Celastrol, an active component found in the Chinese herb tripterygium wilfordii has been identified as a neuroprotective agent for neurodegenerative diseases including Parkinson's disease (PD) through unknown mechanism. Celastrol can induce autophagy, which plays a neuroprotective role in PD. We tested the protective effect of celastrol on rotenone-induced injury and investigated the underlying mechanism using human neuroblastoma SH-SY5Y cells. The SH-SY5Y cells were treated with celastrol before rotenone exposure. The cells survival, apoptosis, accumulation of α-synuclein, oxidative stress and mitochondrial function, and autophagy production were analyzed. We found celastrol (500 nM) pre-treatment enhanced cell viability (by 28.99%, P<0.001), decreased cell apoptosis (by 54.<em>3</em>8%, P<0.001), increased <em>SOD</em> and GSH (by 120.5<em>3</em>% and 90.46%, P<0.01), reduced accumulation of α-synuclein (by <em>3</em>5.9<em>3</em>%, P<0.001) and ROS generation (by <em>3</em><em>3</em>.99%, P<0.001), preserved MMP (<em>3</em><em>3</em>.9<em>3</em>±<em>3</em>.62%, vs. 15.10±0.71% of JC-1 monomer, P<0.001) and reduced the level of cytochrome C in cytosol (by 45.57%, P<0.001) in rotenone treated SH-SY5Y cells. Moreover, celastrol increased LC<em>3</em>-II/LC<em>3</em> I ratio by 60.92% (P<0.001), indicating that celastrol activated autophagic pathways. Inhibiting autophagy by <em>3</em>-methyladenine (<em>3</em>-MA) abolished the protective effects of celastrol. Our results suggested that celastrol protects SH-SY5Y cells from rotenone induced injuries and autophagic pathway is involved in celastrol neuroprotective effects.

Diabetic encephalopathy, characterized by cognitive deficits involves hyperglycemia-induced oxidative stress. Impaired mitochondrial functions might play an important role in accelerated oxidative damage observed in diabetic brain. The aim of the present study was to examine the role of mitochondrial oxidative stress and dysfunctions in the development of diabetic encephalopathy along with the neuroprotective potential of N-acetylcysteine (NAC). Chronic hyperglycemia accentuated mitochondrial oxidative stress in terms of increased ROS production and lipid peroxidation. Significant decrease in Mn-<em>SOD</em> activity along with protein and non-protein thiols was observed in the mitochondria from diabetic brain. The activities of mitochondrial enzymes; NADH dehydrogenase, succinate dehydrogenase and cytochrome oxidase were decreased in the diabetic brain. Increased mitochondrial oxidative stress and dysfunctions were associated with increased cytochrome c and active caspase-<em>3</em> levels in cytosol. Electron microscopy revealed mitochondrial swelling and chromatin condensation in neurons of diabetic animals. NAC administration, on the other hand was found to significantly improve diabetes-induced biochemical and morphological changes, bringing them closer to the controls. The results from the study provide evidence for the role of mitochondrial oxidative stress and dysfunctions in the development of diabetic encephalopathy and point towards the clinical potential of NAC as an adjuvant therapy to conventional anti-hyperglycemic regimens for the prevention and/or delaying the progression of CNS complications.

Isoquercetin (Iso) has been found to have neuroprotective effects against cerebral ischemic stroke. However, the exact molecular mechanism underlying its neuroprotective ability remains unclear. In this study, we aimed to evaluate the neuroprotective effects of Iso in primary culture of rat hippocampal neurons exposed to oxygen and glucose deprivation and reperfusion (OGD/R) injury and in rats subjected to middle cerebral artery occlusion and reperfusion (MCAO/R) injury. We found that rats treated with Iso exhibited a lower degree of infarct volume, and brain water content than the vehicle-treated rats. Treatment with Iso also improved the neurological deficits in MCAO/R rats as shown by the decreased modified neurological severity score. Iso treatment decreased the reactive oxygen species (ROS) and malondialdehyde (MDA) production, and increased the activity of superoxide dismutase (<em>SOD</em>) and catalase (CAT) in brains of MCAO/R rats and primary culture of rat hippocampal neurons exposed to OGD/R. Iso treatment prevents I/R-induced neuronal apoptosis in vivo and in vitro as indicated by increased cell viability and decreased number of TUNEL-positive cells, accompanying with downregulation of cleaved caspase-<em>3</em> protein and upregulation of Bcl-2 protein. Moreover, Nrf2 knockdown weakened the anti-apoptotic and anti-oxidant activities of Iso in primary culture of rat hippocampal neurons exposed to OGD/R. Interestingly, we found that Iso could induce Nrf2 translocation from cytoplasm to nucleus in primary culture of rat hippocampal neurons exposed to OGD/R. Iso activated the NOX4/ROS/NF-κB signaling pathway in in vivo and in vitro cerebral I/R injury models. Nrf2 knockdown blocked the inhibitory effect of Iso on protein expression of NOX4, p-IκBα and p-p65 in primary culture of rat hippocampal neurons exposed to OGD/R. All the data suggested that Iso protected against oxidative stress and neuronal apoptosis in in vivo and in vitro cerebral I/R injury models via Nrf2-mediated inhibition of the NOX4/ROS/NF-κB signaling pathway. Our findings suggested that Iso could be a potential agent for I/R brain injury.

