Inhibition of Fast Axonal Transport by Pathogenic SOD1 Involves Activation of p38 MAP Kinase

Dying-back degeneration of motor neuron axons represents an established feature of familial amyotrophic lateral sclerosis (FALS) associated with superoxide dismutase 1 (SOD1) mutations, but axon-autonomous effects of pathogenic SOD1 remained undefined. Characteristics of motor neurons affected in FALS include abnormal kinase activation, aberrant neurofilament phosphorylation, and fast axonal transport (FAT) deficits, but functional relationships among these pathogenic events were unclear. Experiments in isolated squid axoplasm reveal that FALS-related SOD1 mutant polypeptides inhibit FAT through a mechanism involving a p38 mitogen activated protein kinase pathway. Mutant SOD1 activated neuronal p38 in mouse spinal cord, neuroblastoma cells and squid axoplasm. Active p38 MAP kinase phosphorylated kinesin-1, and this phosphorylation event inhibited kinesin-1. Finally, vesicle motility assays revealed previously unrecognized, isoform-specific effects of p38 on FAT. Axon-autonomous activation of the p38 pathway represents a novel gain of toxic function for FALS-linked SOD1 proteins consistent with the dying-back pattern of neurodegeneration characteristic of ALS.     

Advanced glycation endproducts in neurofilament conglomeration of motoneurons in familial and sporadic amyotrophic lateral sclerosis.

BACKGROUND: Massive neurofilament conglomeration in motor neurons has been described to occur in the early stages of both familial and sporadic amyotrophic lateral sclerosis (ALS). Previously, neurofilament conglomerates were immunolabeled for both superoxide dismutase (SOD1) and nitrotyrosine, suggesting the potential for oxidative nitration damage to neurofilament protein by peroxynitrite. Long-lived neurofilaments may also undergo modification by advanced glycation endproducts (AGEs) with concomitant generation of free radicals, including superoxide. This radical species may then react with nitric oxide to form the potent oxidant, peroxynitrite, which in turn can nitrate neurofilament protein. Such a glycated and nitrated neurofilament protein may become resistant to proteolytic systems, forming high-molecular-weight protein complexes and cytotoxic, neuronal inclusions. MATERIALS AND METHODS: Paraffin sections containing both neurofilament conglomerates and neuronal inclusions were obtained from patients with sporadic (n = 5) and familial (n = 2) ALS and were probed with specific antibodies directed against the AGEs cypentodine/piperidine-enolone, arginine-lysine imidazole, pentosidine, and pyrraline. RESULTS: Neurofilament conglomerates, but not neuronal inclusions, were intensely immunolabeled with each of the anti-AGE antibodies tested. The immunoreactivity was selective for neurofilament conglomerates and suggested that AGEs may form inter- or intramolecular cross-links in neurofilament proteins. CONCLUSIONS: These data support the hypothesis that AGE formation affects neurofilament proteins in vivo and is associated with the concomitant induction of SODI and protein nitration in neurofilament conglomerates. AGE formation in neurofilament protein may not only cause covalent cross-linking but also generate superoxide and block nitric oxide-mediated responses, thereby perpetuating neuronal toxicity in patients with ALS.     

Proteomic analysis of specific brain proteins in aged SAMP8 mice treated with alpha-lipoic acid: implications for aging and age-related neurodegenerative disorders

Free radical-mediated damage to neuronal membrane components has been implicated in the etiology of Alzheimer's disease (AD) and aging. The senescence accelerated prone mouse strain 8 (SAMP8) exhibits age-related deterioration in memory and learning along with increased oxidative markers. Therefore, SAMP8 is a suitable model to study brain aging and, since aging is the major risk factor for AD and SAMP8 exhibits many of the biochemical findings of AD, perhaps as a model for and the early phase of AD. Our previous studies reported higher oxidative stress markers in brains of 12-month-old SAMP8 mice when compared to that of 4-month-old SAMP8 mice. Further, we have previously shown that injecting the mice with alpha-lipoic acid (LA) reversed brain lipid peroxidation, protein oxidation, as well as the learning and memory impairments in SAMP8 mice. Recently, we reported the use of proteomics to identify proteins that are expressed differently and/or modified oxidatively in aged SAMP8 brains. In order to understand how LA reverses the learning and memory deficits of aged SAMP8 mice, in the current study, we used proteomics to compare the expression levels and specific carbonyl levels of proteins in brains from 12-month-old SAMP8 mice treated or not treated with LA. We found that the expressions of the three brain proteins (neurofilament triplet L protein, alpha-enolase, and ubiquitous mitochondrial creatine kinase) were increased significantly and that the specific carbonyl levels of the three brain proteins (lactate dehydrogenase B, dihydropyrimidinase-like protein 2, and alpha-enolase) were significantly decreased in the aged SAMP8 mice treated with LA. These findings suggest that the improved learning and memory observed in LA-injected SAMP8 mice may be related to the restoration of the normal condition of specific proteins in aged SAMP8 mouse brain. Moreover, our current study implicates neurofilament triplet L protein, alpha-enolase, ubiquitous mitochondrial creatine kinase, lactate dehydrogenase B, and dihydropyrimidinase-like protein 2 in process associated with learning and memory of SAMP8 mice.     

