8-hydroxy-2--deoxyguanosine and Cognition-Disorders

It is vital for astronauts to develop effective countermeasures to prevent their decline of cognitive performance in microgravity to make space-flight missions successful. The traditional Chinese herbal formula Kai Xin San (KXS) has been used to treat amnesia for thousands years. It is a traditional complex prescription comprising of ginseng (Panax ginseng C. A. Meyer), hoelen (Poria cocos (Schw.) Wolf), polygala (Polygala tenaifolia Willd), and acorus (Acorus tatarinowii Schott). Previous study showed KXS could improve CMS-induced memory impairment in rats.. In this paper, a unique environmental factor-microgravity (weightlessness) was simulated as hindlimb suspension (HLS) by tail in rats for two weeks as the HLS animal model. The KXS at the doses of 0.3 or 0.6g/kg p.o. daily was administrated to HLS rats for two weeks at the same time of HLS, the memory behavior tests were investigated with Morris water maze (MWM) and Shuttle Box (SB) test. The levels of ROS, 8-OHdG and 3-nitrotyrosine (3-NT) in the serum, and AChE and ChAT activity in the brain of rats were determined by ELISA or biochemical analysis.. After HLS for two weeks, the escape latency and the swimming distance were significantly increased in the MWM test in rats in the HLS group, compared with control group. The percent of swimming distance in target quadrant and the number of target crossing was significantly decreased in rats in the HLS group compared with the control group. Performance in the SB test showed, the numbers and the distance of active avoidance was decreased from day 4 to day 7, the time spent in electric area was increased in rats in the HLS group compared with the control group. Administration of KXS 0.3 or 0.6g/kg to the HLS rats for two weeks significantly reduced the escape latency and the swimming distance, increased the percentage of swimming distance in target quadrant and the number of target crossings (P<0.01, compared with the HLS group) in the MWM test. Similar treatment with KXS increased the numbers and the distance of active avoidance (P<0.01, compared with the HLS group) and reduced the time spent in electric area after training 3 days in the SB test (P<0.01, compared with the HLS group). The HLS induced the increase of the ROS, 8-OHdG and 3-NT in the serum of rats, but has little influence on the AChE, ChAT activity in the brain. Only the AChE activity in the cortex and the ChAT activity in the hippocampus had some changes in rats in the HLS model group. After administration of KXS 0.6g/kg for two weeks, the abnormal levels of ROS, 8-OHdG, 3-NT were found reversed in the serum of rats (P<0.05, compared with HLS model group). And KXS 0.3g/kg was found reversed the increased AChE activity in the cortex.. Experimental results from this study show that KXS may improve memory deficiency induced by HLS, its mechanisms are major related to antioxidant activities, rather than the central cholinergic system.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Acetylcholinesterase; Animals; Avoidance Learning; Brain; Choline O-Acetyltransferase; Cognition Disorders; Deoxyguanosine; Disease Models, Animal; Drugs, Chinese Herbal; Escape Reaction; Hindlimb Suspension; Male; Memory; Neuroprotective Agents; Phytotherapy; Rats, Sprague-Dawley; Reactive Oxygen Species; Swimming; Tyrosine; Weightlessness

Chronic kidney disease (CKD) is frequently associated with uremic encephalopathy and cognitive impairment. Recent studies have demonstrated that cerebral oxidative stress contributes to cognitive dysfunction. Although oxidative stress has been reported to increase in the uremic rat brain, the relationship between increased oxidative stress and cognitive impairment in uremia is unclear. In the present study, the effects of tempol (TMP), an antioxidant drug, were investigated in uremic mice.. CKD was induced in male C57BL/6 mice (n = 8) by left nephrectomy and 2/3 electrocoagulation of the right renal cortex. Working memory performance was tested by the radial arm water maze test. We have prepared two protocols ('time course study' and 'treatment study'). First, we examined the working memory test and histological examination of mouse brains after 4 and 8 weeks. Next, we investigated the effect of TMP (3 mM) against uremia-induced neurodegeneration and oxidative stress in the mouse brain.. Eight weeks after CKD induction, vehicle-treated mice made significantly more errors than sham-operated control mice, while TMP improved working memory performance in CKD mice. CKD was associated with accumulation of 8-hydroxy-2'-deoxyguanosine in the hippocampal neuronal cells, but not in TMP-treated CKD mice. Increased numbers of pyknotic neuronal cells were observed in the hippocampus of CKD mice at 8 weeks, but pyknotic neuronal cell numbers were decreased under the influence of TMP in uremic mice.. The present study provided evidence that uremia is associated with spatial working memory dysfunction in mice and that treatment with TMP protects against cerebral oxidative stress and improves cognitive dysfunction in uremic mice, suggesting their potential usefulness for the treatment of cognitive dysfunction in uremia.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antioxidants; Cognition Disorders; Cyclic N-Oxides; Deoxyguanosine; Drug Evaluation, Preclinical; Hippocampus; Male; Maze Learning; Memory Disorders; Memory, Short-Term; Mice, Inbred C57BL; Neuroprotective Agents; Oxidative Stress; Renal Insufficiency, Chronic; Spatial Memory; Spin Labels; Uremia

