34 resultados para Superoxide-dismutase

em Deakin Research Online - Australia


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This study investigated the effects of riluzole (Ril), creatine (Cr) and a combination of these treatments on the onset and progression of clinical signs and neuropathology in an animal model of familial amyotrophic lateral sclerosis, the G93A transgenic mouse (n=13–17 per group). The onset of clinical signs was delayed (P<0.05) by about 12 days in all treatment groups compared with control; however, no differences occurred between treatments. All animals were killed at 199 days of age. At the end of the experimental period the severity of clinical signs was less (P<0.05) with all treatments compared with control. Again no differences between treatments were observed. The treatments had no effect on the number of neurons in ventral horns of the lumbar region of the spinal cord. Transgenic mice ingesting Cr displayed elevated (P<0.05) total Cr levels in cerebral hemispheres (5%) and spinal cord (8%), but not skeletal muscles. These data demonstrate that treatment with Ril and Cr were both effective in delaying disease onset and clinical disability. To the age of killing, no additional benefit was conferred by co-administration of Ril and Cr.

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Using two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (2-D SDS-PAGE) of 32P-labeled cytosolic and membrane extracts, we identified a 21.5 kDa phosphoprotein with an isoelectric point of 6.0 in NFS-60 cells that was phosphorylated maximally at 15 min by treatment with granulocyte-colony stimulating factor (G-CSF) but not with interlevkin-3 (IL-3) or colony-stimulating factor-1 (macrophage-colony stimulating factor (CSF-1 (M-CSF)). The phosphorylation of this protein, designated 21.5/6.0, was unaffected by a series of antiproliferative agents [32]. These findings suggested that the 21.5/6.0 phosphoprotein may be involved in specific G-CSF-mediated biological responses such as activation and/or differentiation. We sought to characterize this 21.5/6.0 by a novel combination of 2-D SDS-PAGE and hydroxyapatite (HTP)-chromatography. Amino acid sequence determination of 21.5/6.0 revealed it to share a high level of homology with copper/zinc superoxide dismutase (Cu/Zn-SOD), indicating that a Cu/Zn-SOD is phosphorylated following treatment with G-CSF. This is the first report of the phosphorylation and possible involvement of Cu/Zn-SOD protein in granulocyte activation/differentiation events. In addition, Cu/Zn-SOD levels and activity were diminished by G-CSF but not IL-3 treatment. This new protocol combining 2-D SDS-PAGE and HTP-chromatography allows the characterization of low abundance phosphoproteins involved in the cellular responses to G-CSF and presumably to other cytokines/growth factors.

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Copper is an essential element for the activity of a number of physiologically important enzymes. Enzyme-related malfunctions may contribute to severe neurological symptoms and neurological diseases: copper is a component of cytochrome c oxidase, which catalyzes the reduction of oxygen to water, the essential step in cellular respiration. Copper is a cofactor of Cu/Zn-superoxide-dismutase which plays a key role in the cellular response to oxidative stress by scavenging reactive oxygen species. Furthermore, copper is a constituent of dopamine-β-hydroxylase, a critical enzyme in the catecholamine biosynthetic pathway. A detailed exploration of the biological importance and functional properties of proteins associated with neurological symptoms will have an important impact on understanding disease mechanisms and may accelerate development and testing of new therapeutic approaches. Copper binding proteins play important roles in the establishment and maintenance of metal-ion homeostasis, in deficiency disorders with neurological symptoms (Menkes disease, Wilson disease) and in neurodegenerative diseases (Alzheimer’s disease). The Menkes and Wilson proteins have been characterized as copper transporters and the amyloid precursor protein (APP) of Alzheimer’s disease has been proposed to work as a Cu(II) and/or Zn(II) transporter. Experimental, clinical and epidemiological observations in neurodegenerative disorders like Alzheimer’s disease and in the genetically inherited copper-dependent disorders Menkes and Wilson disease are summarized. This could provide a rationale for a link between severely dysregulated metal-ion homeostasis and the selective neuronal pathology.

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By the method of artificial soil pollution, an exposure experiment with different concentrations of pyrene (0, 60, 120, 240, 480, 960 microg x kg(-1)) was conducted to determine the cytochrome P450 and MDA contents and the glutathione-S-transferase (GST), superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities in earthworm gut after exposure for 1, 3, 7 and 14 days. The results indicated that within the range of test pyrene concentrations, all the biochemical indices tested differed in their sensitivity to pyrene toxicity, among which, P450 content and GST and SOD activities were most sensitive, followed by POD and CAT activities, while MDA content did not show any obvious response. Exposure duration had stronger effects than exposure dosage. In diagnosing the ecotoxicity of soil pollutant, it could be necessary to use a combined multi-time and multi-index diagnostic method to enhance the sensitivity and effectiveness of the indices adopted.

