Brain Redox Status Research Articles

Neurodevelopment and Cognitive Impairment in Parents and Progeny of Perinatal Dietary Protein Deficiency Models.

There is an absolute dependence of the concept of development on supply of adequately balanced nutrients especially during the perinatal age which is critical to development. Therefore, an upgraded nutrition is specially required during gestation and lactation, as this is the critical period of neurodevelopment. This study sought to investigate the effect of protein deficiency during gestation (F0) and lactation through to adolescence on neurological functions of subsequent (F1 and F2) generations, establishing the possible consequential mechanistic association. Rats in four groups were fed different rations of protein diets (PD) as formulated: 21% PD, 10% PD, 5% PD and control diet (standard rat chow, containing 16–18% protein), from adolescent through to gestation and lactation, next generations were weaned to the maternal diet group. Neurobehavioral studies (which include; Surface righting reflex, Negative geotaxis, Learning and Memory tests), brain oxidative stress and quantification of serotonin and dopamine levels in the brain were conducted. Result shows significantly altered neurobehavior, reflected in the reduction of reflex response and postural reaction score at P ≤ 0.05. There was also a transgenerational cognitive impairment of brain function in the F-generations, following perinatal protein malnutrition as shown in the Y-maze result, measuring spatial memory and Morris water maze result (cognition), providing a background for the observed sensorimotor response. The significant increase in dopamine level, decrease in the antioxidant capacity of the protein deficient brain groups are consistent with significantly altered serotonin system, critical to neurodevelopment and functional activities of learning and memory. Therefore, persistent early life protein deficiency mediates dysfunction in neurodevelopment and this involves life-long changes in key neurotransmitters and the brain redox status underlying the neurobehavioral display.

Bezafibrate In Vivo Administration Prevents 3-Methylglutaric Acid-Induced Impairment of Redox Status, Mitochondrial Biogenesis, and Neural Injury in Brain of Developing Rats.

3-Methylglutaric acid (MGA) is an organic acid that accumulates in 3-methylglutaconic (MGTA) and 3-hydroxy-3-methylglutaric (HMGA) acidurias. Patients affected by these disorders present with neurological dysfunction that usually appears in the first years of life. In order to elucidate the pathomechanisms underlying the brain injury in these disorders, we evaluated the effects of MGA administration on redox homeostasis, mitochondrial respiratory chain activity, and biogenesis in the cerebral cortex of developing rats. Neural damage markers and signaling pathways involved in cell survival, and death were also measured after MGA administration. Furthermore, since the treatment for MGTA and HMGA is still limited, we tested whether a pre-treatment with the pan-peroxisome proliferator-activated receptor (PPAR) agonist bezafibrate could prevent the alterations caused by MGA. MGA provoked lipid peroxidation, increased heme oxygenase-1 content, and altered the activities of antioxidant enzymes, strongly suggestive of oxidative stress. MGA also impaired mitochondrial function and biogenesis by decreasing the activities of succinate dehydrogenase and various respiratory chain complexes, as well as the nuclear levels of PGC-1α and NT-PGC-1α, and cell content of Sirt1. AMPKα1 was further increased by MGA. Neural cell damage was also observed following the MGA administration, as verified by decreased Akt and synaptophysin content and reduced ERK phosphorylation, and by the increase of active caspase-3 and p38 and Tau phosphorylation. Importantly, bezafibrate prevented MGA-elicited toxic effects towards mitochondrial function, redox homeostasis, and neural cell injury, implying that this compound may be potentially used as an adjunct therapy for MGTA and HMGA and other disorders with mitochondrial dysfunction.

Brain Redox Imaging Using In Vivo Electron Paramagnetic Resonance Imaging and Nitroxide Imaging Probes

Reactive oxygen species (ROS) are produced by living organisms as a result of normal cellular metabolism. Under normal physiological conditions, oxidative damage is prevented by the regulation of ROS by the antioxidant network. However, increased ROS and decreased antioxidant defense may contribute to many brain disorders, such as stroke, Parkinson’s disease, and Alzheimer’s disease. Noninvasive assessment of brain redox status is necessary for monitoring the disease state and the oxidative damage. Continuous-wave electron paramagnetic resonance (CW-EPR) imaging using redox-sensitive imaging probes, such as nitroxides, is a powerful method for visualizing the redox status modulated by oxidative stress in vivo. For conventional CW-EPR imaging, however, poor signal-to-noise ratio, low acquisition efficiency, and lack of anatomic visualization limit its ability to achieve three-dimensional redox mapping of small rodent brains. In this review, we discuss the instrumentation and coregistration of EPR images to anatomical images and appropriate nitroxide imaging probes, all of which are needed for a sophisticated in vivo EPR imager for all rodents. Using new EPR imaging systems, site-specific distribution and kinetics of nitroxide imaging probes in rodent brains can be obtained more accurately, compared to previous EPR imaging systems. We also describe the redox imaging studies of animal models of brain disease using newly developed EPR imaging.

