DNA Damage In Brain Research Articles

Neuropharmacological and genotoxic evaluation of ethanol extract from Erythrina falcata leaves, a plant used in Brazilian folk medicine

The aim of the present study was to determine neurobehavioral and genotoxic activities of ethanol extract of Erythrina falcata Benth., Fabaceae, leaves on rats. Animals were treated with ethanol extract of E. falcata (100, 300 or 500mg/ kg; i.p.) and the open field and elevated plus-maze tasks were used as behavioral models to investigate a possible effect on the locomotor and exploratory activity and anxiety, respectively. Genotoxic effect was investigated using the Comet assay. Ethanol extract of E. falcata leaves decreased the number of crossings and rearings in the open field task and increased the latency to start locomotion, though it was not able to affect habituation to apparatus measured 24h after the first session. Behavioral parameters in the plus-maze test were not affected by E. falcata. Ethanol extract did not increase damage index and damage frequency in blood or brain, indicating no genotoxic effect. The results suggest that ethanol extract of E. falcata leaves was able to affect locomotion, exploration, and motivation of animals without anxiolytic/anxiogenic effect, indicating a possible depressant action on the central nervous system. Furthermore, the lack of DNA damage in brain is an indicative that ethanol extract of E. falcata leaves may not induce neurotoxic effects.

Arsenosugar Induced Blood and Brain Oxidative Stress, DNA Damage and Neurobehavioral Impairments

The effect of Arsenosugar on motor function and contextual memory-related to place and event; the extent of DNA damage and oxidative stress in male swiss albino mice was investigated. Passive avoidance test was used for memory test; rota motor test was used for motor function. Several biochemical parameters were used for assessing oxidative stress due to arsenosugar ingestion. Decreased passive avoidance time and decreased retention time in rotating rod indicated disruption of normal neurobehavior. Significant dose-dependent DNA damage was found in mice blood and brain. Decreased super oxide dismutase, increased lipid peroxidation, decreased protein sulfohydryl content, increased protein carbonyl content in blood and hippocampal tissue; glutathione in blood and glutathione peroxidase in hippocampal tissue indicated the ability of arsenosugar to cause oxidative stress. This study concludes with evidence that arsenosugar ingestion causes higher oxidative stress, increases DNA damage in the blood and hippocampus in vivo. This might be responsible for the dysfunction of cognitive and motor functions. However, further investigation is suggested for deciphering the biomolecular mechanism.

Absence of genotoxic effects of the coumarin derivative 4‐methylesculetin in vivo and its potential chemoprevention against doxorubicin‐induced DNA damage

4-Methylesculetin (4-ME) is a synthetic derivative of coumarin that displays a potent reactive oxygen species (ROS) scavenger and metal chelating agent and therefore has been produced to help reduce the risk of human disease. The main objective of this study was to investigate the in vivo genotoxicity of 4-ME and initially to verify its potential antigenotoxicity on doxorubicin (DXR)-induced DNA damage. Different doses of 4-ME (500, 1000 and 2000 mg kg(-1) body weight) were administered by gavage only or with a simultaneous intraperitoneal (i.p.) injection of DXR (80 mg kg(-1)). The following endpoints were analyzed: DNA damage in peripheral blood, liver, bone marrow, brain and testicle cells according to an alkaline (pH > 13) comet assay and micronucleus induction in bone marrow cells. Cytotoxicity was assessed by scoring polychromatic (PCE) and normochromatic (NCE) erythrocytes (PCE/NCE ratio). No differences were observed between the negative control and the groups treated with a 4-ME dose for any of the endpoints analyzed, indicating that it lacks genotoxic and cytotoxic effects. Moreover, 4-ME demonstrated protective effects against DXR-induced DNA damage at all tested doses and in all analyzed cell types, which ranged from 34.1% to 93.3% in the comet assay and 54.4% to 65.9% in the micronucleus test.

