ascorbic-acid and Brain-Injuries

There is a need for novel neuroprotective therapies. We aimed to review the evidence for exogenous vitamin C as a neuroprotective agent. MEDLINE, Embase, and Cochrane library databases were searched from inception to May 2020. Pre-clinical and clinical reports evaluating vitamin C for acute neurological injury were included. Twenty-two pre-clinical and 11 clinical studies were eligible for inclusion. Pre-clinical studies included models of traumatic and hypoxic brain injury, subarachnoid and intracerebral hemorrhage, and ischemic stroke. The median [IQR] maximum daily dose of vitamin C in animal studies was 120 [50-500] mg/kg. Twenty-one animal studies reported improvements in biomarkers, functional outcome, or both. Clinical studies included single reports in neonatal hypoxic encephalopathy, traumatic brain injury, and subarachnoid hemorrhage and eight studies in ischemic stroke. The median maximum daily dose of vitamin C was 750 [500-1000] mg, or ∼10 mg/kg for an average-size adult male. Apart from one case series of intracisternal vitamin C administration in subarachnoid hemorrhage, clinical studies reported no patient-centered benefit. Although pre-clinical trials suggest that exogenous vitamin C improves biomarkers of neuroprotection, functional outcome, and mortality, these results have not translated to humans. However, clinical trials used approximately one tenth of the vitamin C dose of animal studies.

Topics: Animals; Ascorbic Acid; Brain Injuries; Humans; Neuroprotection

Oxygen radical-mediated lipid peroxidation appears to be a critical factor in posttraumatic neuronal degeneration. Thus, numerous studies have evaluated the neuroprotective efficacy of pharmacologic agents with lipid antioxidant activity in models of spinal cord and brain injury. Intensive pretreatment of animals with the endogenous lipid peroxyl radical scavenger alpha tocopherol (i.e., vitamin E) has been shown to decrease posttraumatic spinal cord ischemia and to enhance chronic neurologic recovery. However, the slow CNS tissue uptake of vitamin E requires chronic dosing, making it an impractical agent for the treatment of acute neural injury. The glucocorticoid steroid methylprednisolone has been shown to possess significant antioxidant efficacy and, when administered to animals or humans in antioxidant dosages, improves chronic neurologic recovery after spinal cord injury. This activity of methylprednisolone is independent of the steroid's glucocorticoid receptor-mediated actions. Novel antioxidant 21-aminosteroids have been developed that are devoid of glucocorticoid activity but have greater antioxidant efficacy than methylprednisolone. One of these, U74006F or tirilazed mesylate, has been shown to be effective in animal models of brain and spinal cord injury and is currently undergoing phase II clinical trials. Compounds that combine the amino functionality of the 21-aminosteroids with the peroxyl radical scavenging chromanol portion of vitamin E (i.e., 2-methylaminochromans) have also recently shown promise as neuroprotective agents. The consistent benefit afforded by antioxidant compounds adds further support to the concept that lipid peroxidation is an important therapeutic target for acute pharmacologic neuroprotection.

Topics: Animals; Antioxidants; Ascorbic Acid; Brain Injuries; Methylprednisolone; Spinal Cord Injuries; Steroids; Vitamin E

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antioxidants; Ascorbic Acid; Brain Edema; Brain Injuries; Cohort Studies; Dose-Response Relationship, Drug; Double-Blind Method; Female; Glasgow Outcome Scale; Humans; Male; Middle Aged; Treatment Outcome; Vitamin E; Young Adult

Vitamin C has recently been identified as an epigenetic regulator by activating ten-eleven translocases (TETs), enzymes involved in generating DNA hydroxymethylcytosine (5hmC). Currently, we investigated whether high-dose vitamin C promotes neuroprotection through epigenetic modulation of 5hmC, if there are sex-specific differences in outcome, and the therapeutic potential of vitamin C in stroke-related comorbidities in adult mice. Post-stroke treatment with ascorbate (reduced form), but not dehydroascorbate (oxidized form), increased TET3 activity and 5hmC levels and reduced infarct following focal ischemia. Hydroxymethylation DNA immunoprecipitation sequencing showed that ascorbate increased 5hmC across the genome and specifically in promoters of several stroke pathophysiology-related genes, particularly anti-inflammatory genes. Ascorbate also decreased markers of oxidative stress, mitochondrial fragmentation, and apoptosis in cortical peri-infarct neurons and promoted motor and cognitive functional recovery in both sexes via TET3. Furthermore, post-stroke ascorbate treatment reduced infarct volume and improved motor function recovery in aged, hypertensive and diabetic male and female mice. Delayed ascorbate treatment at 6 h of reperfusion was still effective at reducing infarct volume and motor impairments in adult mice. Collectively, this study shows that post-stroke treatment with high-dose ascorbate protects the brain through epigenetic reprogramming and may function as a robust therapeutic against stroke injury.

Topics: 5-Methylcytosine; Animals; Ascorbic Acid; Brain; Brain Injuries; Brain Ischemia; DNA; Epigenesis, Genetic; Female; Infarction; Male; Mice; Neuroprotection; Stroke

Lipid peroxidation represents a marker of secondary brain injury both in traumatic and in non-traumatic conditions-as in major neurosurgical procedures-eventually leading to brain edema amplification and further brain damage. Malondialdehyde (MDA), a lipid peroxidation marker, and ascorbate, a marker of antioxidant status, can represent early indicators of this process within the cerebrospinal fluid (CSF). We hypothesized that changes in cerebral lipid peroxidation can be measured ex vivo following neurosurgery in children.. Thirty-six children (M:F = 19/17, median age 32.9 months; IQR 17.6-74.6) undergoing neurosurgery for brain tumor removal were admitted to the pediatric intensive care unit (PICU) in the postoperative period with an indwelling intraventricular catheter for intracranial pressure monitoring and CSF drainage. Plasma and CSF samples were obtained for serial measurement of MDA, ascorbate, and cytokines.. An early brain-limited increase in lipid peroxidation was measured, with a significant increase from baseline of MDA in CSF (p = 0.007) but not in plasma. In parallel, ascorbate in CSF decreased (p = 0.05). Systemic inflammatory response following brain surgery was evidenced by plasma IL-6/IL-8 increase (p 0.0022 and 0.0106, respectively). No correlation was found between oxidative response and tumor site or histology (according to World Health Organization grading). Similarly, lipid peroxidation was unrelated to the length of surgery (mean 321 ± 73 min), or intraoperative blood loss (mean 20.9 ± 16.8% of preoperative volemia, 44% given hemotransfusions). Median PICU stay was 3.5 days (IQL range 2-5.5 d.), and postoperative ventilation need was 24 h (IQL range 20-61.5 h). The elevation in postoperative MDA in CSF compared with preoperative values correlated significantly with postoperative ventilation need (P = 0.05, r. Our results indicate that lipid peroxidation increases consistently following brain surgery, and it is accompanied by a decrease in antioxidant defences; intraventricular catheterization offers a unique chance of oxidative process monitoring. Further studies are needed to evaluate whether monitoring post-neurosurgical oxidative stress in CSF is of prognostic utility.