Chemopreventive potential of Acacia nilotica bark extract (ANBE) against single intraperitoneal injection of N-nitrosodiethylamine (NDEA, 200mg/kg) followed by weekly subcutaneous injections of carbon tetrachloride (CCl(4), <em>3</em> ml/kg) for 6 weeks induced hepatocellular carcinoma (HCC) in rats was studied. At 45 day after administration of NDEA, 100 and 200mg/kg of ANBE were administered orally once daily for 10 weeks. The levels of liver injury and liver cancer markers such as alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), gamma-glutamyl transferase (gamma-GT), total bilirubin level (TBL), alpha-feto protein (AFP) and carcinoembryonic antigen (CEA) were substantially increased following NDEA treatment. However, ANBE treatment reduced liver injury and restored liver cancer markers. ANBE also significantly prevented hepatic malondialdehyde (MDA) formation and reduced glutathione (GSH) in NDEA-treated rats which was dose dependent. Additionally, ANBE also increased the activities of antioxidant enzymes viz., catalase (CAT), superoxide dismutase (<em>SOD</em>), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) in the liver of NDEA-administered rats. Eventually, ANBE also significantly improved body weight and prevented increase of relative liver weight due to NDEA treatment. Histological observations of liver tissues too correlated with the biochemical observations. HPLC analysis of ANBE showed the presence of gallic, protocatechuic, caffeic and ellagic acids, and also quercetin in ANBE. The results strongly support that A. nilotica bark prevents lipid peroxidation (LPO) and promote the enzymatic and non-enzymatic antioxidant defense system during NDEA-induced hepatocarcinogenesis which might be due to activities like scavenging of oxy radicals by the phytomolecules in ANBE.

This study aimed to investigate the supplemental effects of probiotic Bacillus subtilis fmbJ (BS fmbJ) on growth performance, antioxidant capacity, and meat quality of broiler chickens. A total of 240 day-old male Arbor Acres (AA) broiler chickens were randomly allotted to 4 treatments and raised for 6 wk. Each treatment had 6 replicate pens with ten birds per replicate. Birds in the control group (CON) were fed diets without BS fmbJ and antibiotics. The BS groups were fed the basal diets with BS fmbJ at 2 × 1010 cfu/kg (BS-1 group), BS fmbJ at <em>3</em> × 1010 cfu/kg (BS-2 group), BS fmbJ at 4 × 1010 cfu/kg (BS-<em>3</em> group) without antibiotics for 42 d. In the study, dietary supplementation with BS fmbJ significantly improved (P < 0.05) the average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) of broilers from 21 to 42 d and 1 to 42 d. At 42 d, the final body weight was increased (P < 0.05) in BS-2 group compared with that in CON. Dietary BS fmbJ significantly increased (P < 0.05) serum IgA and IgG concentrations of broilers after 42 days raising. The glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GSH-Px), and superoxide dismutase (<em>SOD</em>) activity of serum and liver were increased (P < 0.05), and methane dicarboxylic aldehyde (MDA) contents in serum and liver were decreased (P < 0.05) by BS fmbJ added into the broiler diets. Dietary supplementation with BS fmbJ significantly decreased (P < 0.05) reactive oxygen species (ROS) contents in liver mitochondria of broilers. Additionally, the expression of antioxidant enzyme gene including nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), superoxide dismutase (<em>SOD</em>), and glutathione peroxidase (GPx) were improved (P < 0.05) by BS fmbJ added into the broiler diets. Among measuring items of chicken breast meat quality, the drip loss, cooking loss, shear force, L*24 h, a*24 h, b*45 min, and b*24 h values were influenced (P < 0.05) by BS fmbJ provided in the diet. Based on these results, Bacillus subtilis fmbJ could be acted as a beneficial feed additive with antioxidant capacity in broiler diets.

OBJECTIVE

Pulmonary hypertension (PH) is characterized by an oxidant/antioxidant imbalance that promotes abnormal vascular responses. Reactive oxygen species, such as superoxide (O(2)(•-)), contribute to the pathogenesis of PH and vascular responses, including vascular remodeling and inflammation. This study sought to investigate the protective role of a pharmacological catalytic antioxidant, a superoxide dismutase (<em>SOD</em>) mimetic (MnTE-2-PyP), in hypoxia-induced PH, vascular remodeling, and NALP<em>3</em> (NACHT, LRR, and PYD domain-containing protein <em>3</em>)-mediated inflammation.

RESULTS

Mice (C57/BL6) were exposed to hypobaric hypoxic conditions, while subcutaneous injections of MnTE-2-PyP (5 mg/kg) or phosphate-buffered saline (PBS) were given <em>3</em>× weekly for up to <em>3</em>5 days. <em>SOD</em> mimetic-treated groups demonstrated protection against increased right ventricular systolic pressure, indirect measurements of pulmonary artery pressure, and RV hypertrophy. Vascular remodeling was assessed by Ki67 staining to detect vascular cell proliferation, α-smooth muscle actin staining to analyze small vessel muscularization, and hyaluronan (HA) measurements to assess extracellular matrix modulation. Activation of the NALP<em>3</em> inflammasome pathway was measured by NALP<em>3</em> expression, caspase-1 activation, and interleukin 1-beta (IL-1β) and IL-18 production. Hypoxic exposure increased PH, vascular remodeling, and NALP<em>3</em> inflammasome activation in PBS-treated mice, while mice treated with MnTE-2-PyP showed an attenuation in each of these endpoints.

