Ethanol consumption and cigarette smoking are common in societies worldwide and have been identified as injurious to human health. This study was undertaken to examine the interactive effects of chronic ethanol and nicotine consumption on the antioxidant defense system in different tissues of rat. Male Fisher-<em>3</em>44 rats were divided into four groups of five animals each and treated for 6.5 weeks as follows: (1) Control rats were administered normal saline orally; (2) ethanol (20% [wt./vol.]) was given orally at a dose of 2 g/kg; (<em>3</em>) nicotine was administered subcutaneously at a dose of 0.1 mg/kg; and (4) a combination of ethanol plus nicotine was administered by the route and at the dose described above. The animals were killed 20 h after the last treatment, and liver, lung, kidney, and testes were isolated and analyzed. Chronic ingestion of ethanol resulted in a significant depletion of glutathione (GSH) content in liver, lung, and testes, whereas chronic administration of nicotine significantly depleted GSH content in liver and testes. The combination of ethanol plus nicotine resulted in a significant depletion of GSH content in liver, lung, and testes. Ethanol, nicotine, or a combination of ethanol plus nicotine significantly increased superoxide dismutase (<em>SOD</em>) activity in liver and decreased <em>SOD</em> activity in kidney. Ethanol, nicotine, or a combination of ethanol plus nicotine significantly decreased catalase (CAT) activity in liver and increased CAT activity in kidney and testes. Chronic ingestion of ethanol resulted in a significant decrease in glutathione peroxidase (GSH-Px) activity in liver and kidney, whereas a combination of ethanol plus nicotine increased GSH-Px activity in liver and decreased GSH-Px activity in kidney and testes. Ethanol, nicotine, or a combination of ethanol plus nicotine significantly increased lipid peroxidation, respectively, in liver. It is suggested that prolonged exposure to ethanol and nicotine produce similar, and in some cases additive, oxidative tissue injuries in rat.

The extracellular superoxide dismutase <em>3</em> (<em>SOD</em><em>3</em>) is highly expressed in both blood vessels and lungs. In different models of pulmonary injury, <em>SOD</em><em>3</em> is reduced; however, it is unclear whether this contributes to lung injury. To study the role of acute <em>SOD</em><em>3</em> reduction in lung injury, the <em>SOD</em><em>3</em> gene was deleted in adult mice by using the Cre-Lox technology. Acute reduction of <em>SOD</em><em>3</em> led to a fivefold increase in lung superoxide, marked inflammatory cell infiltration, a threefold increase in the arterial-alveolar gradient, respiratory acidosis, histological changes similar to those observed in adult respiratory distress syndrome, and 85% mortality. Treatment with the <em>SOD</em> mimetic MnTBAP and intranasal administration of <em>SOD</em>-containing polyketal microparticles reduced mortality, prevented the histological alterations, and reduced lung superoxide levels. To understand how mice with the <em>SOD</em><em>3</em> embryonic deletion survived without lung injury, gene array analysis was performed. These data demonstrated the up-regulation of <em>3</em>7 genes and down-regulation of nine genes, including those involved in cell signaling, inflammation, and gene transcription in <em>SOD</em><em>3</em>-/- mice compared with either mice with acute <em>SOD</em><em>3</em> reduction or wild-type controls. These studies show that <em>SOD</em><em>3</em> is essential for survival in the presence of ambient oxygen and that acute loss of this enzyme can lead to severe lung damage. Strategies either to prevent <em>SOD</em><em>3</em> inactivation or to augment its levels might prove useful in the treatment of acute lung injury.

XTT (<em>3</em>'-{1-[(phenylamino)-carbonyl]-<em>3</em>, 4-tetrazolium}bis(4-methoxy-6-nitro)benzenesulfonic acid hydrate) was reduced to a water-soluble product with an absorbance maximum at about 470 nm by superoxide anion generated by xanthine-xanthine oxidase (XO). The rate of XTT reduction was linearly related to XO activity and the reduction was inhibited by superoxide dismutase (<em>SOD</em>). A perfect inhibition of the reduction of XTT by <em>SOD</em> was achieved, suggesting that XTT does not interact with XO. The present XTT-based assay had a higher sensitivity than a conventional nitroblue tetrazolium-based assay by a factor of 2.5 at pH 10.2. This method was applicable to the <em>SOD</em> assay in the pH range 8.0-10.2.

