) led to negative symptoms reductions in chronic patients (3). We aim to study NAC impact on symptoms and neurocognition in early psychosis (EP) and to explore whether glutathione (GSH)/redox markers could represent valid biomarkers to guide treatment. Methods: In a double-blind, randomized, placebo-controlled trial in 63 EP patients, we assessed the effect of NAC supplementation (2700 mg/day, 6 months) on PANSS, neurocognition (MATRICS Consensus Cognitive Battery [MCCB]), and redox markers (brain GSH [GSH-mPFC], blood cells GSH [GSH-BC] levels, and GSH peroxidase activity [GPx-BC]). Results: No changes in negative, positive symptoms, or functional outcome were observed with NAC, but significant improvements were found in favor of NAC on the MCCB Processing Speed factor and two of its components: Trail Making and Verbal Fluency. NAC leads to increases in GSH-mPFC by 23% (P = .005) and GSH-BC by 19% (P = .05). In patients with high-baseline GPx-BC (>22.3U/gHb), subgroup explorations revealed an improvement with NAC of positive symptoms when compared to patients with low-baseline GPx (P = .02), with an improvement of positive symptoms in parallel with that of the redox status. Conclusion: In conclusion, NAC supplementation in a limited sample of EP patients did not improve negative symptoms, which were at modest levels at baseline. However, NAC leads to neurocognition improvement as well as to brain GSH levels increases, pointing to good target engagement. Blood GPx activity, a redox peripheral index associated with brain GSH levels, could help to identify a subgroup of patients who improve their positive symptoms with NAC. Future trials with antioxidant in EP should consider biomarker-guided treatment.

Camel whey protein improves oxidative stress and histopathological alterations in lymphoid organs through Bcl-XL/Bax expression in a streptozotocin-induced type 1 diabetic mouse model.

Type I diabetes (T1D) is a characterized by the inflammation of pancreatic islets and destruction of β cells. Long and persistent uncontrolled diabetes tends to degenerate the immune system and increase the incidence of infections in diabetic individuals. Most serious diabetic complications are mediated by the free radicals, which damage multiple cellular components through direct effects of the cell cycle regulatory proteins. Camel whey protein (CWP) has antioxidant activity and decreases the effects of free radicals. However, the effects of CWP on lymphoid organs have not been studied in the context of diabetes. Therefore, the present study was designed to investigate the dietary influence of CWP supplementation on the lymphoid organs in streptozotocin (STZ)-induced type 1 diabetic mouse model. Three experimental groups were used: non diabetic control mice, diabetic mice, and diabetic mice treated with CWP. Induction of diabetes was associated with a marked reduction in glutathione (GSH) levels; decreased activities of GSH peroxidase (GSH Px), manganese superoxide dismutase (MnSOD) and catalase; increased reactive oxygen species (ROS) levels and iNOS activity in plasma and lymphoid organs. Furthermore, diabetic mice exhibited alterations in the expression of Bax and Bcl-XL, and subsequently pathological alterations in the architecture of the bone marrow, pancreas, thymus, and spleen. Interestingly, treatment of diabetic mice with CWP robustly restored glucose, insulin, GSH, and ROS levels and the activities of GSH Px, MnSOD, catalase and iNOS. Additionally, supplementation of diabetic mice with CWP improvement in the architecture of lymphoid tissues and rescued from apoptosis through direct effects on the Bax and Bcl-XL proteins. These data revealed the therapeutic potential of CWP against diabetic complications mediated damages of lymphoid organs.

Changes of Oxidative Stress, Glutathione, and Its Dependent Antioxidant Enzyme Activities in Patients with Hepatocellular Carcinoma before and after Tumor Resection.