Diabetes mellitus-induced metabolic disturbances underlie the action of many systems including some higher functions of the brain such as learning and memory. Plenty of evidence supports the effects of probiotics on the function of many systems including the nervous system. Here we report the effect of probiotics treatment on the behavioral and electrophysiological aspects of learning and memory disorders. Diabetic rats were made through intraperitoneal injection of streptozocin. The control and diabetic rats were fed with either normal regimen (control rats recieving normal regimen (CO) and diabetics rats receiving normal regimen (DC), respectively) or normal regimen plus probiotic supplementation for 2months (control rats receiving probiotic supplementation (CP) and diabetics rats recieving probiotic supplementation (DP), respectively). The animals were first introduced to spatial learning task in the Morris water maze. Then, in electrophysiological experiments, stimulating the Schaffer collaterals the basic and potentiated excitatory postsynaptic potential (EPSPs) were recorded in the CA1 area of the hippocampus. Finally, the serum levels of glucose, insulin, superoxide dismutase and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were measured. We found that probiotics administration considerably improved the impaired spatial memory in the diabetic animals. The probiotics supplementation in the diabetic rats recovered the declined basic synaptic transmission and further restored the hippocampal long-term potentiation (LTP). While the probiotics administration enhanced the activation of superoxide dismutase and increased the insulin level of serum it decreased both the glucose level of serum and the 8-OHdG factor. From the present results we concluded that probiotics efficiently reverse deteriorated brain functions in the levels of cognitive performances and their proposed synaptic mechanisms in diabetes mellitus. These considerations imply on the necessity of an optimal function of the microbiome-gut-brain axis in the behavioral as well as electrophysiological aspects of brain action.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Analysis of Variance; Animals; Biophysics; Blood Glucose; Brain; Cognition Disorders; Deoxyguanosine; Diabetes Mellitus, Experimental; Disease Models, Animal; Drug Administration Schedule; Electric Stimulation; Hippocampus; In Vitro Techniques; Insulin; Long-Term Potentiation; Male; Maze Learning; Metagenome; Probiotics; Rats; Rats, Wistar; Streptozocin; Superoxide Dismutase

Intermittent hypoxia (IH) during sleep, such as occurs in obstructive sleep apnea (OSA), leads to degenerative changes in the hippocampus, and is associated with spatial learning deficits in adult mice. In both patients and murine models of OSA, the disease is associated with suppression of growth hormone (GH) secretion, which is actively involved in the growth, development, and function of the central nervous system (CNS). Recent work showed that exogenous GH therapy attenuated neurocognitive deficits elicited by IH during sleep in rats. Here, we show that administration of the Growth Hormone Releasing Hormone (GHRH) agonist JI-34 attenuates IH-induced neurocognitive deficits, anxiety, and depression in mice along with reduction in oxidative stress markers such as MDA and 8-hydroxydeoxyguanosine, and increases in hypoxia inducible factor-1α DNA binding and up-regulation of insulin growth factor-1 and erythropoietin expression. In contrast, treatment with a GHRH antagonist (MIA-602) during intermittent hypoxia did not affect any of the IH-induced deleterious effects in mice. Thus, exogenous GHRH administered as the formulation of a GHRH agonist may provide a viable therapeutic intervention to protect IH-vulnerable brain regions from OSA-associated neurocognitive dysfunction. Sleep apnea, characterized by chronic intermittent hypoxia (IH), is associated with substantial cognitive and behavioral deficits. Here, we show that administration of a GHRH agonist (JI-34) reduces oxidative stress, increases both HIF-1α nuclear binding and downstream expression of IGF1 and erythropoietin (EPO) in hippocampus and cortex, and markedly attenuates water maze performance deficits in mice exposed to intermittent hypoxia during sleep.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Cognition Disorders; Deoxyguanosine; Depression; Erythropoietin; Growth Hormone-Releasing Hormone; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Learning Disabilities; Lipid Peroxidation; Male; Maze Learning; Mice; Mice, Inbred C57BL; Oxidative Stress; Receptor, IGF Type 1; Sermorelin; Signal Transduction; Sleep