Experimental studies have proven that melatonin has many beneficial pleiotropic actions. The aim of this study was to assess melatonin efficacy in patients with metabolic syndrome (MS). The study included <em>3</em><em>3</em> healthy volunteers (who were not treated with melatonin) and <em>3</em>0 patients with MS, who did not respond to <em>3</em>-month lifestyle modification. Patients with MS were treated with melatonin (5 mg/day, 2 hr before bedtime) for 2 months. The following parameters were studied: systolic and diastolic blood pressure (SBP, DBP), levels of glucose, serum lipids, C-reactive protein, fibrinogen, activities of antioxidative enzymes: catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (<em>SOD</em>), thiobarbituric acid reactive substrates (TBARS). After 2-month therapy in comparison with baseline, the following significant changes were measured: systolic blood pressure (1<em>3</em>2.8±9.8 versus 120.5±11.0 mmHg, P<0.001), DBP (81.7±8.8 versus 75±7.4 mmHg, P<0.01), low-density lipoprotein cholesterol (LDL-C) (149.7±26.4 versus 1<em>3</em>9.9±<em>3</em>0.2 mg/dL, P<0.05), TBARS (0.5±0.2 versus 0.4±0.1 μm/gHb, P<0.01), and CAT (245.9±46.9 versus 276.8±<em>3</em>9.4 U/gHb). Melatonin administered for 2 months significantly improved antioxidative defense (increase in CAT activity, decrease in TBARS level) and lipid profile (decrease in LDL-C), and lowered blood pressure. We conclude that melatonin therapy may be of benefit for patients with MS, particularly with arterial hypertension. Further studies with higher doses of melatonin or prolonged supplementation are awaited.

Human hepatitis C virus (HCV) is the leading cause of chronic hepatitis, which often results in liver cirrhosis and hepatocellular carcinoma. The HCV RNA genome codes for at least ten proteins. The HCV non-structural protein 5A (NS5A) has generated considerable interest due to its effect on interferon sensitivity via binding and inactivating the cellular protein kinase, PKR. It has been shown that NS5A engages in the endoplasmic reticulum (ER)-nucleus signal transduction pathway. The expression of NS5A in the ER induces an ER stress ultimately leading to the activation of STAT-<em>3</em> and NF-kappaB. This pathway is sensitive to inhibitors of Ca(2+) uptake in the mitochondria (ruthenium red), Ca(2+) chelators (TMB-8, EGTA-AM), and antioxidants (PDTC, NAC, Mn-<em>SOD</em>). The inhibitory effect of protein tyrosine kinase (PTK) inhibitors indicates the involvement of PTK in NF-kappaB activation by NS5A. This implicates an alternate pathway of NF-kappaB activation by NS5A. The actions of NS5A have also been studied in the context of an HCV subgenomic replicon inducing a similar intracellular event. Thus, activation of NF-kappaB leads to the induction of cellular genes, which are largely antiapoptotic in function. These studies suggest a potential function of NS5A in inducing chronic liver disease and hepatocellular carcinoma associated with HCV infection.

We examined the role of oxygen free radicals in cisplatin-induced acute renal failure (ARF). The intravenous injection of cisplatin (5 mg/kg body weight) induced an increase in serum creatinine and tubular damage in the outer stripe of the outer medulla in rats. The renal content of malondialdehyde (MDA) transiently increased. Treatment with the free radical scavengers dimethylthiourea (DMTU) or lecithinized superoxide dismutase (L-<em>SOD</em>) attenuated the increase in serum creatinine. The beneficial effect of DMTU, a hydroxyl radical scavenger, was associated with less accumulation of MDA, less tubular damage, and enhanced expression of proliferating cell nuclear antigen (PCNA) in the damaged tubular cells, but not with improvement of reduced renal blood flow (RBF). On the other hand, the beneficial effect of L-<em>SOD</em>, a superoxide anion scavenger, was associated with preservation of RBF and increased urinary guanosine <em>3</em>',5'-cyclic monophosphate excretion but not with modification of tubular damage or PCNA expression. These results suggest that (1) cisplatin-induced nephrotoxicity was associated with lipid peroxidation, (2) the hydroxyl radical scavenger prevented ARF through both attenuation of tubular damage and enhanced regenerative response of the damaged tubular cells, and (<em>3</em>) the superoxide anion scavenger did the same through preservation of RBF. It follows that oxygen free radicals may play an important role in cisplatin-induced ARF by reducing RBF and inducing tubular damage.

Berberine is the major active constituent of Rhizoma coptidis. The present study was carried out to investigate the effect of berberine on diabetes in rats and its possible mechanisms. Diabetes was induced by tail vein injection with alloxan in Wistar rats. The amount of alloxan administered was 55 mg/kg. Diabetic rats were fed with a high-cholesterol diet. The fasting blood glucose, total cholesterol (TC), triglyceride (TG) and low density lipoprotein-cholesterol (LDL-c), high density lipoprotein-cholesterol (HDL-c), nitric oxide (NO) levels in serum and malondialdehyde (MDA),superoxide dismutase (<em>SOD</em>),glutathione peroxidase (GSH-px) contents in heart tissue were assayed by spectrophotometry. Pancreas samples collected after <em>3</em> weeks of alloxan treatment were stained with hematoxylin-eosin (HE) and examined under a light microscope, and scored. Intragastric administration of berberine (100 and 200 mg/kg) significantly decreased fasting blood glucose levels, serum content of TC, TG, LDL-c, and effectively increased HDL-c, NO level in diabetic rats. Furthermore, berberine treatment significantly blocked the increase of MDA, increased <em>SOD</em> and GSH-px levels in diabetic rats. Histopathological scores showed that berberine had restored the damage of pancreas tissues in rats with diabetes mellitus. The results showed berberine significantly inhibited the progression of diabetes induced by alloxan, and the inhibitory effect of berberine on diabetes might be associated with its hypoglycemic effect, modulating lipids metabolic effects and its ability to scavenge free radical.

