Brain and tissue distribution of polyethylene glycol-conjugated superoxide dismutase in rats.

BACKGROUND AND PURPOSE: The purpose of this study was to determine the distribution of polyethylene glycol-conjugated superoxide dismutase in the brain, cerebrospinal fluid, and various organs. METHODS: Distribution of iodine-125-labeled polyethylene glycol-conjugated superoxide dismutase was determined in three groups of male Sprague-Dawley rats: a normotensive sham control group (n = 9) and groups given 125I-labeled polyethylene glycol-conjugated superoxide dismutase either 30 minutes before (n = 10) or 30 minutes after (n = 7) norepinephrine-induced hypertensive injury. RESULTS: In the first 30 minutes after intravenous administration, polyethylene glycol-conjugated superoxide dismutase plasma activity declined to 70% of the initial value and then decreased negligibly between 30 and 90 minutes. Levels of 125I-labeled polyethylene glycol-conjugated superoxide dismutase in normotensive animals were low in the brain and cerebrospinal fluid and highest in kidney. Brain levels of polyethylene glycol-conjugated superoxide dismutase were elevated only in those rats that received it before hypertensive injury; however, cerebrospinal fluid levels were elevated in animals receiving the drug either before or after hypertensive injury. CONCLUSION: Our results suggest that the blood-brain barrier becomes more permeable to polyethylene glycol-conjugated superoxide dismutase only during the hypertensive period but that the blood-cerebrospinal fluid barrier sustains more permanent injury. We suggest that the therapeutic effectiveness of polyethylene glycol-conjugated superoxide dismutase in hypertensive brain injury is due to its action in the vascular wall or to its extracellular activity in the cerebrospinal fluid.     

Polyethylene glycol superoxide dismutase and catalase attenuate increased blood-brain barrier permeability after ischemia in piglets.

BACKGROUND AND PURPOSE: Transport of urea across the blood-brain barrier is increased during postischemic cerebral reperfusion in the piglet. Ischemia/reperfusion also has been observed to increase apparent superoxide anion generation on the surface of the brain. The present study was designed to address the hypothesis that the increased transfer of urea into the brain after ischemia/reperfusion could be due to superoxide anion-induced alterations in blood-brain barrier permeability. METHODS: Blood-to-brain transfer of carbon-14-labeled urea was measured in four groups (n = 7 each) of newborn pigs: 1) control (no ischemia, no pretreatment), 2) pretreatment with polyethylene glycol superoxide dismutase (1,000 IU/kg) and polyethylene glycol catalase (10,000 IU/kg i.v.) but no ischemia, 3) no pretreatment and 20 minutes of ischemia followed by 2 hours of reperfusion, and 4) pretreatment with polyethylene glycol superoxide dismutase and polyethylene glycol catalase in addition to ischemia/reperfusion. The following brain regions were investigated: cerebrum, caudate, midbrain, pons, medulla, and cerebellum. RESULTS: Polyethylene glycol superoxide dismutase inhibited generation of superoxide anion by the brain during reperfusion after ischemia. Regional transfer of [14C]urea from blood to brain increased at 2 hours' reperfusion. This ischemia-induced increase in blood-to-brain transfer of [14C]urea was attenuated by pretreatment with polyethylene glycol superoxide dismutase and polyethylene glycol catalase: e.g., cerebrum Kin was 28 +/- 2 in the control group, 26 +/- 3 in the pretreated/no ischemia group, 67 +/- 5 in the untreated/ischemia group, and 40 +/- 2 ml.g-1.s-1.10(6) in the pretreated/ischemia group. After ischemia/reperfusion, cerebral blood flow was unchanged by pretreatment with polyethylene glycol superoxide dismutase and polyethylene glycol catalase. CONCLUSIONS: These data suggest that production of a partially reduced species of oxygen contributes to the increased urea transfer across the blood-brain barrier after ischemia in the newborn pig.     