Protective Effect of a Synthetic Antioxidant “Acetyl Gallate Derivative” Against Dimethoate Induced DNA Damage and Oxidant/Antioxidant Status in Male Rats

The present study was conducted to investigate the protective effects of a synthetic antioxidant “acetyl gallate derivative” (SAC) against hepatic oxidative stress and brain DNA damage induced by dimethoate (DM) in male rats. DM was orally administrated to the rats at a dose of 38.7 mg kg-1 b.wt. (1/10 LD50), for 28 consecutive days. Additional DM groups received either SAC or vitamin C (VC) at a dose of 200 mg kg-1 b.wt. 30 min before DM administration. Compared to the control, DM induced a statistical reduction in body weight gain, while induced a statistical increase in absolute and relative liver weights. Oral administration of DM significantly caused increases in hepatic lipid peroxidation (LPO) and activities of antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD) and glutathione-s-transferease (GST), while caused decreases in glutathione content (GSH) and serum cholinesterase(ChE) activity. Administration of SAC attenuates LPO, GSH content and antioxidant enzymes system. The severity of brain DNA damage monitored by damage index (DI) and damage frequency % (DF) induced by DM was mitigated after administration of SAC. In conclusion, supplementation of SAC is more reliable than VC in attenuating relative liver weight, SOD, GST, and brain DNA damage.

Does the cycad genotoxin MAM implicated in Guam ALS-PDC induce disease-relevant changes in mouse brain that includes olfaction?

Western Pacific amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC), a prototypical neurodegenerative disease (tauopathy) affecting distinct genetic groups with common exposure to neurotoxic chemicals in cycad seed, has many features of Parkinson's and Alzheimer's diseases (AD), including early olfactory dysfunction. Guam ALS-PDC incidence correlates with cycad flour content of cycasin and its aglycone methylazoxymethanol (MAM), which produces persistent DNA damage (O6-methylguanine) in the brains of mice lacking O6-methylguanine methyltransferase (Mgmt-/-). We described in Mgmt-/- mice up to 7 days post-MAM treatment that brain DNA damage was linked to brain gene expression changes found in human neurological disease, cancer, and skin and hair development. This addendum reports 6 months post-MAM treatment- related brain transcriptional changes as well as elevated mitogen activated protein kinases and increased caspase-3 activity, both of which are involved in tau aggregation and neurofibrillary tangle formation typical of ALS-PDC and AD, plus transcriptional changes in olfactory receptors. Does cycasin act as a "slow (geno)toxin" in ALS-PDC?

Resveratrol ameliorates oxidative DNA damage and protects against acrylamide-induced oxidative stress in rats

Acrylamide (ACR), used in many fields from industrial manufacturing to laboratory personnel work is also formed during the heating process through interactions of amino acids. Therefore ACR poses a significant risk to human health. This study aimed to elucidate whether resveratrol (RVT) treatment could modulate ACR-induced oxidative DNA damage and oxidative changes in rat brain, lung, liver, kidney and testes tissues. Rats were divided into four groups as control (C); RVT (30mg/kg i.p. dissolved in 0.9% NaCl), ACR (40mg/kg i.p.) and RVT+ACR groups. After 10days rats were decapitated and tissues were excised. 8-hydroxydeoxyguanosine (8-OHdG) is a biomarker of oxidative DNA damage. 8-OHdG content in the extracted DNA solution was determined by enzyme-linked immunosorbent assay method. Malondialdehyde (MDA), glutathione (GSH) levels and myeloperoxidase activity (MPO) were determined in tissues, while oxidant-induced tissue fibrosis was determined by collagen contents. Serum enzyme activities, cytokine levels, leukocyte apoptosis were assayed in plasma. As an indicator of oxidative DNA damage, 8-OHdG levels significantly increased in ACR group and this was reversed significantly by RVT treatment. In ACR group, GSH levels decreased significantly while the MDA levels, MPO activity and collagen content increased in the tissues suggesting oxidative organ damage. In RVT-treated ACR group, oxidant responses reversed significantly. Serum enzyme activities, cytokine levels and leukocyte late apoptosis which increased following ACR administration, decreased with RVT treatment. Therefore supplementing with RVT can be useful in individuals at risk of ACR toxicity.