The response of the antioxidative systems of leaf cell mitochondria and peroxisomes of the cultivated tomato Lycopersicon esculentum (Lem) and its wild salt-tolerant related species Lycopersicon pennellii (Lpa) to NaCl 100 mM stress was investigated. Salt-dependent oxidative stress was evident in Lem mitochondria as indicated by their raised levels of lipid peroxidation and H2O2 content whereas their reduced ascorbate and reduced glutathione contents decreased. Concomitantly, <em>SOD</em> activity decreased whereas APX and GPX activities remained at control level. In contrast, the mitochondria of salt-treated Lpa did not exhibit salt-induced oxidative stress. In their case salinity induced an increase in the activities of superoxide dismutase (<em>SOD</em>), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione-dependent peroxidase (GPX). Lpa peroxisomes exhibited increased <em>SOD</em>, APX, MDHAR and catalase activity and their lipid peroxidation and H2O2 levels were not affected by the salt treatment. The activities of all these enzymes remained at control level in peroxisomes of salt-treated Lem plants. The salt-induced increase in the antioxidant enzyme activities in the Lpa plants conferred cross-tolerance towards enhanced mitochondrial and peroxisomal reactive oxygen species production imposed by salicylhydroxamic acid (SHAM) and <em>3</em>-amino-1,2,4-triazole (<em>3</em>-AT), respectively.

Despite recent advances in understanding molecular mechanisms involved in glioblastoma progression, the prognosis of the most malignant brain tumor continues to be dismal. Because the flavonoid kaempferol is known to suppress growth of a number of human malignancies, we investigated the effect of kaempferol on human glioblastoma cells. Kaempferol induced apoptosis in glioma cells by elevating intracellular oxidative stress. Heightened oxidative stress was characterized by an increased generation of reactive oxygen species (ROS) accompanied by a decrease in oxidant-scavenging agents such as superoxide dismutase (<em>SOD</em>-1) and thioredoxin (TRX-1). Knockdown of <em>SOD</em>-1 and TRX-1 expression by small interfering RNA (siRNA) increased ROS generation and sensitivity of glioma cells to kaempferol-induced apoptosis. Signs of apoptosis included decreased expression of Bcl-2 and altered mitochondrial membrane potential with elevated active caspase-<em>3</em> and cleaved poly(ADP-ribose) polymerase expression. Plasma membrane potential and membrane fluidity were altered in kaempferol-treated cells. Kaempferol suppressed the expression of proinflammatory cytokine interleukin-6 and chemokines interleukin-8, monocyte chemoattractant protein-1, and regulated on activation, normal T-cell expressed and secreted. Kaempferol inhibited glioma cell migration in a ROS-dependent manner. Importantly, kaempferol potentiated the toxic effect of chemotherapeutic agent doxorubicin by amplifying ROS toxicity and decreasing the efflux of doxorubicin. Because the toxic effect of both kaempferol and doxorubicin was amplified when used in combination, this study raises the possibility of combinatorial therapy whose basis constitutes enhancing redox perturbation as a strategy to kill glioma cells.

Kaempferol (<em>3</em>,4',5,7-tetrahydroxyflavone) is a flavonoid with anti- and pro-oxidant activity present in various natural sources. Kaempferol has been shown to posses anticancer properties through the induction of the apoptotic program. Here we report that treatment of the chronic myelogenous leukemia cell line K562 and promyelocitic human leukemia U9<em>3</em>7 with 50 microM kaempferol resulted in an increase of the antioxidant enzymes Mn and Cu/Zn superoxide dismutase (<em>SOD</em>). Kaempferol treatment induced apoptosis by decreasing the expression of Bcl-2 and increasing the expressions of Bax. There were also induction of mitochondrial release of cytochrome c into cytosol and significant activation of caspase-<em>3</em>, and -9 with PARP cleavage. Kaempferol treatment increased the expression and the mitochondria localization of the NAD-dependent deacetylase SIRT<em>3</em>. K562 cells stably overexpressing SIRT<em>3</em> were more sensitive to kaempferol, whereas SIRT<em>3</em> silencing did not increase the resistance of K562 cells to kaempferol. Inhibition of PI<em>3</em>K and de-phosphorylation of Akt at Ser47<em>3</em> and Thr<em>3</em>08 was also observed after treating both K562 and U9<em>3</em>7 cells with kaempferol. In conclusion our study shows that the oxidative stress induced by kaempferol in K562 and U9<em>3</em>7 cell lines causes the inactivation of Akt and the activation of the mitochondrial phase of the apoptotic program with an increase of Bax and SIRT<em>3</em>, decrease of Bcl-2, release of cytochrome c, caspase-<em>3</em> activation, and cell death.