Modulation of dopamine metabolizing enzymes and antioxidant status by Capsicum annuum Lin in rotenone-intoxicated rat brain.

Rotenone is a natural pesticide and environmental neurotoxin which mimics key aspects of Parkinson's disease. This study evaluated the effect of ethyl acetate extract of Capsicum annuum L. (C. annuum) in rotenone-intoxicated rats. Oral doses of C. annuum extract (50, 100 & 200 mg kg-1) and rotenone (2 mg kg-1 i.p.) were co-administered for 25 days during which rearing behavior was monitored. Biochemical alterations in the levels of tyrosine hydroxylase (TH), monoamine oxidase (MAO), superoxide dismutase (SOD) as well as reduced and oxidized glutathione (GSH) were estimated. Decrease in rearing behavior resulting from rotenone exposure was ameliorated by 200 mg kg-1 of C. annuum. Furthermore, rotenone exposure significantly (P < 0.05) decreased TH and increased MAO levels respectively. Impaired brain antioxidant capacity, typified by significantly (P < 0.05) decreased GSH redox status and SOD levels were also observed in rotenone-treated rats. However, co-administration of C. annuum ameliorated rotenone-induced derangements and potentiated the effect of levodopa. These results taken together suggests that C. annuum protects against rotenone-induced neurotoxicity by modulating dopamine metabolism and GSH redox status in rat brain.

Advances in cellular and integrative control of oxygen homeostasis within the central nervous system.

Mammals must continuously regulate the levels of O2 and CO2 , which is particularly important for the brain. Failure to maintain adequate O2 /CO2 homeostasis has been associated with numerous disorders including sleep apnoea, Rett syndrome and sudden infant death syndrome. But, O2 /CO2 homeostasis poses major regulatory challenges, even in the healthy brain. Neuronal activities change in a differentiated, spatially and temporally complex manner, which is reflected in equally complex changes in O2 demand. This raises important questions: is oxygen sensing an emergent property, locally generated within all active neuronal networks, and/or the property of specialized O2 -sensitive CNS regions? Increasing evidence suggests that the regulation of the brain's redox state involves properties that are intrinsic to many networks, but that specialized regions in the brainstem orchestrate the integrated control of respiratory and cardiovascular functions. Although the levels of O2 in arterial blood and the CNS are very different, neuro-glial interactions and purinergic signalling are critical for both peripheral and CNS chemosensation. Indeed, the specificity of neuroglial interactions seems to determine the differential responses to O2 , CO2 and the changes in pH.

Possible involvement of tetrahydrobiopterin in the disturbance of redox homeostasis in sepsis – Induced brain dysfunction

Background and aimTetrahydrobiopterin (BH4) is an essential co-factor that regulates nitric oxide (NO) and reactive oxygen species (ROS) production by nitric oxide synthases (NOS). In this study, we evaluated the effects of sepsis on BH4 level and redox status in the brain by using the rat model of sepsis-induced by cecal ligation and puncture (CLP) and examined whether BH4 and/or acetyl-L-carnitine (ALC) could prevent the neuronal apoptosis and neurological changes induced by sepsis. Material and methodMale albino rats were randomly and blindly divided into 8 groups: sham, sham + BH4, sham + ALC, sham +BH4+ ALC, CLP, CLP + BH4, CLP + ALC, and CLP+BH4+ ALC. We measured neurological indicators, brain levels of BH4, guanosine triphosphate cyclohydrolase (GTPCH), sepiapterin reductase (SR) and dihydropteridine reductase (DHPR) genes expression (Essential enzymes in BH4 biosynthesis and recycling pathways). We investigated also brain redox status and both endothelial and inducible NOS expressions. ResultsBrain of septic rats demonstrated a reduced BH4 bioavailability, downregulation of BH4 synthetic enzymes, increased production of hydrogen peroxide and impaired antioxidant enzymes activities. Treatments with BH4 and/or ALC increased BH4 level, upregulated BH4 synthetic enzymes expressions, and attenuated oxidative-induced neuronal apoptosis. ConclusionOur results suggest that BH4 and/or ALC might protect the brain against oxidative stress induced neuronal apoptosis by restoring bioavailability of BH4 and upregulating of BH4 synthetic enzymes in the brain during sepsis.