The changes in and relationship between oxidative stress and the glutathione (GSH) antioxidant system in the plasma and tissues of patients with hepatocellular carcinoma (HCC) before and after tumor resection have not been clearly determined. We investigated the changes in oxidative stress, GSH status and its dependent antioxidant enzyme activities in HCC patients before and after tumor resection, and to determine the association of oxidative stress with GSH and its dependent antioxidant enzyme activities in plasma and tissues. This study employed a cross-sectional design. Forty-four men and 16 women with HCC were recruited. Fasting blood was drawn on the day before the tumor resection and one month after the tumor resection. HCC tissue and adjacent normal liver tissue were obtained at the time of surgical resection. Patients had significantly increased plasma malondialdehyde (MDA) and oxidized-low density lipoprotein levels but decreased GSH and oxidized GSH levels before tumor resection compared with the corresponding post-resection values. GSH and trolox equivalent antioxidant capacity (TEAC) levels and activities of GSH peroxidase were significantly increased while MDA level was significantly lower in HCC tissue when compared with the adjacent normal tissue. The pre-resection plasma MDA level was significantly correlated with pre-resection plasma GSH concentration, and MDA level in HCC and adjacent normal tissues. Pre-resection plasma GSH concentration was significantly correlated with GSH and TEAC level in HCC tissue. HCC patients had increased oxidative stress, decreased GSH, and lower dependent antioxidant capacities before tumor resection. However, hepatocellular tumor had increased GSH and TEAC levels as well as GSH peroxidase activities which might protect itself against increased oxidative stress.

60 - The Phospholipase A2 (PLA2) and Phospholipid Hydroperoxide Glutathione Peroxidase Activities of Peroxiredoxin 6 (Prdx6) Are Required for Repair of Peroxidized Lung Cell Membranes

Lipid peroxidation associated with peroxidative stress gradually resolves over several hours in wild type (WT) mouse lungs and isolated pulmonary endothelial cells (FRBM 87:356, 2015). However, resolution is greatly delayed in lungs or cells that are null for peroxiredoxin 6 (Prdx6). Prdx6 expresses 3 distinct enzymatic activities: phospholipase A 2 (PLA 2 ), GSH peroxidase (GPx), and lysophosphatidylcholine acyltransferase (LPCAT). All 3 activities contribute to the repair of peroxidized cell membranes. For the present study, we evaluated a mouse in which the H26 amino acid residue of Prdx6 was mutated (H26A). H26A-Prdx6 does not bind to phospholipids and, therefore, it lacks both PLA 2 activity and the ability to reduce phospholipid hydroperoxides (PLOOH GPx activity), but retains both LPCAT and peroxidase with H 2 O 2 substrate activities. Lungs were perfused with tert -butyl hydroperoxide (tBOOH, 15-25mM) for 1 h followed by 2 h perfusion with tBOOH–free solution. Lungs were assayed at intervals for lipid peroxidation by the ferrous xylenol orange and TBARS reactions. Lipid peroxidation in WT lungs increased approximately 3-fold after 2 h of lung perfusion with tBOOH but then returned to control values during during the subsequent 2 h of peroxide-free perfusion. However, lungs from H26A-Prdx6 mice showed no significant change in lipid peroxidation during the 2 h post-tBOOH period. These results indicate that the reduction (PLOOH GPx activity) or hydrolysis (PLA 2 activity) of phospholipid hydroperoxides by Prdx6 is required for reversal of lung lipid peroxidation. Further, the scavenging of low mol wt peroxides (eg, tBOOH) does not play a role in cell membrane repair.

Rutin, an antioxidant flavonoid, induces glutathione and glutathione peroxidase activities to protect against ethanol effects in cadmium-induced oxidative stress in the testis of adult rats.

Exposure to cadmium (Cd) reduces sperm quality and induces oxidative stress in the testis. Rutin is an effective antioxidant flavonoid. We studied the effect of ethanol (EtOH, 5g/kg b.wt.) intake on Cd (50mg/kg b.wt.)-induced testicular toxicity with or without RUT pre-treatment (25, 50, 100mg/kg b.wt.) in rats. At the end of the 15-day oral treatment, co-treatment with EtOH decreased the activities of glutathione (GSH), GSH-peroxidase and superoxide dismutase resulting to slight increase in the testicular MDA level compared to Cd-treated rats. The Cd+EtOH animals had higher levels of abnormal spermatozoa, decreased epididymal sperm number and serum testosterone levels (p<.05) compared to the Cd-treated animals. Rutin co-administration protected against the EtOH effects in a dose-dependent manner, with the Cd+EtOH+50mg/kg RUT- and Cd+EtOH+100mg/kg RUT-treated animals having higher GSH and GSH-Px activities beyond the control values (p<.05). In a supplementary study, animals treated daily with RUT alone (25, 50, 100mg/kg b.wt.) for 15days dose-dependently increased testicular GSH-peroxidase and GSH activities by 9.38%, 31.25%, 56.25% and 7.14%, 32.14%, 60.71%, respectively, compared to control values. Therefore, RUT induces GSH and GSH-Px activities to protect against Cd+EtOH-induced testis oxidative stress in rats.