It has been reported that supplementation with the antioxidant vitamins C and E prevents the adaptive increases in mitochondrial biogenesis and GLUT4 expression induced by endurance exercise. We reevaluated the effects of these antioxidants on the adaptive responses of rat skeletal muscle to swimming in a short-term study consisting of 9 days of vitamins C and E with exercise during the last <em>3</em> days and a longer-term study consisting of 8 wk of antioxidant vitamins with exercise during the last <em>3</em> wk. The rats in the antioxidant groups were given 750 mg·kg body wt(-1)·day(-1) vitamin C and 150 mg·kg body wt(-1)·day(-1) vitamin E. In rats euthanized immediately after exercise, plasma TBARs were elevated in the control rats but not in the antioxidant-supplemented rats, providing evidence for an antioxidant effect. In rats euthanized 18 h after exercise there were large increases in insulin responsiveness of glucose transport in epitrochlearis muscles mediated by an approximately twofold increase in GLUT4 expression in both the short- and long-term treatment groups. The protein levels of a number of mitochondrial marker enzymes were also increased about twofold. Superoxide dismutases (<em>SOD</em>) 1 and 2 were increased about twofold in triceps muscle after <em>3</em> days of exercise, but only <em>SOD</em>2 was increased after <em>3</em> wk of exercise. There were no differences in the magnitudes of any of these adaptive responses between the control and antioxidant groups. These results show that very large doses of antioxidant vitamins do not prevent the exercise-induced adaptive responses of muscle mitochondria, GLUT4, and insulin action to exercise and have no effect on the level of these proteins in sedentary rats.

Pomegranate (Punica granatum) peel extracts have been shown to possess significant antioxidant activity in various in vitro models. Dried pomegranate peels were powdered and extracted with methanol for 4 h. The dried methanolic extract was fed to albino rats of the Wistar strain, followed by carbon tetrachloride (CCl4), and the levels of various enzymes, such as catalase, peroxidase, and superoxide dismutase (<em>SOD</em>), and lipid peroxidation were studied. Treatment of rats with a single dose of CCl4 at 2.0 g/kg of body weight decreases the levels of catalase, <em>SOD</em>, and peroxidase by 81, 49, and 89% respectively, whereas the lipid peroxidation value increased nearly <em>3</em>-fold. Pretreatment of the rats with a methanolic extract of pomegranate peel at 50 mg/kg (in terms of catechin equivalents) followed by CCl4 treatment causes preservation of catalase, peroxidase, and <em>SOD</em> to values comparable with control values, wheres lipid peroxidation was brought back by 54% as compared to control. Histopathological studies of the liver were also carried out to determine the hepatoprotection effect exhibited by the pomegranate peel extract against the toxic effects of CCl4. Histopathological studies of the liver of different groups also support the protective effects exhibited by the MeOH extract of pomegranate peel by restoring the normal hepatic architecture.

A crucial cause of the decreased bioactivity of nitric oxide (NO) in cardiovascular diseases is the uncoupling of the endothelial NO synthase (eNOS) caused by the oxidative stress-mediated deficiency of the NOS cofactor tetrahydrobiopterin (BH(4)). The reversal of eNOS uncoupling might represent a novel therapeutic approach. The treatment of apolipoprotein E knockout (ApoE-KO) mice with resveratrol resulted in the up-regulation of superoxide dismutase (<em>SOD</em>) isoforms (<em>SOD</em>1-<em>SOD</em><em>3</em>), glutathione peroxidase 1 (GPx1), and catalase and the down-regulation of NADPH oxidases NOX2 and NOX4 in the hearts of ApoE-KO mice. This was associated with reductions in superoxide, <em>3</em>-nitrotyrosine, and malondialdehyde levels. In parallel, the cardiac expression of GTP cyclohydrolase 1 (GCH1), the rate-limiting enzyme in BH(4) biosynthesis, was enhanced by resveratrol. This enhancement was accompanied by an elevation in BH(4) levels. Superoxide production from ApoE-KO mice hearts was reduced by the NOS inhibitor L-N(G)-nitro-arginine methyl ester, indicating eNOS uncoupling in this pathological model. Resveratrol treatment resulted in a reversal of eNOS uncoupling. Treatment of human endothelial cells with resveratrol led to an up-regulation of <em>SOD</em>1, <em>SOD</em>2, <em>SOD</em><em>3</em>, GPx1, catalase, and GCH1. Some of these effects were preventable with sirtinol, an inhibitor of the protein deacetylase sirtuin 1. In summary, resveratrol decreased superoxide production and enhanced the inactivation of reactive oxygen species. The resulting reduction in BH(4) oxidation, together with the enhanced biosynthesis of BH(4) by GCH1, probably was responsible for the reversal of eNOS uncoupling. This novel mechanism (reversal of eNOS uncoupling) might contribute to the protective effects of resveratrol.