Assembly of type IV neuronal intermediate filaments in nonneuronal cells in the absence of preexisting cytoplasmic intermediate filaments

We report here on the in vivo assembly of alpha-internexin, a type IV neuronal intermediate filament protein, in transfected cultured cells, comparing its assembly properties with those of the neurofilament triplet proteins (NF-L, NF-M, and NF-H). Like the neurofilament triplet proteins, alpha-internexin coassembles with vimentin into filaments. To study the assembly characteristics of these proteins in the absence of a preexisting filament network, transient transfection experiments were performed with a non-neuronal cell line lacking cytoplasmic intermediate filaments. The results showed that only alpha-internexin was able to self-assemble into extensive filamentous networks. In contrast, the neurofilament triplet proteins were incapable of homopolymeric assembly into filamentous arrays in vivo. NF-L coassembled with either NF-M or NF-H into filamentous structures in the transfected cells, but NF-M could not form filaments with NF-H. alpha- internexin could coassemble with each of the neurofilament triplet proteins in the transfected cells to form filaments. When all but 2 and 10 amino acid residues were removed from the tail domains of NF-L and NF-M, respectively, the resulting NF-L and NF-M deletion mutants retained the ability to coassemble with alpha-internexin into filamentous networks. These mutants were also capable of forming filaments with other wild-type neurofilament triplet protein subunits. These results suggest that the tail domains of NF-L and NF-M are dispensable for normal coassembly of each of these proteins with other type IV intermediate filament proteins to form filaments.     

A monoclonal antibody specific for the 200 K polypeptide of the neurofilament triplet

A mouse monoclonal antibody, designated NF1, was obtained from a cloned hybridoma isolated from a fusion of mouse myeloma Sp2 cells with spleen cells from a BALB/c mouse immunized with a crude neurofilament preparation from porcine spinal cord. NF1 is an IgG1 and recognizes, in immune blotting procedures, only the 200 K neurofilament triplet component. Its neurofilament-specific nature is further revealed by immunofluorescence microscopy studies on frozen tissue sections and various cultured cells. Immunoelectron microscopy studies on cytoskeletons of cultured neurones emphasize the discontinuous display along each neurofilament previously observed with polyclonal antibodies specific for the 200 K component after appropriate but rather cumbersome cross-absorption steps. Use of NF1 on various neuronal cells strongly supports the previous proposal of the existence of certain subpopulations of neurofilament-free neurones and the observation that certain neuronal arrangements, (e.g., those in dendrites of pyramidal cells of the hippocampus), although rich in neurofilaments, probably lack the normal 200 K triplet component. Since NF1 shows a broad cross-species reactivity and is able to react on formaldehyde-fixed tissue, it should be a useful reagent to study differential neurofilament expression and organization in embryonic, adult and pathological tissues.     

Deregulation of Cdk5 in a mouse model of ALS: toxicity alleviated by perikaryal neurofilament inclusions

Recent studies suggest that increased activity of cyclin-dependent kinase 5 (Cdk5) may contribute to neuronal death and cytoskeletal abnormalities in Alzheimer's disease. We report here such deregulation of Cdk5 activity associated with the hyperphosphorylation of tau and neurofilament (NF) proteins in mice expressing a mutant superoxide dismutase (SOD1(G37R)) linked to amyotrophic lateral sclerosis (ALS). A Cdk5 involvement in motor neuron degeneration is supported by our analysis of three SOD1(G37R) mouse lines exhibiting perikaryal inclusions of NF proteins. Our results suggest that perikaryal accumulations of NF proteins in motor neurons may alleviate ALS pathogenesis by acting as a phosphorylation sink for Cdk5 activity, thereby reducing the detrimental hyperphosphorylation of tau and other neuronal substrates.     

