Neonatal iron exposure induces oxidative stress in adult Wistar rat

Potential Role of Oxidative Stress in the Effects of Chronic Administration of Iron on Affective and Cognitive Behavior on Male Wistar Rat

In this work, we studied the impact of chronic iron exposure, in the form of iron sulfate (FeSo4), on affective and cognitive disorders and oxidative stress in the male Wistar rat. The treatment was carried out for 8 weeks, the rats received an intraperitoneal injection of iron at different doses: 0.25, 0.5, and 1 mg/kg. Affective and cognitive disorders are assessed in open field test (OFT), elevated plus maze (EPM), forced swimming test (FST), Morris water maze (MWM), and Y-maze. The hippocampus and prefrontal cortex of each animal were taken for biochemical examination. Our results show that iron exerts anxiogenic and depressogenic effects, which were observed first at the dose of 0.5 mg/kg and continued in a dose-dependent manner up to the maximum tested dose of 1 mg/kg. According to results from the MWM and Y-maze tests, continuous exposure to iron induces cognitive disorders that are defined by the disturbance of working memory and influences spatial learning performance causing a deficit of spatial memory retention. We noted that chronic exposure to iron can be associated with the appearance of a state of oxidative stress in the hippocampus and the prefrontal cortex demonstrated by an increase in lipid peroxidation, an increase in nitric oxide, and also by disturbances in the antioxidant defense systems following a determination of the concentrations of catalase. In conclusion, we can deduce from this work that chronic iron exposure can be related to the induction of cognitive and affective disorders and oxidative stress.

Dietary pattern in autism increases the need for probiotic supplementation: A comprehensive narrative and systematic review on oxidative stress hypothesis

Autism spectrum disorders (ASDs) are associated with specific dietary habits, including limited food selection and gastrointestinal problems, resulting in an altered gut microbiota. Autistic patients have an elevated abundance of certain gut bacteria associated with increased oxidative stress in the gastrointestinal tract. Probiotic supplementation has been shown to decrease oxidative stress in a simulated gut model, but the antioxidant effects of probiotics on the oxidative stress of the gut in autistic patients have not been directly studied. However, it is speculated that probiotic supplementation may help decrease oxidative stress in the gastrointestinal tract of autistic patients due to their specific dietary habits altering the microbiota. PubMed, Scopus and Web of Science databases and Google Scholar were searched up to May 2023. This systematic-narrative review aims to present the latest evidence regarding the changes in eating habits of autistic children which may further increase the gut microbiota induced oxidative stress. Additionally, this review will assess the available literature on the effects of probiotic supplementation on oxidative stress parameters.

Benefits and Risks of Early Life Iron Supplementation

Infants are frequently supplemented with iron to prevent iron deficiency, but iron supplements may have adverse effects on infant health. Although iron supplements can be highly effective at improving iron status and preventing iron deficiency anemia, iron may adversely affect growth and development, and may increase risk for certain infections. Several reviews exist in this area; however, none has fully summarized all reported outcomes of iron supplementation during infancy. In this review, we summarize the risks and benefits of iron supplementation as they have been reported in controlled studies and in relevant animal models. Additionally, we discuss the mechanisms that may underly beneficial and adverse effects.

BXD Recombinant Inbred Mice as a Model to Study Neurotoxicity

BXD recombinant inbred (RI) lines represent a genetic reference population derived from a cross between C57BL/6J mice (B6) and DBA/2J mice (D2), which through meiotic recombination events possesses recombinant chromosomes containing B6 or D2 haplotype segments. The quantitative trait loci (QTLs) are the locations of segregating genetic polymorphisms and are fundamental to understanding genetic diversity in human disease susceptibility and severity. QTL mapping represents the typical approach for identifying naturally occurring polymorphisms that influence complex phenotypes. In this process, genotypic values at markers of known genomic locations are associated with phenotypic values measured in a segregating population. Indeed, BXD RI strains provide a powerful tool to study neurotoxicity induced by different substances. In this review, we describe the use of BXD RI lines to understand the underlying mechanisms of neurotoxicity in response to ethanol and cocaine, as well as metals and pesticide exposures.

(-)-Epicatechin Reduces the Blood Pressure of Young Borderline Hypertensive Rats During the Post-Treatment Period

This study investigated the effects of (–)-epicatechin (Epi) in young male borderline hypertensive rats (BHR) during two weeks of treatment (Epi group, 100 mg/kg/day p.o.) and two weeks post treatment (PE group). Epi reduced blood pressure (BP), which persisted for two weeks post treatment. This was associated with delayed reduction of anxiety-like behaviour. Epi significantly increased nitric oxide synthase (NOS) activities in the aorta and left heart ventricle (LHV) vs. the age-matched controls without affecting the brainstem and frontal neocortex. Furthermore, Epi significantly reduced the superoxide production in the aorta and relative content of iron-containing compounds in blood. Two weeks post treatment, the NOS activities and superoxide productions in the heart and aorta did not differ from the age-matched controls. The gene expressions of the NOSs (nNOS, iNOS, eNOS), nuclear factor erythroid 2-related factor 2 (Nrf2), and peroxisome proliferator-activated receptor-γ (PPAR-γ) remained unaltered in the aorta and LHV of the Epi and PE groups. In conclusion, while Epi-induced a decrease of the rats’ BP persisted for two weeks post treatment, continuous Epi treatments seem to be necessary for maintaining elevated NO production as well as redox balance in the heart and aorta without changes in the NOSs, Nrf2, and PPAR-γ gene expressions.