METHODS

This study is the first to demonstrate activation of the NALP<em>3</em> inflammasome with cleavage of caspase-1 and release of active IL-1 β and IL-18 in chronic hypoxic PH, as well as its attenuation by the <em>SOD</em> mimetic, MnTE-2-PyP.

CONCLUSIONS

The ability of the SOD mimetic to scavenge extracellular O(2)(•-) supports our previous observations in EC-SOD-overexpressing mice that implicate extracellular oxidant/antioxidant imbalance in hypoxic PH and implicates its role in hypoxia-induced inflammation.

Cells of the facultative photosynthetic bacterium Rhodobacter capsulatus (MT11<em>3</em>1 strain) incubated with 10 microg ml-1 of the toxic oxyanion tellurite (TeO2-(<em>3</em>)) exhibited an increase in superoxide dismutase activity. The latter effect was also seen upon incubation with sublethal amounts of paraquat, a cytosolic generator of superoxide anions (O2-), in parallel with a strong increase in tellurite resistance (TeR). A mutant strain (CW10) deficient in SenC, a protein with similarities to peroxiredoxin/thiol:disulfide oxidoreductases and a homologue of mitochondrial Sco proteins, was constructed by interposon mutagenesis via the gene transfer agent system. Notably, the absence of SenC affected R. capsulatus resistance to periplasmic O2- generated by xanthine/xanthine oxidase but not to cytosolic O2- produced by paraquat. Further, the absence of SenC did not affect R. capsulatus tellurite resistance. We conclude that: (1) cytosolic-generated O2- enhances TeR of this bacterial species; (2) small amounts of tellurite increase <em>SOD</em> activity so as to mimic the early cell response to oxidative stress; (<em>3</em>) SenC protein is required in protection of R. capsulatus against periplasmic oxidative stress; and finally, (4) SenC protein is not involved in TeR, possibly because tellurite does not generate O-2 at the periplasmic space level.

Cisplatin mediated nephrotoxicity is remarkably documented by reactive oxygen species. Carnosine is a naturally occurring dipeptide and has a scavenging property. The aim of present study was to assess the lipid peroxidation and antioxidant enzymes in association with oxidative stress in cisplatin -treated and 10 subsequent doses of carnosine-pretreated rats. 24 male Albino Wistar rats, were randomly divided into four groups (n=6). Group I remains untreated; Group II received Cisplatin (<em>3</em> mg / kg) for 5 alternate days; Group III received Carnosine (10 mg / kg) for consecutive 10 days; Group IV received Carnosine (10 mg / kg) before administration of Cisplatin (<em>3</em> mg / kg). The effects of carnosine on cisplatin-induced nephrotoxicity were evaluated by plasma creatinine, urea, malondialdehyde, nitrate; kidney tissue malondialdehyde, 4-HNE, superoxide dismutase and catalase activities. Cisplatin-induced oxidative stress was indicated by increased level of tissue MDA, 4-HNE and decreased level of tissue GSH, <em>SOD</em> and Catalase. Marked elevation of kidney weight and reduced body weight and pathological changes in kidney tissues were also observed in Cisplatin-treated rats. Carnosine reduced these pathological changes and counteracted the deleterious effects of cisplatin. The results divulge the beneficial effect of Carnosine pretreatment with cisplatin in experimental rat model.

BACKGROUND

Ischemia reperfusion injury (IRI) is a leading cause of acute kidney injury (AKI) in both native and transplanted kidneys. The objective of the present study was to evaluate whether low-molecular-weight fucoidan (LMWF) could attenuate renal IRI in an animal model and in vitro cell models and study the mechanisms in which LMWF protected from IRI.

RESULTS

Male mice were subjected to right renal ischemia for <em>3</em>0 min and reperfusion for 24 h, or to a sham operation with left kidney removed. Kidneys undergone IR showed characteristic morphological changes, such as tubular dilatation, and brush border loss. However, LMWF significantly corrected the renal dysfunction and the abnormal levels of MPO, MDA and <em>SOD</em> induced by IR. LMWF also inhibited the activation of MAPK pathways, which consequently resulted in a significant decrease in the release of cytochrome c from mitochondria, ratios of Bax/Bcl-2 and cleaved caspase-<em>3</em>/caspase-<em>3</em>, and phosphorylation of p5<em>3</em>. LMWF alleviated hypoxia-reoxygenation or CoCl(2) induced cell viability loss and ΔΨm dissipation in HK2 renal tubular epithelial cells, which indicates LMWF may result in an inhibition of the apoptosis pathway through reducing activity of MAPK pathways in a dose-dependent manner.

CONCLUSIONS

Our in vivo and in vitro studies show that LMWF ameliorates acute renal IRI via inhibiting MAPK signaling pathways. The data provide evidence that LMWF may serve as a potential therapeutic agent for acute renal IRI.