Topics: Antioxidants; Ascorbic Acid; Brain Injuries; Brain Neoplasms; Child; Child, Preschool; Cytokines; Drainage; Female; Humans; Infant; Intensive Care Units, Pediatric; Interleukin-6; Interleukin-8; Intracranial Pressure; Lipid Peroxidation; Male; Malondialdehyde; Monitoring, Physiologic; Neurosurgical Procedures; Oxidative Stress; Postoperative Complications; Respiration, Artificial

Pesticides, such as organophosphorus and pyrethroids, are extensively used in the agrofields which can significantly increase crop productivity. Humans are exposed to pesticides via dermal contact, inhalation and ingestion due to occupational exposure. The objective of the present study was to evaluate the protective role of the aqueous extract of Crataegus oxyacantha during acute exposure of rats to the combination of deltamethrin (DM) and chlorpyrifos (CPF) in rats (DCF). The combination of vitamins C and E (Vit CE) was used as a standard antioxidant. The Crataegus oxyacantha extract revealed the presence of a high level of phenolic compounds identified by HPLC analysis. Male wistar rats were divided into six groups: (I) corn oil, (II) AECO (1 ml/100 g), (III) DCF (DM 5 mg/kg, CPF 1 mg/kg), (IV) AECO + DCF, (V) Vit CE (Vit C 100 mg/kg, Vit E 100 mg/kg), and (VI) Vit CE + DCF. AECO and Vit CE were administered 10 days before the administration of DCF. The findings revealed that the administration of DM and CPF mixture induced a significant decrease in serum AChE and DNA damage, as indicated by brain DNA fragmentation. In addition, behavioral tests by open field and elevated plus maze showed impaired recognition memory. The results showed that AECO or Vit CE alleviated significantly neurobehavioral alterations, reduced lipid peroxidation in brain, and restored the antioxidant parameters (SOD, CAT, GPx and GSH) to normal levels. Furthermore, brain DNA fragmentation and histopathology in DCF treated rats were improved by AECO administration. All results revealed that C. oxyacantha extract, rich in polyphenolic compounds, had potential antioxidant effects on the combination of DM and CPF-induced oxidative brain damage.

Topics: Animals; Antioxidants; Ascorbic Acid; Brain; Brain Injuries; Chlorpyrifos; Crataegus; Glutathione Peroxidase; Insecticides; Lipid Peroxidation; Male; Nitriles; Oxidative Stress; Pesticides; Plant Extracts; Pyrethrins; Rats; Rats, Wistar; Vitamin E

Brain damage is a major complication of fulminant hepatic failure. d-Galactosamine (d-GalN)-induced liver toxicity causes damage to brain. The effects of vitamins and selenium mixture against d-GalN stimulated brain injury were investigated in this study. Sprague-Dawley female rats aged 2.0-2.5 months were used for the study. The rats were divided into four categories. A 0.9% NaCl solution was intraperitoneally given to the experimental rats in the first group. Using gavage technique, the second group of animals were subjected to a formulation consisting of 100 mg·kg

Topics: alpha-Tocopherol; Animals; Ascorbic Acid; beta Carotene; Brain; Brain Injuries; Chemical and Drug Induced Liver Injury; Female; Galactosamine; Rats; Rats, Sprague-Dawley; Selenium

A number of neurological disorders such as epidural hematoma can cause compression of cerebral cortex. We here tested the hypothesis that sustained compression of primary somatosensory cortex may affect stellate neurons and thalamocortical afferent (TCA) fibers. A rat model with barrel cortex subjected to bead epidural compression was used. Golgi-Cox staining analyses showed the shrinkage of dendritic arbors and the stripping of dendritic spines of stellate neurons for at least 3 months post-lesion. Anterograde tracing analyses exhibited a progressive decline of TCA fiber density in barrel field for 6 months post-lesion. Due to the abrupt decrease of TCA fiber density at 3 days after compression, we further used electron microscopy to investigate the ultrastructure of TCA fibers at this time. Some TCA fiber terminal profiles with dissolved or darkened mitochondria and fewer synaptic vesicles were distorted and broken. Furthermore, the disruption of mitochondria and myelin sheath was observed in some myelinated TCA fibers. In addition, expressions of oxidative markers 3-nitrotyrosine and 4-hydroxynonenal were elevated in barrel field post-lesion. Treatment of antioxidant ascorbic acid or apocynin was able to reverse the increase of oxidative stress and the decline of TCA fiber density, rather than the shrinkage of dendrites and the stripping of dendritic spines of stellate neurons post-lesion. Together, these results indicate that sustained epidural compression of primary somatosensory cortex affects the TCA fibers and the dendrites of stellate neurons for a prolonged period. In addition, oxidative stress is responsible for the reduction of TCA fiber density in barrels rather than the shrinkage of dendrites and the stripping of dendritic spines of stellate neurons.

Topics: Acetophenones; Afferent Pathways; Aldehydes; Animals; Antioxidants; Ascorbic Acid; Biotin; Brain Injuries; Dendrites; Dextrans; Disease Models, Animal; Electron Transport Complex IV; Epidural Space; Functional Laterality; Male; Neurons; Oxidative Stress; Rats; Somatosensory Cortex; Thalamus; Time Factors; Tyrosine

The GluN2B subunit of NMDA receptors (NMDARs) is an attractive drug target for therapeutic intervention in Parkinson's disease (PD). We have used whole-cell patch clamp recordings in brain slices to examine the contribution of GluN2B and GluN2D to functional NMDARs in the striatum of the unilateral 6-hydroxydopamine-lesioned mouse model of PD. We found that current/voltage relationships of NMDAR-mediated excitatory post synaptic currents were altered in a population of medium spiny projection neurons (MSNs) in the dopamine-depleted striatum. Using antagonists for GluN2B- and GluN2D-containing NMDARs, we found that GluN2B contributes to functional NMDARs in MSNs in the intact striatum and in the striatum of control mice. The function of GluN2B-containing NMDARs is however reduced in MSNs from the dopamine-depleted striatum. GluN2D is absent in MSNs from intact striatum and from control mice, but the contribution of this subunit to functional NMDARs is increased in the dopamine-depleted striatum. These changes in the subunit composition of NMDARs are associated with a decreased protein level of GluN2B and an increased level of GluN2D in the dopamine-depleted striatum. In cholinergic interneurons from the intact striatum and control mice, both GluN2B and GluN2D contribute to functional NMDARs. The functions of GluN2D, and to some extent GluN2B, are reduced in the dopamine-depleted striatum. Our findings demonstrate a cell-type specific reorganization of GluN2B and GluN2D in a mouse model of PD and suggest GluN2D as a potential target for the management of the disease.

