Region specific increase in the antioxidant enzymes and lipid peroxidation products in the brain of rats exposed to lead

Shortened Daily Photoperiod Alleviates Anxiety-like Behaviour by Antioxidant Effect and Changes Serum Fatty Acid Profile in Diabetic Rats

The aim of our study was to investigate the effects of a shortened daily photoperiod on anxiety-like behaviour, brain oxidative stress, lipid status and fatty acid composition of serum lipids in a streptozotocin (STZ)-induced model of diabetes mellitus in rats. Male Wistar rats were divided into the following groups: first group-control group (C_12/12); second group-diabetic group (DM_12/12; 100 mg/kg STZ); third group-control group exposed to a light/dark cycle 6/18 h (C_6/18); fourth group-diabetic group exposed to a light/dark cycle 6/18 h (DM_6/18). Anxiety-like behaviour was tested three weeks following STZ injection by elevated plus maze (EPM) and open-field test (OFT). Oxidative stress parameters were measured in the cortex, hippocampus and thalamus, while lipid status and fatty acid methyl esters (FAMEs) were measured in the serum. Both EPM and OFT showed a lower degree of anxiety-like behaviour in the DM_6/18 vs. DM_12/12 group. Lipid peroxidation in the cortex, hippocampus and thalamus was significantly lower in the DM_6/18 vs. DM_12/12 group (p < 0.05), associated with an increased level of antioxidant enzymes and protein thiols in the cortex and thalamus. In the DM_6/18 group, oleic, vaccenic, dihomo-γ-linolenic and docosahexaenoic acid concentrations were significantly higher in comparison to the DM_12/12 group. A shortened daily photoperiod alleviates anxiety-like behaviour in diabetic rats by reduced lipid peroxidation and changes in the serum fatty acids profile.

Protective Effect of 3-Benzoyl-7-Hydroxy Coumarin on Lipid Peroxidation and Minerals on Rat Liver Tissues Induced Oxidative Stress with Lead Acetate

Lead is a toxic substance and damages human metabolism. Coumarin-derived substances have many effects such as antioxidant, anticancer, and antibacterial ones. In this study, the effects of 3-benzoyl-7-hydroxy coumarin on rat liver tissues under oxidative stress with lead acetate were investigated. In the study, rats were divided into 4 groups. Control group (K), Coumarin group (KUM), Lead acetate group (P) and Coumarin+Lead acetate group (KUMP) groups were formed. Malondialdehyde (MDA), lead (Pb), iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) levels were determined in the liver tissues of the rats. MDA level of P group increased compared to the other groups. A decrease was observed in the KUMP group compared to the P group MDA level. While the Pb and Fe levels of the P group increased compared to the K group, the Pb and Fe levels of the KUMP group decreased compared to the P group. As a result, it is concluded that the 3-benzoyl-7-hydroxy coumarin molecule protects the high lipid peroxidation, lead, and iron metabolism caused by lead acetate in the liver.

The protective effects of pomegranate juice on lead acetate-induced neurotoxicity in the male rat: A histomorphometric and biochemical study

The purpose of this study was to investigate the potential side-effects of lead acetate (LA), which is toxic to the nerves, blood and muscles, in the rat brain. The neuroprotective effects of pomegranate juice (PJ) against LA exposure were also observed. The experiment involved 28 male Wistar albino rats aged 12 weeks. These were divided into four groups: Control, PJ, LA and LA+PJ. Stereological techniques were employed to determine hippocampal volume in each rat brain. Biochemical investigations and histopathological examinations were also performed. Analysis demonstrated a significant decrease in hippocampal volume in the LA group compared to the control group (p < .05). The stereology results also indicated that PJ has protective effects when compared with the LA and LA+PJ groups. A significant increase was also determined in malondialdehyde (MDA) levels and glutathione S-transferase (GST) activity in the LA group compared to the control group, in contrast to glutathione (GSH) levels and carboxylesterase (CaE) and acetylcholinesterase (AchE) activities. MDA and GST activity decreased significantly in the LA+PJ group compared to the LA group in contrast to GSH levels and CaE and AchE activities. Histopathological examination revealed a number of degenerative changes in the LA group. Exposure to LA adversely affects the hippocampus on the male rat brain. It might also be suggested that PJ may ameliorate these deleterious effects.