Hydrogen Sulfide Ameliorates Developmental Impairments of Rat Offspring with Prenatal Hyperhomocysteinemia.

Maternal high levels of the redox active amino acid homocysteine—called hyperhomocysteinemia (hHCY)—can affect the health state of the progeny. The effects of hydrogen sulfide (H2S) treatment on rats with maternal hHCY remain unknown. In the present study, we characterized the physical development, reflex ontogeny, locomotion and exploratory activity, muscle strength, motor coordination, and brain redox state of pups with maternal hHCY and tested potential beneficial action of the H2S donor—sodium hydrosulfide (NaHS)—on these parameters. Our results indicate a significant decrease in litter size and body weight of pups from dams fed with methionine-rich diet. In hHCY pups, a delay in the formation of sensory-motor reflexes was observed. Locomotor activity tested in the open field by head rearings, crossed squares, and rearings of hHCY pups at all studied ages (P8, P16, and P26) was diminished. Exploratory activity was decreased, and emotionality was higher in rats with hHCY. Prenatal hHCY resulted in reduced muscle strength and motor coordination assessed by the paw grip endurance test and rotarod test. Remarkably, administration of NaHS to pregnant rats with hHCY prevented the observed deleterious effects of high homocysteine on fetus development. In rats with prenatal hHCY, the endogenous generation of H2S brain tissues was lower compared to control and NaHS administration restored the H2S level to control values. Moreover, using redox signaling assays, we found an increased level of malondialdehyde (MDA), the end product of lipid peroxidation, and decreased activity of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the brain tissues of rats of the hHCY group. Notably, NaHS treatment restored the level of MDA and the activity of SOD and GPx. Our data suggest that H2S has neuroprotective/antioxidant effects against homocysteine-induced neurotoxicity providing a potential strategy for the prevention of developmental impairments in newborns.

Short-term effects of aluminum and selenium on redox status in mice brain and blood

Short-term effects of aluminum and selenium on redox status in mice brain and blood

Non-invasive imaging of the levels and effects of glutathione on the redox status of mouse brain using electron paramagnetic resonance imaging

Glutathione (GSH) is the most abundant non-protein thiol that buffers reactive oxygen species in the brain. GSH does not reduce nitroxides directly, but in the presence of ascorbates, addition of GSH increases ascorbate-induced reduction of nitroxides. In this study, we used electron paramagnetic resonance (EPR) imaging and the nitroxide imaging probe, 3-methoxycarbonyl-2,2,5,5-tetramethyl-piperidine-1-oxyl (MCP), to non-invasively obtain spatially resolved redox data from mouse brains depleted of GSH with diethyl maleate compared to control. Based on the pharmacokinetics of the reduction reaction of MCP in the mouse heads, the pixel-based rate constant of its reduction reaction was calculated as an index of the redox status in vivo and mapped as a “redox map”. The obtained redox maps from control and GSH-depleted mouse brains showed a clear change in the brain redox status, which was due to the decreased levels of GSH in brains as measured by a biochemical assay. We observed a linear relationship between the reduction rate constant of MCP and the level of GSH for both control and GSH-depleted mouse brains. Using this relationship, the GSH level in the brain can be estimated from the redox map obtained with EPR imaging.

380 - In Vivo Brain Redox Status in Diethylmaleate-Treated Mice Using EPR Imaging

Under normal physiological conditions, oxidative damage is prevented by the regulation of ROS by the antioxidant network. Major antioxidants in brain are ascorbic acid (AsA) and glutathione (GSH), and the levels of these antioxidants change depending on the disease state. Nitroxides are redox-sensitive compounds and reduced in vivo in the presence of AsA and GSH. Therefore, EPR imaging with nitroxides has been used to visualize the redox status in oxidative brain diseases, but the role of GSH on the reduction reaction of nitroxides is not clear. In the present study, using the mouse model of GSH depletion with diethylmaleate (DEM), the role of GSH in the brain redox status was examined non-invasively by EPR imaging with blood brain barrier-permeable 3-methoxycarbonyl-PROXYL (MCP). The pixel-based reduction rates of MCP in control and DEM-treated mouse heads were calculated and plotted as a redox map. The obtained redox map clearly showed that reduction rates of MCP significantly decreased in DEM-treated mouse brain. The GSH assay showed a significant reduction of GSH levels in DEM-treated mouse brain compared with untreated one. Alteration of the GSH level correlates well with the change in redox status of mouse brain image.