The Combined Extract of Black Sticky Rice and Dill Improves Poststroke Cognitive Impairment in Metabolic Syndrome Condition

Despite the increase in cognitive deficit following stroke in metabolic syndrome (MetS) condition, the therapeutic strategy is still limited. Since oxidative stress and neuroinflammation play the crucial roles on the pathophysiology of aforementioned conditions, the cognitive enhancing effect of the combined extract of Oryza sativa and Anethum graveolens was considered based on their antioxidant, anti-inflammation, and neuroprotective effects together with the synergistic effect concept. Male Wistar rats weighing 180-220 g were induced metabolic syndrome-like condition by using a high-carbohydrate high-fat diet (HCHF diet). Then, reperfusion injury following cerebral ischemia was induced by the occlusion of right middle cerebral artery and treated with the combined extract of O. sativa and A. graveolens (OA extract) at doses of 0.5, 5, and 50 mg/kg BW once daily for 21 days. Spatial memory was assessed every 7 days throughout the experimental period. At the end of the study, neuron and glial fibrillary acidic protein- (GFAP-) positive cell densities, the oxidative stress status, AChE, and the expression of proinflammatory cytokines (TNF-α, IL-6) in the hippocampus were determined. The results showed that OA extract at all doses used in this study significantly improved memory together with the reductions of MDA, TNF-α, IL-6, AChE, and density of GFAP-positive cell but increased neuron density in the hippocampus. Taken together, OA is the potential cognitive enhancer in memory impairment following stroke in MetS condition. The possible underlying mechanism may occur partly via the reductions of oxidative stress status, GFAP-positive cell density, and neuroinflammatory cytokines such as TNF-α and IL-6 together with the suppression of AChE activity in the hippocampus. This study suggests that OA is the potential functional ingredient to improve the cognitive enhancer. However, further clinical research is required.

Iron and manganese-related CNS toxicity: mechanisms, diagnosis and treatment

INTRODUCTION

Iron (Fe) and manganese (Mn) are essential nutrients for humans. They act as cofactors for a variety of enzymes. In the central nervous system (CNS), these two metals are involved in diverse neurological activities. Dyshomeostasis may interfere with the critical enzymatic activities, hence altering the neurophysiological status and resulting in neurological diseases. Areas covered: In this review, the authors cover the molecular mechanisms of Fe/Mn-induced toxicity and neurological diseases, as well as the diagnosis and potential treatment. Given that both Fe and Mn are abundant in the earth crust, nutritional deficiency is rare. In this review the authors focus on the neurological disorders associated with Mn and Fe overload. Expert commentary: Oxidative stress and mitochondrial dysfunction are the primary molecular mechanism that mediates Fe/Mn-induced neurotoxicity. Although increased Fe or Mn concentrations have been found in brain of patients, it remains controversial whether the elevated metal amounts are the primary cause or secondary consequence of neurological diseases. Currently, treatments are far from satisfactory, although chelation therapy can significantly decrease brain Fe and Mn levels. Studies to determine the primary cause and establish the molecular mechanism of toxicity may help to adapt more comprehensive and satisfactory treatments in the future.

Antiapoptotic effects of cannabidiol in an experimental model of cognitive decline induced by brain iron overload

Iron accumulation in the brain has been recognized as a common feature of both normal aging and neurodegenerative diseases. Cognitive dysfunction has been associated to iron excess in brain regions in humans. We have previously described that iron overload leads to severe memory deficits, including spatial, recognition, and emotional memory impairments in adult rats. In the present study we investigated the effects of neonatal iron overload on proteins involved in apoptotic pathways, such as Caspase 8, Caspase 9, Caspase 3, Cytochrome c, APAF1, and PARP in the hippocampus of adult rats, in an attempt to establish a causative role of iron excess on cell death in the nervous system, leading to memory dysfunction. Cannabidiol (CBD), the main non-psychotropic component of Cannabis sativa, was examined as a potential drug to reverse iron-induced effects on the parameters analyzed. Male rats received vehicle or iron carbonyl (30 mg/kg) from the 12th to the 14th postnatal days and were treated with vehicle or CBD (10 mg/kg) for 14 days in adulthood. Iron increased Caspase 9, Cytochrome c, APAF1, Caspase 3 and cleaved PARP, without affecting cleaved Caspase 8 levels. CBD reversed iron-induced effects, recovering apoptotic proteins Caspase 9, APAF1, Caspase 3 and cleaved PARP to the levels found in controls. These results suggest that iron can trigger cell death pathways by inducing intrinsic apoptotic proteins. The reversal of iron-induced effects by CBD indicates that it has neuroprotective potential through its anti-apoptotic action.