NAP prevents acute cerebral oxidative stress and protects against long-term brain injury and cognitive impairment in a model of neonatal hypoxia–ischemia

Hypoxia–ischemia (HI) is a common cause of neonatal brain damage with lifelong morbidities in which current therapies are limited. In this study, we investigated the effect of neuropeptide NAP (NAPVSIPQ) on early cerebral oxidative stress, long-term neurological function and brain injury after neonatal HI. Seven-day-old rat pups were subjected to an HI model by applying a unilateral carotid artery occlusion and systemic hypoxia. The animals were randomly assigned to groups receiving an intraperitoneal injection of NAP (3 μg/g) or vehicle immediately (0 h) and 24 h after HI. Brain DNA damage, lipid peroxidation and reduced glutathione (GSH) content were determined 24 h after the last NAP injection. Cognitive impairment was assessed on postnatal day 60 using the spatial version of the Morris water maze learning task. Next, the animals were euthanized to assess the cerebral hemispheric volume using the Cavalieri principle associated with the counting point method. We observed that NAP prevented the acute HI-induced DNA and lipid membrane damage and also recovered the GSH levels in the injured hemisphere of the HI rat pups. Further, NAP was able to prevent impairments in learning and long-term spatial memory and to significantly reduce brain damage up to 7 weeks following the neonatal HI injury. Our findings demonstrate that NAP confers potent neuroprotection from acute brain oxidative stress, long-term cognitive impairment and brain lesions induced by neonatal HI through, at least in part, the modulation of the glutathione-mediated antioxidant system.

Nandrolone androgenic hormone presents genotoxic effects in different cells of mice

Nandrolone is an androgenic-anabolic steroid (AAS) with diverse medical applications but taken indiscriminately by some to rapidly increase muscle mass. The aim of this study was to evaluate the genotoxic and clastogenic potential of nandrolone (deca-durabolin®) in vivo in different cells of mice, using the comet assay and micronucleus test, respectively. The animals received subcutaneous injection of the three doses of the steroid (1.0, 2.5 and 5.0 mg kg⁻¹ body weight). Cytotoxicity was assessed by scoring 200 consecutive total polychromatic (PCE) and normochromatic (NCE) erythrocytes (PCE-NCE ratio). The results showed a significant dose-related increase in the frequency of DNA damage in leukocytes, liver, bone marrow, brain and testicle cells at the three tested doses and a significant increase of the micronucleated polychromatic erythrocytes at all tested doses. Under our experimental conditions, the nandrolone steroid hormone showed genotoxic and clastogenic effects when administered subcutaneously to mice.

Genomic damage in the progression of chronic kidney disease in rats

Patients with chronic renal failure exhibit massive oxidative genome damage and an elevated risk of cancer. Previous studies have demonstrated the relationship between DNA damage and carcinogenesis. The current study aimed to investigate whether the progression of chronic kidney disease induces genomic damage in an animal model. Adult Wistar rats were assigned to either the control or chronic kidney disease groups. The chronic kidney disease group was subdistributed into five groups with progressively longer durations of disease (30, 60, 90, 120 and 150days). The results showed that chronic kidney disease induced genomic damage in the blood, liver and kidney cells during all periods evaluated, as indicated by the mean tail moment measured in the comet assay. In brain cells, no genetic damage was induced at early/intermediate disease durations; however, positive genotoxicity was found at 120 and 150days. Blood pressure and pro-inflammatory cytokine levels (IL-1α, IL-1β, IL-6 and TNFα) were increased after chronic kidney disease induction, while blood iron concentration was significantly reduced in these animals. The results suggest that chronic kidney disease progression contributes to DNA damage in blood, liver, kidney and brain and that such damage can be mediated by hypertension, an inflammatory status and iron deficiency. Additionally, the brain was sensitive to genotoxic insult after extended chronic kidney disease, suggesting a potentially important role of genetic damage in the neurological disorders of end-stage renal patients.