Increased activity of superoxide dismutase in kindled brain and suppression of kindled seizure following intra-amygdaloid injection of superoxide dismutase in rats

The possible role played by superoxide dismutase (SOD), a major defense system for counteracting the toxic effects of oxygen free radicals, in amygdaloid (AM) kindling was examined in rats. A significant increase of total SOD activity in the whole brain was observed 30 days after completion of AM kindling. Intra-AM injection of 3 ng of one of the 2 SOD enzymes present in mammalian brain, i.e. cytosolic SOD containing copper and zinc (CuZn-SOD) caused suppression of kindled seizure. These results suggest that SOD participates in the persistence of AM kindled seizure susceptibility and the initiation of kindled AM seizure.     

Regional brain superoxide dismutase activity is altered differently by heat in warm and cool mice

The significant regional variation in brain superoxide dismutase (SOD) activity was similar in mice from both warm and cool cohorts. Mice in the cool cohort generally had higher SOD activity, which varied significantly with body temperature in striatum and in preoptic area of the hypothalamus. Changes in SOD activity following heating were revealed only when warm and cool cohorts were analysed separately. SOD activity decreased significantly in striatum, hypothalamus, and hippocampus of the cool cohort only. The decline was to levels consistent with those of the warm cohort. Body temperature of cool mice increased more than that of warm mice following each increment of heating so resultant body temperatures became similar. The role of SOD as part of a differential defense against heat stress in warm and cool mice is presented.     

Astrocytes induce manganese superoxide dismutase in brain capillary endothelial cells

Astrocytes induce blood-brain barrier (BBB) properties in brain endothelial cells (EC)*O(2)*, generated in blood and EC, opens the BBB. Hence, high activity of superoxide dismutase (SOD) is a prerequisite for normal BBB function. Therefore, the influence of rat astrocytes on the expression of manganese (Mn)SOD in rat EC was investigated in two coculture models of the BBB, allowing either exchange of soluble factors or additionally cellular contacts. Activity, protein content and mRNA expression of endothelial MnSOD were significantly increased in both coculture models in comparison to monoculture by soluble astrocytic factors, such as cytokines. High activity of endothelial MnSOD may be considered as a further essential property of the BBB, which is induced and maintained by astrocytes.     

Immunohistochemical localization of superoxide dismutase in congenital hydrocephalic rat brain

The effects of active oxygen species in the development of congenital hydrocephalus have been investigated. Superoxide dismutase (SOD) is one of the scavengers of active oxygen species and there have been many recent reports on the relationship between neurological disorders by active oxygen species following reperfusion for ischemic brain and SOD. In this study, the localization of Cu-SOD and Zn-SOD in WIC-Hyd congenitally hydrocephalic rat brains was identified by the enzyme unlabeled antibody method. We examined the localization of SOD in the choroid plexus, hippocampus, and ependymal cells of the lateral ventricle and aqueduct of WIC-Hyd rats. SOD was hardly observed in the choroid plexus and faintly localized in the hippocampus and ependymal cells of the congenitally hydrocephalic brain, but was observed equally in the cytoplasm of the choroid plexus, hippocampus, and ependymal cells in control animals. In the hippocampus, less SOD was found in hydrocephalic rats than in controls. The SOD was slightly observed in the CA1 pyramidal cells in hydrocephalic rats. In the lateral ventricle and aqueductal ependyma, less SOD was found in hydrocephalic than in control rats. The amount of Cu, Zn-SOD in the congenitally hydrocephalic rat brain was less than in the control, especially in the choroid plexus. Therefore, we suspect that the production of SOD is congenitally reduced in the congenitally hydrocephalic rat brain, and this may promote the impairment of the function of choroid plexus and cilia due to increased active oxygen species. The reduction of SOD in the choroid plexus, hippocampus and ependymal cells of ventricles or aqueduct may promote the development of hydrocephalus in the congenitally hydrocephalic rat.     