The db/db mouse is the most widely used animal model of type 2 diabetic nephropathy. Recent studies have utilized genetic backcrossing with transgenic mouse strains to create novel db/db strains that either lack or overexpress specific genes. These novel strains [ICAM-1-/-, CCL2-/-, MKK<em>3</em>-/-, osteopontin-/-, plasminogen activator inhibitor-1 (PAI-1)-/-, endothelial nitric oxide synthase-/-, <em>SOD</em>-Tg, rCAT-Tg] have provided valuable insights into the molecular mechanisms which promote diabetic renal injury. In addition, surgical removal of one kidney has been shown to accelerate injury in the remaining kidney of diabetic db/db mice. A number of novel therapeutic agents have also been tested in db/db mice, including inhibitors of inflammation (chemokine receptor antagonists, anti-CCL2 RNA aptamer, anti-c-fms antibody); oxidative stress (oxykine, biliverdin); the renin-angiotensin-aldosterone system (aliskiren, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, eplerenone); advanced glycation end products (AGE; pyridoxamine, alagebrium, soluble AGE receptor); angiogenesis (NM-<em>3</em>, anti-CXCL12 RNA aptamer, soluble Flt-1); lipid accumulation (statins, farnesoid X receptor agonists, Omacor); intracellular signaling pathways (PKC-β or JNK inhibitors); and fibrosis [transforming growth factor (TGF)-β antibody, TGF-βR kinase inhibitor, soluble betaglycan, SMP-5<em>3</em>4, CTGF-antisense oligonucleotide, mutant PAI-1, pirfenidone], which have identified potential therapeutic targets for clinical translation. This review summarizes the advances in knowledge gained from studies in genetically modified db/db mice and treatment of db/db mice with novel therapeutic agents.

We evaluated the mechanism of capsaicin-mediated ROS generation in pancreatic cancer cells. The generation of ROS was about 4-6 fold more as compared to control and as early as 1 h after capsaicin treatment in BxPC-<em>3</em> and AsPC-1 cells but not in normal HPDE-6 cells. The generation of ROS was inhibited by catalase and EUK-1<em>3</em>4. To delineate the mechanism of ROS generation, enzymatic activities of mitochondrial complex-I and complex-III were determined in the pure mitochondria. Our results shows that capsaicin inhibits about 2.5-9% and 5-20% of complex-I activity and 8-75% of complex-III activity in BxPC-<em>3</em> and AsPC-1 cells respectively, which was attenuable by <em>SOD</em>, catalase and EUK-1<em>3</em>4. On the other hand, capsaicin treatment failed to inhibit complex-I or complex-III activities in normal HPDE-6 cells. The ATP levels were drastically suppressed by capsaicin treatment in both BxPC-<em>3</em> and AsPC-1 cells and attenuated by catalase or EUK-1<em>3</em>4. Oxidation of mitochondria-specific cardiolipin was substantially higher in capsaicin treated cells. BxPC-<em>3</em> derived ρ(0) cells, which lack mitochondrial DNA, were completely resistant to capsaicin mediated ROS generation and apoptosis. Our results reveal that the release of cytochrome c and cleavage of both caspase-9 and caspase-<em>3</em> due to disruption of mitochondrial membrane potential were significantly blocked by catalase and EUK-1<em>3</em>4 in BxPC-<em>3</em> cells. Our results further demonstrate that capsaicin treatment not only inhibit the enzymatic activity and expression of <em>SOD</em>, catalase and glutathione peroxidase but also reduce glutathione level. Over-expression of catalase by transient transfection protected the cells from capsaicin-mediated ROS generation and apoptosis. Furthermore, tumors from mice orally fed with 2.5 mg/kg capsaicin show decreased <em>SOD</em> activity and an increase in GSSG/GSH levels as compared to controls. Taken together, our results suggest the involvement of mitochondrial complex-I and III in capsaicin-mediated ROS generation and decrease in antioxidant levels resulting in severe mitochondrial damage leading to apoptosis in pancreatic cancer cells.