Reduced expression of DNA glycosylases in post-hypoxic newborn pigs undergoing therapeutic hypothermia

Supplementary oxygen during resuscitation of the asphyxiated newborn is associated with increased generation of reactive oxygen species and oxidative stress. It is suspected that hyperoxic reoxygenation may cause increased damage to DNA, resulting in replication errors, and cell death or potential fixation of mutations if unrepaired. Therapeutic hypothermia may attenuate the development of brain damage after asphyxia, but it is not known how post-hypoxic hyperoxia and hypothermia affect accumulation of DNA-damage and DNA repair. Anaesthetised newborn pigs were randomised to control ( n = 6) or severe global hypoxia ( n = 46). After 20 min of reoxygenation with either room air or 100% O 2, followed by 6.5 h of normothermia (deep rectal temperature 39 °C) or total body cooling (35 °C), oxidative DNA damage (8-hydroxy-2′-deoxyguanosine) in brain, liver and urine, and transcription of DNA repair glycosylases ( NEIL1, NEIL3, and OGG1) in brain and liver were measured. Hypoxic pigs displayed increased urinary 8-oxodG levels: mean (SD) 8-oxodG/creatinine was 3.55 (1.46) vs. control 2.02 (0.53), p < 0.05, but levels were not affected by hyperoxia or hypothermia. Accumulation of 8-oxodG in the brain and liver did not differ across groups. Post-hypoxic transcription of DNA glycosylases was down-regulated by hypothermia: OGG1 in hippocampus and liver ( p < 0.01); NEIL1 in hippocampus ( p < 0.01), cortex and striatum ( p < 0.05) and liver ( p < 0.001); and NEIL3 in hippocampus ( p < 0.01) and cerebellum ( p < 0.001). Hyperoxia did not affect transcription of glycosylases in the brain. We confirm increased oxidative stress after hypoxia. DNA repair glycosylases were down-regulated by hypothermia but with no effect on accumulation of oxidative damage in genomic DNA.

Effects of static magnetic field and cadmium on oxidative stress and DNA damage in rat cortex brain and hippocampus

The present study was undertaken to determine the effect of co-exposure to static magnetic field (SMF) and cadmium (Cd) on the antioxidant enzymes activity and DNA integrity in rat brain. Sub-chronic exposure to CdCl (CdCl(2), 40 mg/L, per os) for 30 days resulted in a significant reduction in antioxidant enzyme activity such as the glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) in frontal cortex and hippocampus. Total GSH were decreased in the frontal cortex of the Cd-exposed group. Cd exposure induced an increase in malondialdehyde (MDA) concentration in the frontal cortex and hippocampus. Moreover, the same exposure increased 8-oxo-7,8-dihydro-2-desoxyguanosine (8-oxodGuo) level in rat brain. Interestingly, the combined effect of SMF (128 mT, 1 hour/day for 30 consecutive days) and CdCl (40 mg/L, per os) decreased the SOD activity and glutathione level in frontal cortex as compared with the Cd group. Moreover, the association between SMF and Cd increased MDA concentration in frontal cortex as compared with Cd-exposed rats. DNA analysis revealed that SMF exposure failed to alter 8-oxodGuo concentration in Cd-exposed rats. Our data showed that Cd exposure altered the antioxidant enzymes activity and induced oxidative DNA lesions in rat brain. The combined effect of SMF and Cd increased oxidative damage in rat brain as compared with Cd-exposed rats.

Therapeutic potential of N-acetyl cysteine with antioxidants (Zn and Se) supplementation against dimethylmercury toxicity in male albino rats