Transduced human PEP-1–catalase fusion protein attenuates ischemic neuronal damage

Antioxidant enzymes are considered to have beneficial effects against various diseases mediated by reactive oxygen species (ROS). Ischemia is characterized by both oxidative stress and changes in the antioxidant defense system. Catalase (CAT) and superoxide dismutase (SOD) are major antioxidant enzymes by which cells counteract the deleterious effects of ROS. To investigate the protective effects of CAT, we constructed PEP-1–CAT cell-permeative expression vectors. When PEP-1–CAT fusion proteins were added to the culture medium of neuronal cells, they rapidly entered the cells and protected them against oxidative stress-induced neuronal cell death. Immunohistochemical analysis revealed that PEP-1–CAT prevented neuronal cell death in the hippocampus induced by transient forebrain ischemia. Moreover, we showed that the protective effect of PEP-1–CAT was observed in neuronal cells treated with PEP-1–SOD. Therefore, we suggest that transduced PEP-1–CAT and PEP-1–SOD fusion proteins could be useful as therapeutic agents for various human diseases related to oxidative stress, including stroke.     

Superoxide dismutase 1 modulates expression of transferrin receptor

Copper–zinc superoxide dismutase (SOD1) plays a protective role against the toxicity of superoxide, and studies in Saccharomyces cerevisiae and in Drosophila have suggested an additional role for SOD1 in iron metabolism. We have studied the effect of the modulation of SOD1 levels on iron metabolism in a cultured human glial cell line and in a mouse motoneuronal cell line. We observed that levels of the transferrin receptor and the iron regulatory protein 1 were modulated in response to altered intracellular levels of superoxide dismutase activity, carried either by wild-type SOD1 or by an SOD-active amyotrophic lateral sclerosis (ALS) mutant enzyme, G93A-SOD1, but not by a superoxide dismutase inactive ALS mutant, H46R-SOD1. Ferritin expression was also increased by wild-type SOD1 overexpression, but not by mutant SOD1s. We propose that changes in superoxide levels due to alteration of SOD1 activity affect iron metabolism in glial and neuronal cells from higher eukaryotes and that this may be relevant to diseases of the nervous system.     

Transgenic mouse models of amyotrophic lateral sclerosis

The discovery of missense mutations in the gene coding for the Cu/Zn superoxide dismutase 1 (SOD1) in subsets of familial cases was rapidly followed by the generation of transgenic mice expressing various forms of SOD1 mutants. The mice overexpressing high levels of mutant SOD1 mRNAs do develop motor neuron disease but unraveling the mechanisms of pathogenesis has been very challenging. Studies with mouse lines suggest that the toxicity of mutant SOD1 is unrelated to copper-mediated catalysis but rather to propensity of a subfraction of mutant SOD1 proteins to form misfolded protein species and aggregates. However, the mechanism of toxicity of SOD1 mutants remains to be elucidated. Involvement of cytoskeletal components in ALS pathogenesis is supported by several mouse models of motor neuron disease with neurofilament abnormalities and with genetic defects in microtubule-based transport. Here, we describe how transgenic mouse models have been used for understanding pathogenic pathways of motor neuron disease and for pre-clinical drug testing.     

Aberrant expression of cytoskeleton proteins in hippocampus from patients with mesial temporal lobe epilepsy

Summary. Mesial temporal lobe epilepsy (MTLE), the most common form of epilepsy, is characterised by cytoarchitectural abnormalities including neuronal cell loss and reactive gliosis in hippocampus. Determination of aberrant cytoskeleton protein expression by proteomics techniques may help to understand pathomechanism that is still elusive. We searched for differential expression of hippocampal proteins by an analytical method based on two-dimensional gel electrophoresis (2-DE) coupled with mass spectrometry unambiguously identifying 77 proteins analysed in eight control and eight MTLE hippocampi. Proteins were quantified and we observed 18 proteins that were altered in MTLE. Cytoskeleton proteins tubulin α-1 chain, β-tubulin, profilin II, neuronal tropomodulin were significantly reduced and one actin spot was missing, whereas ezrin and vinculin were significantly increased in MTLE. Proteins of several classes as e.g. antioxidant proteins (peroxiredoxins 3 and 6), chaperons (T-complex protein 1-α, stress-induced-phosphoprotein 1), signaling protein MAP kinase kinase 1, synaptosomal proteins (synaptotagmin I, α-synuclein), NAD-dependent deacetylase sirtuin-2 and 26S protease regulatory subunit 7 protein, neuronal-specific septin 3 were altered in MTLE. Taken together, the findings may represent or lead to cytoskeletal impairment; aberrant antioxidant proteins, chaperons, MAP kinase kinase 1 and NAD-dependent deacetylase sirtuin-2 may have been involved in pathogenetic mechanisms and altered synaptosomal protein expression possibly reflects synaptic impairment in MTLE. J. W. Yang and T. Czech have equally contributed to the paper.     