The Aging of Iron Man

Brain iron is tightly regulated by a multitude of proteins to ensure homeostasis. Iron dyshomeostasis has become a molecular signature associated with aging which is accompanied by progressive decline in cognitive processes. A common theme in neurodegenerative diseases where age is the major risk factor, iron dyshomeostasis coincides with neuroinflammation, abnormal protein aggregation, neurodegeneration, and neurobehavioral deficits. There is a great need to determine the mechanisms governing perturbations in iron metabolism, in particular to distinguish between physiological and pathological aging to generate fruitful therapeutic targets for neurodegenerative diseases. The aim of the present review is to focus on the age-related alterations in brain iron metabolism from a cellular and molecular biology perspective, alongside genetics, and neuroimaging aspects in man and rodent models, with respect to normal aging and neurodegeneration. In particular, the relationship between iron dyshomeostasis and neuroinflammation will be evaluated, as well as the effects of systemic iron overload on the brain. Based on the evidence discussed here, we suggest a synergistic use of iron-chelators and anti-inflammatories as putative anti-brain aging therapies to counteract pathological aging in neurodegenerative diseases.

Novel insights into mitochondrial molecular targets of iron-induced neurodegeneration: Reversal by cannabidiol

Evidence has demonstrated iron accumulation in specific brain regions of patients suffering from neurodegenerative disorders, and this metal has been recognized as a contributing factor for neurodegeneration. Using an experimental model of brain iron accumulation, we have shown that iron induces severe memory deficits that are accompanied by oxidative stress, increased apoptotic markers, and decreased synaptophysin in the hippocampus of rats. The present study aims to characterize iron loading effects as well as to determine the molecular targets of cannabidiol (CBD), the main non-psychomimetic compound of Cannabis sativa, on mitochondria. Rats received iron in the neonatal period and CBD for 14 days in adulthood. Iron induced mitochondrial DNA (mtDNA) deletions, decreased epigenetic modulation of mtDNA, mitochondrial ferritin levels, and succinate dehydrogenase activity. CBD rescued mitochondrial ferritin and epigenetic modulation of mtDNA, and restored succinate dehydrogenase activity in iron-treated rats. These findings provide new insights into molecular targets of iron neurotoxicity and give support for the use of CBD as a disease modifying agent in the treatment of neurodegenerative diseases.

An altered blood-brain barrier contributes to brain iron accumulation and neuroinflammation in the 6-OHDA rat model of Parkinson's disease

Brain iron accumulation is a common feature shared by several neurodegenerative disorders including Parkinson's disease. However, what produces this accumulation of iron is still unknown. In this study, the 6-hydroxydopamine (6-OHDA) hemi-parkinsonian rat model was used to investigate abnormal iron accumulation in substantia nigra. We investigated three possible causes of iron accumulation; a compromised blood-brain barrier (BBB), abnormal expression of ferritin, and neuroinflammation. We identified alterations in the BBB subsequent to the injection of 6-OHDA using gadolinium-enhanced magnetic resonance imaging (MRI). Moreover, detection of extravasated IgG suggested that peripheral components are able to enter the brain through a leaky BBB. Presence of iron following dopamine cell degeneration was studied by MRI, which revealed hypointense signals in the substantia nigra. The presence of iron deposits was further validated in histological evaluations. Furthermore, iron inclusions were closely associated with active microglia and with increased levels of L-ferritin indicating a putative role for microglia and L-ferritin in brain iron accumulation and dopamine neurodegeneration.

Impact of high iron intake on cognition and neurodegeneration in humans and in animal models: a systematic review

Context

Accumulation of brain iron is linked to aging and protein-misfolding neurodegenerative diseases. High iron intake may influence important brain health outcomes in later life.

Objective

The aim of this systematic review was to examine evidence from animal and human studies of the effects of high iron intake or peripheral iron status on adult cognition, brain aging, and neurodegeneration.

Data Sources

MEDLINE, Scopus, CAB Abstracts, the Cochrane Central Register of Clinical Trials, and OpenGrey databases were searched.

Study Selection

Studies investigating the effect of elevated iron intake at all postnatal life stages in mammalian models and humans on measures of adult brain health were included.

Data Extraction

Data were extracted and evaluated by two authors independently, with discrepancies resolved by discussion. Neurodegenerative disease diagnosis and/or behavioral/cognitive, biochemical, and brain morphologic findings were used to study the effects of iron intake or peripheral iron status on brain health. Risk of bias was assessed for animal and human studies. PRISMA guidelines for reporting systematic reviews were followed.

Results

Thirty-four preclinical and 14 clinical studies were identified from database searches. Thirty-three preclinical studies provided evidence supporting an adverse effect of nutritionally relevant high iron intake in neonates on brain-health-related outcomes in adults. Human studies varied considerably in design, quality, and findings; none investigated the effects of high iron intake in neonates/infants.

Conclusions

Human studies are needed to verify whether dietary iron intake levels used in neonates/infants to prevent iron deficiency have effects on brain aging and neurodegenerative disease outcomes.