Progressive age-associated increases in cerebral dysfunction have been shown to occur following traumatic brain injury (TBI). Moreover, levels of neuronal mitochondrial antioxidant enzymes in the aged brain are reduced, resulting in free radical-induced cell death. It was hypothesized that cognitive impairment after TBI in the aged progresses to a greater degree than in younger individuals, and that damage involves neuronal degeneration and death by free radicals. In this study, we investigated the effects of free radicals on neuronal degeneration, cell death, and cognitive impairment in 10-week-old (young group) and 24-month-old rats (aged group) subjected to TBI. Young and aged rats received TBI with a pneumatic controlled injury device. At 1, 3 and 7 days after TBI, immunohistochemistry, lipid peroxidation and behavioral studies were performed. At 1, 3 and 7 days post-TBI, the number of 8-hydroxy-2'-deoxyguanosine-, 4-hydroxy-2-nonenal- and single-stranded DNA (ssDNA)-positive cells, and the levels of malondialdehyde around the damaged area after TBI significantly increased in the aged group when compared with the young group (P < 0.05). In addition, the majority of ssDNA-positive cells in both groups co-localized with neuronal cells around the damaged area. There was a significant decrease in the number of surviving neurons and an increase in cognitive impairment after TBI in the aged group when compared with the young group (P < 0.05). These results indicate that following TBI, high levels of free radicals are produced in the aged rat brain, which induces neuronal degeneration and apoptotic cell death around the damaged area, resulting in cognitive impairment.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Age Factors; Aldehydes; Animals; Antigens, Nuclear; Apoptosis; Behavior, Animal; Brain; Brain Injuries; Cognition; Cognition Disorders; Deoxyguanosine; Disease Models, Animal; DNA Breaks, Single-Stranded; DNA, Single-Stranded; Immunohistochemistry; Lipid Peroxidation; Male; Malondialdehyde; Maze Learning; Motor Activity; Nerve Tissue Proteins; Neurons; Oxidative Stress; Rats; Rats, Wistar; Reactive Oxygen Species; Time Factors

Traumatic axonal injury (TAI), a feature of traumatic brain injury (TBI), progressively evolves over hours through impaired axonal transport and is thought to be a major contributor to cognitive dysfunction. In spite of various studies suggesting that pharmacologic or physiologic interventions might reduce TAI, clinical neuroprotective treatments are still unavailable. Edaravone, a free radical scavenger, has been shown to exert neuroprotective effects in animal models of several brain disorders. In this study, to evaluate whether edaravone suppresses TAI following TBI, mice were subjected to weight drop injury and had either edaravone (3.0mg/kg) or saline administered intravenously immediately after impact. Axonal injury and oxidative stress were assessed using immunohistochemistry with antibodies against amyloid precursor protein, a marker of impaired axonal transport, and with 8-hydroxy-2'-deoxyguanosine, a marker of oxidative DNA damage. Edaravone significantly suppressed axonal injury and oxidative stress in the cortex, corpus callosum, and hippocampus 24h after injury. The neuroprotective effects of edaravone were observed in mice receiving 1.0, 3.0, or 10mg/kg of edaravone immediately after impact, but not after 0.3mg/kg of edaravone. With treatment 1h after impact, axonal injury was also significantly suppressed and this therapeutic effect persisted up to 6h after impact. Furthermore, behavioral tests performed 9 days after injury showed memory deficits in saline-treated traumatized mice, which were not evident in the edaravone-treated group. These results suggest that edaravone protects against memory deficits following TBI and that this protection is mediated by suppression of TAI and oxidative stress.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antipyrine; Brain Injuries; Cognition; Cognition Disorders; Deoxyguanosine; Diffuse Axonal Injury; DNA Damage; Dose-Response Relationship, Drug; Edaravone; Exploratory Behavior; Free Radical Scavengers; Immunohistochemistry; Male; Memory Disorders; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Oxidative Stress; Recognition, Psychology