Neuroprotective Effects of Carnitine and Its Potential Application to Ameliorate Neurotoxicity

Carnitine is an essential metabolite that is absorbed from the diet and synthesized in the kidney, liver, and brain. It ferries fatty acids across the mitochondrial membrane to undergo β-oxidation. Carnitine has been studied as a therapy or protective agent for many neurological diseases and neurotoxicity (e.g., prolonged anesthetic exposure-induced developmental neurotoxicity in preclinical models). Preclinical and clinical data support the notion that carnitine or acetyl carnitine may improve a patient's quality of life through increased mitochondrial respiration, release of neurotransmitters, and global gene expression changes, showing the potential of carnitine beyond its approved use to treat primary and secondary carnitine deficiency. In this review, we summarize the beneficial effects of carnitine or acetyl carnitine on the central nervous system, highlighting protective effects against neurotoxicity-induced damage caused by various chemicals and encouraging a thorough evaluation of carnitine use as a therapy for patients suffering from neurotoxicant exposure.

Redox and essential metal status in the brain of Wistar rats acutely exposed to a cadmium and lead mixture

Most Pb and Cd neurotoxicity studies investigate exposure to either of the toxic metals alone, while data on co-exposure are scarce. The aim of our study was to fill that gap by investigating acute combined effects of Pb and Cd on redox and essential metal status in the brain of Wistar rats. Animals were randomised in four groups of six to eight rats, which received 15 or 30 mg/kg of Cd, 150 mg/kg of Pb, or 150 mg/kg of Pb + 15 mg/kg of Cd by gavage. The fifth, control, group received distilled water only. Co-treatment with Pb and Cd induced significant increase in malondialdehyde (MDA) and thiobarbituric acid-reactive substances (TBARS) compared to control and groups receiving either metal alone. This is of special importance, as MDA presence in the brain has been implicated in many neurodegenerative disorders. The groups did not significantly differ in Zn, Cu, Mn, and Fe brain levels. Our findings highlight the importance of metal mixture studies. Neurotoxicity assessments of single chemicals do not provide a real insight into exposure to mixtures in real life. Further research should look into interactions between these metals to reveal complex molecular mechanisms of their neurotoxicity.

Vitamin C and Turmeric Attenuate Bax and Bcl-2 Proteins' Expressions and DNA Damage in Lead Acetate-Induced Liver Injury

Background:

Lead is a common environmental and occupational pollutant which induced multiorgans dysfunction. The present study was designed to investigate the hepatoprotective effects of turmeric (TUR) and/or vitamin C (Vit-C) alone or together against lead acetate toxicity and to explore novel molecular pathways.

Method:

Acute hepatotoxicity was induced by lead acetate (100 mg/kg/day, i.p.) in male rats, and the effect of TUR (200 mg/kg/day, orally) and/or Vit-C (250 mg/kg/day, orally) along with lead acetate for 7 days was studied.

Results:

Lead acetate increased serum alanine transaminase, aspartate transaminase, lactate dehydrogenase, hepatic lipid peroxidation and nitric oxide; while, hepatic superoxide dismutase and glutathione activities were downregulated. Hepatic Bcl-2-associated X (Bax) and B-cell lymphoma-2 (Bcl-2) proteins expressions were altered and hepatic DNA damaged was increased as well. Liver/body weight ratio was decreased. Hematoxylin and eosin demonstrated that lead acetate induced focal areas of massive hepatic degeneration of the hepatocytes. Treatment with both antioxidants ameliorated all the altered parameters and induced marked improvement of liver architecture.

Conclusion:

The combination of TUR and Vit-C has shown the most protective effects against lead acetate-induced hepatotoxicity.

Antioxidant and nephro-protective effect of Juglans regia vegetable oil against lead-induced nephrotoxicity in rats and its characterization by GC-MS