3-Nitropropionic Acid Neurotoxicity Is Attenuated in Copper/Zinc Superoxide Dismutase Transgenic Mice

Abstract: The mitochondrial toxin 3-nitropropionic acid (3-NP) produces selective striatal lesions in both experimental animals and humans. The pathogenesis of the lesions involves secondary excitotoxicity that may then lead to free radical generation. To test this further we examined the effects of 3-NP in both transgenic (Tg) mice that carry the complete sequence for the human copper/zinc superoxide dismutase (SOD) gene as well as non-Tg littermate controls. The Tg-SOD mice showed a pronounced attenuation of Nissl-stained striatal lesions compared with non-Tg mice. Systemic administration of 3-NP resulted in production of hydroxyl free radicals as assessed by the conversion of salicylate to 2,3- and 2,5-dihydroxybenzoic acid. This production was attenuated significantly in Tg-SOD mice. In a similar way, 3-NP produced significant increases in 3-nitrotyrosine/tyrosine, a marker for peroxynitrite-mediated damage, which were significantly attenuated in Tg-SOD mice. These results support that oxygen free radicals and peroxynitrite play an important role in the pathogenesis of 3-NP neurotoxicity.     

Mitochondrial proteomic analysis of a cell line model of familial amyotrophic lateral sclerosis

Mutations in copper-zinc superoxide dismutase (SOD1) have been linked to a subset of familial amytrophic lateral sclerosis (fALS), a fatal neurodegenerative disease characterized by progressive motor neuron death. An increasing amount of evidence supports that mitochondrial dysfunction and apoptosis activation play a critical role in the fALS etiology, but little is known about the mechanisms by which SOD1 mutants cause the mitochondrial dysfunction and apoptosis. In this study, we use proteomic approaches to identify the mitochondrial proteins that are altered in the presence of a fALS-causing mutant G93A-SOD1. A comprehensive characterization of mitochondrial proteins from NSC34 cells, a motor neuron-like cell line, was achieved by two independent proteomic approaches. Four hundred seventy unique proteins were identified in the mitochondrial fraction collectively, 75 of which are newly discovered proteins that previously had only been reported at the cDNA level. Two-dimensional gel electrophoresis was subsequently used to analyze the differences between the mitochondrial proteomes of NSC34 cells expressing wild-type and G93A-SOD1. Nine and 36 protein spots displayed elevated and suppressed abundance respectively in G93A-SOD1-expressing cells. The 45 spots were identified by MS, and they include proteins involved in mitochondrial membrane transport, apoptosis, the respiratory chain, and molecular chaperones. In particular, alterations in the post-translational modifications of voltage-dependent anion channel 2 (VDAC2) were found, and its relevance to regulating mitochondrial membrane permeability and activation of apoptotic pathways is discussed. The potential role of other proteins in the mutant SOD1-mediated fALS is also discussed. This study has produced a short list of mitochondrial proteins that may hold the key to the mechanisms by which SOD1 mutants cause mitochondrial dysfunction and neuronal death. It has laid the foundation for further detailed functional studies to elucidate the role of particular mitochondrial proteins, such as VDAC2, in the pathogenesis of familial ALS.     