Effect of ischemia induced by middle cerebral artery occlusion on superoxide dismutase activity in rat brain

Acute cerebral ischemia increases the generation of free radicals, causing cell damage, and theoretically may decrease the activity of the scavenging enzyme superoxide dismutase. To investigate the role of superoxide dismutase in cerebral ischemia, we used a model of middle cerebral artery occlusion in rats. In this model an infarct is produced in the pyriform and frontoparietal cortices, extending into the lateral basal ganglia. We measured superoxide dismutase activity by using the xanthine oxidase cytochrome c reduction assay in these areas of rat brains. Tissue samples were analyzed 20 minutes, 2, 6, or 24 hours, or 7 days after middle cerebral artery occlusion and 2 or 24 hours or 7 days after sham operation (n = 8-10 at each time). There was no significant change in superoxide dismutase activity relative to control values in any brain area at any time up to 24 hours after surgery. However, 7 days after middle cerebral artery occlusion a significant decline in superoxide dismutase activity, to 55%-68% (p less than 0.05) of that in unoperated controls, was observed in all brain areas. Our results do not support an important role for changes in the activity of endogenous superoxide dismutase during the acute phase of cerebral ischemia. However, the decrease in superoxide dismutase activity 7 days after ischemia could indicate ongoing additional damage to peri-infarct tissue.     

Red cell superoxide dismutase activity in sporadic amyotrophic lateral sclerosis

Specific biologic markers are not available for definitive diagnosis and monitoring of disease progression in sporadic amyotrophic lateral sclerosis (SALS). Oxidative stress plays a role in ALS pathogenesis. The purpose of this study was to determine the association between Cu/Zn superoxide dismutase (SOD1) activity, diagnosis and prognosis. The present study included 25 SALS patients (SALS group; age 51+/-12 years) and 10 healthy subjects (age 45+/-5 years) as a control group. Patients were divided into groups representing four levels of diagnostic certainty of ALS in accordance with the El Escorial Revisited criteria. The disease state was determined using the modified ALS health state scale of Riviere et al. (Arch Neurol 1998:55;526-8). Red-cell SOD1 activity was determined by spectrophotometry. SOD1 activity in red cells was compared statistically with diagnostic criteria and disease state. Red cell SOD1 activity was high in all SALS patients, but there was no significant association between enzyme activity and diagnostic criteria and disease state. In this preliminary study, we did not find any correlation between SOD1 activity level and diagnosis or prognosis. Measured SOD1 activity sometimes supports ALS diagnosis, but it is neither a specific nor a prognostic factor.     

Effect of a superoxide dismutase derivative on cold-induced brain edema

Although the involvement of reactive oxygen species has been suggested in the pathogenesis of brain edema, direct evidence supporting this concept is lacking. To elucidate a critical role of oxygen radicals, effect of a superoxide dismutase (SOD) derivative that circulated bound to albumin with a half-life of 6 h on the occurrence of cold-induced brain edema was studied in the rat. When animals were challenged with brain injury by applying a liquid-nitrogen-cold probe to one side of the cerebral hemisphere over the bony skull for 20 s, the vascular permeability of the underlying tissue increased significantly and unilateral brain edema occurred as determined by the accumulation of intravenously injected Evan's blue and the increase in brain weight. Intravenous administration of the SOD derivative markedly suppressed the increase in vascular permeability and the occurrence of brain edema, particularly at their early stages. These and other results suggest that superoxide anion and/or its metabolite(s) might play a critical role in the pathogenesis of traumatic brain injury.     

Protective effects of liposome-entrapped superoxide dismutase on posttraumatic brain edema

Oxygen-derived free radicals and membrane lipid peroxidation have been postulated to be involved in brain edema and cell death, secondary to ischemia and traumatic injury. Using a model of brain edema induced by cold-induced injury, we have demonstrated an early elevation of superoxide radicals followed by permeability changes in the blood-brain barrier and development of edema in injured brain. Intravenous injection of liposome-entrapped copper-zinc-superoxide dismutase 5 minutes before the injury-enhanced entry of the enzyme into endothelial cells of the blood-brain barrier of injured brain reduced the brain level of superoxide radicals and ameliorated blood-brain barrier permeability changes and brain edema. Identical treatment 5 minutes after injury was also effective. These data demonstrate that superoxide radicals play an important role in the delayed development of vasogenic brain edema following brain injury.     