Evaluation of Brain Redox Status and Its Association with Cognitive Dysfunction in Diabetic Animal Models by Redox Molecular Imaging (ReMI).

Oxidative stress contributes to the development of diabetic complications. Increasing epidemiologic evidence suggests that diabetes mellitus is associated with dementia and cognitive decline. However, the underlying mechanisms are not fully understood. We have evaluated brain redox status and its association of cognitive dysfunction in diabetic animal models by dynamic nuclear polarization-magnetic resonance imaging (DNP-MRI) and other oxidative stress markers. In this review, we discuss the role of oxidative stress in the development of diabetes-related dementia and clinical regulation of the redox state in new approaches to augmenting diabetes-related dementia.

Guanosine Exerts Neuroprotective Effect in an Experimental Model of Acute Ammonia Intoxication

The nucleoside guanosine (GUO) increases glutamate uptake by astrocytes and acts as antioxidant, thereby providing neuroprotection against glutamatergic excitotoxicity, as we have recently demonstrated in an animal model of chronic hepatic encephalopathy. Here, we investigated the neuroprotective effect of GUO in an acute ammonia intoxication model. Adult male Wistar rats received an intraperitoneal (i.p.) injection of vehicle or GUO 60mg/kg, followed 20min later by an i.p. injection of vehicle or 550mg/kg of ammonium acetate. Afterwards, animals were observed for 45min, being evaluated as normal, coma (i.e., absence of corneal reflex), or death status. In a second cohort of rats, video-electroencephalogram (EEG) recordings were performed. In a third cohort of rats, the following were measured: (i) plasma levels of glucose, transaminases, and urea; (ii) cerebrospinal fluid (CSF) levels of ammonia, glutamine, glutamate, and alanine; (iii) glutamate uptake in brain slices; and (iv) brain redox status and glutamine synthetase activity in cerebral cortex. GUO drastically reduced the lethality rate and the duration of coma. Animals treated with GUO had improved EEG traces, decreased CSF levels of glutamate and alanine, lowered oxidative stress in the cerebral cortex, and increased glutamate uptake by astrocytes in brain slices compared with animals that received vehicle prior to ammonium acetate administration. This study provides new evidence on mechanisms of guanine-derived purines in their potential modulation of glutamatergic system, contributing to GUO neuroprotective effects in a rodent model of by acute ammonia intoxication.

The Dietary Components Carnosic Acid and Carnosol as Neuroprotective Agents: a Mechanistic View.

Carnosic acid (CA) and carnosol are the major diterpenes found in Rosmarinus officinalis (rosemary), a culinary spice. CA and carnosol account for over 90% of its anti-oxidant activity in rosemary leaves. The diterpenes exert anti-oxidant, anti-inflammatory, and anti-carcinogenic activities, and present neuroprotective effects in both in vitro and in vivo experimental models. In some cases, CA exerted protective effects upon neuronal cells more intensely than resveratrol or sulforaphane. Therefore, CA and carnosol demonstrate a potential pharmacological role for rosemary diterpenes in ameliorating mammalian brain redox status, among other parameters, as for instance the modulation of neuroinflammation. The aim of this review is to discuss the biological effects of CA and carnosol on neuronal and glial cells with focus on the mechanism of action of such diterpenes.

Brain redox imaging in the pentylenetetrazole (PTZ)-induced kindling model of epilepsy by using in vivo electron paramagnetic resonance and a nitroxide imaging probe