Neuroteratology and Animal Modeling of Brain Disorders

Over the past 60 years, a large number of selective neurotoxins were discovered and developed, making it possible to animal-model a broad range of human neuropsychiatric and neurodevelopmental disorders. In this paper, we highlight those neurotoxins that are most commonly used as neuroteratologic agents, to either produce lifelong destruction of neurons of a particular phenotype, or a group of neurons linked by a specific class of transporter proteins (i.e., dopamine transporter) or body of receptors for a specific neurotransmitter (i.e., NMDA class of glutamate receptors). Actions of a range of neurotoxins are described: 6-hydroxydopamine (6-OHDA), 6-hydroxydopa, DSP-4, MPTP, methamphetamine, IgG-saporin, domoate, NMDA receptor antagonists, and valproate. Their neuroteratologic features are outlined, as well as those of nerve growth factor, epidermal growth factor, and that of stress. The value of each of these neurotoxins in animal modeling of human neurologic, neurodegenerative, and neuropsychiatric disorders is discussed in terms of the respective value as well as limitations of the derived animal model. Neuroteratologic agents have proven to be of immense importance for understanding how associated neural systems in human neural disorders may be better targeted by new therapeutic agents.

Early-Life Toxic Insults and Onset of Sporadic Neurodegenerative Diseases-an Overview of Experimental Studies

The developmental origin of health and disease hypothesis states that adverse fetal and early childhood exposures can predispose to obesity, cardiovascular, and neurodegenerative diseases (NDDs) in adult life. Early exposure to environmental chemicals interferes with developmental programming and induces subclinical alterations that may hesitate in pathophysiology and behavioral deficits at a later life stage. The mechanisms by which perinatal insults lead to altered programming and to disease later in life are still undefined. The long latency between exposure and onset of disease, the difficulty of reconstructing early exposures, and the wealth of factors which the individual is exposed to during the life course make extremely difficult to prove the developmental origin of NDDs in clinical and epidemiological studies. An overview of animal studies assessing the long-term effects of perinatal exposure to different chemicals (heavy metals and pesticides) supports the link between exposure and hallmarks of neurodegeneration at the adult stage. Furthermore, models of maternal immune activation show that brain inflammation in early life may enhance adult vulnerability to environmental toxins, thus supporting the multiple hit hypothesis for NDDs' etiology. The study of prospective animal cohorts may help to unraveling the complex pathophysiology of sporadic NDDs. In vivo models could be a powerful tool to clarify the mechanisms through which different kinds of insults predispose to cell loss in the adult age, to establish a cause-effect relationship between "omic" signatures and disease/dysfunction later in life, and to identify peripheral biomarkers of exposure, effects, and susceptibility, for translation to prospective epidemiological studies.

Nigral iron elevation is an invariable feature of Parkinson's disease and is a sufficient cause of neurodegeneration

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor deficits accompanying degeneration of substantia nigra pars compactor (SNc) neurons. Although familial forms of the disease exist, the cause of sporadic PD is unknown. Symptomatic treatments are available for PD, but there are no disease modifying therapies. While the neurodegenerative processes in PD may be multifactorial, this paper will review the evidence that prooxidant iron elevation in the SNc is an invariable feature of sporadic and familial PD forms, participates in the disease mechanism, and presents as a tractable target for a disease modifying therapy.

Cannabidiol normalizes caspase 3, synaptophysin, and mitochondrial fission protein DNM1L expression levels in rats with brain iron overload: implications for neuroprotection

We have recently shown that chronic treatment with cannabidiol (CBD) was able to recover memory deficits induced by brain iron loading in a dose-dependent manner in rats. Brain iron accumulation is implicated in the pathogenesis of neurodegenerative diseases, including Parkinson's and Alzheimer's, and has been related to cognitive deficits in animals and human subjects. Deficits in synaptic energy supply have been linked to neurodegenerative diseases, evidencing the key role played by mitochondria in maintaining viable neural cells and functional circuits. It has also been shown that brains of patients suffering from neurodegenerative diseases have increased expression of apoptosisrelated proteins and specific DNA fragmentation. Here, we have analyzed the expression level of brain proteins involved with mitochondrial fusion and fission mechanisms (DNM1L and OPA1), the main integral transmembrane protein of synaptic vesicles (synaptophysin), and caspase 3, an apoptosis-related protein, to gain a better understanding of the potential of CBD in restoring the damage caused by iron loading in rats. We found that CBD rescued iron-induced effects, bringing hippocampal DNM1L, caspase 3, and synaptophysin levels back to values comparable to the control group. Our results suggest that iron affects mitochondrial dynamics, possibly trigging synaptic loss and apoptotic cell death and indicate that CBD should be considered as a potential molecule with memory-rescuing and neuroprotective properties to be used in the treatment of cognitive deficits observed in neurodegenerative disorders.

