Enzymatic antioxidant system in the cestode Hymenolepis diminuta after chronic infection of the rat

Background

The aim of the present paper was to describe the enzymatic antioxidant system in Hymenolepis diminuta collected from rats exposed to chronic cestode invasion.

Methodology

We dissected different tissues of H. diminuta (immature proglottids, genital primordia, hermaphroditic proglottids, early uterus, and gravid uterus) and studied activity of: superoxide dismutases (SOD1 and SOD2), catalase (CAT), glutathione peroxidases (non-Se-dependent GSHPx and Se-dependent GSHPx), glutathione-S-transferase (GST) and glutathione reductase (GSHR), and oxidative stress markers ?? reduced glutathione (GSH), and the lipid peroxidation level (TBARS).

Results

We demonstrated changes in antioxidant enzyme activities and levels of oxidative stress markers in different tissues of the parasite. The levels of TBARS and GSH indicate that oxidative stress occurred in tissues located proximal to the intestine wall. Activity of SOD1 was high in all parts of H. diminuta, but the GST activity was the highest of all studied antioxidant enzymes. SOD2 activity differed significantly in various parts of H. diminuta. Significant differences were observed for nonSeGSHPx and activity of other GSH-dependent enzymes was generally similar in all the tissues.

Conclusions

Our results show that the enzymatic antioxidant system of H. diminuta, allows the parasite to adapt and live under conditions of chronic oxidative stress. It suggests an oxidative-antioxidative balance during interactions between parasite and host.     

Oxidative Stress in Cerebrospinal Fluid of Patients with Aseptic and Bacterial Meningitis

This study aimed to determine whether patients with aseptic and bacterial meningitis presented alterations in oxidative stress parameters of cerebrospinal fluid (CSF). A total of 30 patients were used in the research. The CSF oxidative stress status has been evaluated through many parameters, such as lipid peroxidation through thiobarbituric acid reactive substances (TBARS) and antioxidant defense systems such as superoxide dismutase (SOD), glutathione S-transferase (GST), reduced glutathione (GSH) and ascorbic acid. TBARS levels, SOD and GST activity increase in aseptic meningitis and in bacterial meningitis. The ascorbic acid concentration increased significantly in patients with both meningitis types. The reduced glutathione levels were reduced in CSF of patients with aseptic and bacterial meningitis. In present study we may conclude that oxidative stress contributes at least in part to the severe neurological dysfunction found in meningitis.     

Vulnerability of the mid aged rat myocardium to the age-induced oxidative stress: Influence of exercise training on antioxidant defense system

This study investigated the onset of age-related changes in the myocardial antioxidant defense system (ADS) and the vulnerability of the myocardium to oxidative stress following exercise training. Few studies have investigated the influence of the most prevalent life-prolonging strategy physical exercise, on the age-dependent alterations in the myocardial antioxidant enzyme system of female rats at mid age and to determine whether exercise-induced ADS could attenuate lipid peroxidation. Two age groups young (3 months old) and mid age (12 months old) Wistar strain female albino rats were given chronic exercise training for a period of 12 weeks. We found a striking decrease (p < 0.01) in the activity levels of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) in the myocardium of mid aged rats when compared to young rats by 36, 50 and 29%, respectively, suggesting the onset of age-dependent decrease in the myocardial ADS. A similar age-related decrease (p < 0.01) was observed in the reduced glutathione (GSH) content (36%). Despite the reduction in ADS, lipid peroxidation (LPO) (20%) was also decreased. In contrast, exercise training significantly elevated (p < 0.01) these antioxidant enzyme activities and the content of GSH. The increase in SOD and CAT activities were more pronounced in the mid aged rats when compared to younger rats, but increased the level of lipid peroxidation to higher levels in the mid-age group following the training regimen. The findings of the present study suggest that, although the activity levels of the myocardial antioxidant enzymes were elevated with the 12 weeks of exercise training, the changes were not sufficient enough in attenuating oxidative stress in the myocardium of female rats during this short period of exercise training.     