Lead (Pb) intoxication remains a major health hazard causing various deleterious effects especially on renal and hematologic system. The current study elucidated the potential protective effect of JRVO against nephrotoxicity induced by lead. Male rats were randomly divided into three groups: group one (control) received ad libitum distilled water and 1 mL of saline solution (0.9 %) given by intra-peritoneal (i.p) injection, group two (Pb) was kept on tap distilled water and animals were i.p, injected daily with lead every two days from day five until day ten, namely the sacrifice day, and group three (Pb+J) was administered by intra-peritoneal injection of Pb with the same dose and same way with Group two, while JRVO extract was administered daily by gavage during ten days. The exposure of lead reduced the number of red and white blood cells. Besides, plasma biomarkers (urea, uric acid, creatinine, LDH and ALP) levels were reduced. Lipid and protein per-oxidations increased and objectified by high TBARS and PCOs levels, while glutathione peroxidase, superoxide dismutase and catalase activities showed a significant decline after ten-day treatment. Conversely, the JRVO prevented kidney biomarker changes by improving hepatotoxicity induced by lead as evidenced by restoring the biochemical markers cited above to near normal levels. Kidney histoarchitecture confirmed the biochemical parameters and the beneficial role of JRVO. It can be concluded that the administration of JRVO alleviates Pb-induced toxicity, thus demonstrating its potent antioxidant efficacy.

Effects of co-exposure to lead and zinc on redox status, kidney variables, and histopathology in adult albino rats

Lead (Pb) is a toxic metal that induces a wide range of biochemical and physiological effects in humans. Oxidative damage has been proposed as a possible mechanism involved in Pb toxicity. The current study was carried out to evaluate the antioxidant activities of zinc (Zn) supplement against lead acetate-induced kidney injury in rats. In this study, adults male rats were treated for 15 days with Pb (0.344 g/kg body weight (bw)) associated or not with Zn (10 mg/kg bw). Our study showed that supplementation with Zn prevented renal dysfunction as indicated by plasma biomarkers (urea, uric acid, creatinine, lactate dehydrogenase, and alkaline phosphatase levels) and oxidative stress-related parameters (thiobarbituric acid reactive substances, protein carbonyl, advanced oxidation protein product, superoxide dismutase, catalase, glutathione peroxidase, and vitamins (A, E)) in kidney tissue. The corrective effect of Zn on Pb-induced kidney nephrotoxicity recovered normal kidney histology. Overall, this study indicates that Zn alleviated the toxic effects of this heavy metal on renal tissue, suggesting its role as a potential antioxidant and nephroprotective agent.

Ameliorative effects of l-carnitine on rats raised on a diet supplemented with lead acetate

Lead intoxication has been a major health hazard in humans. It affects people at all ages. Its toxicity is associated with various organs of the body and affects different metabolic pathways. Based on histological data, l-carnitine reduced the severity of tissue damage produced as a result of exposure of rats to lead acetate. The main objective of this study was to evaluate the underlying mechanism of protection offered by l-carnitine against lead acetate intoxication using male Sprague-Dawley rats. Forty male Sprague-Dawley rats were randomly divided into four groups with ten rats in each. The first group (G1) served as the control group and animals received standard diet only. The second group (G2) received lead acetate in their diet. The third group (G3) was the l-carnitine treated group and received the normal standard diet supplemented with l-carnitine. While the fourth group (G4) had a diet supplemented with both lead acetate and l-carnitine. At the end of each experiment, blood (serum and whole blood) were collected from each animal and analyzed for the following parameters: serum testosterone levels, serum nitric oxide and serum malondialdehyde. This is in addition to looking at the enzymatic activities of two important enzymes (superoxide dismutase and catalase) and on (glutathione reductase) which are indicative of the antioxidant activities in the whole blood. The results indicated that l-carnitine will counteract the undesirable effects of lead intoxication. It exerted its antioxidant potential by reducing the production of ROS and scavenging free radicals by maintaining and protecting the level of the of antioxidant enzymes SOD, CAT and glutathione peroxidase. Conclusion:l-Carnitine may play an important role in reversing the undesirable effects of lead intoxication. Future studies should be conducted to see whether such an effect is applicable in humans exposed to lead poising.

In Vivo Effects of Naringenin and Lead on Rat Erythrocyte Carbonic Anhydrase Enzyme

OBJECTIVES

Carbonic anhydrase (CA) enzyme catalyses the reversible reactions of CO2 with water and takes part in metabolically important events such as systemic acid-base regulation and respiration. In this study, in vivo effects of lead, which is a heavy metal and to which living beings are exposed by different ways, with naringenin, a flavanone, were investigated.

MATERIALS AND METHODS

For this purpose, four different rat groups were established and one of them was chosen as the control group. The other three groups were given lead, naringenin and lead+naringenin substances to analyze the changes in the CA enzyme of rat erythrocytes.

RESULTS

The research findings showed that the enzyme activity in the control group was higher than that in the other groups. The naringenin group showed the highest inhibition effect, while the lead group showed the lowest inhibition.