Mutation of Serine 32 to Threonine in Peroxiredoxin 6 Preserves Its Structure and Enzymatic Function but Abolishes Its Trafficking to Lamellar Bodies

Peroxiredoxin 6 (Prdx6), a bifunctional protein with phospholipase A2 (aiPLA2) and GSH peroxidase activities, protects lungs from oxidative stress and participates in lung surfactant phospholipid turnover. Prdx6 has been localized to both cytosol and lamellar bodies (LB) in lung epithelium, and its organellar targeting sequence has been identified. We propose that Prdx6 LB targeting facilitates its role in the metabolism of lung surfactant phosphatidylcholine (PC). Ser-32 has been identified as the active site in Prdx6 for aiPLA2 activity, and this activity was abolished by the mutation of serine 32 to alanine (S32A). However, aiPLA2 activity was unaffected by mutation of serine 32 in Prdx6 to threonine (S32T). Prdx6 protein expression and aiPLA2 activity were normal in the whole lung of a "knock-in" mouse model carrying an S32T mutation in the Prdx6 gene but were absent from isolated LB. Analyses by proximity ligation assay in lung sections demonstrated the inability of S32T Prdx6 to bind to the chaperone protein, 14-3-3ϵ, that is required for LB targeting. The content of total phospholipid, PC, and disaturated PC in lung tissue homogenate, bronchoalveolar lavage fluid, and lung LB was increased significantly in Prdx6-S32T mutant lungs, whereas degradation of internalized [(3)H]dipalmitoyl-PC was significantly decreased. Thus, Thr can substitute for Ser for the enzymatic activities of Prdx6 but not for its targeting to LB. These results confirm an important role for LB Prdx6 in the degradation and remodeling of lung surfactant phosphatidylcholine.

Early Abscisic Acid Accumulation Regulates Ascorbate and Glutathione Metabolism in Soybean Leaves Under Progressive Water Stress

Ascorbate (AsA) and glutathione (GSH) play an important role in improving the tolerance of plants to water stress. The objective of this study was to investigate the effect of early abscisic acid (ABA) accumulation on AsA and GSH metabolism in soybean plants after 24 h of exposure to progressive water stress. The results showed that AsA, total AsA, GSH and total GSH content, and ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), GSH reductase (GR), GSH peroxidase (GPX), l-galactono-1,4-lactone dehydrogenase (GLDH), and γ-glutamylcysteine synthetase (γ-GCS) activities were increased by progressive water stress. The above increases, except for total GSH content and the activities of GLDH and γ-GCS, were blocked by pretreatment with tungstate, an ABA biosynthesis inhibitor, which significantly suppressed the early increase in ABA and reactive oxygen species (ROS) in stressed plants. Application of ABA reversed the effects of tungstate. Pretreatments with several ROS scavengers, such as Tiron and dimethylthiourea (DMTU), and an inhibitor of NADPH oxidase, diphenyleneiodonium (DPI), significantly arrested the early accumulation of ROS but not ABA in stressed plants. Furthermore, the above-mentioned pretreatments remarkably prevented any increase in APX, MDHAR, DHAR, GR, and GPX activities, as well as AsA, total AsA and GSH levels in stressed plants. Our results indicated that early ABA accumulation caused by progressive water stress triggers an early rise in ROS levels, which, in turn, leads to regulation of AsA and GSH metabolism.