Expression of superoxide dismutase messenger RNA in adult rat brain cholinergic neurons

Superoxide dismutase (SOD) protects cells exposed to an excess of the free radical nitric oxide, by preventing the formation of peroxynitrite. Certain central cholinergic neurons express constitutive nitric oxide synthase (nNOS), and presumably they are at risk from peroxynitrite intoxication. Immunocytochemistry for choline acetyltransferase (ChAT) was combined with in situ hybridization histochemistry (ISHH) to examine whether brain cholinergic populations differ with respect to their expression of the messenger RNA molecules (mRNAs) for the manganese-dependent (Mn-SOD) and copper/zinc-dependent superoxide dismutases (Cu/Zn-SOD). The cholinergic neurons located in the reticular formation of the upper brainstem (the laterodorsal tegmental nucleus [LDTN] and the pedunculopontine nucleus [PPN]) were found to express relatively high levels of Mn-SOD mRNA, whereas cholinergic neurons located in the basal forebrain (substantia innominata [SI], diagonal band [DB], medial septum [MS], and the nucleus basalis magnocellularis [nBM]), and the striatal cholinergic interneurons expressed low to intermediate levels of Mn-SOD mRNA. The rank order of median Mn-SOD mRNA density per cholinergic cell was LDTN > PPN > SI > striatum = nBM = DB > MS. This is similar to the rank order of nNOS mRNA densities in the cholinergic cells in these regions (R=0.9, p<0.02). The rank order of Cu/Zn-SOD mRNA levels in cholinergic populations (DB > LDTN = PPN = MS > SI = nBM = striatum) was not correlated with nNOS mRNA (R = 0.29, P>0.05). Thus, for cholinergic neurons, Mn-SOD may be important for protection from NO-related oxidative stress.     

Sleep deprivation decreases superoxide dismutase activity in rat hippocampus and brainstem

Sleep deprivation by the disk-over-water technique results in a predictable syndrome of physiological changes in rats. It has been proposed that reactive oxygen species (ROS) may be responsible for some of these effects. A variety of antioxidative enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) help to regulate the level of ROS. In this study we investigated the effects of prolonged (5-11 days) sleep deprivation on the activities of SOD and GPx as well as the metabolic activity of the mitochondria (using alamar blue) in several brain regions (cortex, hippocampus, hypothalamus, brainstem and cerebellum). We show that prolonged sleep deprivation significantly decreased Cu/Zn-SOD activity in the hippocampus and brainstem, suggesting an alteration in the metabolism of ROS resulting in oxidative stress.     

Orcadian variations of superoxide dismutase activity in the rat pineal gland

Summary The 24 h profile of the activity of the antioxidant enzyme Superoxide dismutase (SOD) in the pineal gland of rats was studied. Rhythmic analysis showed a significant 24 h rhythm with an amplitude of oscillation of 25% of the 24 h mean value, that was 100.34±1.6 U SOD (nitrite). An ultradian rhythm of 9 h was also detected. The diurnal profile of Superoxide dismutase activity is discussed in relation to the oxidative metabolism of the pineal gland.     

Changes in nitric oxide level and superoxide dismutase activity during antimanic treatment

Oxidant nitric oxide (NO) and antioxidant superoxide dismutase (SOD) have been implicated to play a role in the pathogenesis of bipolar disorders. This is the first prospective study aimed to evaluate NO levels and SOD activity in bipolar disorder (type I manic episode) (BD-ME). 29 inpatient subjects with BD-ME and 30 healthy controls were included. Serum NO levels and SOD activity have been studied at 1st (NO [1st] and SOD [1st] respectively) and 30th days (NO [30th] and SOD [30th] respectively) after treatment. The clinical outcome was measured by Bech-Rafaelson Mania Scale (BRMS). The mean NO [1st] (p<.001) and NO [30th] levels (p<.001) were higher than controls, but SOD [1st] (p<.001) and SOD [30th] (p<.001) activities in BD-ME were lower than controls. SOD(1) activity was higher than SOD [30th] (p<.001), while there was no significance in comparison between NO [1st] and NO [30th] (p>.05). SOD [30th] activity is negatively correlated with the number of previous manic attacks and NO [1st] was negatively correlated with sleep item score of BRMS at first day. Also there was a significant correlation between NO [1st] levels and with the existence of a delusion. NO and SOD appear to play a role in the pathophysiological events occurring in BD, especially in BD-ME. This study for the first time showed the possible role of NO on sleep and the generation of delusions in the pathophysiology of BD. In the light of literature, induced glutamate pathway might be responsible for delusions in BD. The results of this research need further investigation to understand the oxidative vs antioxidative process in BD.     