Topics: Adrenergic Agents; Animals; Antioxidants; Ascorbic Acid; Brain Injuries; Corpus Striatum; Disease Models, Animal; Dopamine; Dose-Response Relationship, Drug; Excitatory Amino Acid Agents; Excitatory Postsynaptic Potentials; Gene Expression Regulation; Male; Mice; Mice, Inbred C57BL; Neurons; Oxidopamine; Patch-Clamp Techniques; Receptors, N-Methyl-D-Aspartate; Tyrosine 3-Monooxygenase

Traumatic brain injury (TBI) and hemorrhagic shock (HS) can be associated with coagulopathy and inflammation, but the mechanisms are poorly understood. We hypothesized that a combination of TBI and HS would disturb coagulation, damage the endothelium, and activate inflammatory and complement systems.. A total of 33 swine were allocated to either TBI + HS (n = 27, TBI and volume-controlled 40% blood loss) or controls (n = 6, anesthesia and instrumentation). TBI + HS animals were left hypotensive (mean arterial pressure, 30-35 mm Hg) for 2 hours. Blood samples were drawn at baseline, 3 minutes and 15 minutes after injury, as well as following 2 hours of hypotension. Markers of coagulation, anticoagulation, endothelial activation/glycocalyx shedding, inflammation, complement, and sympathoadrenal function were measured.. The TBI + HS group demonstrated an immediate (3 minutes after injury) activation of coagulation (prothrombin fragment 1 + 2, 289 ng/mL vs. 232 ng/mL, p = 0.03) and complement (C5a, 2.83 ng/mL vs. 2.05 ng/mL, p = 0.05). Shedding of the endothelial glycocalyx (syndecan 1) was evident 15 minutes after injury (851.0 ng/ml vs. 715.5 ng/ml, p = 0.03) while inflammation (tumor necrosis factor α [TNF-α], 81.1 pg/mL vs. 50.8 pg/mL, p = 0.03) and activation of the protein C system (activated protein C, 56.7 ng/mL vs. 26.1 ng/mL, p = 0.01) were evident following the 2-hour hypotension phase.. The combination of TBI and shock results in an immediate activation of coagulation and complement systems with subsequent endothelial shedding, protein C activation, and inflammation.

Topics: Animals; Ascorbic Acid; Blood Coagulation Disorders; Brain Injuries; Complement Activation; Disease Models, Animal; Endothelium; Female; Fibrinolysis; Hemorrhage; Inflammation; Shock, Hemorrhagic; Swine

Stroke is a devastating disease. Both excitotoxicity and oxidative stress play important roles in ischemic brain injury, along with harmful impacts on ischemic cerebral tissue. As guanosine plays an important neuroprotective role in the central nervous system, the purpose of this study was to evaluate the neuroprotective effects of guanosine and putative cerebral events following the onset of permanent focal cerebral ischemia.. Permanent focal cerebral ischemia was induced in rats by thermocoagulation. Guanosine was administered immediately, 1 h, 3 h and 6 h after surgery. Behavioral performance was evaluated by cylinder testing for a period of 15 days after surgery. Brain oxidative stress parameters, including levels of ROS/RNS, lipid peroxidation, antioxidant non-enzymatic levels (GSH, vitamin C) and enzymatic parameters (SOD expression and activity and CAT activity), as well as glutamatergic parameters (EAAC1, GLAST and GLT1, glutamine synthetase) were analyzed.. After 24 h, ischemic injury resulted in impaired function of the forelimb, caused brain infarct and increased lipid peroxidation. Treatment with guanosine restored these parameters. Oxidative stress markers were affected by ischemic insult, demonstrated by increased ROS/RNS levels, increased SOD expression with reduced SOD activity and decreased non-enzymatic (GSH and vitamin C) antioxidant defenses. Guanosine prevented increased ROS/RNS levels, decreased SOD activity, further increased SOD expression, increased CAT activity and restored vitamin C levels. Ischemia also affected glutamatergic parameters, illustrated by increased EAAC1 levels and decreased GLT1 levels; guanosine reversed the decreased GLT1 levels and did not affect the EAAC1 levels.. The effects of brain ischemia were strongly attenuated by guanosine administration. The cellular mechanisms involved in redox and glutamatergic homeostasis, which were both affected by the ischemic insult, were also modulated by guanosine. These observations reveal that guanosine may represent a potential therapeutic agent in cerebral ischemia by preventing oxidative stress and excitotoxicity.

Topics: Animals; Ascorbic Acid; Blotting, Western; Brain Injuries; Brain Ischemia; Catalase; Dose-Response Relationship, Drug; Drug Administration Schedule; Electrocoagulation; Excitatory Amino Acid Transporter 3; Exploratory Behavior; Forelimb; Glutamate Plasma Membrane Transport Proteins; Glutamate-Ammonia Ligase; Glutathione; Guanosine; Lipid Peroxidation; Male; Neuroprotective Agents; Nitric Oxide; Rats, Wistar; Reactive Oxygen Species; Superoxide Dismutase

Myelophil is composed of Astragali Radix and Salviae Miltiorrhizae Radix, according to the long traditional pharmacological practices, and it has been used for patients with chronic fatigue-associated symptoms including concentration problem or memory loss.. This study aimed to evaluate the clinical relevance of Myelophil on brain oxidative damage using a chronic cold stress mice model.. Balb/c mice were subjected to cold stress (4°C for 4h) six times per week for 2 weeks with or without oral administration of Myelophil (50, 100, or 200mg/kg), or ascorbic acid (50mg/kg).. Chronic cold stress induced histopathological hippocampal apoptosis with drastically increased serum levels of total reactive oxygen species and nitric oxide, as well as brain lipid peroxidation levels, protein carbonyl, and caspase-3/7 activity. These alterations were significantly ameliorated by Myelophil treatment. Myelophil administration significantly recovered the depleted glutathione and its enzymes, superoxide dismutase activity, and catalase protein and gene expression levels. Serum levels of corticosterone, dopamine, and adrenaline were notably altered by chronic cold stress but were significantly ameliorated by Myelophil treatment. Myelophil also normalized alterations in tumor necrosis factor-α, interleukin (IL)-1β, and IL-10 gene expression and protein levels. Chronic cold stress up-regulated gene expression levels of phenylethanolamine N-methyltransferase and monoamine oxidase-B, and glucocorticoid receptors in the hypothalamus and hippocampus, respectively, whereas Myelophil treatment completely normalized these levels.. These results suggest that Myelophil has potent pharmaceutical effects against chronic cold-stress-induced brain damage by relieving oxidative stress and inflammation and regulating stress hormones in mice.

Topics: Animals; Apoptosis; Ascorbic Acid; Brain Injuries; Caspase 3; Caspase 7; Corticosterone; Disease Models, Animal; Dopamine; Drugs, Chinese Herbal; Epinephrine; Glutathione; Hippocampus; Hypothalamo-Hypophyseal System; Interleukin-10; Interleukin-1beta; Lipid Peroxidation; Male; Mice; Mice, Inbred BALB C; Monoamine Oxidase; Nitric Oxide; Oxidative Stress; Phenylethanolamine N-Methyltransferase; Pituitary-Adrenal System; Reactive Oxygen Species; Receptors, Glucocorticoid; Superoxide Dismutase; Tumor Necrosis Factor-alpha