Mercury (Hg) is currently one of the most prevalent pollutants in the environment. Many studies have examined its effects on the health of both humans and animals. Experimental studies have shown that sulfur-containing nutrients play an important role as detoxification and protecting cell against the detrimental properties of mercury. The present study was undertaken to elucidate the toxicity induced by dimethylmercury in male rats through the activities of transaminases, alkaline phosphatase, lactate dehydrogenase in serum and oxidative damage as acetyl cholinesterase activity in different regions of brain and lipid peroxidation, reduced glutathione content, mean DNA damage in liver, kidney and brain of rats given dimethylmercury (10 mg/kg, p.o., once only) along with combination therapy of N-acetyl cysteine (2 mM/kg, i.p.), zinc (2 mM/kg, p.o.) and selenium (0.5 mg/kg, p.o.) for 3 days. In the dimethylmercury group, activities of transaminases, alkaline phosphatase, lactate dehydrogenase in serum, level of lipid peroxidation, mean DNA damage and mercury ion concentration were significantly higher whereas reduced glutathione content and the activity of acetyl cholinesterase were significantly lower compared to controls ( P ≤ 0.05). Combined treatment of zinc and selenium with N-acetyl cysteine to dimethylmercury-exposed rats showed a substantial reduction in the levels of DMM-induced oxidative damage and comet tail length. In conclusion, the results of this study support that the supplementation of zinc and selenium with N-acetyl cysteine can improve the DMM induced blood and tissue biochemical oxidative stress and molecular alterations by recoupment in mean DNA damage.

Vitamin C prevents DNA damage induced by renovascular hypertension in multiple organs of Wistar rats

The aim of this study was to investigate, through the single-cell gel (comet) assay, whether vitamin C is able to protect against renovascular hypertension-induced genotoxicity in multiple organs. A total of 32 male Wistar rats were divided into four groups: negative control (n = 6); animals treated with vitamin C (n = 6); hypertensive rats (n = 10) and hypertensive rats and treated with vitamin C (n = 10). Hypertension was induced as a result of partial obstruction of the left renal artery by means of a silver clip during 6 weeks. Vitamin C was administered at 150 mg/kg during 7 consecutive days before the end of the experimental period. The results showed that vitamin C was able to protect blood cells against hypertension-induced genotoxicity. Brain, liver and heart cells were also protected by vitamin C following hypertension-induced genotoxic damage. Regarding blood pressure, vitamin C reduced the hypertensive state. In conclusion, our results suggest that vitamin C can prevent hypertension-induced DNA damage in blood, liver, brain and heart cells as well as to normalize the blood pressure of rats.

BRIEF REPORT: Single exposure to cocaine or ecstasy induces DNA damage in brain and other organs of mice

We evaluated the overall genetic damage induced by different doses of cocaine and MDMA (3,4-Methylenedioxymethamphetamine) in several organs. One hour after intraperitoneal drug administration, mice were euthanized; peripheral blood, liver and brain were collected, and the cellular suspensions were used for the single cell gel (comet) assay. We determined that all doses of cocaine and MDMA tested were able to induce DNA damage in blood cells. Extensive genotoxic damage was induced by cocaine or MDMA at the highest doses used in liver cells. Brain cells were affected by all doses administrated. These findings demonstrate that cocaine and MDMA are potent genotoxins.

Effects of Embryonic Neural Stem Cell Transplantation on DNA Damage in the Brain and Spinal Cord Following Spinal Cord Injury

Embryonic neural stem cell (ENSC) transplantation is used experimentally for the improvement of spinal cord repair following spinal cord injury (SCI). However, the effects of such intervention on oxidative stress and cell death remain unknown. We used in vivo Comet assay in the acute and chronic SCI groups compared with the SCI+ENSC transplantation groups of experimental rats in order to evaluate DNA damage in the spinal cord. Chronic SCI resulted in the generation of oxidative DNA damage in the spinal cord brain and kidneys, as indicated by high Comet assay parameters, including the percentage of DNA in the tail (T%, or TD), tail moment (TM), and tail length (TL). The DNA damage levels significantly decreased after ENSC transplantation in the spinal cords of acute and chronic SCI groups within the lesion site and rostrally and caudally to the injury, and in the brains and kidneys of the chronic SCI group. Thus, ENSC transplantation is found to be an effective tool for limitation of DNA damage following spinal cord injury.