In rodents, exposure to intermittent hypoxia (IH), a hallmark of obstructive sleep apnea (OSA), is associated with neurobehavioral impairments, increased apoptosis in the hippocampus and cortex, as well as increased oxidant stress and inflammation. Such findings are markedly attenuated in rodents exposed to sustained hypoxia 9SH) of similar magnitude. The hypoxia-sensitive gene erythropoietin (EPO) has emerged as a major endogenous neuroprotectant, and could be involved in IH-induced neuronal dysfunction.. IH induced only transiently increased expression of EPO mRNA in hippocampus, which was continued in (SH)-exposed mice. IH, but not SH, adversely affected two forms of spatial learning in the water maze, and increased markers of oxidative stress. However, on a standard place training task, mice treated with exogenously administered EPO displayed normal learning, and were protected from the spatial learning deficits observed in vehicle-treated (C) littermates exposed to IH. Moreover, anxiety levels were increased in IH as compared to normoxia, while no changes in anxiety emerged in EPO-treated mice. Additionally, C mice, but not EPO-treated IH-exposed mice had significantly elevated levels of NADPH oxidase expression, as well as increased MDA and 8-OHDG levels in cortical and hippocampal lysates.. The oxidative stress responses and neurobehavioral impairments induced by IH during sleep are mediated, at least in part, by imbalances between EPO expression and increased NADPH oxidase activity, and thus pharmacological agents targeting EPO expression in CNS may provide a therapeutic strategy in sleep-disordered breathing.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Analysis of Variance; Animals; Cells, Cultured; Cerebral Cortex; Cognition Disorders; Deoxyguanosine; Disease Models, Animal; Embryo, Mammalian; Erythropoietin; Escape Reaction; Gene Expression Regulation; Humans; Hypoxia; Injections, Intraperitoneal; Lipid Peroxidation; Male; Malondialdehyde; Maze Learning; Memory; Mice; Mice, Inbred C57BL; NADPH Oxidases; Neurons; Phosphopyruvate Hydratase; Sleep Apnea Syndromes; Swimming; Time Factors

Intermittent hypoxia (IH) during sleep, such as occurs in sleep apnea (SA), induces increased NADPH oxidase activation and deficits in hippocampal learning and memory. Similar to IH, high fat-refined carbohydrate diet (HFD), a frequent occurrence in patients with SA, can also induce similar oxidative stress and cognitive deficits under normoxic conditions, suggesting that excessive NADPH oxidase activity may underlie CNS dysfunction in both conditions. The effect of HFD and IH during the light period on two forms of spatial learning in the water maze as well as on markers of oxidative stress was assessed in male mice lacking NADPH oxidase activity (gp91phox⁻/Y) and wild-type littermates fed on HFD. On a standard place training task, gp91phox⁻/Y displayed normal learning, and was protected from the spatial learning deficits observed in wild-type littermates exposed to IH. Moreover, anxiety levels were increased in wild-type mice exposed to HFD and IH as compared to controls, while no changes emerged in gp91phox⁻/Y mice. Additionally, wild-type mice, but not gp91phox⁻/Y mice, had significantly elevated levels of malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG) in hippocampal lysates following IH-HFD exposures. The cognitive deficits of obesity and westernized diets and those of sleep disorders that are characterized by IH during sleep are both mediated, at least in part, by excessive NADPH oxidase activity.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Analysis of Variance; Animals; Cognition Disorders; Deoxyguanosine; Diet, High-Fat; Disease Models, Animal; Male; Malondialdehyde; Maze Learning; Memory; Mice; Mice, Inbred C57BL; Mice, Transgenic; Multivariate Analysis; NADPH Oxidases; Oxidative Stress; Reaction Time; Receptors, Immunologic; Sleep Apnea Syndromes; Space Perception; Swimming

In rodents, exposure to intermittent hypoxia (IH), a hallmark of obstructive sleep apnea (OSA), is associated with neurobehavioral impairments, increased apoptosis in the hippocampus and cortex, as well as increased oxidant stress and inflammation. Excessive NADPH oxidase activity may play a role in IH-induced CNS dysfunction.. The effect of IH during light period on two forms of spatial learning in the water maze and well as markers of oxidative stress was assessed in mice lacking NADPH oxidase activity (gp91phox(_/Y)) and wild-type littermates. On a standard place training task, gp91phox(_/Y) displayed normal learning, and were protected from the spatial learning deficits observed in wild-type littermates exposed to IH. Moreover, anxiety levels were increased in wild-type mice exposed to IH as compared to room air (RA) controls, while no changes emerged in gp91phox(_/Y) mice. Additionally, wild-type mice, but not gp91phox(_/Y) mice had significantly elevated levels of NADPH oxidase expression and activity, as well as MDA and 8-OHDG in cortical and hippocampal lysates following IH exposures.. The oxidative stress responses and neurobehavioral impairments induced by IH during sleep are mediated, at least in part, by excessive NADPH oxidase activity, and thus pharmacological agents targeting NADPH oxidase may provide a therapeutic strategy in sleep-disordered breathing.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Cognition Disorders; Deoxyguanosine; Disease Models, Animal; Hypoxia; Lipid Peroxidation; Male; Maze Learning; Membrane Glycoproteins; Mice; Mice, Inbred C57BL; Mice, Knockout; NADPH Oxidase 2; NADPH Oxidases; Sleep Apnea Syndromes; Swimming