Preventive effect of safranal against oxidative damage in aged male rat brain

An imbalance between production of reactive oxygen species (ROS) and its elimination by antioxidant defense system in the body has been implicated for causes of aging and neurodegenerative diseases. This study was design to assess the changes in activities of antioxidant enzymes (superoxide dismutase (SOD), glutathione-S-transferase (GST), catalase), lipid peroxidation and reduced glutathione (GSH) levels in the brain of 2, 10 and 20 month old rats, and to determine the effect of safranal on the status of selected oxidative stress indices in the 10 and 20 month old rats. The aged rats (10 and 20 months) were given intraperitoneal injections of safranal (0.5 mg/kg day) daily for one month. The results of this study demonstrated that aging caused significant increase in the level of lipid peroxidation as well decrease in the GSH level and activities of SOD and GST in the brain of aging rats. The results of this study showed that safranal ameliorated the increased lipid peroxidation level as well as decreased GSH content of the brain of 10 and 20 month old rats. In addition, safranal treatment to the 20 month old rats, which restored the SOD and GST activities. In conclusion, safranal can be effective to protect susceptible aged brain from oxidative damage by increasing antioxidant defenses.     

Exercise training with ageing protects against ethanol induced myocardial glutathione homeostasis

Glutathione plays a central role in the maintenance of cellular antioxidant defense. The alterations in the glutathione and associated recyclic enzymes caused by both exercise training and ethanol are well documented; however, their interactive effects with age are not well understood. Therefore, the influence of ageing and the interactive effects of exercise training and ethanol on the myocardial glutathione system in 3 months and 18 months old rats were examined. The results showed a significant (p<0.01) reduction in GSH content, Se and non-Se GSH-Px, GR and GST activities in the myocardium of rat with age. A significant increase (p<0.05) in the activities of these enzymes was observed in both age groups of rats in response to exercise training. This exercise-induced elevation of Se and non-Se GSH-Px and GR activities was more pronounced in the 18 months old rats when compared to 3 months old rats. Ethanol consumption significantly (p<0.05) reduced the GSH content, Se and non-Se GSH-Px and GR activities in both age groups of rats. In contrast, ethanol consumption significantly (p<0.05) increased the activity of GST. The combined action of exercise plus ethanol significantly (p<0.05) elevated the GSH content, Se and non-Se GSH-Px, GR and GST activities when compared to the ethanol treated rats in both age groups, indicating the suppression of ethanol-induced oxidative stress by exercise training. In conclusion, there was a compensatory myocardial response lessening ethanol-induced oxidative stress by exercise training, which seemed to result from the higher activity of glutathione recycling and utilizing enzymes, which may be critical for preventing chronic oxidative damage to the myocardium during ageing and even due to ethanol consumption.     

Tinospora cordifolia induces enzymes of carcinogen/drug metabolism and antioxidant system, and inhibits lipid peroxidation in mice

The present study is an effort to identify a potent chemopreventive agent against various diseases (including cancer) in which oxidative stress plays an important causative role. Here, we investigated the effect of a hydroalcoholic (80% ethanol: 20% distilled water) extract of aerial roots of Tinospora cordifolia (50 and 100mg/kg body wt./day for 2 weeks) on carcinogen/drug metabolizing phase-I and phase-II enzymes, antioxidant enzymes, glutathione (GSH) content, lactate dehydrogenase and lipid peroxidation in liver of 8-week-old Swiss albino mice. The modulatory effect of the extract was also examined on extrahepatic organs, i.e., lung, kidney and forestomach, for the activities of GSH S-transferase (GST), DT-diaphorase (DTD), superoxide dismutase (SOD) and catalase. Significant increases in the levels of acid-soluble sulfhydryl (-SH) and cytochrome P(450) contents, and enzyme activities of cytochrome P(450) reductase, cytochrome b(5) reductase, GST, DTD, SOD, catalase, GSH peroxidase (GPX) and GSH reductase (GR) were observed in the liver. Both treated groups showed decreased malondialdehyde (MDA) formation. In lung SOD, catalase and GST; in kidney SOD and catalase; and in forestomach SOD, DTD and GST showed significant increase at both dose levels of treatment. BHA (0.75%, w/w in diet), a pure antioxidant compound, was used as a positive control. This group showed increase in hepatic levels of GSH content, cytochrome b(5), DTD, GST, GR and catalase, whereas MDA formation was inhibited significantly. In the BHA-treated group, the lung and kidney showed increased levels of catalase, DTD and GST, whereas SOD was significantly increased in the kidney and forestomach; the latter also showed an increase in the activities of DTD and GST. The enhanced GSH level and enzyme activities involved in xenobiotic metabolism and maintaining antioxidant status of cells are suggestive of a chemopreventive efficacy of T. cordifolia against chemotoxicity, including carcinogenicity, which warrants further investigation of active principle (s) present in the extract responsible for the observed effects employing various carcinogenesis models.     