Much evidence supports the idea that oxidative stress is involved in the pathogenesis of epilepsy, and therapeutic interventions with antioxidants are expected as adjunct antiepileptic therapy. The aims of this study were to non-invasively obtain spatially resolved redox data from control and pentylenetetrazole (PTZ)-induced kindled mouse brains by electron paramagnetic resonance (EPR) imaging and to visualize the brain regions that are sensitive to oxidative damage. After infusion of the redox-sensitive imaging probe 3-methoxycarbonyl-2,2,5,5-tetramethyl-piperidine-1-oxyl (MCP), a series of EPR images of PTZ-induced mouse heads were measured. Based on the pharmacokinetics of the reduction reaction of MCP in the mouse heads, the pixel-based rate constant of its reduction reaction was calculated as an index of redox status in vivo and mapped as a redox map. The obtained redox map showed heterogeneity in the redox status in PTZ-induced mouse brains compared with control. The co-registered image of the redox map and magnetic resonance imaging (MRI) for both control and PTZ-induced mice showed a clear change in the redox status around the hippocampus after PTZ. To examine the role of antioxidants on the brain redox status, the levels of antioxidants were measured in brain tissues of control and PTZ-induced mice. Significantly lower concentrations of glutathione in the hippocampus of PTZ-kindled mice were detected compared with control. From the results of both EPR imaging and the biochemical assay, the hippocampus was found to be susceptible to oxidative damage in the PTZ-induced animal model of epilepsy.

High-intensity Exercise Modifies the Effects of Stanozolol on Brain Oxidative Stress in Rats

We analyzed the effects of high-intensity exercise (HIE) and anabolic androgenic steroids (AAS) on brain redox status. 40 male Wistar rats were randomly distributed in 4 experimental groups (n=10) with or without HIE and with or without weekly Stanozolol administration. Thiobarbituric acid-reactive substances (TBARs) and protein carbonyl content (PCC) were assessed. Total superoxide dismutase (tSOD), manganese superoxide dismutase (Mn-SOD), copper/zinc superoxide dismutase (CuZn-SOD) and catalase (CAT) activities were measured. Finally, protein expression levels of glutathione peroxidase (GPx), NAD(P)H dehydrogenase, Quinone 1 (NQO1), NF-E2-Related Factor 2 (Nrf2), glial fibrillary acidic protein (GFAP), nuclear factor kappa β p65 (NF-κβ) and signal transducer and activator of transcription 3 were determined. Brain PCC concentrations were lower in the HIE groups compared to the untrained controls, whereas CAT activity was higher (both, p<0.01). Both HIE and AAS groups exhibited higher expression levels of GFAP and GPx, but lower NQO1 levels (all, p<0.05). There were increased expression levels of NF-κβ in the AAS groups (p<0.01). In addition, there was increased expression of Nrf2 in the HIE groups (p<0.001). HIE*AAS interactions were found on TBARs content and GFAP expression, with HIE downregulating and upregulating AAS-mediated increases in TBARs and GFAP, respectively (p<0.05). Overall, HIE appeared to reduce the AAS-mediated negative effect on brain redox status.

Brain imaging in methamphetamine-treated mice using a nitroxide contrast agent for EPR imaging of the redox status and a gadolinium contrast agent for MRI observation of blood–brain barrier function

Methamphetamine (METH)-induced neurotoxicity is associated with mitochondrial dysfunction and enhanced oxidative stress. The aims of the present study conducted in the mouse brain repetitively treated with METH were to (1) examine the redox status using the redox-sensitive imaging probe 3-methoxycarbonyl-2,2,5,5-tetramethylpiperidine-1-oxyl (MCP) and (2) non-invasively visualize the brain redox status with electron paramagnetic resonance (EPR) imaging. The rate of reduction of MCP was measured from a series of temporal EPR images of mouse heads, and this rate was used to construct a two-dimensional map of rate constants called a “redox map.” The obtained redox map clearly illustrated the change in redox balance in the METH-treated mouse brain that is a known result of oxidative damage. Biochemical assays also showed that the level of thiobarbituric acid-reactive substance, an index of lipid peroxidation, was increased in mouse brains by METH. The enhanced reduction in MCP observed in mouse brains was remarkably suppressed by treatment with the dopamine synthase inhibitor, α-methyl-p-tyrosine, suggesting that enhancement of the reduction reaction of MCP resulted from enzymatic reduction in the mitochondrial respiratory chain. Furthermore, magnetic resonance imaging (MRI) of METH-treated mice using a blood–brain barrier (BBB)-impermeable paramagnetic contrast agent revealed BBB dysfunction after treatment with METH for 7 days. MRI also indicated that the impaired BBB recovered after withdrawal of METH. EPR imaging and MRI are useful tools not only for following changes in the redox status and BBB dysfunction in mouse brains repeatedly administered METH, but also for tracing the drug effect after withdrawal of METH.

A ¹¹C-labeled 1,4-dihydroquinoline derivative as a potential PET tracer for imaging of redox status in mouse brain.