CONCLUSION

Therefore, it can be said that naringenin is a strong inhibitor of the CA enzyme.

Neuroprotective Efficacy of Mitochondrial Antioxidant MitoQ in Suppressing Peroxynitrite-Mediated Mitochondrial Dysfunction Inflicted by Lead Toxicity in the Rat Brain

Lead (Pb) is one of the most pollutant metals that accumulate in the brain mitochondria disrupting mitochondrial structure and function. Though oxidative stress mediated by reactive oxygen species remains the most accepted mechanism of Pb neurotoxicity, some reports suggest the involvement of nitric oxide (^•NO) and reactive nitrogen species in Pb-induced neurotoxicity. But the impact of Pb neurotoxicity on mitochondrial respiratory enzyme complexes remains unknown with no relevant report highlighting the involvement of peroxynitrite (ONOO^-) in it. Herein, we investigated these effects in in vivo rat model by oral application of MitoQ, a known mitochondria-specific antioxidant with ONOO^- scavenging activity. Interestingly, MitoQ efficiently alleviated ONOO^--mediated mitochondrial complexes II, III and IV inhibition, increased mitochondrial ATP production and restored mitochondrial membrane potential. MitoQ lowered enhanced caspases 3 and 9 activities upon Pb exposure and also suppressed synaptosomal lipid peroxidation and protein oxidation accompanied by diminution of nitrite production and protein-bound 3-nitrotyrosine. To ascertain our in vivo findings on mitochondrial dysfunction, we carried out similar experiments in the presence of different antioxidants and free radical scavengers in the in vitro SHSY5Y cell line model. MitoQ provided better protection compared to mercaptoethylguanidine, N-nitro-L-arginine methyl ester and superoxide dismutase suggesting the predominant involvement of ONOO^- compared to ^•NO and O₂^•-. However, dimethylsulphoxide and catalase failed to provide protection signifying the noninvolvement of ^•OH and H₂O₂ in the process. The better protection provided by MitoQ in SHSY5Y cells can be attributed to the fact that MitoQ targets mitochondria whereas mercaptoethylguanidine, N-nitro-L-arginine methyl ester and superoxide dismutase are known to target mainly cytoplasm and not mitochondria. Taken together the results from the present study clearly brings out the potential of MitoQ against ONOO^--induced toxicity upon Pb exposure indicating its therapeutic potential in metal toxicity.

Effects of Naringenin on Oxidative Stress and Histopathological Changes in the Liver of Lead Acetate Administered Rats

Lead has several adverse effects on the body due to one of the environmental pollutants. We aimed to determine the effects of naringenin on the oxidative stress and the hepatic damage against lead acetate treatment in the liver of male rats. Naringenin was administered by orogastric gavage (50 mg/kg) and lead acetate was given as daily 500 parts per million in drinking water for 4 weeks. Lead and antioxidant activities were measured, and histopathological evaluation was performed in the liver. Lead concentrations, malondialdehyde, and antioxidant activity were restored by the naringenin. The grade of necrosis, hydropic degeneration, and hepatic cord disorganization was decreased by the naringenin. However, there were no differences in the degree of sinusoidal congestion, hepatic steatosis, and capsular fibrosis between lead acetate and naringenin + lead acetate groups. We can suggest that naringenin has antioxidant and chelating effects in the liver. Nevertheless, this effect is not enough against the lead acetate induced hepatic injury.

Direct contact with particulate matter increases oxidative stress in different brain structures

INTRODUCTION

Several experimental and epidemiological studies have demonstrated the neurological adverse effects caused by exposure to air pollution, specifically in relation to pollutant particulate matter (PM). The objective of this study was to investigate the direct effect of PM in increased concentrations in different brain regions, as well as the mechanisms involving its neurotoxicity, by evaluating oxidative stress parameters in vitro.

METHODS

Olfactory bulb, cerebral cortex, striatum, hippocampus and cerebellum of rats were homogenized and incubated with PM < 2.5 μm of diameter (PM2.5) at concentrations of 3, 5 and 10 µg/mg of tissue. The oxidative damage caused by lipid peroxidation of these structures was determined by testing the thiobarbituric acid reactive species (TBA-RS). In addition, we measured the activity of antioxidant enzyme catalase (CAT) and superoxide dismutase (SOD).