Accumulation and oxidative stress biomarkers in Japanese flounder larvae and juveniles under chronic cadmium exposure

This study investigated how Cd exposure affected oxidative biomarkers in Japanese flounder, Paralichthys olivaceus, at early life stages (ELS). Fish were exposed to waterborne Cd (0–48 µg L^− 1) from embryonic to juvenile stages for 80 days. Growth, Cd accumulation, activities of superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), glutathione S-transferase (GST, EC 2.5.1.18), and levels of glutathione (GSH) and lipid peroxidation (LPO) were investigated at three developmental stages. Flounder growth decreased and Cd accumulation increased with increasing Cd concentration. In metamorphosing larvae, CAT and SOD activities were inhibited and GSH level was elevated, while LPO was enhanced by increasing Cd concentrations. CAT and GST activities of settling larvae were inhibited but GSH level was elevated at high Cd concentrations. In juveniles, SOD activity and LPO level were increased but GST activity was inhibited as Cd concentration increased. Antioxidants in flounder at ELS were able to develop ductile responses to defend against oxidative stress, but LPO fatally occurred due to Cd exposure. These biochemical parameters could be used as effective oxidative biomarkers for evaluating Cd contamination and toxicity in marine environments: CAT, SOD, GSH, and LPO for metamorphosing stage; CAT, GSH, and GST for settling stage; and SOD, GST, and LPO for juvenile stage.     

The use of biomarkers in the antioxidant responses of Daphnia magna to the acute and chronic exposure to no. 20 diesel oil and 2,4-dichlorophenol

Abstract

The effects of no. 20 diesel oil exposure, 2,4-dichlorophenol (2,4-DCP) exposure and combined exposure on the antioxidant defences of Daphnia magna have been studied systematically for the first time. Daphnia magna was exposed for 1 day or 10 days to several concentrations of 0, 0.005, 0.01, 0.05, 0.1, 0.5 or 1.0 mg L^?1 solutions. Antioxidant defences consisting of the levels of reduced glutathione (GSH) and glutathione disulfide (GSSG) and activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), selenium dependent glutathione peroxidase (Se-GPx) and glutathione S-transferase (GST) of daphnids were determined to evaluate their protective roles and to analyse the occurrence of oxidative stress. The possible antioxidant defence mechanisms are discussed. Furthermore, GST can be a potential biomarker and an early-warning index for the pollutants in waters in that GST responded sensitively to 1 day and 10 days of exposure to diesel oil and 2,4-DCP and 10 days of combined exposure. Crossover comparisons showed an antagonistic action about the no-observed-effect concentration (NOEC) against Daphnia magna, which needs further studies.     

Protective effect of green tea on lead-induced oxidative damage in rat’s blood and brain tissue homogenates

Recent studies have shown that lead (Pb) could disrupt tissue prooxidant/antioxidant balance which lead to physiological dysfunction. Natural antioxidants are particularly useful in such situation. Current study was designed to investigate efficacy of green tea extract (GTE), on oxidative status in brain tissue and blood caused by chronic oral Pb administration in rats. Four groups of adult male rats (each 15 rats) were utilized: control group; GTE-group (oral 1.5% w/v GTE for 6 weeks); Pb-group (oral 0.4% lead acetate for 6 weeks), and Pb+GTE-group (1.5% GTE and 0.4% lead acetate for 6 weeks). Levels of prooxidant/antioxidant parameters [lipid peroxides (LPO), nitric oxides (NO), total antioxidant capacity (TAC), glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD)] in plasma, erythrocytes, and brain tissue homogenate were measured using colorimetric methods. Pb concentrations in whole blood and brain tissue homogenate were measured by atomic absorption. In Pb-group, levels of LPO were higher while NO and GSH were lower in plasma, erythrocytes, and brain tissue than controls. TAC in plasma, SOD in erythrocytes, and GST in brain tissue homogenate were lower in Pb-group versus control. GTE co-administrated with Pb-reduced Pb contents, increased antioxidant status than Pb-group. In erythrocytes, Pb correlated positively with LPO and negatively with NO, GSH, SOD, and Hb. In brain tissue homogenate, Pb correlated positively with LPO and negatively with GSH. This study suggests that lead induce toxicity by interfering balance between prooxidant/antioxidant. Treatment of rats with GTE combined with Pb enhances antioxidant/ detoxification system which reduced oxidative stress. These observations suggest that GTE is a potential complementary agent in treatment of chronic lead intoxication.     