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Three pairs of parental (ρ+) and established mitochondrial DNA depleted (ρ0) cells, derived from bone, lung and muscle were used to verify the influence of the nuclear background and the lack of efficient mitochondrial respiratory chain on antioxidant defences and homeostasis of intracellular reactive oxygen species (ROS). Mitochondrial DNA depletion significantly lowered glutathione reductase activity, glutathione (GSH) content, and consistently altered the GSH2 : oxidized glutathione ratio in all of the ρ0 cell lines, albeit to differing extents, indicating the most oxidized redox state in bone ρ0 cells. Activity, as well as gene expression and protein content, of superoxide dismutase showed a decrease in bone and muscle ρ0 cell lines but not in lung ρ0 cells. GSH peroxidase activity was four times higher in all three ρ0 cell lines in comparison to the parental ρ+, suggesting that this may be a necessary adaptation for survival without a functional respiratory chain. Taken together, these data suggest that the lack of respiratory chain prompts the cells to reduce their need for antioxidant defences in a tissue-specific manner, exposing them to a major risk of oxidative injury. In fact bone-derived ρ0 cells displayed the highest steady-state level of intracellular ROS (measured directly by 2',7'-dichlorofluorescin, or indirectly by aconitase activity) compared to all the other ρ+ and ρ0 cells, both in the presence or absence of glucose. Analysis of mitochondrial and cytosolic/iron regulatory protein-1 aconitase indicated that most ROS of bone ρ0 cells originate from sources other than mitochondria.

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In the current study, we compared purified Salvia miltiorrhiza extract (PSME) with Angiotensin-converting enzyme inhibitor, Ramipril, in in vitro experiments and also in vivo using animal model of myocardial infarction. PSME was found to have a significantly higher trolox equivalent antioxidant capacity which indicated a great capacity for scavenging free radicals. PSME could also prevent pyrogallo red bleaching and DNA damage.

After 2 weeks treatment with PSME or Ramipril, survival rates of rats with experimental myocardial infarction were marginally increased (68.2% and 71.4%) compared with saline (61.5%). The ratios of infarct size to left ventricular size in both PSME-and Ramipril-treated rats were significantly less than that in the saline-treated group. Activity of cardiac antioxidant enzyme superoxide dismutase (SOD) was significant higher while level of Thiobarbituric acid-reactive substances (TBARs) was lower in the PSME treated group. Purified and standardized Chinese herb could provide an alternative regimen for the prevention of ischemic heart disease.

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Maize (Zea mays L.) for the tested plants, meadow brown soil as the soil tested in order to microsomal cytochrome P450 content, superoxide dismutase (SOD), catalase (CAT) and peroxidase enzyme (POD) activity of indicators, the soil phenanthrene and pyrene in response to exposure to eco-toxicological studies. The results show that phenanthrene, pyrene exposure can cause detoxification of plant metabolism and antioxidant defense system of the stress response, caused varying degrees of detoxification of plant metabolism and changes in antioxidant capacity. P450 enzyme activity and low concentrations of phenanthrene and pyrene in a single - relevant exposure concentration (r = 0.834, P <0.01), and phenanthrene and pyrene exposure concentration was negatively correlated compound, saying that Ming Fei, pyrene compound exposed to lead detoxification metabolism of a reduced ability to detoxify the metabolism of plants have synergistic toxic effects; SOD activity and phenanthrene and pyrene in a single exposure concentration was negatively correlated, CAT activity and phenanthrene and pyrene in a single - exposure concentration was positively correlated, POD activity and water solubility of the Philippines positively correlated with the total concentration of pyrene in a negative correlation. SOD, CAT and POD activity and phenanthrene and pyrene were positively related to the concentration of compound exposure, saying that Ming Fei, pyrene complex degree of exposure to lead to reduced oxidative damage, oxidative damage of plants with antagonistic effects .

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Wheat (Triticum aestivum) was chosen to analyze the effect of two polycyclic aromatic hydrocarbons (PAHs), Phenanthrene (PHE) and Pyrene (PY) in brown meadow soil at low concentrations. The effects of PHE and PY were determined by analyzing the changes in activity of Cytochrome P450 (CytP450) and antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT). Results indicated that both PHE and PY caused changes in activity of CytP450 and the antioxidant enzymes, SOD, POD and CAT. CytP450 activity was significantly stimulated with 1 mg kg-1 of both PHE and PY individually and significantly inhibited with 4 mg kg-1, which showed that pollution stress of PHE or PY can damage the metabolism and detoxification systems of plants. Moreover, as PHE and PY combined at 1 mg kg-1, CytP450 was increased significantly more than when PHE and PY were applied individually, which illustrates obvious synergistic effects. No significant variation were found in activity of SOD in response to individual exposure of PHE or PY in soil, but SOD activity decreased slightly in response to a combined PHE and PY exposure. Great decrease variation was found in CAT and POD activity in response to individual exposure of PHE or PY in soil. No enhanced toxic effects were shown by POD in response to a PHE and PY combined exposure, however CAT showed increased inhibition. From the aspects of metabolism and detoxification as well as antioxidant enzyme activity, our study has provided experimental basis for the pollution diagnosis of PAHs in soils at low concentrations.