RESULTS

All PM concentrations were able to damage the cerebellum and hippocampus, strongly enhancing the lipid peroxidation in both structures. PM incubation also decreased the CAT activity of the hippocampus, cerebellum, striatum and olfactory bulb, though it did not generate higher levels of lipid peroxidation in either of the last two structures. PM incubation did not alter any measurement of the cerebral cortex.

CONCLUSION

The cerebellum and hippocampus seem to be more susceptible than other brain structures to in vitro direct PM exposure assay and the oxidative stress pathway catalyzes the neurotoxic effect of PM exposure, as evidenced by high consumption of CAT and high levels of TBA-RS. Thus, PM direct exposure seems to activate toxic neurological effects.

Cerium and yttrium oxide nanoparticles against lead-induced oxidative stress and apoptosis in rat hippocampus

Due to numerous industrial applications, lead has caused widespread pollution in the environment; it seems that the central nervous system (CNS) is the main target for lead in the human body. Oxidative stress and programmed cell death in the CNS have been assumed as two mechanisms related to neurotoxicity of lead. Cerium oxide (CeO2) and yttrium oxide (Y2O3) nanoparticles have recently shown antioxidant effects, particularly when used together, through scavenging the amount of reactive oxygen species (ROS) required for cell apoptosis. We looked into the neuroprotective effects of the combinations of these nanoparticles against acute lead-induced neurotoxicity in rat hippocampus. We used five groups in this study: control, lead, CeO2 nanoparticles + lead, Y2O3 nanoparticles + lead, and CeO2 and Y2O3 nanoparticles + lead. Nanoparticles of CeO2 (1000 mg/kg) and Y2O3 (230 mg/kg) were administered intraperitoneally during 2 days prior to intraperitoneal injection of the lead (25 mg/kg for 3 days). At the end of the treatments, oxidative stress markers, antioxidant enzymes activity, and apoptosis indexes were investigated. The results demonstrated that pretreatments with CeO2 and/or Y2O3 nanoparticles recovered lead-caused oxidative stress markers (ROS, lipid peroxidation, and total thiol molecules) and apoptosis indexes (Bax/Bcl-2 and caspase-3 protein expression). Besides, these nanoparticles reduced the activities of lead-induced superoxide dismutase and catalase as well as the ADP/ATP ratio. Interestingly, the best recovery resulted from the compound of these nanoparticles. Based on these outcomes, it appears that this combination may potentially be beneficial for protection against lead-caused acute toxicity in the brain through improving the oxidative stress-mediated programmed cell death pathway.

Effects of xenobiotics on total antioxidant capacity

The objective of this article was to review the effects of xenobiotics on total antioxidant capacity (TAC). Measurement of TAC is appropriate for evaluation of the total antioxidant defenses of blood, cells, and different kinds of tissues and organs. TAC is reduced by alcoholism, smoking, and exposure to radiation, herbicides, carbon monoxide, carbon tetrachloride, lead, arsenic, mercury, cadmium, aluminum, and other toxic elements. The test is also an important tool in evaluating environmental and occupational exposure.

Lead neurotoxicity: effects on brain nitric oxide synthase

Lead (Pb), a ubiquitous and potent neurotoxicant, induces several neurophysiological and behavioural changes, while Pb alters the function of multiple organs and systems, it primarily affects the central nervous system. In human adults, encephalopathy resulting from Pb intoxication is often characterized by sleeplessness, poor attention span, vomiting, convulsions and coma; in children, Pb-induced encephalopathy is associated with mental dullness, vomiting, irritability and anorexia; diminished cognitive function resulting in a mental deficit has been also observed during Prolonged exposure to Pb. Pb can produce oxidative stress, disrupt the blood-brain barrier and alter several Ca(2+)-dependent processes, including physiological processes that involve nitric oxide synthesis on central nervous system in development and adult animals. This review summarizes recent evidence showing that Pb can interfere with the production of nitric oxide and can disrupt the function of nitric oxide synthase. Lead interferes with nitric oxide-related physiological mechanisms, and Pb neurotoxicity may affect processes involved in learning and memory.

Neuroprotector effect of comenic acid against cytotoxic action of glutamate in vitro in cultured neurons of lead-poisoned rat pups

We demonstrated an increase in glutamate neurocytotoxicity in cultured cerebellar cells from rat pups subjected to lead poisoning during the prenatal development or early lactation period. The toxic effect of glutamate was weaker, if lead was applied in combination with antioxidant comenic acid. These data are discussed in view of practical use of comenic acid for the therapy of the brain tissues subjected to lead poisoning.