Increase in endogenous brain superoxide dismutase as a potential mechanism of lipopolysaccharide-induced brain ischemic tolerance.

A low dose (0.5 mg/kg) of lipopolysaccharide (LPS), administered 72 hours before 60-minute middle cerebral artery occlusion, induced a delayed neuroprotection proven by the significant decrease (-35%) of brain infarct volume in comparison with control, whereas infarct volumes remained unchanged in rats treated 12, 24, or 168 hours before ischemia. This delayed neuroprotective effect of LPS was induced only with low doses (0.25 to 1 mg/kg), whereas this effect disappeared with a higher dose (2 mg/kg). The delayed neuroprotection of LPS was induced in the cortical part of the infarcted zone, not in the subcortical part. The beneficial effect of LPS on consequences of middle cerebral artery occlusion was suppressed by dexamethasone (3 mg/kg) and indomethacin (3 mg/ kg) administered 1 hour before LPS, whereas both drugs had no direct effect on infarct volume by themselves, suggesting that activation of inflammatory pathway is involved in the development of LPS-induced brain ischemic tolerance. Preadministration of cycloheximide, an inhibitor of protein synthesis, also blocked LPS-induced brain ischemic tolerance suggesting that a protein synthesis is also necessary as a mediating mechanism. Superoxide dismutase (SOD) could be one of the synthesized proteins because lipopolysaccharide increased SOD brain activity 72 hours, but not 12 hours, after its administration, which paralleled the development of brain ischemic tolerance. In contrast, catalase brain activity remained unchanged after LPS administration. The LPS-induced delayed increase in SOD brain content was suppressed by a previous administration of indomethacin. These data suggest that the delayed neuroprotective effect of low doses of LPS is mediated by an increased synthesis of brain SOD that could be triggered by activation of inflammatory pathway.     

Superoxide dismutase deficiency enhances superoxide levels in brain tissues during oxygenation and hypoxia-reoxygenation

To determine whether the mitochondria or cytoplasm produces superoxide during ischemia-reperfusion of the brain, we analyzed lucigenine-enhanced chemiluminescence emission in slices of brain tissue prepared from manganese-superoxide dismutase (Mn-SOD)-deficient (Sod2-deficient) and copper and zinc-superoxide dismutase (Cu,Zn-SOD)-deficient (Sod1-deficient) mice during oxygenation and hypoxia-reoxygenation. The steady-state level of chemiluminescence under oxygenated conditions was significantly enhanced by a lack of either Sod. We hypothesize that the enhanced chemiluminescence produced by Sod2 and Sod1 deficiency reflects in situ superoxide generation in the mitochondria and cytoplasm, respectively. Based on this hypothesis, the major site of intracellular superoxide generation was assumed to be the cytoplasm. However, mitochondria occupy less cellular space than the cytoplasm. In terms of volume, the superoxide concentration is assumed to be higher in mitochondria than in the cytoplasm. Mn-SOD activity was 18% of the Cu,Zn-SOD activity observed in the wild-type mouse brain. However, when mitochondrial SOD activity was expressed as per volume, it was assumed to be equal to that observed in the cytoplasm. This imbalance between superoxide and SOD activity is expected to cause mitochondrial oxidative damage. The chemiluminescence intensity increased significantly during reoxygenation and was enhanced by Sod2 deficiency but was not significantly affected by Sod1 deficiency. The superoxide concentration in the reoxygenated brain would be higher in the mitochondria than in the cytoplasm. The present study indicated that the major site of intracellular superoxide generation in the brain during oxygenation is the cytoplasm, whereas it is the mitochondria during reoxygenation.     

Erythrocyte superoxide dismutase activity differs in clinical subgroups of Parkinson's disease patients

There is controversy as to whether there are clinical subgroups in Parkinson's disease (PD). Six tremor-dominant and six bradykinesia-dominant patients identified among 29 cases with PD were compared in terms of erythrocyte superoxide dismutase (SOD) activity and several clinical variables. Erythrocyte SOD activity in tremor-dominant patients was higher than in bradykinesia-dominant patients. According to our preliminary results obtained from small number of patients, the difference of SOD activity in clinically distinct subgroups suggests there may be separate clinical subgroups of PD which can be differentiated by a biological marker.     