Cytotoxic effects of 4-octylphenol on fish hepatocytes

The present study was conducted to determine cytotoxic effects of 4-octylphenol (4-OP) on primary cultured hepatocytes of pearl mullet (Alburnus tarichi). Lactate dehydrogenase (LDH) release, malondialdehyde (MDA) level, antioxidant enzymes [superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST)] and glutathione (GSH) content were measured after 24-h exposure to 4-OP. 4-OP caused dose- and time-dependent increases in LDH release. Significant induction of MDA level and decrease in GSH content were found. SOD and GPx activities were decreased while GST activity was increased. These findings suggest that 4-OP leads to cytotoxicity by depressing antioxidant defenses in fish hepatocytes.     

Effect of Terminalia chebula aqueous extract on oxidative stress and antioxidant status in the liver and kidney of young and aged rats

We evaluated the preventive effects of Terminalia chebula (T. chebula) aqueous extract on oxidative and antioxidative status in liver and kidney of aged rats compared to young albino rats. The concentrations of malondialdehyde (MDA), lipofuscin (LF), protein carbonyls (PCO), activities of xantione oxidase (XO), manganese‐superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione‐S‐transferase (GST), and glucose‐6‐phosphate dehydrogenase (G6PDH), levels of glutathione (GSH), vitamin C and vitamin E were used as biomarkers. In the liver and kidney of aged animals, enhanced oxidative stress was accompanied by compromised antioxidant defences. Administration of aqueous extract of T. cheubla effectively modulated oxidative stress and enhanced antioxidant status in the liver and kidney of aged rats. The results of the present study demonstrate that aqueous extract of T. cheubla inhibits the development of age‐induced damages by protecting against oxidative stress. Copyright © 2009 John Wiley & Sons, Ltd.     

Parameters related to oxygen free radicals in erythrocytes,plasma and epidermis of the hairless rat

The following parameters related to oxygen free radicals (OFR) were determined in erythrocytes and the epidermis of hairless rats: catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), reduced (GSH) and oxidized (GSSG) glutathione, glutathione S-transferase (GST), superoxide dismutase (SOD) and thiobarbituric acid reactive substances (TBARS). GSH, GSSG and TBARS were also analyzed in plasma. In erythrocytes, the Pearson correlation coefficients (r) were significant (p < 0.001) between glutathione and other parameters as follows: GSH correlated negatively with GSSG (r = -0.665) and TBARS (r = -0.669); GSSG correlated positively with SOD (r = 0.709) and TBARS (r = 0.752). Plasma GSSG correlated negatively with erythrocytic thermostable GST activity (r = -0.608; p=0.001) and with erythrocytic total GST activity (r = -0.677; p < 0.001). In epidermis (p < 0.001 in all cases), GSH content correlated with GSSG (r = 0.682) and with GPx (r = 0.663); GSSG correlated with GPx (r = 0.731) and with GR (r = 0.794). By multiple linear regression analysis some predictor variables (R(2)) were found: in erythrocytes, thermostable GST was predicted by total GST activity and GSSG, GSSG content was predicted by GSH and by the GSH/GSSG ratio and GPx activity was predicted by GST, CAT and SOD activities; in epidermis, GSSG was predicted by GR and SOD activities and GR was predicted by GSSG, TBARS and GPx. It is concluded that the hairless rat is a good model for studying OFR-related parameters simultaneously in blood and skin, and that it may provide valuable information about other animals under oxidative stress.     

Oxidative Stress in the Heart of Rats Infected with Trypanosoma evansi

This study was conducted to investigate the occurrence of oxidative stress in the heart tissue of rats infected with Trypanosoma evansi. Rats were divided into 2 groups (A and B) with 12 animals each, and further subdivided into 4 subgroups (A1 and A2, 6 animals/each; and B1 and B2, 6 animals/each). Animals in the groups B1 and B2 were subcutaneously inoculated with T. evansi. Thiobarbituric acid reactive substances (TBARS), superoxide dismutase activity (SOD), glutathione S-transferase activity (GST), reduced glutathione activity (GSH), and non-protein thiols (NPSH) in the heart tissue were evaluated. At day 5 and 15 post-infection (PI), an increase in the TBARS levels and a decrease in the SOD activity (P<0.05) were observed. GSH and GST activities were decreased in infected animals at day 15 PI (P<0.05). Considering the proper functioning of the heart, it is possible that the changes in the activity of these enzymes involved in the oxidative stress may be related, at least in part, in the pathophysiology of rats infected with T. evansi.     