Ascorbic acid ameliorates oxidative damage induced by maternal low-level lead exposure in the hippocampus of rat pups during gestation and lactation

This study was to investigate the effects of ascorbic acid on the hippocampus of suckling rats in the presence of lead (Pb)-induced oxidative stress. Pregnant Sprague-Dawley rats received treatment with drinking water, divided into three groups, as follows: (1) distilled water; (2) 0.2% Pb; (3) 0.2% Pb+ascorbic acid (100mg/kg/day). Rat pups were euthanized at the age of 21days and their brain tissue was examined using light microscopy. Protein levels of Cu/Zn superoxide dismutase (Cu/Zn SOD), manganese superoxide dismutase (Mn SOD), and catalase (CAT) in the hippocampus were determined by Western blotting. We found a significant decrease in levels of Cu/Zn SOD and Mn SOD among Pb-exposed pups. Ascorbic acid supplementation appeared to negate the decrease in protein levels for Cu/Zn SOD and Mn SOD. In the case of CAT, there was no effect from Pb administration alone and Pb plus ascorbic acid appeared to increase the levels. In histopathology, ascorbic acid decreased the number of damaged cells in cornu ammonis areas CA1, CA3, and the dentate gyrus (DG) in hippocampus. Our results showed that administration of ascorbic acid during pregnancy and lactation could ameliorate some of the oxidative damage induced by Pb exposure in the developing rat hippocampus.

Brain region-specific changes in oxidative stress and neurotrophin levels in autism spectrum disorders (ASD)

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders characterized by social and language deficits, stereotypic behavior, and abnormalities in motor functions. The particular set of behavioral impairments expressed in any given individual is variable across the spectrum. These behavioral abnormalities are consistent with our current understanding of the neuropathology of ASD which suggests abnormalities in the amygdala, temporal and frontal cortexes, hippocampus, and cerebellum. However, regions unrelated to these behavioral deficits appear largely intact. Both genetic predisposition and environmental toxins and toxicants have been implicated in the etiology of autism; the impact of these environmental triggers is associated with increases in oxidative stress, and is further exacerbated when combined with genetic susceptibility. We have previously reported increased levels of 3-nitrotyrosine (3-NT), a marker of oxidative stress, in ASD cerebella. We have also shown that this increase was associated with an elevation in neurotrophin-3 (NT-3) levels. The objectives of the current study were to determine whether the increase in oxidative stress in ASD is brain region-specific, to identify the specific brain regions affected by oxidative stress, and to compare brain region-specific NT-3 expression between ASD and control cases. The levels of 3-NT and NT-3 were measured with specific ELISAs in individual brain regions of two autistic and age- and postmortem interval (PMI)--matched control donors. In the control brain, the levels of 3-NT were uniformly low in all brain regions examined ranging from 1.6 to 12.0 pmol/g. On the other hand, there was a great variation in 3-NT levels between individual brain regions of the autistic brains ranging from 1.7 to 281.2 pmol/g. The particular brain regions with the increased 3-NT and the magnitude of the increase were both different in the two autistic cases. In the older autistic case, the brain regions with highest levels of 3-NT included the orbitofrontal cortex (214.5 pmol/g), Wernicke's area (171.7 pmol/g), cerebellar vermis (81.2 pmol/g), cerebellar hemisphere (37.2 pmol/g), and pons (13.6 pmol/g); these brain areas are associated with the speech processing, sensory and motor coordination, emotional and social behavior, and memory. Brain regions that showed 3-NT increase in both autistic cases included the cerebellar hemispheres and putamen. Consistent with our earlier report, we found an increase in NT-3 levels in the cerebellar hemisphere in both autistic cases. We also detected an increase in NT-3 level in the dorsolateral prefrontal cortex (BA46) in the older autistic case and in the Wernicke's area and cingulate gyrus in the younger case. These preliminary results reveal, for the first time, brain region-specific changes in oxidative stress marker 3-NT and neurotrophin-3 levels in ASD.