Oxidative stress is a mechanism of cell death induced by seizures. Antioxidant compounds have neuroprotective effects due to their ability to inhibit free radical production. Autophagy is a process in which cytoplasmic components such as organelles and proteins are delivered to the lysosomal compartment for degradation, and plays an essential role in the maintenance of cellular homeostasis. The activity of autophagy is enhanced during oxidative stress. The objectives of this work were first to study the inhibitory action of antioxidant ascorbic acid on behavioral changes and brain damage induced by high doses of pilocarpine, then to study the effect of ascorbic acid on oxidative stress (MDA and SOD were used to estimate oxidative stress) and activated autophagy (beclin 1 was used to estimate autophagy) induced by seizures, aiming to further clarify the mechanism of action of this antioxidant compound. In order to determinate neuroprotective effects, we studied the effects of ascorbic acid (500 mg/kg, i.p.) on the behavior and brain lesions observed after seizures induced by pilocarpine (340 mg/kg, i.p., P340 model) in rats. Ascorbic acid injections prior to pilocarpine suppressed behavioral seizure episodes by increasing the latency to the first myoclonic, clonic and tonic seizure and decreasing the percentage of incidence of clonic and tonic seizures as well as the mortality rate. These findings suggested that oxidative stress can be produced and autophagy is increased during brain damage induced by seizures. In the P340 model, ascorbic acid significantly decreased cerebral damage, reduced oxidative stress and inhibited autophagy by reducing de novo synthesis of beclin 1. Antioxidant compound can exert neuroprotective effects associated with inhibition of free radical production and autophagy. These results highlighted the promising therapeutic potential of ascorbic acid in treatment for seizures.

Topics: Animals; Antioxidants; Ascorbic Acid; Autophagy; Brain; Brain Injuries; Lipid Peroxidation; Male; Malondialdehyde; Neuroprotective Agents; Oxidative Stress; Pilocarpine; Rats; Rats, Wistar; Seizures; Superoxide Dismutase

Lactate has been identified as an alternative fuel for the brain in situations of increased energy demand, as following a traumatic brain injury (TBI). This study investigates the effect of treatment with sodium lactate (NaLac) on the changes in brain energy state induced by a severe diffuse TBI. Rats were assigned to one of the eight groups (n=10 per group): 1-sham, normal saline; 2-TBI, normal saline; 3-TBI, hypertonic saline; 4-TBI, 100mM NaLac, 5-TBI, 500 mM NaLac; 6-TBI, 1280 mM NaLac; 7-TBI, 2000 mM NaLac and 8-TBI-500 mM NaLac+magnesium sulfate. Cerebrums were removed 6h after trauma. Metabolites representative of the energy state (ATP, ATP-catabolites), N-acetylaspartate (NAA), antioxidant defenses (ascorbic acid, glutathione), markers of oxidative stress (malondialdehyde, ADP-ribose) and nicotinic coenzymes (NAD(+)) were measured by HPLC. TBI induced a marked decrease in the cerebral levels of ATP, NAA, ascorbic acid, glutathione and NAD(+) and a significant rise in the content of ATP-catabolites, malondialdehyde and ADP-ribose. These alterations were not ameliorated with NaLac infusion. We observed a significant reduction in cerebral NAD(+), an essential co-enzyme for mitochondrial lactate-dehydrogenase that converts lactate into pyruvate and thus replenishes the tricarboxylic acid cycle. These results suggest that the metabolic pathway necessary to consume lactate may be compromised following a severe diffuse TBI in rats.

Topics: Adenosine Triphosphate; Animals; Ascorbic Acid; Aspartic Acid; Blood Gas Analysis; Blood Pressure; Brain Chemistry; Brain Injuries; Cerebral Cortex; Chromatography, High Pressure Liquid; Disease Models, Animal; Energy Metabolism; Glutathione; Male; Models, Biological; NAD; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Sodium Lactate

We have previously demonstrated that acute arginine administration induces oxidative stress and compromises energy metabolism in rat hippocampus. In the present study, we initially investigated the effect of intracerebroventricular infusion of arginine (0.1, 0.5 and 1.5 mM solution) on Na(+),K(+)-ATPase activity and on some parameters of oxidative stress, namely thiobarbituric acid-reactive substances (TBA-RS) and total radical-trapping antioxidant parameter (TRAP) in the hippocampus of rats. Results showed that 1.5 mM arginine solution significantly increases TBA-RS and reduces Na(+),K(+)-ATPase activity and TRAP in the rat hippocampus. We also evaluated the influence of the nitric oxide synthase inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME), and antioxidants, namely alpha-tocopherol plus ascorbic acid, on the effects elicited by arginine on Na(+),K(+)-ATPase activity, TBA-RS and TRAP. Results showed that treatment with alpha-tocopherol plus ascorbic acid per se did not alter these parameters but prevented these effects. Furthermore, intracerebroventricular infusion of L-NAME prevented the inhibition caused by arginine on Na(+),K(+)-ATPase activity, as well as the increased of TBA-RS. Our findings indicate that intracerebroventricular infusion of arginine induces oxidative stress in rat hippocampus and that the inhibition of Na(+),K(+)-ATPase activity caused by this amino acid was probably mediated by NO and/or its derivatives ONOO(-) and/or other free radicals. Finally, we suggest that the administration of antioxidants should be considered as an adjuvant therapy to specific diets in hyperargininemia.

Topics: alpha-Tocopherol; Amidines; Analysis of Variance; Animals; Antioxidants; Arginine; Ascorbic Acid; Brain Injuries; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Interactions; Enzyme Inhibitors; Hippocampus; Injections, Intraventricular; Male; NG-Nitroarginine Methyl Ester; Oxidative Stress; Rats; Rats, Wistar; Sodium-Potassium-Exchanging ATPase; Thiobarbituric Acid Reactive Substances

Urate and ascorbate play a major role in the defense mechanism of the brain against oxidative damage induced by traumatic brain injury. The severity and extent of brain damage are known to increase with age. This may be due to different basal levels of endogenous antioxidants, and/or to impaired ability of the old brain to recruit and elevate the levels of antioxidants following injury. To investigate this hypothesis, we measured basal ascorbate and urate levels in the hippocampus, using microdialysis in young, adults and old rats, and performed closed head injury (CHI) in young (5-6 weeks) and old rats (19-20 months). Basal ascorbate, but not urate levels in old rats were significantly lower than in the adults. The ability of the old rats to increase ascorbate levels after CHI was significantly lower than that of the young ones, as indicated by lower levels of ascorbate and urate in the dialysate of old rats. This lower level of antioxidant mobilization in the old brain may explain the extended damage found in histology. Evaluation of hippocampal cell loss (p<0.05) and axonal degeneration in the corpus callosum showed more extensive damage in old as compared to young rats (chi(2)=4.25; p<0.05). These findings shed more light on the susceptibility of old rat brain to CHI-induced oxidative damage.

Topics: Aging; Animals; Antioxidants; Ascorbic Acid; Axons; Brain Injuries; Corpus Callosum; Extracellular Matrix; Hippocampus; Male; Microdialysis; Nerve Degeneration; Neurons; Oxidative Stress; Rats; Rats, Wistar; Uric Acid

The mechanism of ethanol, morphine, methamphetamine (MAP), and nicotine-induced ascorbic acid (AA) release in striatum, and nucleus accumbens (NAc) is not well understood. Our previous study showed that the glutamatergic system was involved in the addictive drug-induced AA release in NAc and striatum. Furthermore, frontal decortication eliminates drug-induced ascorbic acid release in the striatum but not in the NAc. In the present study, the roles of the hippocampus in drug-induced AA release in the striatum and NAc were studied by using microdialysis coupled to high performance liquid chromatography with electrochemical detection (HPLC-ECD). Ethanol (3.0 g/kg, i.p.), methamphetamine (3.0 mg/kg, i.p.), and nicotine (1.5 mg/kg, i.p.) significantly stimulated AA release in the striatum and NAc, respectively. Morphine (20 mg/kg, i.p.) significantly stimulated AA release in the striatum, but not in the NAc. After hippocampal lesion by kainic acid, AA release induced by ethanol, methamphetamine, and nicotine could be eliminated in NAc, but not in the striatum. These results suggest that the hippocampus might be a common and necessary area in addictive drug-induced AA release in the NAc, which also imply that different pathways might be involved in drug-induced AA release in the striatum and the NAc of the rats.