Oxidative stress and cholinesterase inhibition in plasma, erythrocyte and brain of rats' pups following lactational exposure to malathion

The organophosphorus (OP) pesticide malathion is a highly neurotoxic compound. Some studies have reported neurotoxicity signs after in utero exposure to OP pesticides. However there is no evidence of the exclusive contribution of the lactational exposure to malathion as a possible cause of neurotoxicity in rats' pups. In this respect, we investigated the exclusive contribution of malathion (200 mg/kg, b.w.) exposure through maternal milk in rat pups during lactation. We evaluated the activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), as well as on biochemical parameters related to the oxidative stress such lipoperoxidation and antioxidant enzyme activities as superoxide dismutase (SOD) and catalase (CAT) in the brain, plasma and erythrocytes of rats' pups at 21st postnatal day (Pnd). These parameters were also evaluated in the same tissues but at 51 Pnd. Our results showed that the malathion exposure during lactation induced a high inhibitory effect of the brain, plasma and erythrocyte AChE and BChE activities in rat pups. Many changes were observed in the biochemical parameters related to the oxidative stress for pups brain, plasma and erythrocyte. The present study shows, for the first time, that the exposure of postnatal pups to malathion via lactation inhibits the activity of brain, plasma and erythrocytes cholinesterase in the pups. These findings suggest that malathion exposure during lactation induced a cerebral alterations and oxidative stress in rat pups.

Memory-rescuing effects of cannabidiol in an animal model of cognitive impairment relevant to neurodegenerative disorders

RATIONALE

Cannabidiol, the main nonpsychotropic constituent of Cannabis sativa, possesses a large number of pharmacological effects including anticonvulsive, sedative, hypnotic, anxiolytic, antipsychotic, anti-inflammatory, and neuroprotective, as demonstrated in clinical and preclinical studies. Many neurodegenerative disorders involve cognitive deficits, and this has led to interest in whether cannabidiol could be useful in the treatment of memory impairment associated to these diseases.

OBJECTIVES

We used an animal model of cognitive impairment induced by iron overload in order to test the effects of cannabidiol in memory-impaired rats.

METHODS

Rats received vehicle or iron at postnatal days 12-14. At the age of 2 months, they received an acute intraperitoneal injection of vehicle or cannabidiol (5.0 or 10.0 mg/kg) immediately after the training session of the novel object recognition task. In order to investigate the effects of chronic cannabidiol, iron-treated rats received daily intraperitoneal injections of cannabidiol for 14 days. Twenty-four hours after the last injection, they were submitted to object recognition training. Retention tests were performed 24 h after training.

RESULTS

A single acute injection of cannabidiol at the highest dose was able to recover memory in iron-treated rats. Chronic cannabidiol improved recognition memory in iron-treated rats. Acute or chronic cannabidiol does not affect memory in control rats.

CONCLUSIONS

The present findings provide evidence suggesting the potential use of cannabidiol for the treatment of cognitive decline associated with neurodegenerative disorders. Further studies, including clinical trials, are warranted to determine the usefulness of cannabidiol in humans suffering from neurodegenerative disorders.

Reversion of age-related recognition memory impairment by iron chelation in rats

It is now generally accepted that iron accumulates in the brain during the ageing process. Increasing evidence demonstrate that iron accumulation in selective regions of the brain may generate free radicals, thereby possessing implications for the etiology of neurodegenerative disorders. In a previous study we have reported that aged rats present recognition memory deficits. The aim of the present study was to evaluate the effect of desferoxamine (DFO), an iron chelator agent, on age-induced memory impairment. Aged Wistar rats received intraperitoneal injections of saline or DFO (300mg/kg) for 2 weeks. The animals were submitted to a novel object recognition task 24h after the last injection. DFO-treated rats showed normal recognition memory while the saline group showed long-term recognition memory deficits. The results show that DFO is able to reverse age-induced recognition memory deficits. We also demonstrated that DFO reduced the oxidative damage to proteins in cortex and hippocampus. Thus, the present findings provide the first evidence that iron chelators might prevent age-related memory dysfunction.

Amelioration of recognition memory impairment associated with iron loading or aging by the type 4-specific phosphodiesterase inhibitor rolipram in rats

Increasing evidence indicates that iron deposition in the brain might play a role in cognitive dysfunction associated with neurodegenerative disorders and aging. Previous studies have not examined whether iron-induced memory deficits can be attenuated by acute treatments with memory-enhancing agents. Phosphodiesterase type 4 (PDE4) inhibitors such as rolipram (ROL) ameliorate memory impairments in several rodent models of amnesia and have been proposed as candidate cognitive-enhancing drugs. Here we show that a single posttraining systemic injection of ROL dose-dependently attenuates the impairment of memory for novel object recognition (NOR) in rats given neonatal iron loading, a model of iron-induced cognitive impairment. Posttraining administration of ROL also recovered NOR deficits associated with aging in rats. These findings provide the first evidence that stimulation of an intracellular second messenger signaling pathway can attenuate iron-induced memory impairment, and support the view that PDE4 inhibitors might ameliorate cognitive dysfunction associated with aging and neurodegenerative disorders.

Desferoxamine reverses neonatal iron-induced recognition memory impairment in rats

We have previously demonstrated that rats given iron neonatally presented memory deficits. The aim of the present study was to evaluate the effect of desferoxamine, a metal chelating agent, on memory deficits in an iron overload model in rats. Male rats received vehicle or iron orally at postnatal days 12-14 and desferoxamine (30 or 300 mg/kg) in the adulthood. After desferoxamine treatment, they were trained in a novel-object recognition task. Iron-treated rats showed recognition memory impairments when compared to controls. Iron-treated rats that received desferoxamine 300 mg/kg, showed normal recognition memory, suggesting that desferoxamine can reverse recognition memory deficits associated with iron accumulation. Further research is required to examine whether the findings from animal models of iron overload have implications for humans.