Effect of lead on oxidative stress, Na+K+ATPase activity and mitochondrial electron transport chain activity of the brain of Clarias batrachus L

The present invivo study was designed to elucidate the toxic effect of lead on oxidative stress, Na(+)K(+)ATPase and mitochondrial electron transport chain activity of the brain of Clarias batrachus. The fish were exposed to 10 and 20% of the derived 96 h LC(50) value, 37.8 and 75.6 mg L(-1), respectively, and sampled on 20, 40 and 60 days. Exposure of fish brain to lead demonstrated an increased production of reactive oxygen species, increased lipid peroxidation, loss of protein thiol groups in synaptosomal fraction with the decreased activity of Na(+)K(+)ATPase, partial inactivation of mitochondrial electron transport chain activity and energy depletion. However, no change in protein carbonyl content in synaptosomal fraction was observed due to lead exposure. Concluding the results of our investigation we suggest that lead exposure induces oxidative stress in the brain of Clarias batrachus and the decline in Na(+)K(+)ATPase activity was presumeably mediated by the combined action of lipid peroxidation and deficient mitochondrial electron transport chain activity.

Influence of lead acetate on glutathione and its related enzymes in different regions of rat brain

This study is intended to determine the effect of lead acetate on glutathione and its associated enzymes of rat brain. Wistar male rats were treated with lead acetate (500 ppm) through drinking water for a period of 8 weeks and parallel controls were maintained. They were sacrificed at the first, fourth and eighth week to isolate whole brains, which were separated into cerebellum, hippocampus, frontal cortex and brain stem. The data indicate enhanced (P < 0.05) glutathione peroxidase (G-Px) activity at most of the intervals for cerebellum, frontal cortex and brain stem, suggesting conversion of GSH to GSSG, while the hippocampus showed decreased levels. In contrast, glutathione reductase (GR) decreased significantly (P < 0.05) in cerebellum, frontal cortex and brain stem at all intervals except the fourth week in frontal cortex and brain stem. Hippocampus exhibited a gradual and significant (P < 0.05) increase in GR activity. Glutathione-S-transferase (GSTase) activity increased with exposure time in all four brain tissues, showing protection against lead acetate toxicity. The GSH and GSSG levels correlated well with the activities of GPx, GR and GSTase in all four regions of the brain. Overall the results indicate that lead acetate affects glutathione-related enzymes differentially and these changes can be attributed to differences in tissue susceptibility.

Salicylic acid-involved in lead tolerance associated with the maintenance of reducing conditions in mice

Lead (Pb(2+)) intoxication may initiate many disorders in human and animals. In a previous study, we demonstrate that application of salicylic acid protects nuclear DNA integrity against Pb(2+) stress in mice. In this study, further evidence showed that the exogenous salicylic acid-involved in Pb(2+) tolerance in mice was associated with the maintenance of reducing conditions in cells, as revealed by an increased antioxidative enzyme activity, elevated reduced glutathione content and ratio to oxidised form of glutathione, and decreased lipid peroxidation. In addition, the presence of a 30 kD protein was tightly linked to the Pb(2+) detoxification.

Effects of acrylonitrile on antioxidant status of different brain regions in rats

While the adverse effects of acrylonitrile (AN) on the central nervous system (CNS) are known to be mediated, at least in part, by the generation of free radicals and oxidative stress, there is a paucity of data on region-specific alterations in biomarkers of oxidative stress in the brain of AN-exposed animals. The present study was designed to examine the effects of AN on biomarkers of oxidative stress in several brain regions of adult Sprague-Dawley rats. Daily intraperitoneal (i.p.) treatment of animals to 0 (control, normal saline solution), 25, 50 or 75mgAN/kg body weight for 7 days resulted in statistically significant (p<0.05) increases in the levels of lipid peroxidation product, malondialdehyde (MDA), in the cortex and cerebellum; a statistically significant (p<0.05) decrease MDA levels were noted in the striatum. Contents of reduced glutathione (GSH) were significantly (p<0.05) decreased in cortex, cerebellum and hippocampus. The activities of the antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GPx) were differentially affected by AN and these effects were brain region-specific and AN dose-dependent. Taken together, these data suggest brain region-specific effects of AN on lipid peroxidation, activities of antioxidant enzymes and non-enzymatic antioxidant levels. These effects may provide biochemical evidence for AN-induced neurobehavioral damage and disturbance of monoamine neurotransmitters.