Topics: Analysis of Variance; Animals; Ascorbic Acid; Brain Chemistry; Brain Injuries; Central Nervous System Depressants; Central Nervous System Stimulants; Corpus Striatum; Ethanol; Hippocampus; Interneurons; Kainic Acid; Male; Methamphetamine; Microdialysis; Morphine; Narcotics; Nicotine; Nicotinic Agonists; Nucleus Accumbens; Rats; Rats, Wistar

To compare biochemical and clinical parameters in a case of fatal severe traumatic brain injury (TBI) with secondary insult.. A TBI patient was catheterized for intracranial pressure (ICP) monitoring and cerebrospinal fluid (CSF) analysis of ascorbate, malondialdehyde, oxypurines, and nucleosides.. Oxidative brain damage preceded ATP catabolite increment in the CSF even with ICP below 20 mm Hg. Sustained oxidative stress caused irreversible energy state derangement followed by a refractory ICP rise. Massive oxypurine and nucleoside release was recorded 36 h before brain death.. Molecular events, detected by biochemical CSF analysis and preceding modification of clinical parameters in severe TBI with secondary insult, are discussed.

Topics: Ascorbic Acid; Brain Death; Brain Injuries; Humans; Male; Malondialdehyde; Middle Aged; Nucleosides; Oxidative Stress; Purines; Time Factors

The combined effect of traumatic brain injury (TBI) and secondary insult on biochemical changes of cerebral tissue is not well known. For this purpose, we studied the time-course changes of parameters reflecting ROS-mediated oxidative stress and modifications of cell energy metabolism determined in rats subjected to cerebral insult of increasing severity.. Rats were divided into four groups: 1) sham-operated, 2) subjected to 10 minutes of hypoxia and hypotension (HH), 3) subjected to severe diffuse TBI, and 4) subjected to severe diffuse TBI + HH. Rats were killed at different times after injury, and analyses of malondialdehyde, ascorbate, high-energy phosphates, nicotinic coenzymes, oxypurines, nucleosides, and N-acetylaspartate (NAA) were made by high-performance liquid chromatography on whole-brain tissue extracts.. Data indicated a close relationship between degree of oxidative stress and severity of brain insult, as evidenced by the highest malondialdehyde values and lowest ascorbate levels in rats subjected to TBI + HH. Similarly, modifications of parameters related to cell energy metabolism were modulated by increasing severity of brain injury, as demonstrated by the lowest values of energy charge potential, nicotinic coenzymes, and NAA and the highest levels of oxypurines and nucleosides recorded in TBI + HH rats. Both the intensity of oxidative stress-mediated cerebral damage and perturbation of energy metabolism were minimally affected in rats subjected to HH only.. These results showed that the severity of brain insult can be graded by measuring biochemical modifications, specifically, reactive oxygen species-mediated damage, energy metabolism depression, and NAA, thereby validating the rodent model of closed-head diffuse TBI coupled with HH and proposing NAA as a marker with diagnostic relevance to monitor the metabolic state of postinjured brain.

Topics: Animals; Ascorbic Acid; Aspartic Acid; Biomarkers; Brain; Brain Chemistry; Brain Injuries; Chromatography, High Pressure Liquid; Energy Metabolism; Head Injuries, Closed; Hypotension; Hypoxia; Male; Malondialdehyde; NAD; NADP; Nucleosides; Oxidative Stress; Phosphates; Purines; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species

Traumatic brain injury is a common event associated with neurological dysfunction. Oxidative damage, may contribute to some of these pathologic changes. We used a specific and sensitive marker of lipid peroxidation, the isoprostane 8,12-iso-iPF(2alpha) -VI, to investigate whether local and also systemic lipid peroxidation were induced following lateral fluid percussion (FP) brain injury in the rat. Animals were anesthetized and subjected to lateral FP brain injury of moderate severity, or to sham injury as controls. Urine was collected before anesthesia (baseline), 6 and 24 h after injury. Blood was collected at baseline, 1, 6 and 24 h after injury. Animals were killed 24 h after surgery and their brains removed for biochemical analysis. No significant difference was observed at baseline (preinjury) for urine and plasma 8,12-iso-iPF(2alpha) -VI levels between injured and sham-operated animals. By contrast, plasma and urinary levels increased significantly already at 1 and further increased 24 h following brain injury, when compared to sham-operated animals. Finally, compared with sham, injured animals had a significant increase in brain 8,12-iso-iPF(2alpha) -VI levels. These results demonstrate that moderate brain injury induces widespread brain lipid peroxidation, which is accompanied by a similar increase in urine and plasma. Peripheral measurement of 8,12-iso-iPF(2alpha) -VI levels after brain injury may be a reliable marker of brain oxidative damage.

Topics: Animals; Antioxidants; Ascorbic Acid; Biomarkers; Brain Chemistry; Brain Injuries; Dinoprost; Disease Models, Animal; Lipid Peroxidation; Male; Rats; Rats, Sprague-Dawley; Vitamin E

Studies in experimental traumatic brain injury (TBI) support a key role for oxidative stress. The degree of oxidative injury in clinical TBI, however, remains to be defined. We assessed antioxidant defenses and oxidative stress in pediatric TBI by applying a comprehensive battery of assays to cerebrospinal fluid samples. Using a protocol approved by our institutional review board, 87 cerebrospinal fluid samples from 11 infants and children with severe TBI (Glasgow Coma Scale score < or = 8) and 8 controls were studied. Cerebrospinal fluid was drained as standard care after TBI. CSF was assessed on d 1, 2, and 5-7 after ventricular drain placement. Biochemical markers of oxidative stress included F(2)-isoprostane and protein sulfhydryl (detected by ELISA and fluorescence assay, respectively). Antioxidant defenses were measured by determination of total antioxidant reserve (via chemiluminescence assay), and ascorbate (via HPLC) and glutathione (via fluorescence assay) concentrations. Free radical production (ascorbate radical) was assessed by electron paramagnetic resonance spectroscopy. F(2)-isoprostane was markedly increased versus control, maximal on d 1 (93.8 +/- 30.8 pg/mL versus 7.6 +/- 5.1 pg/mL, p < 0.05). Total antioxidant reserve was reduced versus control. Reduction was maximal on d 5-7 (81.8 +/- 3.7 microM versus 178.9 +/- 2.2 microM, p < 0.05). Ascorbate was remarkably reduced (53.8 +/- 8 microM versus 163.8 +/- 21 microM on d 1, p < 0.05). Ascorbate depletion was likely associated with its free radical oxidation, as evidenced by electron paramagnetic resonance spectroscopy. Glutathione levels increased on d 1, then decreased versus control (0.19 +/- 0.05 microM versus 1.2 +/- 0.16 microM, p < 0.05). This is the first comprehensive study of antioxidant reserve and oxidative injury in clinical TBI. Progressive compromise of antioxidant defenses and evidence of free radical-mediated lipid peroxidation are noted. These markers could be used to monitor antioxidant strategies in clinical trials.