Emerging evidence has implicated reactive oxygen species (ROS) in the pathogenesis of inflammatory bowel disease (IBD). Although intestinal epithelial cells produce the ROS-neutralizing enzyme superoxide dismutase (<em>SOD</em>), the protein and activity levels of copper/zinc (Cu/Zn) and manganese (Mn) <em>SOD</em> are perturbed in inflamed tissues of IBD patients. Thus we investigated the ability of Mn<em>SOD</em> from Streptococcus thermophilus to reduce colitis symptoms in interleukin (IL) 10-deficient mice using Lactobacillus gasseri as a delivery vehicle. Cohorts of 1<em>3</em>-15 IL-10-deficient mice were left untreated or supplemented with native L. gasseri or L. gasseri expressing Mn<em>SOD</em> for 4 wk. Colonic tissue was collected and inflammation was histologically scored. The presence of innate immune cells was investigated by immunohistochemistry and the host antioxidant response was determined by quantitative PCR. It was demonstrated that L. gasseri was stably maintained in mice for at least <em>3</em> days. L. gasseri producing Mn<em>SOD</em> significantly reduced inflammation in IL-10-deficient mice compared with untreated controls (P < 0.05), whereas the anti-inflammatory effects of both native and Mn<em>SOD</em> producing L. gasseri were more pronounced in males. The anti-inflammatory effects of L. gasseri were associated with a reduction in the infiltration of neutrophils and macrophages. Transcripts of antioxidant genes were equivalent in colonic tissues obtained from control and probiotic-treated IL-10-deficient mice. This study demonstrates that L. gasseri producing Mn<em>SOD</em> has significant anti-inflammatory activity that reduces the severity of colitis in the IL-10-deficient mouse.

Baicalin is an important medicinal herb purified from the dry roots of Scutellaria baicalensis Georgi. The present study was undertaken to evaluate the neuroprotective effects of baicalin in gerbils subjected to transient global cerebral ischemic-reperfusion injury. Baicalin at doses of 50, 100 and 200mg/kg was intraperitoneally injected into the gerbils immediately after cerebral ischemia. Seven days after reperfusion, hematoxylin and eosin (HE) staining was performed to analyze hippocampal CA1 pyramidal damage histopathologically. In addition, in order to understand the potential protective mechanism of baicalin, we examined anti-oxidative enzymes, such superoxide dismutase (<em>SOD</em>), glutathione peroxidase (GSH-PX), non-enzymatic scavenger glutathione (GSH) and measured the content of malondialdehyde (MDA) in hippocampus. The mRNA and protein expressions of BDNF were determined in ischemic hippocampus by real-time RT-PCR and Western blot, respectively. Evidence for neuronal apoptosis was detected by real-time RT-PCR, Western blot and caspase-<em>3</em> activity measurement. Histopathological examination showed that the administration of baicalin by the dose of 100 and 200mg/kg significantly attenuated ischemia-induced neuronal cell damage. Reduced level of MDA, obviously elevated activities of <em>SOD</em> and GSH as well as GSH-PX were also found in baicalin-treated groups. Further investigation demonstrated that treatment with baicalin remarkably promoted the expression of BDNF and inhibited the expression of caspase-<em>3</em> at mRNA and protein levels by real-time RT-PCR and Western blot, respectively. Besides, caspase-<em>3</em> activity assay also elucidated that the administration of baicalin could significantly suppress caspase-<em>3</em> in ischemic gerbils hippocampus. Theses findings suggest that baicalin's neuroprotection appears to be associated with its anti-oxidative and anti-apoptotic properties in global cerebral ischemia in the gerbils.

Manganese superoxide dismutase (Mn<em>SOD</em>) provides the first line of defense against superoxide generated in mitochondria. <em>SOD</em> competes with nitric oxide for reaction with superoxide and prevents generation of peroxynitrite, a potent oxidant that can modify proteins to form <em>3</em>-nitrotyrosine. Thus, sufficient amounts of catalytically competent Mn<em>SOD</em> are required to prevent mitochondrial damage. Increased nitrotyrosine immunoreactivity has been reported after traumatic brain injury (TBI); however, the specific protein targets containing modified tyrosine residues and functional consequence of this modification have not been identified. In this study, we show that Mn<em>SOD</em> is a target of tyrosine nitration that is associated with a decrease in its enzymatic activity after TBI in mice. Similar findings were obtained in temporal lobe cortical samples obtained from TBI cases versus control patients who died of causes not related to CNS trauma. Increased nitrotyrosine immunoreactivity was detected at 2 h and 24 h versus 72 h after experimental TBI and co-localized with the neuronal marker NeuN. Inhibition and/or genetic deficiency of neuronal nitric oxide synthase (nNOS) but not endothelial nitric oxide synthase (eNOS) attenuated Mn<em>SOD</em> nitration after TBI. At 24 h after TBI, there was predominantly polymorphonuclear leukocytes accumulation in mouse brain whereas macrophages were the predominant inflammatory cell type at 72 h after injury. However, a selective inhibitor or genetic deficiency of inducible nitric oxide synthase (iNOS) failed to affect Mn<em>SOD</em> nitration. Nitration of Mn<em>SOD</em> is a likely consequence of peroxynitrite within the intracellular milieu of neurons after TBI. Nitration and inactivation of Mn<em>SOD</em> could lead to self-amplification of oxidative stress in the brain progressively enhancing peroxynitrite production and secondary damage.