Lead-induced alteration of apoptotic proteins in different regions of adult rat brain

In our earlier investigations, we have demonstrated the alteration of antioxidant enzymes in adult rat brain exposed to lead. This study was carried out to investigate the effect of lead on inducing apoptosis by choosing poly (ADP-ribose) polymerase (PARP), bcl-2 and caspase-3 expression as marker proteins in the cerebellum, the hippocampus, the brain stem and the frontal cortex. Adult male rats were treated with lead acetate (500ppm) through drinking water for a period of 8 weeks and parallel controls were maintained on sodium acetate. Both control and exposed rats were sacrificed at intervals of 4 and 8 weeks, brains were isolated and different regions namely the cerebellum, the hippocampus, the frontal cortex and the brain stem were separated and processed to investigate PARP, bcl-2 and caspase-3 expression using western blotting. The results suggest that lead induces region-specific response of expression in apoptotic proteins of rat brain showing more effect in hippocampus and cerebellum and less effect in frontal cortex and brain stem and it is tissue specific. However, results appear to conclude that PARP induced expression in hippocampus and cerebellum was more followed by mitochondrial and cytosolic damage.

Evidence for altered hippocampal volume and brain metabolites in workers occupationally exposed to lead: a study by magnetic resonance imaging and (1)H magnetic resonance spectroscopy

Environmental and occupational exposure to lead (Pb) remains to be a major public health issue. The purpose of this cross-sectional study was to use non-invasive magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy ((1)H MRS) techniques to investigate whether chronic exposure to Pb in an occupational setting altered brain structure and function of Pb-exposed workers. The Pb-exposed group consisted of 15 workers recruited from either a Pb-smelting factory or a Pb-battery manufacturer. The control group had 19 healthy volunteers who had no history of Pb exposure in working environment or at home. The average airborne Pb concentrations in fume and dust were 0.43 and 0.44 mg/m(3), respectively, in the smeltery, and 0.10 and 1.06 mg/m(3), respectively, in the Pb battery workshop. The average blood Pb concentrations (BPb) in Pb-exposed and control workers were 63.5 and 8.7 microg/dL, respectively. The MRI examination showed that brain hippocampal volume among Pb-exposed workers was significantly diminished in comparison to age-matched control subjects (p < 0.01), although the extent of this reduction was relatively small (5-6% of the control values). Linear regression analyses revealed significant inverse associations between BPb and the decreased hippocampal volume on both sides of brain hemisphere. Among five brain metabolites investigated by MRS, i.e., N-acetyl-aspartate (NAA), creatine (Cr), choline (Cho), inosine (mI), glutamate/glutamine (Glx) and lipids (Lip), a significant decrease in NAA/Cr ratio (7% of controls, p < 0.05) and a remarkable increase in Lip/Cr ratio (40%, p < 0.01) were observed in the brains of Pb-exposed workers as compared to controls. Furthermore, the increased Lip/Cr ratio was significantly associated with BPb (r = 0.46, p < 0.01). Taken together, this study suggests that occupational exposure to Pb may cause subtle structural and functional alteration in human brains. The MRI and MRS brain imaging techniques can be used as the non-invasive means to evaluate Pb-induced neurotoxicity.

Quercetin relieves chronic lead exposure-induced impairment of synaptic plasticity in rat dentate gyrus in vivo

Increasing evidence suggests that lead (Pb) produces impairments partly through oxidative stress. Though many researchers have investigated protective effect of some antioxidant nutrients against Pb toxicity, little information is available about the effect of antioxidants on Pb-induced impairment of synaptic plasticity. Quercetin, a strong antioxidant and radical scavenger, is the representative natural flavonoid molecule abundant in fruits and vegetables. Previous studies have found that quercetin was neuroprotective in many cases. This study was designed to evaluate the effect of quercetin on chronic Pb exposure-induced impairment of synaptic plasticity in adult rat dentate gyrus (DG) area in vivo. The input/output (I/O) functions, paired-pulse reactions (PPR), excitatory postsynaptic potential (EPSP), and population spike (PS) amplitude were measured in the DG area of different groups of rats in response to stimulation applied to the lateral perforant path. The results showed that the depressed I/O, PPR, and long-term potentiation (LTP) of Pb-exposed group were significantly increased by quercetin treatment. In addition, hippocampal Pb concentration was partially reduced after quercetin treatment. These findings suggest that quercetin treatment could relieve chronic Pb exposure-induced impairment of synaptic plasticity and might be a potential therapeutic intervention to cure cognitive deficits induced by Pb.