Topics: Adolescent; Antioxidants; Ascorbic Acid; Brain Injuries; Cerebrospinal Fluid Proteins; Cerebrospinal Fluid Shunts; Child; Child, Preschool; Chromatography, High Pressure Liquid; Electron Spin Resonance Spectroscopy; F2-Isoprostanes; Female; Free Radicals; Glasgow Coma Scale; Glutathione; Humans; Infant; Luminescent Measurements; Male; Oxidative Stress; Sulfhydryl Compounds

There is an increasing recognition of the damaging role played by oxygen radicals in mediating necrotic neuronal injury. As such, it becomes important to understand the transport mechanisms that help maintain appropriate levels of small molecule antioxidants such as ascorbate in the brain. It has long been known that the transport of dehydroascorbate (DHA) into a variety of cell types is accomplished through the Glut-1 glucose transporter. In this paper, we characterize interactions among the transports of ascorbate, DHA and glucose in hippocampal cultures. We find: (a) sodium-dependent transport of ascorbate in mixed neuronal/glial, pure glial, and neuron-enriched hippocampal cultures; in contrast, we observed no such transport of DHA; (b) such ascorbate transport appeared to be independent of the glucose transporter, in that glucose did not compete for such transport, and overexpression of the Glut-1 glucose transporter did not alter ascorbate uptake; (c) in contrast, ascorbate, at concentrations ranging from 1 to 20 mM inhibited 2-dexogyglucose transport in mixed, glial and enriched neuronal hippocampal cultures; (d) potentially, ascorbate, by acting as an electron donor, could impair the function of molecules involve in the transport or metabolism of glucose. We observed mild inhibition of glucose transport by one unrelated electron donor (glutathione). Moreover, transport was also inhibited by an ascorbate analog which is not an electron donor. Thus, we conclude that ascorbate transport in hippocampal neurons and glia occurs independent of the glucose transporter but that, nevertheless, ascorbate, at concentrations generally thought to be supraphysiological, has the potential for disrupting glucose transport.

Topics: Animals; Ascorbic Acid; Brain Injuries; Carbon Radioisotopes; Cells, Cultured; Dehydroascorbic Acid; Deoxyglucose; Drug Interactions; Fetus; Glucose; Glucose Transporter Type 1; Glutathione; Hippocampus; Monosaccharide Transport Proteins; Nerve Degeneration; Neuroglia; Neurons; Oxidative Stress; Rats

Reactive oxygen species (ROS) are a major cause of secondary brain injury following head trauma. Low molecular weight antioxidants (LMWA) protect the tissue against oxidative damage caused by ROS. In the present study, we measured the extracellular levels of the LMWA ascorbic acid and uric acid in the rat brain before, during and after experimental closed head injury (CHI). A dialysis probe was inserted into the right ventral hippocampus through a chronically implanted guide. CHI was applied to the left hemisphere using a weight-drop device. CHI induced a rapid but transient increase in ascorbic acid levels. Uric acid levels increased to 250% of baseline shortly after CHI and remained elevated at 2 h after CHI. Previous results show that the overall reducing power of brain tissue decreases following CHI. Together with previous results, the current findings suggest that ascorbic acid and uric acid are mobilized from brain cells to the extracellular space.

Topics: Animals; Antioxidants; Ascorbic Acid; Brain Injuries; Extracellular Space; Head Injuries, Closed; Hippocampus; Male; Microdialysis; Neurons; Oxidative Stress; Rats; Rats, Inbred Strains; Reactive Oxygen Species; Up-Regulation; Uric Acid

Oxidative stress may contribute to many pathophysiologic changes that occur after traumatic brain injury. In the current study, contemporary methods of detecting oxidative stress were used in a rodent model of traumatic brain injury. The level of the stable product derived from peroxidation of arachidonyl residues in phospholipids, 8-epi-prostaglandin F(2alpha), was increased at 6 and 24 h after traumatic brain injury. Furthermore, relative amounts of fluorescent end products of lipid peroxidation in brain extracts were increased at 6 and 24 h after trauma compared with sham-operated controls. The total antioxidant reserves of brain homogenates and water-soluble antioxidant reserves as well as tissue concentrations of ascorbate, GSH, and protein sulfhydryls were reduced after traumatic brain injury. A selective inhibitor of cyclooxygenase-2, SC 58125, prevented depletion of ascorbate and thiols, the two major water-soluble antioxidants in traumatized brain. Electron paramagnetic resonance (EPR) spectroscopy of rat cortex homogenates failed to detect any radical adducts with a spin trap, 5,5-dimethyl-1-pyrroline N:-oxide, but did detect ascorbate radical signals. The ascorbate radical EPR signals increased in brain homogenates derived from traumatized brain samples compared with sham-operated controls. These results along with detailed model experiments in vitro indicate that ascorbate is a major antioxidant in brain and that the EPR assay of ascorbate radicals may be used to monitor production of free radicals in brain tissue after traumatic brain injury.

Topics: Animals; Antioxidants; Ascorbic Acid; Biomarkers; Brain Chemistry; Brain Injuries; Cerebral Cortex; Chromatography, High Pressure Liquid; Cyclooxygenase 2; Dinoprost; Disease Models, Animal; Electron Spin Resonance Spectroscopy; F2-Isoprostanes; Free Radicals; Hippocampus; Isoenzymes; Male; Oxidation-Reduction; Oxidative Stress; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Sprague-Dawley; Wounds, Nonpenetrating

Traumatic injury to the brain triggers the accumulation of harmful mediators, including highly toxic reactive oxygen species (ROS). Endogenous defense mechanism against ROS is provided by low molecular weight antioxidants (LMWA), reflected in the reducing power of the tissue, which can be measured by cyclic voltammetry (CV). CV records biological peak potential (type of scavenger), and anodic current intensity (scavenger concentration). The effect of closed head injury (CHI) on the reducing power of various organs was studied. Water and lipid soluble extracts were prepared from the brain, heart, lung, kidney, intestine, skin, and liver of control and traumatized rats (1 and 24 h after injury) and total LMWA was determined. Ascorbic acid, uric acid, alpha-tocopherol, carotene and ubiquinol-10 were also identified by HPLC. The dynamic changes in LMWA levels indicate that the whole body responds to CHI. For example, transient reduction in LMWA (p<0.01) in the heart, kidney, lung and liver at 1 h suggests their consumption, probably due to interaction with locally produced ROS. However, in some tissues (e.g., skin) there was an increase (p<0.01), arguing for recruitment of higher than normal levels of LMWA to neutralize the ROS. alpha-Tocopherol levels in the brain, liver, lung, skin, and kidney were significantly reduced (p<0.01) even up to 24 h. We conclude that although the injury was delivered over the left cerebral hemisphere, the whole body appeared to be under oxidative stress, within 24 h after brain injury.