Sleep fragmentation (SF) is one of the major characteristics of sleep apnea, and has been implicated in its morbid consequences, which encompass excessive daytime sleepiness and neurocognitive impairments. We hypothesized that absence of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity is neuroprotective in SF-induced cognitive impairments.. To examine whether increased NADPH oxidase activity may play a role in SF-induced central nervous system dysfunction.. The effect of chronic SF during the sleep-predominant period on sleep architecture, sleep latency, spatial memory, and oxidative stress parameters was assessed in mice lacking NADPH oxidase activity (gp91phox-(/Y)) and wild-type littermates.. SF for 15 days was not associated with differences in sleep duration, sleep state distribution, or sleep latency in both gp91phox-(/Y) and control mice. However, on a standard place training task, gp91phox-(/Y) mice displayed normal learning and were protected from the spatial learning deficits observed in wild-type littermates exposed to SF. Moreover, anxiety levels were increased in wild-type mice exposed to SF, whereas no changes emerged in gp91phox-(/Y) mice. Additionally, wild-type mice, but not gp91phox-(/Y) mice, had significantly elevated NADPH oxidase gene expression and activity, and in malondialdehyde and 8-oxo-2'-deoxyguanosine levels in cortical and hippocampal lysates after SF exposures.. This work substantiates an important role for NADPH oxidase in hippocampal memory impairments induced by SF, modeling sleep apnea. Targeting NADPH oxidase, therefore, is expected to minimize hippocampal impairments from both intermittent hypoxia and SF associated with the disease.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Analysis of Variance; Animals; Behavior, Animal; Cognition Disorders; Deoxyguanosine; Disease Models, Animal; Lipid Peroxidation; Male; Maze Learning; Mice; Mice, Transgenic; NADPH Oxidases; Oxidative Stress; Sleep Deprivation

DNA oxidative stress has been suggested as an important pathogenic mechanism in cognitive impairment and dementia. With baseline data collected from 2004 to 2008, the authors examined whether urinary 8-hydroxy-2-deoxyguanosine (8-OHdG), a biomarker of global DNA oxidation, was associated with cognitive function in a sample of 1,003 Puerto Rican adults, aged 45-75 years, living in Boston, Massachusetts, and the surrounding area. Cognitive function was measured by using a battery of 7 tests: the Mini-Mental State Examination, word list learning, digit span, clock drawing and figure copying, Stroop, and verbal fluency tests. The primary outcome was a global cognitive score, averaging standardized scores across all cognitive tests. A higher 8-OHdG concentration was significantly associated with lower global cognitive scores, after adjustment for age, education, status of the gene for apolipoprotein E (APOE), and other covariates (P(trend) = 0.01). The difference in the global score, comparing participants in the 2 extreme 8-OHdG quartiles, was -0.11 (95% confidence interval: -0.20, -0.02), which was equivalent to accelerating cognitive aging by about 4 years, as observed in this population. Prospective studies are needed to elucidate whether elevated urinary 8-OHdG concentrations can predict the rate of cognitive decline and incident dementia.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aged; Antibodies, Monoclonal; Apolipoproteins E; Cognition Disorders; Dementia; Deoxyguanosine; Enzyme-Linked Immunosorbent Assay; Female; Humans; Incidence; Male; Massachusetts; Middle Aged; Neuropsychological Tests; Oxidative Stress; Prevalence; Puerto Rico; Severity of Illness Index