Selenium (Se) is an essential micronutrient as well as a toxic trace element in animal and human nutrition. The effects of Se in the immune system and some diseases are well documented. The objective of the present study was to examine the role of Se in reducing the hypoxia induced apoptosis in neuroblastoma cell line. Hypoxia showed an enhanced cytotoxicity, increased free radical production and apoptosis (p<0.001) which was measured in terms of DNA break down by comet assay. Hypoxia has decreased reduced Glutathione (GSH) content, Glutathione Reductase (GR), Glutathione peroxidase (GPx) and Superoxide Dismutase (<em>SOD</em>) activities as compared to control cells. During hypoxic condition the expression of cytochrome C, pro and active caspase-<em>3</em> levels were enhanced significantly followed by nonsignificant upregulation of Bcl-2. But, the Se supplementation inhibited the cytotoxicity, free radical generation and stabilized the HIF-1alpha accumulation in cells under hypoxia. The GSH content, GR, GPx and <em>SOD</em> activities increased significantly in Se-treated hypoxic cells, as compared to control. Further there was an appreciable inhibition of apoptosis by upregulation of Bcl-2 proteins, in the presence of Se under hypoxia. Selenium supplementation to cells significantly inhibited the hypoxia induced DNA fragmentation and restored the antioxidant status back to control levels. This study suggests that Se supplementation prevented the cells from hypoxia induced apoptosis by triggering upregulation of Bcl-2 protein and reducing the oxidative stress.

BACKGROUND

We conducted a study to evaluate reactive oxygen species (ROS) and reactive nitrogen species (RNS) simultaneously together with the antioxidant status in patients with cervical carcinoma.

METHODS

We measured lipid peroxidation product, including malondialdehye (MDA), nitric oxide (NO) products, including nitrite (NO(2)(-)), nitrate (NO(<em>3</em>)(-)) and total nitrite (TNO(2)(-)) and antioxidant enzymes in 45 patients with cervical cancer and compared them against <em>3</em>0 healthy controls.

RESULTS

Plasma as well as erythrocyte MDA and plasma NO levels was higher (p<0.001) in cervical cancer as compared to healthy controls. Antioxidant enzymes, Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities, were decreased (p<0.001) whereas glutathione S-transferase (GST) activity was increased (p<0.001) in cervical cancer patients. Lipid peroxidation and NO products accumulation correlated significantly with a deranged antioxidant system.

CONCLUSIONS

We demonstrated a possible involvement of both oxidative and nitrosative stress, as evidenced by increased lipid peroxidation and NO levels with altered antioxidant defense system in the pathogenesis of cervical cancer.

Thioacetamide (TAA) administration (0.<em>3</em> g/l of tap water for a period of <em>3</em> months) to rats resulted in hepatic cirrhosis as assessed by biochemical and histopathological findings. This treatment caused an increase in the levels of malondialdehyde (MDA) and diene conjugates (DCs) and a decrease in the levels of glutathione (GSH), vitamin E, vitamin C and the activities of glutathione peroxidase (GSH-Px) in the liver of rats. Superoxide dismutase (<em>SOD</em>) activities were unchanged. Taurine (2% w/w, added to the chow diet) was administered together with TAA (0.<em>3</em> g/l of drinking water) for <em>3</em> months. Taurine was found to decrease TAA-induced hepatic lipid peroxidation and to increase TAA-depleted vitamin E levels and GSH-Px activities. Histopathological findings also suggested that taurine has an inhibitive effect on TAA-induced hepatic cirrhosis. These results indicate that taurine treatment has a protective effect against TAA-induced liver cirrhosis by decreasing oxidative stress.

Many individuals with cardiac diseases undergo periodic physical conditioning with or without medication. Therefore, this study investigated the interaction of physical training and chronic nitric oxide synthase (NOS) inhibitor (nitro-L-arginine methyl ester, L-NAME) treatment on blood pressure (BP), heart rate (HR) and cardiac oxidant/antioxidant systems in rats. Fisher <em>3</em>44 rats were divided into four groups and treated as follows: (1) sedentary control (SC), (2) exercise training (ET) for 8 weeks, (<em>3</em>) L-NAME (10 mg/kg, s.c. for 8 weeks) and (4) ET+L-NAME. BP and HR were monitored with tail-cuff method. The animals were sacrificed 24 h after last treatments and hearts were isolated and analyzed. Physical conditioning significantly increased respiratory exchange ratio (RER), cardiac nitric oxide (NO) levels, NOS activity and endothelial (eNOS) and inducible (iNOS) protein expression. Training significantly enhanced cardiac glutathione (GSH) levels, GSH/GSSG ratio and up-regulation of cardiac copper/zinc-superoxide dismutase (CuZn-<em>SOD</em>), manganese (Mn)-<em>SOD</em>, catalase (CAT), glutathione peroxidase (GSH-Px) activity and protein expression. Training also caused depletion of cardiac malondialdehyde (MDA) and protein carbonyls. Chronic L-NAME administration resulted in depletion of cardiac NO level, NOS activity, eNOS, nNOS and iNOS protein expression, GSH/GSSG ratio and down-regulation of cardiac CuZn-<em>SOD</em>, Mn-<em>SOD</em>, CAT, GSH-PX, glutathione-S-transferase (GST) activity and protein expression. Chronic L-NAME administration enhanced cardiac xanthine oxidase (XO) activity, MDA levels and protein carbonyls. These biochemical changes were accompanied by increases in BP and HR after L-NAME administration. Interaction of training and NOS inhibitor treatment resulted in normalization of BP, HR and up-regulation of cardiac antioxidant defense system. The data suggest that physical conditioning attenuated the oxidative injury caused by chronic NOS inhibition by up-regulating the cardiac antioxidant defense system and lowering the BP and HR in rats.