Topics: Animals; Antioxidants; Ascorbic Acid; Brain; Brain Injuries; Carnosine; Carotenoids; Free Radical Scavengers; Head Injuries, Closed; Intestinal Mucosa; Kidney; Lung; Male; Melatonin; Organ Specificity; Oxidative Stress; Rats; Thioctic Acid; Time Factors; Vitamin E

Sodium nitroprusside (disodium nitroferricyanide) has been suggested to cause cytotoxicity through either the release of cyanide and/or nitric oxide. The present study investigated a possible mechanism that after a brief release of nitric oxide, iron moiety of breakdown products of sodium nitroprusside could cause a long lasting oxidative stress, such as hydroxyl radical generation, lipid peroxidation and cytotoxicity. Intranigral administration of sodium nitroprusside (0-16.8 nmol) to rats induced an acute increase in lipid peroxidation in the substantia nigra and a chronic dopamine depletion in the caudate nucleus. Photodegraded (nitric oxide-exhausted) sodium nitroprusside, however, still produced lipid peroxidation and neurotoxicity in the midbrain. Moreover, non-iron containing nitric oxide-donor compounds, such as S-nitroso-N-acetylpenicillamine, did not cause oxidative brain injury in vivo suggesting that nitric oxide may not mediate neurotoxicity induced by sodium nitroprusside. Additional in vitro studies demonstrated that both freshly prepared (nitric oxide donor) and photodegraded (nitric oxide-exhausted) sodium nitroprusside generated hydroxyl radicals in the presence of ascorbate and also increased lipid peroxidation in brain homogenates. These pro-oxidative effects of sodium nitroprusside were blocked by nitric oxide, S-nitroso-N-acetylpenicillamine, oxyhemoglobin, and deferoxamine (iron chelator). The present results suggest that iron moiety, rather than nitric oxide, may mediate the pro-oxidative properties of sodium nitroprusside. With this new information in mind, the misuse of sodium nitroprusside as a selective nitric oxide donor in both basic and clinical uses should be urgently addressed.

Topics: Animals; Ascorbic Acid; Brain Injuries; Deferoxamine; Hydrogen Peroxide; Hydroxyl Radical; In Vitro Techniques; Iron; Lipid Peroxidation; Male; Nerve Degeneration; Nitric Oxide; Nitroprusside; Oxidative Stress; Oxyhemoglobins; Penicillamine; Rats; Rats, Sprague-Dawley

Reactive oxygen species (ROS) are normally generated in the brain during metabolism, and their production is enhanced by various insults. Low molecular weight antioxidants (LMWA) are one of the defense mechanisms of the living cell against ROS. The reducing capacity of brain tissue (total LMWA) was measured by cyclic voltammetry (CV), which records biological oxidation potential specific to the type of scavenger(s) present and anodic current intensity (Ia), which depends on scavenger concentration. In the present study, the reducing capacity of rat brain following closed head injury (CHI) was measured. In addition, CV of heat-acclimated traumatized rats was used to correlate endogenous cerebroprotection after CHI with LMWA activity. Sham-injured rat brains displayed two anodic potentials: at 350 +/- 50 mV (Ia = 0.75 +/- 0.06 microA/mg protein) and at 750 +/- 50 mV (Ia = 1.00 +/- 0.05 microA/mg protein). Following CHI, the anodic waves appeared at the same potentials as in the sham animals. However, within 5 min of CHI, the total reducing capacity was transiently decreased by 40% (p < 0.01). A second dip was detected at 24 h (60%, p < 0.005). By 48 h and at 7 days, the Ia levels normalized. The acclimated rats displayed anodic potentials identical to those of normothermic rats. However, the Ia of both potentials was lower (60% of control, p < 0.001). The Ia profile after CHI was the direct opposite of the normothermic Ia profile: no immediate decrease of Ia and an increase from 4 h and up to 7 days (40-50%, p < 0.001). We suggest that the lowered levels of LMWA in the post-CHI period reflect their consumption due to overproduction of free radicals. The augmented concentration of LMWA found in the brain of the heat-acclimated rats suggests that these rats are better able to cope with these harmful radicals, resulting in a more favorable outcome following CHI.

Topics: Acclimatization; Animals; Antioxidants; Ascorbic Acid; Brain Chemistry; Brain Injuries; Craniocerebral Trauma; Disease Susceptibility; Electric Conductivity; Free Radical Scavengers; Heart; Hot Temperature; Male; Myocardium; Oxidation-Reduction; Oxidative Stress; Rats; Reactive Oxygen Species; Tryptophan

Free radicals may be involved in the pathophysiology of traumatic brain injury (TBI) through oxidative damage of neurovascular structures. Endogenous antioxidants, such as ascorbate and alpha-tocopherol, may play a critical role in combating these oxidative reactions and their oxidized products can serve as an important index of oxidative stress.. We used electron spin resonance (ESR) spectroscopy and in vivo spin trapping (reaction of an organic compound with free radical species) to detect the possible generation of free radicals after TBI. Injury was inflicted by a weight drop technique over the head (5.7 kg-cm). Rats were intravenously infused with either 1 mL, 0.1 M of the spin trap, alpha-phenyl-N-tert-butyl nitrone (PBN), or an equivalent volume of saline immediately before TBI or sham-injury. Animals were divided into four groups: (1) Group I: PBN-infused sham-injured, (2) Group II: PBN-infused injured, (3) Group III: saline-infused sham-injured, and (4) Group IV: saline-infused injured. Additional groups of saline-infused uninjured, saline-infused, and PBN-infused injured animals were used for histopathology. Sixty minutes after TBI or sham-injury, rats were again anesthetized and decapitated. The brains were removed within 1 minute, homogenized, and extracted for lipids. The extracts were analyzed by ESR spectroscopy. Brain ascorbic acid (AA) concentration was determined spectrophotometrically, using the ascorbate oxidase assay.. No PBN spin adduct signals (indicating trapped free radical species) were visible 60 minutes after TBI. All groups of rats showed an ascorbyl free radical signal. The ascorbyl signal intensity (AI) was, however, significantly higher in the injured rats, while the brain (AA) was significantly reduced. In addition, the ratio of AI/AA, which eliminates the effect of variable ascorbate concentrations in the brain, was also significantly higher in the injured animals.. We conclude that 60 minutes following TBI there was a significantly increased level of oxidative stress in the brain. This may reflect formation of free radical species with subsequent interaction with ascorbate (antioxidant) during the 60 minute period. The lack of PBN spin adduct signals 1 hour after TBI may indicate that free radical generation is time dependent and might be detectable earlier or later than the 60 minute period.

Topics: Animals; Ascorbic Acid; Brain Injuries; Electron Spin Resonance Spectroscopy; Free Radicals; Male; Osmolar Concentration; Oxidative Stress; Rats; Rats, Sprague-Dawley

Delayed tissue damage is proposed to be caused by reactive oxygen species. We investigated the effects of microdialysis probe penetration into rat piriform cortex on hydrogen peroxide (H2O2) in brain extracellular fluid (ECF). H2O2 decreased immediately after probe insertion into the brain, but increased over 300% in samples within minutes after collection. We assessed H2O2 changes in vitro in microdialysis perfusion media containing various ascorbic acid concentrations and confirmed ascorbic acid is a source of H2O2. We conclude that decreased H2O2 concentrations in perfusion media as it passes through the brain reflect an extracellular antioxidant effect, whereas the increase in H2O2 with time after sample collection indicates that H2O2 generating substances are present in ECF. Thus, the potential for producing reactive oxygen species in brain ECF exists following penetration injury, especially if transition metals are released into the neuronal microenvironment.