Biochemical, genetic, enzymatic and molecular approaches were used to demonstrate, for the first time, that tellurite (TeO(<em>3</em>) (2-)) toxicity in E. coli involves superoxide formation. This radical is derived, at least in part, from enzymatic TeO(<em>3</em>) (2-) reduction. This conclusion is supported by the following observations made in K(2)TeO(<em>3</em>)-treated E. coli BW2511<em>3</em>: i) induction of the ibpA gene encoding for the small heat shock protein IbpA, which has been associated with resistance to superoxide, ii) increase of cytoplasmic reactive oxygen species (ROS) as determined with ROS-specific probe 2'7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA), iii) increase of carbonyl content in cellular proteins, iv) increase in the generation of thiobarbituric acid-reactive substances (TBARs), v) inactivation of oxidative stress-sensitive [Fe-S] enzymes such as aconitase, vi) increase of superoxide dismutase (<em>SOD</em>) activity, vii) increase of sodA, sodB and soxS mRNA transcription, and viii) generation of superoxide radical during in vitro enzymatic reduction of potassium tellurite.

BACKGROUND

The aim of this study was to determine the possible relationship between the activity of three different antioxidant enzymes--peroxidase superoxide dismutase, catalase, and glutathione peroxidase--and carbon tetrachloride-induced injury.

METHODS

Male Wistar rats weighing 200-250 g were used in the experiments. Rats of the experimental groups were given carbon tetrachloride 0.5 ml/kg i.p. in olive oil (5 mmol/kg body mass) for 1 or <em>3</em> days. Control group rats were injected with olive oil only for the same period. Brain, liver, kidney, and heart supernatants were used for measurement of superoxide dismutase (<em>SOD</em>), catalase, and glutathione peroxidase (GPX) activities.

RESULTS

No statistically significant changes in SOD and GPX activities were observed in the liver after CCl4 administration, but catalase activity was significantly increased after 24 h and remained at that level during the course of the study. In the brain, SOD and catalase activities decreased after 24 h of experiment, but GPX activity statistically significantly increased at all time points studied. Increased activities of SOD, catalase, and GPX were found in heart after CCl4 intoxication. The CCl4 injection in our experiment caused a reduction of SOD and catalase activities and increased GPX activity in the kidney.

CONCLUSIONS

The results suggest that change in antioxidant enzyme activities may be relevant to the ability of the liver and other investigated organs to cope with oxidative stress during CCl4 poisoning.

Ursolic acid (UA), a pentracyclic triterpene, is reported to have an antioxidant activity. Here we assessed the protective effect of UA against the d-galactose (D-gal)-induced neurotoxicity. We found that UA markedly reversed the D-gal induced learning and memory impairment by behavioral tests. The following antioxidant defense enzymes were measured: superoxide dismutases (<em>SOD</em>), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR). The content of the lipid peroxidation product malondialdehyde (MDA) was also analyzed. Our results indicated that the neuroprotective effect of UA against D-gal induced neurotoxicity might be caused, at least in part, by the increase in the activity of antioxidant enzymes with a reduction in lipid peroxidation. And UA also inhibited the activation of caspase-<em>3</em> induced by D-gal. Furthermore, we found that UA significantly increased the level of growth-associated protein GAP4<em>3</em> in the brain of D-gal-treated mice. These results suggest that the pharmacological action of UA may offer a novel therapeutic strategy for the treatment of age-related conditions.

The effects of overexpression of Cu(2+)/Zn(2+) superoxide dismutase-1 (<em>SOD</em>-1) on indexes of renal injury were compared in 5-month-old nontransgenic (NTg) db/db mice and db/db mice hemizygous for the human <em>SOD</em>-1 transgene (<em>SOD</em>-Tg). Both diabetic groups exhibited similar hyperglycemia and weight gain. However, in NTg-db/db mice, albuminuria, glomerular accumulation of immunoreactive transforming growth factor-beta, collagen alpha1(IV), nitrotyrosine, and mesangial matrix were all significantly increased compared with either nondiabetic mice or <em>SOD</em>-Tg-db/db. <em>SOD</em>-1 activity and reduced glutathione levels were higher, whereas malondialdehyde content was lower, in the renal cortex of <em>SOD</em>-Tg-db/db compared with NTg-db/db mice, consistent with a renal antioxidant effect in the transgenic mice. Inulin clearance (C(IN)) and urinary excretion of guanosine <em>3</em>',5'-cyclic monophosphate (U(cGMP)) were increased in <em>SOD</em>-Tg-db/db mice compared with corresponding values in nondiabetic mice or NTg-db/db mice. C(IN) and U(cGMP) were suppressed by Nomega-nitro-L-arginine methyl ester in <em>SOD</em>-Tg-db/db but not in NTg-db/db mice, implying nitric oxide (NO) dependence of these increases and enhanced renal NO bioactivity in <em>SOD</em>-Tg-db/db. Studies of NO-responsive cGMP in isolated glomeruli supported greater quenching of NO in glomeruli from NTg-db/db compared with <em>SOD</em>-Tg-db/db mice. Evidence of increased NO responsiveness and the suppression of glomerular nitrotyrosine may both reflect reduced NO-superoxide interaction in <em>SOD</em>-Tg-db/db mice. The results implicate superoxide in the pathogenesis of diabetic nephropathy.