This study was designed to investigate the cisplatin-induced alteration in renal antioxidant system and the nephroprotection with ebselen. Male Wistar rats were injected with (1) vehicle control; (2) cisplatin; (<em>3</em>) ebselen; and (4) cisplatin plus ebselen. Rats were sacrificed three days post-treatment and plasma as well as kidney were isolated and analyzed. Plasma creatinine increased 598% following cisplatin administration alone which decreased by 158% with ebselen pretreatment. Cisplatin-treated rats showed a depletion of renal glutathione (GSH) levels (52% of control), while cisplatin plus ebselen injected rats had GSH values close to the controls. Antioxidant enzymes superoxide dismutase (<em>SOD</em>), catalase (CAT) and glutathione peroxidase (GSH-Px) activities decreased <em>3</em>8, 75 and 62% of control, respectively, and malondialdehyde (MDA) levels increased 174% of control following cisplatin administration, which were restored to control levels after ebselen treatment. The renal platinum level did not significantly change with ebselen pretreatment. This study suggests that the protection offered by ebselen against cisplatin-induced nephrotoxicity is partly related to the sparing of antioxidant system.

Female transgenic mice (C57BL/6 x CBA/J)F1 with a 1-fold increase in expression of glutathione peroxidase (GP) or with a 1-fold increase in the expression of GP and a <em>3</em>-4-fold increase in the expression of superoxide dismutase (<em>SOD</em>) had an enhanced carcinogenic response to initiation by 7,12-dimethylbenz[a]anthracene (DMBA) followed by promotion with 12-O-tetradecanoylphorbol-1<em>3</em>-acetate (TPA). GP- or GP+<em>SOD</em>-transgenic mice that were initiated by a single topical application of 200 nmol of DMBA followed by promotion with 8 nmol of TPA twice weekly for <em>3</em>0 weeks developed an average of 10.9 or 11.0 skin tumors per mouse and a 100% tumor incidence in comparison with the corresponding nontransgenic mice, which had <em>3</em>.9 tumors per mouse and an 8<em>3</em>% tumor incidence. After stopping TPA application, partial skin tumor regression occurred more rapidly in nontransgenic mice than in either type of transgenic mouse. At 10 weeks after termination of TPA treatment, 9-11% of the tumor-bearing transgenic mice and 26% of the tumor-bearing nontransgenic mice had complete regression of their tumors. Histopathological examination of 96 skin papillomas revealed that the area, location, degree of tumor dysplasia, bromodeoxyuridine labeling index, and p5<em>3</em> protein levels were closely intercorrelated. Further analysis indicated that papillomas with the same grade of dysplasia had a higher bromodeoxyuridine labeling index and a greater p5<em>3</em> protein level in GP- or GP+<em>SOD</em>-transgenic mice than those in nontransgenic mice. The data indicated that overexpression of skin antioxidant enzymes GP or GP+<em>SOD</em>, which are enzymes that are believed to protect cells from oxidative damage by scavenging reactive oxygen species, lead to the increased, rather than the decreased, tumorigenesis in a DMBA/TPA two-stage skin carcinogenesis model.

Hepatic Encephalopathy (HE) is one of the most common complications of acute liver diseases and is known to have profound influence on the brain. Most of the studies, available from the literature are pertaining to whole brain homogenates or mitochondria. Since brain is highly heterogeneous with functions localized in specific areas, the present study was aimed to assess the oxidative stress in different regions of brain-cerebral cortex, cerebellum and pons medulla during acute HE. Acute liver failure was induced in <em>3</em>-month old adult male Wistar rats by intraperitoneal injection of thioacetamide (<em>3</em>00 mg/kg body weight for two days), a well known hepatotoxin. Oxidative stress conditions were assessed by free radical production, lipid peroxidation, nitric oxide levels, GSH/GSSG ratio and antioxidant enzyme machinery in three distinct structures of rat braincerebral cortex, cerebellum and pons medulla. Results of the present study indicate a significant increase in malondialdehyde (MDA) levels, reactive oxygen species (ROS), total nitric oxide levels [(NO) estimated by measuring (nitrites + nitrates)] and a decrease in GSH/GSSG ratio in all the regions of brain. There was also a marked decrease in the activity of the antioxidant enzymes-glutathione peroxidase, glutathione reductase and catalase while the super oxide dismutase activity (<em>SOD</em>) increased. However, the present study also revealed that pons medulla and cerebral cortex were more susceptible to oxidative stress than cerebellum. The increased vulnerability to oxidative stress in pons medulla could be due to the increased NO levels and increased activity of <em>SOD</em> and decreased glutathione peroxidase and glutathione reductase activities. In summary, the present study revealed that oxidative stress prevails in different cerebral regions analyzed during thioacetamide-induced acute liver failure with more pronounced effects on pons medulla and cerebral cortex.