Antioxidant defences of the apoplast

Summary The apoplast of barley and oat leaves contained superoxide dismutase (SOD), catalase, ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione reductase activities. The activities of these enzymes in the apoplastic extracts were greatly modified 24 h after inoculation with the biotrophic fungal pathogenBlumeria graminis. The quantum efficiency of photosystem II, which is related to photosynthetic electron transport flux, was comparable in inoculated and healthy leaves during this period. Apoplastic soluble acid invertase activity was also modified in inoculated leaves. Inoculation-dependent increases in apoplastic SOD activity were observed in all lines. Major bands of SOD activity, observed in apoplastic protein extracts by activity staining of gels following isoelectric focusing, were similar to those observed in whole leaves but two additional minor bands were found in the apoplastic fraction. The apoplastic extracts contained substantial amounts of dehydroascorbate (DHA) but little or no glutathione (GSH). Biotic stress decreased apoplastic ascorbate and DHA but increased apoplastic GSH in resistant lines. The antioxidant cycle enzymes may function to remove apoplastic H₂O₂ with ascorbate and GSH derived from the cytoplasm. DHA and oxidized glutathione may be reduced in the apoplast or returned to the cytosol for rereduction.Abbreviations AA reduced ascorbate - APX ascorbate peroxidase - DHA dehydroascorbate (oxidised ascorbate) - DHAR dehydroascorbate reductase - G6PDH glucose-6-phosphate dehydrogenase - GSH reduced glutathione - GSSG glutathione disulphide - GR glutathione reductase - MDHA monodehydroascorbate - MDHAR monodehydroascorbate reductase - SOD superoxide dismutase     

Induction of oxidative stress and DNA damage in cervix in acute treatment with benzo[a]pyrene

Benzo[a]pyrene [B(a)P] is one of the most prevalent environmental carcinogens and genotoxic agents. However, the mechanisms of B(a)P-induced oxidative damage in cervical tissue are still not clear. The present study was to investigate the oxidative stress and DNA damage in cervix of ICR female mice induced by acute treatment with B(a)P. Oxidative stress was assayed by analysis of malondialdehyde (MDA), superoxide anion and H(2)O(2), and antioxidant enzymes. The alkaline single-cell electrophoresis (SCGE) was used to measure DNA damage. The contents of MDA and glutathione (GSH), and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were significantly increased in cervix 24, 48 and 72h after B(a)P treatment of a single dose of 12.5 and 25mg/kg, while GSH, CAT, SOD and GST had no significant difference with the dose of 50mg/kg B(a)P at post-treatment time 48 and 72h except for SOD activity at 48h which was significant. The maximum values of SOD, CAT, GST and GSH were peaked at 24h and then decreased gradually while GPx activities and MDA levels persisted for up to 72h. Superoxide anion, H(2)O(2) and DNA damage changed similarly as the activity of SOD, CAT or GST. Additionally, increases of formamidopyrimidine DNA glycosylase (FPG) specific DNA damage were observed and can be greatly rescued by vitamin C pretreatment. Overall, B(a)P demonstrated a time- and dose- related oxidative stress and DNA damage in cervix.     

The effects of selenium on oxidative stress biomarkers in the freshwater characid fish matrinxã, Brycon cephalus (Günther, 1869) exposed to organophosphate insecticide Folisuper 600 BR (methyl parathion)

Methyl parathion (MP), an organophosphate widely applied in agriculture and aquaculture, induces oxidative stress due to free radical generation and changes in the antioxidant defense system. The antioxidant roles of selenium (Se) were evaluated in Brycon cephalus exposed to 2 mg L(-1) of Folisuper 600 BR (MP commercial formulation - MPc, 600 g L(-1)) for 96 h. Catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione S-transferase (GST), reduced glutathione (GSH) and lipid peroxidation (LPO) levels in the gills, white muscle and liver were evaluated in fish fed on diets containing 0 or 1.5 mg Se kg(-1) for 8 weeks. In fish treated with a Se-free diet, the MPc exposure increased SOD and CAT activities in all tissues. However, the GPx activity decreased in white muscle and gills whereas no alterations were observed in the liver. MPc also increased GST activity in all tissues with a concurrent decrease in GSH levels. LPO values increased in white muscle and gills and did not change in liver after MPc exposure. A Se-supplemented diet reversed these findings, preventing increases in LPO levels and concurrent decreases in GPx activity in gills and white muscle. Similarly, GSH levels were maintained in all tissue after MPc exposure. These results suggest that dietary Se supplementation protects cells against MPc-induced oxidative stress.     