Pleiotropic and Renoprotective Effects of Erythropoietin Beta on Experimental Diabetic Nephropathy Model

Background: This study aimed at investigating the possible protective effect of erythropoietin beta on experimental diabetic nephropathy (DN) model in rats. Methods: Sprague Dawley rats (n = 32) were allocated into 4 equal groups of 8 each, the control (Group C), diabetes (Group D), erythropoietin beta (Group E), and erythropoietin beta treated DN (Group E + D) groups. Streptozocin (65 mg/kg) was used to induce diabetes in 10-week old rats. Erythropoietin beta was given intraperitoneally at a dose of 500 IU/kg/3 days of a week for 12 weeks. Renal function parameters, intrarenal levels and activities of oxidative stress biomarkers, serum inflammatory parameters and kidney histology were determined. Results: Group E + D had lower mean albumin-to-creatinine ratio (p < 0.001) as well as higher creatinine clearance (p = 0.035) than the diabetic rats (Group D). Intrarenal malondialdehyde levels were significantly lower (p = 0.004); glutathione (GSH) levels (p = 0.003), GSH peroxidase (p = 0.004) and superoxide dismutase (p < 0.005) activities of renal tissue were significantly higher in Group E + D than in Group D. The mean serum levels of interleukin-4 (p < 0.005), interleukin 1 beta (p = 0.012), interferon gamma (p = 0.018) and tumor necrosis factor alpha (p < 0.005) were significantly lower; serum levels of monocyte chemoattractant protein 1 (p = 0.018) was significantly higher in Group E + D when compared to Group D. The mean scores of tubulointerstitial inflammation (p = 0.004), tubular injury (p = 0.013) and interstitial fibrosis (p = 0.003) were also lower in Group E + D when compared to Group D. Conclusion: Our data seem to suggest a potential role of erythropoietin beta for reducing the progression of DN in an experimental rat model. This protective effect is, in part, attributable to the suppression of the inflammatory response and oxidative damage.

Peroxiredoxin 6 homodimerization and heterodimerization with glutathione S-transferase pi are required for its peroxidase but not phospholipase A2 activity

Peroxiredoxin 6 (Prdx6) is a unique 1-Cys member of the peroxiredoxin family with both GSH peroxidase and phospholipase A2 (PLA2) activities. It is highly expressed in the lung where it plays an important role in antioxidant defense and lung surfactant metabolism. Glutathionylation of Prdx6 mediated by its heterodimerization with GSH S-transferase π (πGST) is required for its peroxidatic catalytic cycle. Recombinant human Prdx6 crystallizes as a homodimer and sedimentation equilibrium analysis confirmed that this protein exists as a high affinity dimer in solution. Based on measurement of molecular mass, dimeric Prdx6 that was oxidized to the sulfenic acid formed a sulfenylamide during storage. After examination of the dimer interface in the crystal structure, we postulated that the hydrophobic amino acids L145 and L148 play an important role in homodimerization of Prdx6 as well as in its heterodimerization with πGST. Oxidation of Prdx6 also was required for its heterodimerization. Sedimentation equilibrium analysis and the Duolink proximity ligation assay following mutation of the L145 and L148 residues of Prdx6 to Glu indicated greatly decreased dimerization propensity reflecting the loss of hydrophobic interactions between the protein monomers. Peroxidase activity was markedly reduced by mutation at either of the Leu sites and was essentially abolished by the double mutation, while PLA2 activity was unaffected. Decreased peroxidase activity following mutation of the interfacial leucines presumably is mediated via impaired heterodimerization of Prdx6 with πGST that is required for reduction and re-activation of the oxidized enzyme.

Hypoglycemic, hypolipidemic and antioxidant effects of pioglitazone, insulin and synbiotic in diabetic rats.

Aim:The objective of the study was to assess the effect of combination treatment of insulin, pioglitazone and synbiotic on streptozotocin (STZ)-induced diabetic rats.Materials and Methods:Diabetes mellitus was induced chemically by intraperitoneal administration of STZ (40 mg/kg b.wt) to male Sprague-Dawley rats. The rats were divided randomly into six groups of six rats in each. Group 1 was maintained as a normal control. Group 2 was maintained as diabetic control; Group 3 was treated with insulin; Group 4 with insulin + synbiotic; Group 5 with insulin + pioglitazone; and Group 6 with insulin + synbiotic + pioglitazone. All the animals were treated for 60 days.Results:Body weights, and concentration of reduced glutathione (GSH), and high-density lipoproteins cholesterol were significantly (p<0.05) reduced, whereas the concentration of blood glucose, total cholesterol, triglycerides, protein carbonyls and thiobarbituric acid reacting substances, and the activity of GSH peroxidase were significantly (p<0.05) elevated in Group 2 at the end of 8th week as compared to Group 1. The treatment Groups 3, 4, 5 and 6 revealed improvement in all the parameters, and the highest improvement was observed in combination Group 6.Conclusion:From this study, it is concluded that combination of insulin, pioglitazone and synbiotic is useful in treating diabetes.