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Chemoprevention by dietary constituents in the form of functional food has emerged as a novel approach to control inflammatory diseases and cancers. Recently we reported for the first time that iron content is a critical determinant in the anti-tumour activity of bovine milk lactoferrin (bLf). We therefore wanted to evaluate the chemo-preventative efficacy of Apo-bLF and 100% iron-saturated bLF (Fe-bLF) on hydrogen peroxide (H2O 2)-induced colon carcinogenesis, and their influence on antioxidant enzyme activities within colon carcinogenesis. This was undertaken through observing how oxidative stress induced by H2O2 alters antioxidant enzyme activity within HT29 colon cancer cells, and then observing changes in this activity by treatments with the different antioxidants ascorbic acid (AA), Apo-bLF and Fe-bLF. All antioxidant enzymes (catalase, glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-s-transferase (GsT) and superoxide dismutase (SOD)) appeared to be increased within HT29 cells, even prior to H2O2 exposure, and all enzymes showed significant decreased activity when cells were treated with the antioxidants AA, Apo-bLF or Fe-bLF, with or without H2O2 exposure. The results indicate that all three antioxidants have the ability to scavenge ROS, lower antioxidant enzyme activities within already excited states, and possibly allow colon cancer cells to be overcome by oxidative stress that would normally be prevented, perhaps leading to damage and potential apoptosis of the cancer cells. In conclusion, the anti-oxidative effects of Apo-bLF and Fe-bLf studied for the first time, show dynamic changes that may allow for necessary protection from imbalanced oxidative conditions, and potential at reducing the ability of cancer cells to protect themselves from oxidative stress states.

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Background: This study aimed to determine if 25 days of canola oil intake in the absence of excess dietary salt or together with salt loading affects antioxidant and oxidative stress markers in the circulation. A further aim was to determine the mRNA expression of NADPH oxidase subunits and superoxide dismutase (SOD) isoforms in the aorta of stroke-prone spontaneously hypertensive (SHRSP) rats.

Methods: Male SHRSP rats, were fed a defatted control diet containing 10% wt/wt soybean oil or a defatted treatment diet containing 10% wt/wt canola oil, and given tap water or water containing 1% NaCl. Blood was collected at the end of study for analysis of red blood cell (RBC) antioxidant enzymes, RBC and plasma malondialdehyde (MDA), plasma 8-isoprostane and plasma lipids. The aorta was removed and the mRNA expression of NOX2, p22phox, CuZn-SOD, Mn-SOD and EC-SOD were determined.

Results: In the absence of salt, canola oil reduced RBC SOD and glutathione peroxidase, and increased total cholesterol and LDL cholesterol compared with soybean oil. RBC glutathione peroxidase activity was significantly lower in both the salt loaded groups compared to the soybean oil only group. In addition, RBC MDA and plasma HDL cholesterol were significantly higher in both the salt loaded groups compared to the no salt groups. Plasma MDA concentration was higher and LDL cholesterol concentration lower in the canola oil group loaded with salt compared to the canola oil group without salt. The mRNA expression of NADPH oxidase subunits and SOD isoforms were significantly reduced in the canola oil group with salt compared to canola oil group without salt.

Conclusion: In conclusion, these results indicate that canola oil reduces antioxidant status and increases plasma lipids, which are risk factors for cardiovascular disease. However, canola oil in combination with salt intake increased MDA, a marker of lipid peroxidation and decreased NAPDH oxidase subunits and aortic SOD gene expression.

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Background: Canola oil shortens the life span of stroke-prone spontaneously hypertensive (SHRSP) rats compared with rats fed soybean oil when given as the sole dietary lipid source. One possible mechanism leading to the damage and deterioration of organs due to canola oil ingestion is oxidative stress. This study investigated the effect of canola oil intake on oxidative stress in this animal model.
Method: Male SHRSP rats, were fed a defatted control diet containing 10% wt/wt soybean oil or a defatted treatment diet containing 10% wt/wt canola oil, and given water containing 1% NaCl. Blood pressure was measured weekly. Blood was collected prior to beginning the diets and at the end of completion of the study for analysis of red blood cell (RBC) antioxidant enzymes, RBC and plasma malondialdehyde (MDA), plasma 8- isoprostane and plasma lipids.
Results: Canola oil ingestion significantly decreased the life span of SHRSP rats compared with soybean oil, 85.8 ± 1.1 and 98.3 ± 3.4 days, respectively. Systolic blood pressure increased over time with a significant difference between the diets at the 6th week of feeding. Canola oil ingestion significantly reduced RBC superoxide dismutase, glutathione peroxidase and catalase activities, total cholesterol and low-density lipoprotein cholesterol compared with soybean oil. There were no significant differences in RBC MDA concentration between canola oil fed and soybean oil fed rats. In contrast, plasma MDA and 8-isoprostane concentration was significantly lower in the canola oil group compared to the soybean oil group.
Conclusion: In conclusion, canola oil ingestion shortens the life span of SHRSP rats and leads to changes in oxidative status, despite an improvement in the plasma lipids.