Effects of maintenance electroshock on the oxidative damage parameters in the rat brain

Although several advances have occurred over the past 20 years concerning refining the use and administration of electroconvulsive therapy to minimize side effects of this treatment, little progress has been made in understanding the mechanisms underlying its therapeutic or adverse effects. This work was performed in order to determine the level of oxidative damage at different times after the maintenance electroconvulsive shock (ECS). Male Wistar rats (250-300 g) received a protocol mimicking therapeutic of maintenance or simulated ECS (Sham) and were subsequently sacrificed immediately after, 48 h and 7 days after the last maintenance electroconvulsive shock. We measured oxidative damage parameters (thiobarbituric acid reactive species for lipid peroxidation and protein carbonyls for protein damage, respectively) in hippocampus, cortex, cerebellum and striatum. We demonstrated no alteration in the lipid peroxidation and protein damage in the four structures studied immediately after, 48 h and 7 days after a last maintenance electroconvulsive shock. Our findings, for the first time, demonstrated that after ECS maintenance we did protocol minimal oxidative damage in the brain regions, predominating absence of damage on the findings.

Antioxidant Effects of SelegilIne in Oxidative Stress Induced by Iron Neonatal Treatment in Rats

Increased levels of iron in specific brain regions have been reported in neurodegenerative disorders. It has been postulated that iron exerts its deleterious effects on the nervous system by inducing oxidative damage. In a previous study, we have shown that iron administered during a particular period of the neonatal life induces oxidative damage in brain regions in adult rats. The aim of the present study was to evaluate the possible protective effect of selegiline, a monoamino-oxidase B (MAO-B) inhibitor used in pharmacotherapy of Parkinson's disease, against iron-induced oxidative stress in the brain. Results have shown that selegiline (1.0 and 10.0 mg/kg), when administered early in life was able to protect the substantia nigra as well as the hippocampus against iron-induced oxidative stress, without affecting striatum. When selegiline (10.0 mg/kg) was administered in the adult life to iron-treated rats, oxidative stress was reduced only in the substantia nigra.

Effects of Chronic Haloperidol and/or Clozapine on Oxidative Stress Parameters in Rat Brain

Decreased antioxidant activity is considered as one of the causes of tardive dyskinesia in schizophrenic patients in a prolonged neuroleptic treatment course. Haloperidol (HAL) has been hypothesized to increase oxidative stress, while clozapine (CLO) would produce less oxidative damage. The objective was to determine whether CLO for 28 days could reverse or attenuate HAL-induced oxidative damage in animals previously treated with HAL for 28 days. HAL significantly increased thiobarbituric acid reactive substances levels in the cortex (CX) and striatum and increased protein carbonyls in hippocampus (HP) and CX and this was not attenuated by CLO treatment. In the total radical trapping antioxidant parameter assay there was a decrease in the HP total antioxidant potential induced by HAL and by treatment with HAL + CLO. Our findings demonstrated that the atypical antipsychotic CLO could not revert oxidative damage caused by HAL.

Oxidant/antioxidant status of placenta, blood, and cord blood samples from pregnant women supplemented with iron

OBJECTIVE

In this study, it was aimed to investigate oxidant/antioxidant status in placenta and in blood and cord blood samples from pregnant women supplemented with iron during pregnancy.

METHODS

For this purpose, 27 pregnant women at admission for delivery participated in the study. Fifteen of them did not take iron tablets and the others took oral iron supplements during pregnancy. Following delivery, part of the placenta and blood and cord blood samples were taken from the mothers. In these samples, oxidant parameters (malondialdehyde [MDA] levels and xanthine oxidase [XO] activities) and antioxidant parameters (antioxidant potential [AOP] values, superoxide dismutase [SOD], catalase [CAT] and glutathione peroxidase [GSH-Px] activities) were studied.

RESULTS

It was found that MDA level and SOD activities increased significantly in the placentas from the iron-supplemented group as compared with those from the control group. We also observed that activities of SOD and XO enzymes in maternal erythrocytes, XO in cord blood erythrocytes and GSH-Px activities in cord blood plasma decreased significantly. However, activities of CAT and GSH-Px enzymes in cord blood erythrocytes and MDA levels in maternal plasma increased in the iron-supplemented group as compared with those from the control group.

CONCLUSION

Increased MDA levels in the maternal plasma and the placenta in the iron-supplemented group suggests that iron supplementation may contribute to increased oxidative stress in women taking iron supplements during pregnancy.