A disturbance in redox balance has been implicated in the pathogenesis of a number of diseases. This study sought to examine the feasibility of imaging brain redox status using a (11)C-labeled dihydroquinoline derivative ([(11)C]DHQ1) for positron emission tomography (PET). The lipophilic PET tracer [(11)C]DHQ1 was rapidly oxidized to its hydrophilic form in mouse brain homogenate. The redox modulators diphenyleneiodonium and apocynin significantly reduced the initial velocity of [(11)C]DHQ1 oxidation, and apocynin also caused concentration-dependent inhibition of the initial velocity. Moreover, [(11)C]DHQ1 readily entered the brain by diffusion after administration and underwent oxidation into the hydrophilic cationic form, which then slowly decreased. By contrast, apocynin treatment inhibited the in vivo oxidation of [(11)C]DHQ1 to the hydrophilic cationic form, leading to a rapid decrease of radioactivity in the brain. Thus, the difference in the [(11)C]DHQ1 kinetics reflects the alteration in redox status caused by apocynin. In conclusion, [(11)C]DHQ1 is a potential PET tracer for imaging of redox status in the living brain.

In vivo NAD assay reveals the intracellular NAD contents and redox state in healthy human brain and their age dependences

NAD is an essential metabolite that exists in NAD(+) or NADH form in all living cells. Despite its critical roles in regulating mitochondrial energy production through the NAD(+)/NADH redox state and modulating cellular signaling processes through the activity of the NAD(+)-dependent enzymes, the method for quantifying intracellular NAD contents and redox state is limited to a few in vitro or ex vivo assays, which are not suitable for studying a living brain or organ. Here, we present a magnetic resonance (MR) -based in vivo NAD assay that uses the high-field MR scanner and is capable of noninvasively assessing NAD(+) and NADH contents and the NAD(+)/NADH redox state in intact human brain. The results of this study provide the first insight, to our knowledge, into the cellular NAD concentrations and redox state in the brains of healthy volunteers. Furthermore, an age-dependent increase of intracellular NADH and age-dependent reductions in NAD(+), total NAD contents, and NAD(+)/NADH redox potential of the healthy human brain were revealed in this study. The overall findings not only provide direct evidence of declined mitochondrial functions and altered NAD homeostasis that accompany the normal aging process but also, elucidate the merits and potentials of this new NAD assay for noninvasively studying the intracellular NAD metabolism and redox state in normal and diseased human brain or other organs in situ.

PSS80 - In vivo Imaging of Redox Status and Blood Brain Barrier Function in Methamphetamine-Treated Mouse Brain

PSS80 - In vivo Imaging of Redox Status and Blood Brain Barrier Function in Methamphetamine-Treated Mouse Brain

Glutathione peroxidase contributes with heme oxygenase-1 to redox balance in mouse brain during the course of cerebral malaria

Oxidative stress has been attributed both a key pathogenic and rescuing role in cerebral malaria (CM). In a Plasmodium berghei ANKA murine model of CM, host redox signaling and functioning were examined during the course of neurological damage. Host antioxidant defenses were early altered at the transcriptional level indicated by the gradually diminished expression of superoxide dismutase-1 (sod-1), sod-2, sod-3 and catalase genes. During severe disease, this led to the dysfunctional activity of superoxide dismutase and catalase enzymes in damaged brain regions. Vitagene associated markers (heat shock protein 70 and thioredoxin-1) also showed a decaying expression pattern that paralleled reduced expression of the transcription factors Parkinson disease 7, Forkhead box O 3 and X-box binding protein 1 with a role in preserving brain redox status. However, the oxidative stress markers reactive oxygen/nitrogen species were not accumulated in the brains of CM mice and redox proteomics and immunohistochemistry failed to detect quantitative or qualitative differences in protein carbonylation. Thus, the loss of antioxidant capacity was compensated for in all cerebral regions by progressive upregulation of heme oxygenase-1, and in specific regions by early glutathione peroxidase-1 induction. This study shows for the first time a scenario of cooperative glutathione peroxidase and heme oxygenase-1 upregulation to suppress superoxide dismutase, catalase, heat shock protein-70 and thioredoxin-1 downregulation effects in experimental CM, counteracting oxidative damage and maintaining redox equilibrium. Our findings reconcile the apparent inconsistency between the lack of oxidative metabolite build up and reported protective effect of antioxidant therapy against CM.