Thiol peroxidase activities in rat blood plasma determined with hydrogen peroxide and 5,5`-dithio-bis(2-nitrobenzoic acid)

Earlier it has been shown that extracellular glutathione peroxidase (GPx3) from human plasma is able to use cysteine (Cys-SH) instead of glutathione (GSH) as a thiol substrate. In the present study, the ability of rat plasma to utilize not only GSH, but also Cys-SH and homocysteine (Hcy-SH), in the thiol peroxidase reaction has been confirmed. The molar ratio between thiol and H2O2 in the catalyzed reaction was 2:1. The specific activity increased with fractionation of proteins. At a fixed thiol concentration of 0.23 mM, the saturation by H2O2 with vmax app of 100, 128, and 132 nmol H2O2 / s per 1 ml of plasma was found for DL-Cys-SH, L-GSH, and DL-Hcy-SH, respectively. Rank distributions of activities towards all three thiol substrates within plasma protein fractions are fully identical (the probability of random full coincidence was less than 0.01). The statistical analysis confirms that Cys-SH peroxidase, Hcy-SH peroxidase, and GSH peroxidase activities are closely associated with each other. The most probable outcome of this result is the ability of rat GPx3 to utilize all three thiols as substrates for oxidation. Probably, thiol peroxidase is a participant of formation of plasma cystine (Cys-SS-Cys) from Cys-SH in plasma. If the forms of Hcy exhibit different toxic effects, it can be suggested that thiol peroxidase regulates Hcy toxicity in hyperhomocysteinemia through Hcy-SH oxidation to homocystine (Hcy-SS-Hcy).

Delivery of a protein transduction domain-mediated Prdx6 protein ameliorates oxidative stress-induced injury in human and mouse neuronal cells.

Oxidative stress or reduced expression of naturally occurring antioxidants during aging has been identified as a major culprit in neuronal cell/tissue degeneration. Peroxiredoxin (Prdx) 6, a protective protein with GSH peroxidase and acidic calcium-independent phospholipase A2 activities, acts as a rheostat in regulating cellular physiology by clearing reactive oxygen species (ROS) and thereby optimizing gene regulation. We found that under stress, the neuronal cells displayed reduced expression of Prdx6 protein and mRNA with increased levels of ROS, and the cells subsequently underwent apoptosis. Using Prdx6 fused to TAT transduction domain, we showed evidence that Prdx6 was internalized in human brain cortical neuronal cells, HCN-2, and mouse hippocampal cells, HT22. The cells transduced with Prdx6 conferred resistance against the oxidative stress inducers paraquat, H2O2, and glutamate. Furthermore, Prdx6 delivery ameliorated damage to neuronal cells by optimizing ROS levels and overstimulation of NF-κB. Intriguingly, transduction of Prdx6 increased the expression of endogenous Prdx6, suggesting that protection against oxidative stress was mediated by both extrinsic and intrinsic Prdx6. The results demonstrate that Prdx6 expression is critical to protecting oxidative stress-evoked neuronal cell death. We propose that local or systemic application of Prdx6 can be an effective means of delaying/postponing neuronal degeneration.