Topics: Animals; Ascorbic Acid; Brain Injuries; Extracellular Space; Hydrogen Peroxide; Male; Microdialysis; Rats; Rats, Wistar; Time Factors

To examine the role played by free radicals in brain injury, we performed experiments to detect radicals in the frontal cortex of rats, using electron spin resonance (ESR) and microdialysis. A dialysis probe was inserted into the frontal cortex, and spin adducts in perfusates were immediately detected by ESR. We obtained a relatively stable doublet signal, with parameters of g = 2.0057 and aH = 0.17 mT. This signal corresponded with that of the ascorbyl radical. Ascorbyl radical in the perfusate collected from the frontal cortex was augmented by microinjection of H2O2 and FeCl2 adjacent to the dialysis probe. When the rats were challenged with cold-induced brain injury, ascorbyl radical and lactate dehydrogenase (LDH) level in the perfusate increased significantly. Pretreatment with superoxide dismutase and catalase attenuated the increase in ascorbyl radical and LDH level induced by the cold injury. Infusion of FeCl2 dissolved in perfusate caused a pronounced increase in ascorbyl radical and LDH level after the cold injury. We conclude that the direct detection of free radical formation further supports the hypothesis that free radicals play an important role in traumatic brain injury. Our findings also indicate that combined microdialysis with ESR spectroscopy is a useful in vivo method for monitoring free radical production in the brain.

Topics: Animals; Ascorbic Acid; Brain Injuries; Catalase; Cerebral Cortex; Cold Temperature; Dehydroascorbic Acid; Electron Spin Resonance Spectroscopy; Extracellular Space; Ferrous Compounds; Free Radicals; L-Lactate Dehydrogenase; Male; Microdialysis; Perfusion; Rats; Rats, Wistar; Superoxide Dismutase

We will report on our preliminary findings using microdialysis to monitor three patients in intensive care with either severe head injury (SHI) or severe subarachnoid hemorrhage (SAH) for up to 72 hours. In addition, basal levels in uninjured brain were assessed during an extra-intracranial bypass operation. Samples were collected hourly or half-hourly (flow rate 2 microliters/min, perfusion medium 0.9% saline). Parameters measured were the antioxidants ascorbic acid, uric acid, glutathione and cysteine. In 2 patients, the pH of the dialysate (pHD) was also measured on-line with a specially constructed flow-through meter, and glucose and lactate levels were assessed in the dialysate. In patient 1 (SHI), there was practically no cerebral perfusion pressure because of high ICP; cysteine and lactate levels were very high and glucose not measurable. In patient 2 (SAH) a hypoxic episode was accompanied by increased uric acid and decreased glucose. In patient 3 (SHI), the pHD reflected normalisation of blood gases after hyperventilation. Results indicate that parameters are in the range known from experimental studies, and can be correlated with clinical situations. The pHD as valuable indicator of metabolic changes is also feasible bedside.

Topics: Acid-Base Equilibrium; Adult; Ascorbic Acid; Blood Glucose; Blood-Brain Barrier; Brain Edema; Brain Injuries; Cerebrospinal Fluid Shunts; Craniotomy; Critical Care; Cysteine; Energy Metabolism; Female; Glutathione; Humans; Hydrogen-Ion Concentration; Hypoxia, Brain; Intracranial Pressure; Lactates; Lactic Acid; Male; Microdialysis; Middle Aged; Monitoring, Physiologic; Online Systems; Postoperative Complications; Signal Processing, Computer-Assisted; Subarachnoid Hemorrhage; Uric Acid

The authors present their results regarding the use of a buffered solution of glycerol 30%-sodium ascorbate 20% (GLIAS) for the treatment of brain oedema and intracranial hypertension. GLIAS was perfused intravenously in 80 patients with several types of brain oedema. In every patients serum and urinary osmolarity, diuresis, main blood and urine parameters, and ICP were monitored. Following GLIAS infusion an increase in plasma osmolarity was observed, changing the average basal value plus 13.4% after 15 min., 10.5% after 30'. At the same time there was a reduction of ICP and improvement in cerebral compliance. In each case there was a decrease in intracranial hypertension and brain oedema without significant collateral effects.

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Brain Edema; Brain Injuries; Brain Neoplasms; Buffers; Cerebral Hemorrhage; Child; Dose-Response Relationship, Drug; Female; Glycerol; Humans; Hypertonic Solutions; Infusions, Intravenous; Intracranial Aneurysm; Intracranial Pressure; Male; Middle Aged; Postoperative Complications; Pseudotumor Cerebri

Extracellular (EC) ascorbate concentrations were measured in microdialysates from the cerebral cortex in rats subjected to cortical compression-contusion trauma. The trauma induced a transient, dramatic increase in EC ascorbate compared to the basal level before the insult and compared to control animals. The data support the presence of a releasable intracellular pool of ascorbate in the neocortex. The possibility that ascorbate may influence traumatic brain damage by its proposed neuromodulatory property and/or by its ability to induce lipid peroxidation is considered.

Topics: Animals; Ascorbic Acid; Brain Injuries; Cerebral Cortex; Extracellular Space; Male; Rats; Rats, Inbred Strains

Previous work has shown that unsaturated fatty acid components of model membrane phospholipids in vitro, damaged via a free radical mechanism, are protected by the presence of cholesterol in these membranes. The participation of these membrane lipids in the pathogenesis of traumatic injury to brain was studied in vivo using the Klatzo method of cryogenic injury in rats. Increased edema 4 hr after cryogenic injury was noted on the lesioned side. Total cerebral cholesterol was decreased significantly in the lesioned hemispheres 10 hr following injury. In lesioned animals pretreated and post-treated with methylprednisolone, there were no significant differences in the cholesterol levels. Arachidonic acid isolated from total membrane phospholipids was significantly reduced on the injured side 24 hr after injury, but not before. Other fatty acids were not significantly affected. Methylprednisolone treatment prevented the decrease in arachidonic acid. Animals that had received a cold injury had significant decreases in ascorbic acid levels after 4 hr on the lesioned side of the brain. This decrease was significantly ameliorated by corticosteroid administration. These results support the hypothesis that the protective effect of corticosteroids in cryogenic cerebral trauma may be due to antioxidant protection of major cell membrane lipid components such as cholesterol and phospholipids.

Topics: Animals; Ascorbic Acid; Brain; Brain Edema; Brain Injuries; Cholesterol; Fatty Acids, Unsaturated; Free Radicals; Freezing; Membrane Lipids; Methylprednisolone; Phospholipids; Rats; Rats, Inbred Strains

Topics: Ascorbic Acid; Brain; Brain Injuries; Flavonoids; Humans; Rutin; Vitamins; Wounds and Injuries