Systemic oxidative stress in children and teenagers with Down syndrome

Aims

The aim of this study was to evaluate the antioxidant status and oxidative stress biomarkers in the blood of children and teenagers with Down syndrome.

Main methods

The analysis of enzymatic antioxidant defenses, such as the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione transferase (GST), non-enzymatic antioxidants, such as levels of reduced glutathione (GSH), uric acid (UA) and vitamin E, as well as oxidative damage indicators, such as protein carbonyls (PC) levels and lipoperoxidation (TBARS), of DS individuals (n = 20) compared to healthy controls (n = 18). Except the vitamin E was measured by HPLC, all other markers were measured spectrophotometrically.

Key Findings

Antioxidant enzymes analysis showed significant increases in the SOD (47.2%), CAT (24.7%) and GR (49.6%) activities in DS subjects. No significant difference in GPx activity was detected while GST activity (61.2%) was decreased, and both responses may be consequence of the depletion of GSH (24.9%) levels. There were no significant differences in TBARS levels, while PC levels showed decreased (31.7%) levels compared to healthy controls, which may be related to the increase (16.1%) found in serum UA. Levels of vitamin E showed no significant differences between DS individuals compared to controls.

Significance

The results revealed a systemic pro-oxidant status in DS individuals, evidenced by the increased activity of some important antioxidant enzymes, together with decreased GSH levels in whole blood and elevated UA levels in plasma, probably as an antioxidant compensation related to the redox imbalance in DS individuals.     

Antioxidant Enzymatic System in Neuronal and Glial Cells Enriched Fractions of Rat Brain After Aluminum Exposure

The aim of this work was to investigate as to how neurons and glial cells separated from the brain cortex respond to oxidative stress induced by aluminum. Female SD rats were exposed to aluminum at the dose level of 100 mg/kg b.w. for 8 weeks. Neuronal and glial cell-enriched fractions were obtained from rat cerebral cortex by sieving the trypsinated homogenate through a series of nylon meshes, followed by centrifugation on ficoll density gradient. Total glutathione content, glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-s-transferase (GST) along with antioxidant enzymes superoxide dismutase (SOD), catalase were estimated in neuronal and glial-enriched fractions in both control (N-c and G-c) and aluminum exposed animals (N-a and G-a). Secondary products of lipid peroxidation that is MDA levels were estimated by measuring the (TBARS) levels. Our results indicate that TBARS levels were significantly higher in glial cell fraction of unexposed controls (Gc) than the neuronal cells (Nc). Correspondingly the glial cells had higher levels of GSH, GSSG, GPx and GST where as neurons had higher levels of catalase, SOD and GR. Following aluminum exposures significant increase in the TBARS levels was observed in neurons as compared to glial cells which also showed a significant decrease in SOD and catalase activity. The decrease in the TBARS levels in the glial cells could be related to the increase in the GSH levels, GR activity, and GST activity which were found to be increased in glial enriched fractions following aluminum exposure. The increase in activity of various enzymes viz GR, GST in glial cells as compared to neurons suggests that glial cells are actively involved in glutathione homeostasis. Our conclusion is that glial and neurons isolated from rat cerebral cortex show a varied pattern of important antioxidant enzymes and glial cells are more capable of handling the oxidative stress conditions.     

Glutathione system in young spontaneously hypertensive rats

Glutathione (GSH) forms a part of the antioxidant system that plays a vital role in preventing oxidative stress, and an imbalance in the oxidant/antioxidant system has been linked to the pathogenesis of hypertension. The aim of this study was to investigate the status of the GSH system in the kidney of spontaneously hypertensive rats (SHR). Components of the GSH system, including glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST), and total GSH content, were measured in the kidneys of 4, 6, 8, 12, and 16 weeks old SHR and Wistar–Kyoto (WKY) rats. Systolic blood pressure of SHR was significantly higher from the age of 6 weeks onwards compared with age-matched WKY rats. GPx activity in the SHR was significantly lower from the age of 8 weeks onwards when compared to that in age-matched WKY rats. No significant differences were evident in the GPx-1 protein abundance, and its relative mRNA levels, GR, GST activity, and total GSH content between SHR and age-matched WKY rats. The lower GPx activity suggests of an impairment of the GSH system in the SHR, which might be due to an abnormality in its protein rather than non-availability of a cofactor. Its role in the development of hypertension in SHR however remains unclear.