Co-exposure to arsenic and fluoride on oxidative stress, glutathione linked enzymes, biogenic amines and DNA damage in mouse brain

We studied the effects of combined exposure to arsenic and fluoride on (i) brain biogenic amines, oxidative stress and its correlation with glutathione and linked enzymes; (ii) alterations in the structural integrity of DNA; and (iii) brain and blood arsenic and fluoride levels. Efficacy of α-tocopherol in reducing these changes was also determined. Male mice were exposed to sodium meta arsenite (50 ppm) and sodium fluoride (50 ppm) individually and in combination for ten weeks. Animals were given vitamin E supplementation (5 mg/kg, i.m., alternate days) throughout the experiment. Exposure to arsenic and fluoride significantly decreased the levels of brain biogenic amines. However; acetyl cholinesterase (AChE) and monoamine oxidase (MAO) activities showed an increase on fluoride exposure. There was also an increase in reactive oxygen species, thiobarbituric acid reactive species level, glutathione S-transferase and glutathione peroxidase activities and decreased superoxide dismutase activity, GSH:GSSG ratio, glucose 6-phosphate dehydrogenase activity. Combined exposure to these toxicants produced more pronounced effects on AChE, MAO, SOD and catalase activities. Infrared spectra showed less toxicity during combined exposure as the characteristic peaks of cytosine and α-helical structure of DNA were observed in normal and arsenic plus fluoride-exposed animals. Vitamin E reduced brain fluoride level and tissue oxidative stress but had no effect on arsenic. Combined exposure to arsenic and fluoride does not necessarily lead to more pronounced toxicity and interestingly exhibit some antagonistic effects. Vitamin E supplementation may be of added value in reverting some of the toxic effects.

No increases in biomarkers of genetic damage or pathological changes in heart and brain tissues in male rats administered methylphenidate hydrochloride (Ritalin) for 28 days

Following a 2005 report of chromosomal damage in children with attention deficit/hyperactivity disorder (ADHD) who were treated with the commonly prescribed medication methylphenidate (MPH), numerous studies have been conducted to clarify the risk for MPH-induced genetic damage. Although most of these studies reported no changes in genetic damage endpoints associated with exposure to MPH, one recent study (Andreazza et al. [2007]: Prog Neuropsychopharmacol Biol Psychiatry 31:1282-1288) reported an increase in DNA damage detected by the Comet assay in blood and brain cells of Wistar rats treated by intraperitoneal injection with 1, 2, or 10 mg/kg MPH; no increases in micronucleated lymphocyte frequencies were observed in these rats. To clarify these findings, we treated adult male Wistar Han rats with 0, 2, 10, or 25 mg/kg MPH by gavage once daily for 28 consecutive days and measured micronucleated reticulocyte (MN-RET) frequencies in blood, and DNA damage in blood, brain, and liver cells 4 hr after final dosing. Flow cytometric evaluation of blood revealed no significant increases in MN-RET. Comet assay evaluations of blood leukocytes and cells of the liver, as well as of the striatum, hippocampus, and frontal cortex of the brain showed no increases in DNA damage in MPH-treated rats in any of the three treatment groups. Thus, the previously reported observations of DNA damage in blood and brain tissue of rats exposed to MPH for 28 days were not confirmed in this study. Additionally, no histopathological changes in brain or heart, or elevated serum biomarkers of cardiac injury were observed in these MPH-exposed rats.

Acrylonitrile-induced oxidative stress and oxidative DNA damage in male Sprague-Dawley rats.