Mitochondrial Respiratory Dysfunction and Oxidative Stress after Chronic Malathion Exposure

Malathion is a pesticide used on a large scale and with high potential risk for human exposure. However, it is reasonable to hypothesize that while the malathion is metabolizing reactive oxygen species (ROS) can be generated and subsequently there is onset of an oxidative stress in central nervous system (CNS) structures: hippocampus, cortex, striatum and cerebellum of intoxicated rats due to mitochondrial respiratory chain disfunctions. The present study was therefore undertaken to evaluate malathion-induced lipid peroxidation (LPO), superoxide production from sub-mitochondrial particles and the activity of complexes II and IV of the mitochondrial respiratory chain. Malathion was administered in doses of 25, 50, 100 and 150 mg malathion/kg. After malathion administration LPO increased in hippocampus and striatum. This was accompanied by an increase in the formation of superoxide in submitochondrial particles in the hippocampus. Complex IV suffered significant inhibition of its activity. We could demonstrate in this study that malathion induces oxidative stress and it could be due to inactivation of mitochondrial respiratory complexes.

Long Lasting Effects of Electroconvulsive Seizures on Brain Oxidative Parameters

This work was performed in order to determine the level of oxidative damage and antioxidant enzymes activities late after acute and chronic electroconvulsive shock (ECS) in rats. We measured oxidative parameters in hippocampus, cortex, and striatum, at 45, 60, 90 and 120 days after a single or multiple ECS. We demonstrated an increase in lipid peroxidation after multiple ECS in the hippocampus and striatum. This was also the case for protein carbonyls in the single or multiple protocols. In this way, we demonstrated an increase in catalase in cortex in contrast to striatum and hippocampus, were there were decreases sometimes in chronic ECS. The superoxide dismutase activities decrease in different times after single and multiple ECS in the hippocampus. Our findings demonstrated that there is a delayed increase after ECS in oxidative damage and decrease in antioxidant enzymes activities in hippocampus and striatum.

Methylphenidate treatment induces oxidative stress in young rat brain

Methylphenidate (MPH) is frequently prescribed for the treatment of attention deficit/hyperactivity disorder. Psychostimulants can cause long-lasting neurochemical and behavioral adaptations. Here, we evaluated oxidative damage in the rat brain and the differential age-dependent response to MPH after acute and chronic exposure. We investigated the oxidative damage, assessed by the thiobarbituric acid reactive species (TBARS), and the protein carbonyl assays in cerebellum, prefrontal cortex, hippocampus, striatum, and cerebral cortex of young (25 days old) and adult (60 days old) male Wistar rats after acute and chronic exposure to MPH. Chronic MPH-treated young rats presented a dose-dependent increase in TBARS content and protein carbonyls formation in specific rat brain regions. In the acute exposure, only MPH highest dose increased lipid peroxidation in the hippocampus. No difference in protein carbonylation was observed among groups in all structures analyzed. In adult rats, we did not find oxidative damage in both acute and chronic treatment. Chronic exposure to MPH in induces oxidative damage in young rat brain, differentially from chronic exposure during adulthood. These findings highlight the need for further research to improve understanding of MPH effects on developing nervous system and the potential consequences in adulthood resulting from early-life drug exposure.

Perinatal asphyxia, hyperthermia and hyperferremia as factors inducing behavioural disturbances in adulthood: A rat model

Alertness was studied in adult male Wistar rats after neonatal critical anoxia applied under three different thermal conditions: (i) at physiological neonatal body temperature of 33 degrees C, (ii) at body temperature elevated to 37 degrees C, and (iii) at body temperature elevated to 39 degrees C (both during anoxia and for 2 h postanoxia). To elucidate the effect of iron-dependent postanoxic oxidative damage to the brain, half of the group (iii) was injected with deferoxamine, a chelator of iron. Postanoxic behavioural disturbances were recorded in open-field, elevated plus-maze, and sudden silence tests when the rats reached the age of 4 month. Moreover, spontaneous motor activity of the rats was recorded radiotelemetrically in their home-cages. Both open-field stress-induced and spontaneous motor activity were reduced in rats subjected to neonatal anoxia under hyperthermic conditions. In contrast, these rats were hyperactive in the plus-maze test. Both the plus-maze and sudden silence tests revealed that these rats show reduced alertness to external stimuli signalling potential dangers. The behavioural disturbances were prevented by the body temperature of 33 degrees C and by postanoxic administration of deferoxamine. These data support the conclusion that permanent postanoxic behavioural disturbances are due to iron-dependent oxidative damage to the brain, which can be prevented by the reduced neonatal body temperature.

Recognition memory impairment and brain oxidative stress induced by postnatal iron administration

Iron accumulation in the brain has been implicated in the pathogenesis of neurodegenerative disorders. It is known that iron catalyses the formation of highly reactive hydroxyl radicals. Recent studies have implicated oxidative damage in memory deficits in rats and humans. The purpose of the present study was to investigate the long-term effects of iron treatment in four different phases of the neonatal period on recognition memory in rats. Additionally, parameters of oxidative stress in cerebral regions related to memory formation were evaluated. Male Wistar rats received vehicle or 10.0 mg/kg of Fe2+ orally at postnatal days 5-7, 12-14, 19-21 or 30-32. Animals given iron at any phase of the neonatal period showed impairments in long-term retention of object recognition memory, although only the group given iron from postnatal days 12-14 showed a complete memory blockade. Iron treatment induced oxidative damage in the brain as assessed by the thiobarbituric acid reactive species assay. Moreover, iron administration increased superoxide production in submitochondrial particles, suggesting impaired mitochondrial function; and there was an increase in superoxide dismutase activity in brain regions susceptible to iron administration. The results show that iron load in the early stages of life induces cognitive impairment possibly by inducing oxidative damage in the brain. These findings are consistent with the view that oxidative stress may be related to the cognitive decline observed in normal ageing.