Cell-permeable peptide antioxidants as a novel therapeutic approach in a mouse model of amyotrophic lateral sclerosis

Reactive oxygen species (ROS) play a major role in the pathogenesis of neurodegenerative diseases. They are important contributors to necrotic and apoptotic cell death. A major proportion of cellular ROS is generated at the inner mitochondrial membrane by the respiratory chain. In the present study, we investigated a novel peptide antioxidant (SS-31) targeted to the inner mitochondrial membrane for its therapeutic effects both in vitro and in vivo in the G93A mouse model of amyotrophic lateral sclerosis (ALS). SS-31 protected against cell death induced by hydrogen peroxide in vitro in neuronal cells stably transfected with either wild-type or mutant Cu/Zn superoxide dismutase (SOD1). Daily intraperitoneal injections of SS-31 (5 mg/kg), starting at 30 days of age, led to a significant improvement in survival and motor performance. In comparison with vehicle-treated G93A mice, SS-31-treated mice showed a decreased cell loss and a decrease in immunostaining for markers of oxidative stress in the lumbar spinal cord. This further enhances the concept that pharmacological modification of oxidative stress is a therapeutic option for the treatment of ALS.     

Proteasomal inhibition by misfolded mutant superoxide dismutase 1 induces selective motor neuron death in familial amyotrophic lateral sclerosis

Accumulating evidence indicates that abnormal conformation of mutant superoxide dismutase 1 (SOD1) is an essential feature underlying the pathogenesis of mutant SOD1-linked familial amyotrophic lateral sclerosis (ALS). Here we investigated the role of ubiquitin-proteasome pathway in the mutant SOD1-related cell death and the effect of oxidative stress on the misfolding of mutant SOD1. Transient overexpression of ubiquitin with human SOD1 (wild-type, ala4val, gly85arg, gly93ala) in Neuro2A cells decreased the amount of mutant SOD1, but not of wild-type, while only mutants were co-immunoprecipitated with poly-ubiquitin. Proteasome inhibition by lactacystin augmented accumulation of mutant SOD1 in the non-ionic detergent-insoluble fraction. The spinal cord lysates from mutant SOD1 transgenic mice showed multiple carbonylated proteins, including mutant SOD1 with SDS-resistant dimer formation. Furthermore, the treatment of hSOD1-expressing cells with hydrogen peroxide promoted the oligomerization, and detergent-insolubility of mutant SOD1 alone, and the oxidized mutant SOD1 proteins were more heavily poly-ubiquitinated. In Neuro2A cells stably expressing human SOD1 protein, the proteasome function measured by chymotrypsin-like activity, was decreased over time without a quantitative alteration of the 20S proteasomal component. Finally, primary motor neurons from the mouse embryonic spinal cord were more vulnerable to lactacystin than non-motor neurons. These results indicate that the sustained expression of mutant SOD1 leads to proteasomal inhibition and motor neuronal death, which in part explains the pathogenesis of mutant SOD1-linked ALS.     

Synaptosomal Mitochondrial Dysfunction in 5xFAD Mouse Model of Alzheimer's Disease

Brain mitochondrial dysfunction is hallmark pathology of Alzheimer’s disease (AD). Recently, the role of synaptosomal mitochondrial dysfunction in the development of synaptic injury in AD has received increasing attention. Synaptosomal mitochondria are a subgroup of neuronal mitochondria specifically locating at synapses. They play an essential role in fueling synaptic functions by providing energy on the site; and their defects may lead to synaptic failure, which is an early and pronounced pathology in AD. In our previous studies we have determined early synaptosomal mitochondrial dysfunction in an AD animal model (J20 line) overexpressing human Amyloid beta (Aβ), the key mediator of AD. In view of the limitations of J20 line mice in representing the full aspects of amyloidopathy in AD cases, we employed 5xFAD mice which are thought to be a desirable paradigm of amyloidopathy as seen in AD subjects. In addition, we have also examined the status of synaptosomal mitochondrial dynamics as well as Parkin-mediated mitophagy which have not been previously investigated in this mouse model. In comparison to nontransgenic (nonTg mice), 5xFAD mice demonstrated prominent synaptosomal mitochondrial dysfunction. Moreover, synaptosomal mitochondria from the AD mouse model displayed imbalanced mitochondrial dynamics towards fission along with activated Parkin and LC3BII recruitment correlating to spatial learning & memory impairments in 5xFAD mice in an age-dependent manner. These results suggest that synaptosomal mitochondrial deficits are primary pathology in Aβ-rich environments and further confirm the relevance of synaptosomal mitochondrial deficits to the development of AD.     