Electroconvulsive shock in rats: changes in superoxide dismutase and glutathione peroxidase activity

Seizures trigger a variety of biochemical processes including an influx of extracellular Ca(2+), activation of membrane phospholipases, liberation of free fatty acids, diacylglycerols, eicosanoids, lipid peroxides and free radicals. These lipid metabolites along with abnormal ion homeostasis may be involved in cell injury and cell death. The aim of this study was to determine brain antioxidant enzyme activities in rats with electroconvulsive shock (ECS)-induced seizures. ECS, single or repeated, induced a decrease in superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities in various brain regions. The most prominent changes of enzymatic activities were observed in rats that received five ECSs with 24-h recovery period between them. Decreased SOD activity was observed in the frontal cortex of all treated animals except those sacrificed 24 h after single ECS, in the cerebellum of the animals that received repeated ECSs, in the hippocampus of animals that were decapitated 2 h after a single ECS and in the pons-medulla region of rats that received five daily ECSs. Decreased GPX activity was found in all examined brain regions of the rats that received five ECSs, the cortex and hippocampus of rats that were decapitated 2 h after single ECS and the cortex of those that received 10 ECSs with 48 h between them. The results show that neither 24-h nor 48-h recovery period was sufficient for the normalisation of antioxidative enzyme activities after repeated ECS treatment.     

Effects of basic fibroblast growth factor on superoxide dismutase activity and malondialdehyde content in the rat brain following intracerebral hemorrhage

BACKGROUND: Studies have confirmed that basic fibroblast growth factor (bFGF) promotes neuronal survival and neurite outgrowth. OBJECTIVE: To compare and verify the effects of bFGF on superoxide dismutase activity and malondialdehyde content in rat brain tissues surrounding a hemorrhagic lesion, as well as the hippocampus at the hemorrhagic side. DESIGN, TIME AND SETTING: The randomized, controlled, neurobiological study was performed at the Science Experimental Center and Research Laboratory, Guangxi Medical University, China, from September to December 2006. MATERIALS: Ninety-two adult, healthy, Wistar rats of equal gender were used to establish intraeerebral hemorrhage by infusing type VII collagenase into the left internal capsule. Type Ⅶ collagenase (Sigma, USA), superoxide dismutase and malondialdehyde kits (Jiancheng, China), and bFGF (Institute of Bioengineering, Ji'nan University, China) were used for this study. METHODS: Ninety successfully lesioned rats were equally and randomly divided into three groups. Rats in the bFGF group were intramuscularly injected daily with bFGF (8μg/kg). Rats in the saline control group received an equal volume of saline. The rats in the model group did not receive other interventions. Superoxide dismutase activity was measured using the xanthine oxidase method. Malondialdehyde contents were detected using the thiobarbituric acid method. MAIN OUTCOME MEASURES: At 1, 3, and 7 days following intracerebral hemorrhage, superoxide dismutase and malondialdehyde were determined in the brain tissue surrounding the hematoma and in the hippocampus in the affected hemisphere. RESULTS: In brain tissue surrounding the hematoma, superoxide dismutase activity was significantly increased in the bFGF group at 3 and 7 days after intracerebral hemorrhage compared with the saline control group, whereas malondialdehyde content was significantly decreased (P < 0.05). In the hippocampus, superoxide dismutase activity was significantly increased in the bFGF group at 7 days following intracerebral hemorrhage compared with the saline control group, whereas malondialdehyde content was significantly decreased (P < 0.05). At 1, 3, and 7 days after intracerebral hemorrhage, there was no significant difference between the saline control group and the model group with regards to parameter or brain region (P > 0.05). CONCLUSION: Increased superoxide dismutase activity and decreased malondialdehyde content were detected in tissue surrounding the hematoma, as well as the ipsilateral hippocampus, of intracerebral hemorrhage rats treated with bFGF. Changes in these parameters were detected earlier in tissue adjacent to the lesion, compared with the ipsilateral hippocampus.