Effect of protein malnutrition on redox state of the hippocampus of rat

The protein malnutrition is a worldwide problem, affecting mainly newborns and children of developing countries. This deficiency reaches the brain in the most critical period of the development. Various consequences are related to this insult, such as memory disturbance, learning, and behavioral impairment. Protein content of the diet plays an important role on antioxidant mechanisms. This study observed the effects of protein malnutrition on rat hippocampus redox state. Wistar rats were separate in four groups, receiving different diets: first group with 25% casein, protein deficient group with 8% casein, and the same two groups supplemented with methionine (0.15%). Diets were isocaloric and were administered since the prenatal period up to the sacrifice. Rats were decapitated at 21 or 75 days old and hippocampus were isolated for measuring the lipoperoxidation by TBARS method, protein oxidative damage by carbonyl (DNPH) levels, and the activities of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). There was significant alterations in the activities of the enzyme SOD, lipoperoxidation, and protein oxidation in hippocampus of 21 and 75 day-old rats fed with 25% of protein with methionine and the groups fed with low levels of protein (8%) both supplemented or not with methionine. Our data suggest that both the content of protein in the diet and the essential amino acid methionine may alter the antioxidant system and the redox state of the brain.

Haloperidol- and clozapine-induced oxidative stress in the rat brain

Haloperidol (HAL) is a typical neuroleptic that acts primarily as a D2 dopamine receptor antagonist. It has been proposed that reactive oxygen species play a causative role in neurotoxic effects induced by HAL. Adult male Wistar rats received daily injections of HAL (1.5 mg/kg) or clozapine (CLO, 25 mg/kg), an atypical neuroleptic, for 28 days. Control animals were given saline (SAL; NaCl 0.9%). Oxidative parameters in the brain were measured in the striatum (ST), hippocampus (HP) and cortex (CX). Thiobarbituric acid (TBA) reactive substances (TBAR) levels were increased by HAL treatment in the ST and decreased in CX of both of the HAL- and CLO-treated rats. Protein carbonyls were significantly increased by both HAL and CLO in the HP. The nonenzymatic antioxidant potential was decreased in the HP, and superoxide production was significantly increased in the ST following treatment with HAL. CLO induced an increase in superoxide production in the HP. Neither HAL nor CLO affected catalase (CAT) and superoxide dismutase (SOD) activities. The findings suggest that HAL and CLO can induce oxidative damage to the ST and HP in rats.

No evidence for oxidative damage in the hippocampus after acute and chronic electroshock in rats

Although several advances has occurred over the past 20 years concerning the use of electroconvulsive therapy (ECT), little progress has been made in the mechanisms underlying its therapeutic or adverse effects. Thus, this work was performed in order to determine the level of oxidative damage and antioxidant enzyme activities early and late after acute and chronic electroconvulsive shock (ECS). We demonstrated a decrease in lipid peroxidation in the hippocampus immediately after and up to 30 days after a single or multiple electroconvulsive shock. This was also true for protein carbonyls in the acute protocol. We demonstrated an increase in catalase (CAT) and superoxide dismutase (SOD) activities at different time points after single and multiple electroconvulsive shock. Our findings, for the first time, demonstrated that after electroconvulsive shock, there is an increase in antioxidant enzyme activities and we cannot demonstrate oxidative damage in the hippocampus.

Oxidative parameters and mortality in sepsis induced by cecal ligation and perforation

OBJECTIVE

This study assessed parameters of free radical damage to biomolecules, mitochondrial superoxide production, superoxide dismutase, and catalase activities and their relationship to sepsis mortality.

DESIGN AND SETTING

Prospective animal study in a university laboratory for experimental.

SUBJECTS

140 male Wistar rats.

INTERVENTIONS

The animals were randomly divided into three groups: sham-operated (n=20), cecal ligation and perforation resuscitated with normal saline (n=40), and cecal ligation and perforation with normal saline plus antibiotics (n=40).

MEASUREMENTS AND RESULTS

Blood samples were collected from all animals 3, 12, and 24 h after CLP through a jugular catheter inserted before CLP. Rats were evaluated during 5 days after the intervention. Nonsurvivor animals were grouped according to the duration between sepsis induction and death, and oxidative parameters were compared to survivors and sham-operated. Lipid peroxidation, protein carbonyls, and superoxide dismutase were significantly increased in nonsurvivor septic rats and were predictive of mortality. We demonstrated that there is a different modulation of superoxide dismutase and catalase in nonsurvivors during the course of septic response. There was a marked increase in superoxide dismutase activity without a proportional increase in catalase activity in nonsurvivors.

CONCLUSIONS

This is the first report of plasma superoxide dismutase as an earlier marker of mortality. Ours results might help to clarify an important aspect of oxidative response to sepsis, i.e., an increase in superoxide dismutase activity without a proportional increase in catalase activity