Colon cancer is the third most malignant neoplasm in the world and it remains today an important cause of death, especially in western countries. In this study, we have evaluated the chemopreventive efficacy of morin on tissue lipid peroxidation and antioxidant status, which are used as biomarkers in 1,2-dimethylhydrazine-induced colon carcinogenesis in a rat model. Male Wistar rats were divided into four groups and received high fat diet. Group 1 served as control, groups 2 and 4 were given a daily treatment of morin (50 mg/kg body weight) orally, everyday for a total period of <em>3</em>0 weeks. Groups <em>3</em> and 4 were given weekly subcutaneous injections of DMH at a dose of 20 mg/kg body weight in the groin for 15 weeks. Animals were sacrificed at the end of <em>3</em>0 weeks. The liver, intestine, colon and caecum from different groups were subjected to histopathological studies, determination of lipid peroxidation and antioxidant status. Our results showed decreased levels of liver enzymic and non-enzymic antioxidants and increased levels of lipid peroxidation (LPO) products such as tissue thiobarbituricacid substances (TBARS), lipid hydroperoxides (LOOH) and conjugated dienes (CD) in DMH treated rats, which were significantly (P < 0.05) reversed on morin supplementation. Moreover, intestinal, colonic and caecal TBARS, LOOH, CD and also the antioxidants superoxide dismutase (<em>SOD</em>), catalase (CAT), glutathione S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR) and reduced glutathione (GSH) were significantly diminished in DMH treated rats, which were significantly (P < 0.05) elevated on simultaneous morin supplementation. Moreover, enhanced activity of intestinal, colonic and caecal ascorbic acid and alpha-tocopherol levels were also observed in DMH alone treated rats, which were significantly (P < 0.05) reduced on morin supplementation. These results indicate that morin could exert a significant chemopreventive effect on colon carcinogenesis induced by DMH.

This study was designed to determine the effect of all-trans retinoic acid (RA) on the development of cardiac remodeling in a pressure overload rat model. Male Sprague-Dawley rats were subjected to sham operation and the aortic constriction procedure. A subgroup of sham control and aortic constricted rats were treated with RA for 5 mo after surgery. Pressure-overloaded rats showed significantly increased interstitial and perivascular fibrosis, heart weight-to-body weight ratio, and gene expression of atrial natriuretic peptide and brain natriuretic peptide. Echocardiographic analysis showed that pressure overload induced systolic and diastolic dysfunction, as evidenced by decreased fractional shortening, ejection fraction, stroke volume, and increased E-to-E(a) ratio and isovolumic relaxation time. RA treatment prevented the above changes in cardiac structure and function and hypertrophic gene expression in pressure-overloaded rats. RA restored the ratio of Bcl-2 to Bax, inhibited cleavage of caspase-<em>3</em> and -9, and prevented the decreases in the levels of <em>SOD</em>-1 and <em>SOD</em>-2. Pressure overload-induced phosphorylation of ERK1/2, JNK, and p<em>3</em>8 was inhibited by RA, via upregulation of mitogen-activated protein kinase phosphatase (MKP)-1 and MKP-2. The pressure overload-induced production of angiotensin II was inhibited by RA via upregulation of expression of angiotensin-converting enzyme (ACE)2 and through inhibition of the expression of cardiac and renal renin, angiotensinogen, ACE, and angiotensin type 1 receptor. Similar results were observed in cultured neonatal cardiomyocytes in response to static stretch. These results demonstrate that RA has a significant inhibitory effect on pressure overload-induced cardiac remodeling, through inhibition of the expression of renin-angiotensin system components.

Cyclic nitroxides (RNO(*)) mimic the activity of superoxide dismutase (<em>SOD</em>) and demonstrate antioxidant properties in numerous in vitro and in vivo models. Their broad antioxidant activity may involve the participation of their reduced and oxidized forms, that is, hydroxylamine (RNO-H) and oxoammonium cation (RNO(+)). To examine this possibility we studied the reactions of RNO(*) and RNO(+) with HO(2)(*)/O(2)(*)(-) and with several reductants by pulse radiolysis and rapid-mixing stopped-flow techniques. The oxoammonium cations were generated by electrochemical and radiolytic oxidation of 2,2,6,6-tetramethylpiperidinoxyl (TPO) and <em>3</em>-carbamoyl-2,2,5,5-tetramethylpyrrolidinoxyl (<em>3</em>-CP). The rate constant for the reaction of RNO(*) with HO(2)(*) to form RNO(+) was determined to be (1.2 +/- 0.1) x 10(8) for TPO and (1.<em>3</em> +/- 0.1) x 10(6) M(-)(1) s(-)(1) for <em>3</em>-CP. The kinetics results demonstrate that the reaction of RNO(*) with HO(2)(*) proceeds via an inner-sphere electron-transfer mechanism. The rate constant for the reaction of RNO(*) with O(2)(*)(-) is lower than 1 x 10(<em>3</em>) M(-)(1) s(-)(1). The rate constant for the reaction of RNO(+) with O(2)(*)(-) was determined to be (<em>3</em>.4 +/- 0.2) x 10(9) for TPO(+) and (5.0 +/- 0.2) x 10(9) M(-)(1) s(-)(1) for <em>3</em>-CP(+). Hence, both nitroxides catalyze the dismutation of superoxide through the RNO(*)/RNO(+) redox couple, and the dependence of the catalytic rate constant, k(cat), on pH displayed a bell-shaped curve having a maximum around pH 4. The oxoammonium cation oxidized ferrocyanide and HO(2)(-) by a one-electron transfer, whereas the oxidation of methanol, formate, and NADH proceeded through a two-electron-transfer reaction. The redox potential of RNO(*)/RNO(+) couple was calculated to be 0.75 and 0.89 V for <em>3</em>-CP and TPO, respectively. The elucidated mechanism provides a clearer insight into the biological antioxidant properties of cyclic nitroxides that should permit design of even more effective antioxidants.