The study was designed to investigate whether nuclear factor of kappa B (NF-kappaB) plays regulating role in prenatal stress-induced cognitive impairment and oxidative damage in offspring rats. The authors used a rat model to study plasma levels of corticosterone and oxidative DNA damage (8-OH-dG), protein expression of P65/p50 NF-kappaB, and cognitive function in female and male offspring rats in middle pregnant stage and later pregnant stage. Prenatal stress affected the capability of learning and memory in the offspring, especially in later stage stressed female offspring. The levels of corticosterone and 8-OH-dG were enhanced in response to stress. Both middle and later stage stresses induced a significant decrease in P65 expression and a significant increase in P50 expression in female offspring. In addition, later stage stress induced a significant decrease in P50 expression in male offspring. These results suggest that NF-kappaB complex may be acting in a positive regulatory fashion in prenatal stress-induced cognitive impairment and that oxidative DNA damage may exacerbate the activation of NF-kappaB.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Brain; Cognition Disorders; Corticosterone; Dentate Gyrus; Deoxyguanosine; Escape Reaction; Female; Fetus; Gestational Age; Male; Maze Learning; NF-kappa B; NF-kappa B p50 Subunit; Orientation; Oxidative Stress; Pregnancy; Prenatal Exposure Delayed Effects; Rats; Rats, Sprague-Dawley; Reaction Time; Sex Factors; Spatial Behavior; Stress, Psychological; Synaptotagmin I

In geriatric dogs, Alzheimer-like behavior is frequently observed. This behavior has been classified by several authors using questionnaires and a correlation has been described between cognitive dysfunctions and Alzheimer-like pathology. In the present study, cognitive performance was correlated with brain pathology for 30 dogs of varying ages. Within these animals, two age-matched groups of old dogs with and without behavioral changes were compared. The behavioral changes were analyzed and scored with questionnaires and necropsy was performed to rule out any other cause for changed behavior. Measurements, (immuno)-histochemical staining and fluorescence microscopy were used to detect cortex atrophy, amyloid, rest-products of oxidative damage, demyelination and accumulations of macrophages in the brains of these dogs. Spearman rank correlation coefficients (r) were calculated and adjusted according to Bonferonni. In the whole group (young to very old dogs), the age of the animal showed a significant correlation with various behavioral changes (r = 0.7 to 0.9, P < 0.01). The dementia score correlated significantly (r = 0.6 to 0.8, P < 0.01) with all the brain lesions studied, except one, i.e. demyelination (r = -0.4, P > 0.05). These results suggest that a questionnaire can be used to diagnose Alzheimer-like changes in canine practice. Oxidative damage on a cellular and a nuclear level plays an important role in behavior changes.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Age Factors; Aging; Aldehydes; Alzheimer Disease; Amyloid beta-Peptides; Animals; Atrophy; Behavior, Animal; Cerebral Cortex; Cognition Disorders; Congo Red; Demyelinating Diseases; Deoxyguanosine; Disease Models, Animal; Dogs; Female; Immunohistochemistry; Lipofuscin; Male; Statistics, Nonparametric

A diet high in saturated fat (HF) decreases levels of brain-derived neurotrophic factor (BDNF), to the extent that compromises neuroplasticity and cognitive function, and aggravates the outcome of brain insult. By using the antioxidant power of vitamin E, we performed studies to determine the role of oxidative stress as a mediator for the effects of BDNF on synaptic plasticity and cognition caused by consumption of the HF diet. Male adult rats were maintained on a HF diet for 2 months with or without 500 IU/kg of vitamin E. Supplementation of the HF diet with vitamin E dramatically reduced oxidative damage, normalized levels of BDNF, synapsin I and cyclic AMP-response element-binding protein (CREB), caused by the consumption of the HF diet. In addition, vitamin E supplementation preserved the process of activation of synapsin I and CREB, and reversed the HF-impaired cognitive function. It is known that BDNF facilitates the synapse by modulating synapsin I and CREB, which have been implicated in synaptic plasticity associated to learning and memory. These results show that oxidative stress can interact with the BDNF system to modulate synaptic plasticity and cognitive function. Therefore, studies appear to reveal a mechanism by which events classically related to the maintenance of energy balance of the cell, such as oxidative stress, can interact with molecular events that modulate neuronal and behavioural plasticity.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Behavior, Animal; Blotting, Western; Brain-Derived Neurotrophic Factor; Cognition; Cognition Disorders; Cyclic AMP Response Element-Binding Protein; Deoxyguanosine; Diet, Fat-Restricted; Enzyme-Linked Immunosorbent Assay; Fatty Acids; Hippocampus; Male; Maze Learning; Memory; Neuronal Plasticity; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reaction Time; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Synapsins; Time Factors; Vitamin A