Mitochondrial superoxide dismutase SOD2, but not cytosolic SOD1, plays a critical role in protection against glutamate-induced oxidative stress and cell death in HT22 neuronal cells

Oxidative cell death is an important contributing factor in neurodegenerative diseases. Using HT22 mouse hippocampal neuronal cells as a model, we sought to demonstrate that mitochondria are crucial early targets of glutamate-induced oxidative cell death. We show that when HT22 cells were transfected with shRNA for knockdown of the mitochondrial superoxide dismutase (SOD2), these cells became more susceptible to glutamate-induced oxidative cell death. The increased susceptibility was accompanied by increased accumulation of mitochondrial superoxide and loss of normal mitochondrial morphology and function at early time points after glutamate exposure. However, overexpression of SOD2 in these cells reduced the mitochondrial superoxide level, protected mitochondrial morphology and functions, and provided resistance against glutamate-induced oxidative cytotoxicity. The change in the sensitivity of these SOD2-altered HT22 cells was neurotoxicant-specific, because the cytotoxicity of hydrogen peroxide was not altered in these cells. In addition, selective knockdown of the cytosolic SOD1 in cultured HT22 cells did not appreciably alter their susceptibility to either glutamate or hydrogen peroxide. These findings show that the mitochondrial SOD2 plays a critical role in protecting neuronal cells from glutamate-induced oxidative stress and cytotoxicity. These data also indicate that mitochondria are important early targets of glutamate-induced oxidative neurotoxicity.     

Mutant copper-zinc superoxide dismutase binds to and destabilizes human low molecular weight neurofilament mRNA

The mechanism by which mutated copper-zinc superoxide dismutase (SOD1) causes familial amyotrophic lateral sclerosis is believed to involve an adverse gain of function, independent of the physiological antioxidant enzymatic properties of SOD1. In this study, we have observed that mutant SOD1 (G41S, G85A, and G93A) but not the wild type significantly reduced the stability of the low molecular weight neurofilament mRNA in a dosage-dependent manner. We have also demonstrated that mutant SOD1 but not the wild type bound directly to the neurofilament mRNA 3'-untranslated region and that the binding was necessary to induce mRNA destabilization. These observations provide an explanation for a novel gain of function in which mutant SOD1 expression in motor neurons alters an intermediate filament protein expression.     

Neurofilament protein triplet immunoreactivity in the dorsal root ganglia of the guinea-pig

Summary Immunoreactivity for the neurofilament protein triplet was investigated in neurons of the dorsal root ganglia of the guinea-pig by using a battery of antibodies. In unfixed tissue, nearly all neurons in these ganglia demonstrated some degree of neurofilament protein triplet immunoreactivity. Large neurons generally displayed intense immunoreactivity, whereas most small to medium-sized neurons showed faint to moderate immunoreactivity. Double-labelling immunofluorescence demonstrated that most antibodies to the individual subunits of the neurofilament protein triplet had the same distribution and intensity of labelling in sensory neurons. Increasing durations of tissue fixation in aldehyde solutions selectively diminished neurofilament protein triplet immunoreactivity in small to medium-sized neurons. Double-labelling with neurofilament protein triplet antibodies in combination with antibodies to other neuronal markers, such as neuron-specific enolase, substance P and tyrosine hydroxylase, showed that tissue processing conditions affect the degree of co-localization of immunoreactivity to the neurofilament protein triplet and to these other neuronal markers. These results indicate that, with a judicious manipulation of the duration of tissue fixation, neurofilament protein triplet immunoreactivity can be used in combination with other neuronal markers to distinguish groups of neurons according to their size and chemical coding.     

Oxidative Stress Parameters in Different Brain Structures Following Lateral Fluid Percussion Injury in the Rat

Free radicals mediated damage of phospholipids, proteins and nucleic acids results in subsequent neuronal degeneration and cell loss. Aim of this study was to evaluate the existence of lipid and protein oxidative damage and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in various rat brain structures 24 h after lateral fluid percussion brain injury (LFPI). Parietal cortex, hippocampus, thalamus, entorhinal cortex, and cerebellum from the ipsilateral hemisphere were processed for analyses of the thiobarbituric acid reactive substances (TBARS) and oxidized protein levels as well as for the SOD and GSH-Px activities. Immunohistochemical detection of oxidized proteins was also performed. Results of our study showed that LFPI caused significant oxidative stress in the parietal cortex and hippocampus while other brain regions tested in this study were not oxidatively altered by LFPI. GSH-Px activities were significantly increased in the parietal cortex and hippocampus, while the SOD activities remained unchanged following LFPI in all regions investigated.