Conscious rabbits underwent six 4-min occlusion and 4-min reperfusion cycles for <em>3</em> consecutive days (day 1, 2, and <em>3</em>); on day 1, rabbits received intravenous vehicle [preconditioning (PC)] (group I, n = 6), superoxide dismutase (<em>SOD</em>; group II, n = 5), catalase (group III, n = 6), or the hydroxyl radical (. OH) and peroxynitrite (ONOO-)) scavenger N-2-mercaptopropionyl glycine (MPG [group IV], n = 6). In the PC group, the recovery of systolic wall thickening (WTh) after the sixth reperfusion was markedly improved on days 2 and <em>3</em> compared with day 1 and the total deficit of WTh was correspondingly reduced, indicating a late PC effect against myocardial stunning. Neither <em>SOD</em> nor catalase had any significant effect on the severity of stunning on day 1 or on the development of late PC on days 2 and <em>3</em>, despite high plasma levels. In contrast, MPG markedly attenuated the severity of stunning on day 1 and prevented the development of late PC on day 2. Two additional groups of rabbits received an intracoronary infusion of vehicle (group V, n = 4) or the reactive oxygen species (ROS) generating solution [cumene hydroperoxide (CuOOH, group VI, n = 7)] on day 0, and were then subjected to the six occlusion/reperfusion cycles on days 1, 2, and <em>3</em>. In group VI, infusion of CuOOH elicited a late PC effect 24 h later (on day 1). Taken together, these results demonstrate that oxidant species play an essential role in triggering the development of late PC against stunning in conscious rabbits. The fact that late PC was blocked by MPG and mimicked by CuOOH implicate ONOO- and/or .OH as the oxygen species responsible for the initiation of this phenomenon. In addition, the finding that exogenous ROS (CuOOH) reproduced the phenotype of late PC indicates that ROS are not only necessary but also sufficient to trigger this defensive adaptation of the heart to stress.

Isolated rat hearts (n = 15 per group) were subjected to regional ischemia (10 min) and reperfusion. Superoxide dismutase (<em>SOD</em>; 8 X 10(<em>3</em>), 2 X 10(4), 4 X 10(4), 6 X 10(4), 8 X 10(4), 1.2 X 10(5), or 1.6 X 10(5) IU/l) given early (i.e., throughout the experiment) reduced the incidence of reperfusion-induced ventricular fibrillation (VF), the dose-response characteristics describing an asymmetric U-shaped curve. The optimal dose of <em>SOD</em> (8 X 10(4) IU/l) reduced VF incidence from its control value of 87 to 27% (P less than 0.05). Given late (i.e., 2 min before reperfusion), this dose of <em>SOD</em> exerted a reduced but nonetheless significant antifibrillatory effect. Early administration of catalase (1 X 10(<em>3</em>), 1 X 10(4), 2.5 X 10(4), 5 X 10(4), 1 X 10(5), 1.5 X 10(5), or 1 X 10(6) IU/l) reduced VF incidence in a linear dose-dependent manner, from its control value of 87 to 7% with 1 X 10(6) IU/l (P less than 0.05). Late administration of this dose reduced VF incidence from its control value of 87 to 27% (P less than 0.05). Allopurinol (0.07, 0.15, 0.<em>3</em>7, 0.7<em>3</em>, 1.10, or 1.47 mM added to the perfusate throughout the experiment) significantly reduced VF incidence over a wide range of doses, but low and high doses were ineffective. Pretreatment with allopurinol (0, 0.01, 0.02, 0.05, 0.10, 0.20, or 0.50 g.kg-1.day-1 per os 48, 24, and 1 h before study) reduced VF incidence from its control value of 9<em>3</em> to less than 50% at several doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Eight of <em>3</em>8 patients (21%) with familial and 5 of 175 patients (<em>3</em>%) with sporadic amyotrophic lateral sclerosis (ALS) had missense mutations in the <em>SOD</em>-1 gene. Two novel mutations were identified. One in exon 4 substituting leucine with phenylalanine (L84F) in a familial patient and the second in exon <em>3</em> at substituting glycine with serine (G72S) in an "apparently" sporadic patient. Over 60 point mutations have now been described in all five exons of <em>SOD</em>-1, involving 4<em>3</em> of the 15<em>3</em> residues. Hypotheses about the toxic role of mutant <em>SOD</em>-1 in the pathogenesis of ALS must account for this molecular diversity.