The relation between Al-toxicity and oxidative stress was studied for two inbred lines of maize (Zea mays L.), Cat100-6 (Al-tolerant) and S1587-17 (Al-sensitive). Peroxidase (PX), catalase (CAT) and superoxide dismutase (<em>SOD</em>) activities were determined in root tips of both lines, exposed to different Al(<em>3</em>+) concentrations and times of exposure. No increases were observed in CAT activities in either line, although <em>SOD</em> and PX were found to be 1.7 and 2.0 times greater than initial levels, respectively, in sensitive maize treated with <em>3</em>6 microM of Al(<em>3</em>+) for 48 h. The results indicate that Al(<em>3</em>+) induces the dose- and time dependent formation of reactive oxygen species (ROS) and subsequent protein oxidation in S1587-17, although not in Cat100-6. After exposure to <em>3</em>6 microM of Al(<em>3</em>+) for 48 h, the formation of 20+/-2 nmol of carbonyls per mg of protein was observed in S1587-17. The onset of protein oxidation took place after the drop of the relative root growth observed in the sensitive line, indicating that oxidative stress is not the primary cause of root growth inhibition. The presence of Al(<em>3</em>+) did not induce lipid peroxidation in either lines, contrasting with the observations in other species. These results, in conjunction with the data presented in the literature, indicate that oxidative stress caused by Al may harm several components of the cell, depending on the plant species. Moreover, Al(<em>3</em>+) treatment and oxidative stress in the sensitive maize line induced cell death in root tip cells, an event revealed by the high chromatin fragmentation detected by TUNEL analysis.

OBJECTIVE

Oxidative stress is an important factor in the pathogenesis of acute pancreatitis, as shown in vivo by the beneficial effects of scavenger treatment and in vitro by the potential of free radicals to induce acinar cell damage. However, it is still unclear whether oxygen free radicals (OFR) act only as mediators of tissue damage or represent the initiating event in acute pancreatitis in vivo as well. In the present study the authors aimed to address this issue in an experimental set-up.

METHODS

Two hundred male Wistar rats were randomly assigned to one of the following experimental groups. In two groups, acute necrotizing pancreatitis was induced by retrograde intraductal infusion of <em>3</em>% sodium taurocholate. Through the abdominal aorta, a catheter was advanced to the origin of the celiac artery for continuous regional arterial (CRA) pretreatment with isotonic saline (NP-S group) or superoxide dismutase/catalase (NP-<em>SOD</em>/CAT group). In another group, oxidative stress was generated by CRA administration of xanthine oxidase and intravenous administration of hypoxanthine (HX/XOD group). Sham-operated rats received isotonic saline both arterially and intraductally. After observation periods of 5 and <em>3</em>0 minutes and <em>3</em> and 6 hours, the pancreas was removed for light microscopy and determination of reduced glutathione (GSH), oxidized glutathione (GSSG), conjugated dienes (CD), and malondialdehyde as a marker for OFR-induced lipid peroxidation as well as myeloperoxidase as a parameter for polymorphonuclear leukocyte accumulation.

RESULTS

A significant decrease of GSH was paralleled by an increased ratio of GSSG per total glutathione and elevated CD levels after 5 minutes in the NP-S group versus the sham-operated group. Thereafter, the percentage of GSSG and GSH returned to normal levels until the 6-hour time point. After a temporary decrease after <em>3</em>0 minutes, CD levels increased again at <em>3</em> hours and were significantly higher at 6 hours in contrast to sham-operated rats. Myeloperoxidase levels were significantly elevated at <em>3</em> and 6 hours after pancreatitis induction. In contrast to NP-S rats, treatment with <em>SOD</em>/CAT significantly attenuated the changes in glutathione metabolism within the first <em>3</em>0 minutes and the increase of CDs after 6 hours. HX/XOD administration lead to changes in levels of GSH, GSSG, and CDs at 5 minutes as well as to increased myeloperoxidase levels at <em>3</em> hours; these changes were similar to those observed in NP-S rats. Acinar cell damage including necrosis was present after 5 minutes in both NP groups, but did not develop in HX/XOD rats. In addition, serum amylase and lipase levels did not increase in the latter group. <em>SOD</em>/CAT treatment significantly attenuated acinar cell damage and inflammatory infiltrate compared with NP-S animals during the later time intervals.

CONCLUSIONS

OFRs are important mediators of tissue damage. However, extracellular OFR generation alone does not induce the typical enzymatic and morphologic changes of acute pancreatitis. Factors other than OFRs must be involved for triggering acute pancreatitis in vivo.