카르복시 말단 유비퀴틴 가수분해 효소 활성 보유 PPPDE superfamily member인 Schizosaccharomyces pombe Sdu1의 열 스트레스에 대한 방어적 역할

The sdu1+ gene encodes Sdu1, a PPPDE superfamily member of deubiquitinating enzymes (DUBs) in Schizosaccharomyces pombe. Sdu1 was previously shown to contain an actual ubiquitin C-terminal hydrolase (UCH) activity using the recombinant plasmid pYSTP which harbors the sdu1+ gene. This work was designed to assess a thermotolerant role of Sdu1 against high incubation temperatures. In the temperature-shift experiments, the S. pombe cells harboring pYSTP grew much better after the shifts to 37˚C and 42˚C, when compared with the vector control cells. After being shifted to 37˚C and 42˚C for 6 h, the S. pombe cells harboring pYSTP contained lower reactive oxygen species (ROS) levels, compared with the vector control cells. The nitric oxide (NO) levels of the S. pombe cells harboring pYSTP were slightly lower than those of the vector control cells in the absence or presence of the temperature shifting. The total glutathione (GSH) levels of the S. pombe cells harboring pYSTP were significantly higher than those of the vector control cells. Total superoxide dismutase (SOD) and GSH peroxidase activities were also higher in the S. pombe cells harboring pYSTP after the temperature shifts than in the vector control cells. In brief, the S. pombe Sdu1 plays a thermotolerant role against high incubation temperature through the down-regulation of ROS and NO and the up-regulation of total GSH content, total SOD and GSH peroxidase activities.

Diabetes enhances oxidative stress-induced TRPM2 channel activity and its control by N-acetylcysteine in rat dorsal root ganglion and brain.

N-acetylcysteine (NAC) is a sulfhydryl donor antioxidant that contributes to the regeneration of glutathione (GSH) and also scavengers via a direct reaction with free oxygen radicals. Recently, we observed a modulatory role of NAC on GSH-depleted dorsal root ganglion (DRG) cells in rats. NAC may have a protective role on oxidative stress and calcium influx through regulation of the TRPM2 channel in diabetic neurons. Therefore, we investigated the effects of NAC on DRG TRPM2 channel currents and brain oxidative stress in streptozotocin (STZ)-induced diabetic rats. Thirty-six rats divided into four groups: control, STZ, NAC and STZ + NAC. Diabetes was induced in the STZ and STZ + NAC groups by intraperitoneal STZ (65 mg/kg) administration. After the induction of diabetes, rats in the NAC and STZ + NAC groups received NAC (150 mg/kg) via gastric gavage. After 2 weeks, DRG neurons and the brain cortex were freshly isolated from rats. In whole-cell patch clamp experiments, TRPM2 currents in the DRG following diabetes induction with STZ were gated by H2O2. TRPM2 channel current densities in the DRG and lipid peroxidation levels in the DRG and brain were higher in the STZ groups than in controls; however, brain GSH, GSH peroxidase (GSH-Px), vitamin C and vitamin E concentrations and DRG GSH-Px activity were decreased by diabetes. STZ + H2O2-induced TRPM2 gating was totally inhibited by NAC and partially inhibited by N-(p-amylcinnamoyl) anthranilic acid (ACA) and 2-aminoethyl diphenylborinate (2-APB). GSH-Px activity and lipid peroxidation levels were also attenuated by NAC treatment. In conclusion, we observed a modulatory role of NAC on oxidative stress and Ca(2+) entry through the TRPM2 channel in the diabetic DRG and brain. Since excessive oxidative stress and overload Ca(2+) entry are common features of neuropathic pain, our findings are relevant to the etiology and treatment of pain neuropathology in DRG neurons.

Glutathionyl systems and metabolic dysfunction in obesity.

Oxidative stress is associated with obesity. However, glutathione (GSH), one of the body's most abundant antioxidants, plays dual and seemingly contradictory roles in the development of obesity and its comorbidities. Glutathione has complex metabolic and biochemical fates and is a cofactor for several enzymes that function in modifying obesity-related responses. For example, depletion of GSH increases energy metabolism and reduces adipose accretion, while elevation of GSH peroxidase activity induces insulin resistance. This review summarizes the literature linking GSH and its related enzymes, GSH peroxidase, glutaredoxins, and glutathione S-transferases, to obesity and its pertinent endpoints (e.g., energy metabolism, inflammation, and insulin resistance).

The N-Methyl-d-Aspartate Receptor Antagonist MK-801 Prevents Thallium-Induced Behavioral and Biochemical Alterations in the Rat Brain.