Studies have demonstrated that the induction of oxidative stress may be involved in brain tumor induction in rats by acrylonitrile. The present study examined whether acrylonitrile induces oxidative stress and DNA damage in rats and whether blood can serve as a valid surrogate for the biomonitoring of oxidative stress induced by acrylonitrile in the exposed population. Male Sprague-Dawley rats were treated with 0, 3, 30, 100, and 200 ppm acrylonitrile in drinking water for 28 days. One group of rats were also coadministered N-acetyl cysteine (NAC) (0.3% in diet) with acrylonitrile (200 ppm in drinking water) to examine whether antioxidant supplementation was protective against acrylonitrile-induced oxidative stress. Direct DNA strand breakage in white blood cells (WBC) and brain was measured using the alkaline comet assay. Oxidative DNA damage in WBC and brain was evaluated using formamidopyrimidine DNA glycosylase (fpg)-modified comet assay and with high-performance liquid chromatography-electrochemical detection. No significant increase in direct DNA strand breaks was observed in brain and WBC from acrylonitrile-treated rats. However, oxidative DNA damage (fpg comet and 8'hydroxyl-2-deoxyguanosine) in brain and WBC was increased in a dose-dependent manner. In addition, plasma levels of reactive oxygen species (ROS) increased in rats administered acrylonitrile. Dietary supplementation with NAC prevented acrylonitrile-induced oxidative DNA damage in brain and WBC. A slight, but significant, decrease in the GSH:GSSG ratio was seen in brain at acrylonitrile doses > 30 ppm. These results provide additional support that the mode of action for acrylonitrile-induced astrocytomas involves the induction of oxidative stress and damage. Significant associations were seen between oxidative DNA damage in WBC and brain, ROS formation in plasma, and the reported tumor incidences. Since oxidative DNA damage in brain correlated with oxidative damage in WBC, these results suggest that monitoring WBC DNA damage maybe a useful tool to assess acrylonitrile-induced oxidative stress in humans.

Protective Effect of Vitamin E Against Ethanol‐Induced Hyperhomocysteinemia, DNA Damage, and Atrophy in the Developing Male Rat Brain

Chronic alcoholism leads to elevated plasma and brain homocysteine (Hcy) levels, as demonstrated by clinical investigations and animal experiments. It has been posited that elevated levels of Hcy mediate DNA damage, brain atrophy, and excitotoxicity. The current study sought to elucidate the effect of vitamin E on ethanol-induced hyperhomocysteinemia, DNA damage, and atrophy in the developing hippocampus and cerebellum of rats. Pregnant Wistar rats received ethanol with or without vitamin E from gestation day 7 throughout lactation. Weight changes in the brain, hippocampus and cerebellum, DNA damage, and Hcy levels in the plasma, hippocampus, and cerebellum of male offspring were measured at the end of lactation. The results revealed that along with a significant decrease in brain, cerebellum, and hippocampus weights in animals that received alcohol, the levels of DNA damage and Hcy significantly increased. Significant amelioration of brain atrophy and DNA damage as well as restoration of the elevated level of Hcy to that of controls were found in vitamin E-treated rats. These findings strongly support the idea that ethanol intake by dams during pregnancy and lactation induces Hcy-mediated oxidative stress in the developing hippocampus and cerebellum of offspring rats, and that these effects can be alleviated by vitamin E as an antioxidant.

Excision repair cross-complementing 1 expression protects against ischemic injury following middle cerebral artery occlusion in the rat brain

To study the effects of excision repair cross-complementing 1 (ERCC1) on the pathophysiological process of brain ischemia, we examined the changes in ERCC1 expression, as well as the functional significance of ERCC1 in the rat brain following middle cerebral artery occlusion (MCAO). The results were as follows: (1) ERCC1 immunopositive cells were widely distributed in various brain regions. ERCC1 expression was localized to the nuclei of neurons and astrocytes. (2) ERCC1 expression, as determined by western blot, increased at 3 days, remaining until 14 days, in the ipsilateral cortex and striatum following MCAO. Immunohistochemical analysis demonstrated that ischemia induced increased ERCC1 expression within the periinfarct core, with increasingly less expression toward the core. (3) Knockdown of ERCC1 expression by intraventricular injection of antisense plasmids increased DNA damage and infarct volume in the ischemic brain. (4) ERCC1 overproduction, by injection of expression plasmids, significantly reduced infarct volume and the accumulation of DNA-damaged neurons. Taken together, these results indicate that both endogenous ERCC1 and exogenous ERCC1 have an important neuroprotective function in the brain. In addition, administration of ERCC1 to the brain could prove to be a successful strategy for neuronal protection against ischemic injury.