In this study, heart and diaphragm mitochondria produced 0.69 and 0.77 nmol nitric oxide (NO)/min mg protein, rates that account for 67 and 24% of maximal cellular NO production, respectively. Endotoxemia and septic shock occur with an exacerbated inflammatory response that damages tissue mitochondria. Skeletal muscle seems to be one of the main target organs in septic shock, showing an increased NO production and early oxidative stress. The kinetic properties of mitochondrial nitric oxide synthase (mtNOS) of heart and diaphragm were determined. For diaphragm, the KM values for O2 and L-Arg were 4.6 and <em>3</em>7 microM and for heart were <em>3</em>.<em>3</em> and <em>3</em>6 microM. The optimal pH for mtNOS activity was 6.5 for diaphragm and 7.0 for heart. A marked increase in mtNOS activity was observed in endotoxemic rats, 90% in diaphragm and <em>3</em>0% in heart. Diaphragm and heart mitochondrial O2*- and H2O2 production were 2- to <em>3</em>-fold increased during endotoxemia and Mn-<em>SOD</em> activity showed a 2-fold increase in treated animals, whereas catalase activity was unchanged. One of the current hypotheses for the molecular mechanisms underlying the complex condition of septic shock is that the enhanced NO production by mtNOS leads to excessive peroxynitrite production and protein nitration in the mitochondrial matrix, causing mitochondrial dysfunction and contractile failure.

Cationic Mn(III) N-alkylpyridylporphyrins (MnPs) are potent <em>SOD</em> mimics and peroxynitrite scavengers and diminish oxidative stress in a variety of animal models of central nervous system (CNS) injuries, cancer, radiation, diabetes, etc. Recently, properties other than antioxidant potency, such as lipophilicity, size, shape, and bulkiness, which influence the bioavailability and the toxicity of MnPs, have been addressed as they affect their in vivo efficacy and therapeutic utility. Porphyrin bearing longer alkyl substituents at pyridyl ring, MnTnHex-2-PyP(5+), is more lipophilic, thus more efficacious in vivo, particularly in CNS injuries, than the shorter alkyl-chained analog, MnTE-2-PyP(5+). Its enhanced lipophilicity allows it to accumulate in mitochondria (relative to cytosol) and to cross the blood-brain barrier to a much higher extent than MnTE-2-PyP(5+). Mn(III) N-alkylpyridylporphyrins of longer alkyl chains, however, bear micellar character, and when used at higher levels, become toxic. Recently we showed that meta isomers are ∼10-fold more lipophilic than ortho species, which enhances their cellular accumulation, and thus reportedly compensates for their somewhat inferior <em>SOD</em>-like activity. Herein, we modified the alkyl chains of the lipophilic meta compound, MnTnHex-<em>3</em>-PyP(5+) via introduction of a methoxy group, to diminish its toxicity (and/or enhance its efficacy), while maintaining high <em>SOD</em>-like activity and lipophilicity. We compared the lipophilic Mn(III) meso-tetrakis(N-(6'-methoxyhexyl)pyridinium-<em>3</em>-yl)porphyrin, MnTMOHex-<em>3</em>-PyP(5+), to a hydrophilic Mn(III) meso-tetrakis(N-(2'-methoxyethyl)pyridinium-<em>3</em>-yl)porphyrin, MnTMOE-<em>3</em>-PyP(5+). The compounds were characterized by uv-vis spectroscopy, mass spectrometry, elemental analysis, electrochemistry, and ability to dismute O(2)˙(-). Also, the lipophilicity was characterized by thin-layer chromatographic retention factor, R(f). The <em>SOD</em>-like activities and metal-centered reduction potentials for the Mn(III)P/Mn(II)P redox couple were similar-to-identical to those of N-alkylpyridyl analogs: log k(cat) = 6.78, and E(1/2) = +68 mV vs. NHE (MnTMOHex-<em>3</em>-PyP(5+)), and log k(cat) = 6.72, and E(1/2) = +64 mV vs. NHE (MnTMOE-<em>3</em>-PyP(5+)). The compounds were tested in a superoxide-specific in vivo model: aerobic growth of <em>SOD</em>-deficient E. coli, JI1<em>3</em>2. Both MnTMOHex-<em>3</em>-PyP(5+) and MnTMOE-<em>3</em>-PyP(5+) were more efficacious than their alkyl analogs. MnTMOE-<em>3</em>-PyP(5+) is further significantly more efficacious than the most explored compound in vivo, MnTE-2-PyP(5+). Such a beneficial effect of MnTMOE-<em>3</em>-PyP(5+) on diminished toxicity, improved efficacy and transport across the cell wall may originate from the favorable interplay of the size, length of pyridyl substituents, rotational flexibility (the ortho isomer, MnTE-2-PyP(5+), is more rigid, while MnTMOE-<em>3</em>-PyP(5+) is a more flexible meta isomer), bulkiness and presence of oxygen.