Thallium (Tl(+)) is a toxic heavy metal capable of increasing oxidative damage and disrupting antioxidant defense systems. Thallium invades the brain cells through potassium channels, increasing neuronal excitability, although until now the possible role of glutamatergic transmission in this event has not been investigated. Here, we explored the possible involvement of a glutamatergic component in the Tl(+)-induced toxicity through the N-methyl-d-aspartate (NMDA) receptor antagonist dizocilpine (MK-801) in rats. The effects of MK-801 (1 mg/kg, intraperitoneally [ip]) on early (24 hours) motor alterations, lipid peroxidation, reduced glutathione (GSH) levels, and GSH peroxidase activity induced by Tl(+) acetate (32 mg/kg, ip) were evaluated in adult rats. MK-801 attenuated the Tl(+)-induced hyperactivity and lipid peroxidation in the rat striatum, hippocampus and midbrain, and produced mild effects on other end points. Our findings suggest that glutamatergic transmission via NMDA receptors might be involved in the Tl(+)-induced altered regional brain redox activity and motor performance in rats.

Regular Yoga Practice Improves Antioxidant Status, Immune Function, and Stress Hormone Releases in Young Healthy People: A Randomized, Double-Blind, Controlled Pilot Study.

The aim of the present study is to highlight the beneficial effects of yoga practice on bio-parameters, such as oxidative stress, antioxidant components, immune functions, and secretion of stress hormones, in healthy young people. This study was conducted on healthy volunteers recruited from among university students, who were divided into two groups: a control (no yoga intervention, n=13) group and a yoga (n=12) group. Yoga practice was with an instructor for 90 minutes once a week spread over 12 weeks, with recommendations to practice daily at home for 40 minutes with the help of a DVD. The yoga program consisted of yoga body poses (asanas), exercises involving awareness, voluntary regulation of breath (pranayama), and meditational practices. Whole blood samples were collected when the volunteers had fasted for 8 hours at 0 and 12 weeks. The oxidative stress/antioxidant components, immune-related cytokines, and stress hormones were evaluated in serum or plasma. Serum levels of nitric oxide, F2-isoprostane, and lipid peroxide were significantly decreased by yoga practice (p<0.05 or p=0.01), whereas serum total glutathione (GSH) contents, activities of GSH-peroxidase, and GSH-s-transferase were remarkably increased after yoga practice compared with the control group (p<0.05 or p=0.01). Yoga practice also significantly increased immune-related cytokines, such as interleukin-12, and interferon-γ, in serum (p<0.05 or p=0.01). Yoga practice significantly reduced the plasma levels of adrenalin (p<0.05) and increased plasma levels of serotonin compared with the control group (p<0.05). Regular yoga practice remarkably attenuated oxidative stress and improved antioxidant levels of the body. Moreover, yoga beneficially affected stress hormone releases as well as partially improved immune function.

An evaluation of the effect of pentoxifylline on blood pressure and myocardial oxidative status following intake of western diet

Background: Western diet (WD) has been known to promote cardiac oxidative stress in models of hypertension and obesity. Pentoxifylline (PTX) is a potent antioxidant. The impact of PTX and WD on cardiac oxidative status in healthy hearts is unclear. Aim: we aimed to determine the impact of WD and/or PTX on blood pressure and myocardial oxidative status in normal rat hearts. Method: Young adult Sprague Dawley rats were randomly assigned into four groups; conventional diet (control), WD, PTX, or simultaneous combination of WD + PTX for 10 weeks. Blood pressure, lipids levels, and cardiac levels of oxidants and antioxidants were measured. Result: WD was associated with an increase in triglyceride level and a mild increase in systolic blood pressure (SBP), whereas PTX reduced SBP. Relative to control, no changes were observed in levels of TNF alpha and glutathione (GSH) system, however, a significant decrease in thiobarbituric acid reactive substances (TBARS) level was observed in all groups with a parallel increase in catalase activities. Superoxide dismutase and catalase activities were increased in the PTX group. Relative to the WD group, the WD + PTX group was associated with a significant increase in the activities of GSH peroxidase and reductase. Conclusions: The decrease in TBARS levels and the increase in catalase activities suggest that normal hearts adapt compensatory mechanisms to prevent oxidative damage in response to the mild increase in SBP associated with WD. Use of PTX with WD further enhanced antioxidant activities probably to balance the potential increase in reactive oxygen species.