Enéas Andrade Fontes-Júnior

Chronic Ethanol Exposure during Adolescence in Rats Induces Motor Impairments and Cerebral Cortex Damage Associated with Oxidative Stress

Binge drinking is common among adolescents, and this type of ethanol exposure may lead to long-term nervous system damage. In the current study, we evaluated motor performance and tissue alterations in the cerebral cortex of rats subjected to intermittent intoxication with ethanol from adolescence to adulthood. Adolescent male Wistar rats (35 days old) were treated with distilled water or ethanol (6.5 g/kg/day, 22.5% w/v) during 55 days by gavage to complete 90 days of age. The open field, inclined plane and the rotarod tests were used to assess the spontaneous locomotor activity and motor coordination performance in adult animals. Following completion of behavioral tests, half of animals were submitted to immunohistochemical evaluation of NeuN (marker of neuronal bodies), GFAP (a marker of astrocytes) and Iba1 (microglia marker) in the cerebral cortex while the other half of the animals were subjected to analysis of oxidative stress markers by biochemical assays. Chronic ethanol intoxication in rats from adolescence to adulthood induced significant motor deficits including impaired spontaneous locomotion, coordination and muscle strength. These behavioral impairments were accompanied by marked changes in all cellular populations evaluated as well as increased levels of nitrite and lipid peroxidation in the cerebral cortex. These findings indicate that continuous ethanol intoxication from adolescence to adulthood is able to provide neurobehavioral and neurodegenerative damage to cerebral cortex.

Chronic ethanol exposure during adolescence through early adulthood in female rats induces emotional and memory deficits associated with morphological and molecular alterations in hippocampus

There is increasing evidence that heavy ethanol exposure in early life may produce long-lasting neurobehavioral consequences, since brain structural maturation continues until adolescence. It is well established that females are more susceptible to alcohol-induced neurotoxicity and that ethanol consumption is increasing among women, especially during adolescence. In the present study, we investigated whether chronic ethanol exposure during adolescence through early adulthood in female rats may induce hippocampal histological damage and neurobehavioral impairments. Female rats were treated with distilled water or ethanol (6.5 g/kg/day, 22.5% w/v) by gavage from the 35th–90th day of life. Ethanol-exposed animals displayed reduced exploration of the central area and increased number of fecal boluses in the open field test indicative of anxiogenic responses. Moreover, chronic high ethanol exposure during adolescence induced marked impairments on short-term memory of female rats addressed on social recognition and step-down inhibitory avoidance tasks. These neurobehavioral deficits induced by ethanol exposure during adolescence through early adulthood were accompanied by the reduction of hippocampal formation volume as well as the loss of neurons, astrocytes and microglia cells in the hippocampus. These results indicate that chronic high ethanol exposure during adolescence through early adulthood in female rats induces long-lasting emotional and memory deficits associated with morphological and molecular alterations in the hippocampus.

Is Low Non-Lethal Concentration of Methylmercury Really Safe? A Report on Genotoxicity with Delayed Cell Proliferation.

Human exposure to relatively low levels of methylmercury is worrying, especially in terms of its genotoxicity. It is currently unknown as to whether exposure to low levels of mercury (below established limits) is safe. Genotoxicity was already shown in lymphocytes, but studies with cells of the CNS (as the main target organ) are scarce. Moreover, disturbances in the cell cycle and cellular proliferation have previously been observed in neuronal cells, but no data are presently available for glial cells. Interestingly, cells of glial origin accumulate higher concentrations of methylmercury than those of neuronal origin. Thus, the aim of this work was to analyze the possible genotoxicity and alterations in the cell cycle and cell proliferation of a glioma cell line (C6) exposed to a low, non-lethal and non-apoptotic methylmercury concentration. Biochemical (mitochondrial activity) and morphological (integrity of the membrane) assessments confirmed the absence of cell death after exposure to 3 μM methylmercury for 24 hours. Even without promoting cell death, this treatment significantly increased genotoxicity markers (DNA fragmentation, micronuclei, nucleoplasmic bridges and nuclear buds). Changes in the cell cycle profile (increased mitotic index and cell populations in the S and G2/M phases) were observed, suggesting arrest of the cycle. This delay in the cycle was followed, 24 hours after methylmercury withdrawal, by a decrease number of viable cells, reduced cellular confluence and increased doubling time of the culture. Our work demonstrates that exposure to a low sublethal concentration of MeHg considered relatively safe according to current limits promotes genotoxicity and disturbances in the proliferation of cells of glial origin with sustained consequences after methylmercury withdrawal. This fact becomes especially important, since this cellular type accumulates more methylmercury than neurons and displays a vital role protecting the CNS, especially in chronic intoxication with this heavy metal.

Thiamine deficiency, oxidative metabolic pathways and ethanol-induced neurotoxicity: how poor nutrition contributes to the alcoholic syndrome, as Marchiafava–Bignami disease

Ethanol is an important risk factor for the occurrence of several brain disorders that depend on the amount, period and frequency of its consumption. Chronic use of ethanol often leads to the development of neurodegenerative syndromes, which cause morphological and functional impairments such as foetal alcohol syndrome in newborns exposed to ethanol during pregnancy, Wernicke–Korsakoff Syndrome and, more rarely, Marchiafava–Bignami disease (MBD). MBD is characterized by primary degeneration of the corpus callosum, without inflammation and is associated with oxidative stress and hypovitaminosis, as well as altered mental status, to mention dementia, seizures, depression and so on. This review discusses MBD and poor nutrition as a risk factor for the development of such alcoholic syndrome, with focus on diagnosis, pathogenic aspects, signs and symptoms, as well as therapeutic perspectives. On the basis of the inclusion/exclusion criteria adopted, the performed search in scientific databases (Pubmed, Scielo and Google Scholar) resulted in 100 studies that are being presented and discussed in the present work. Review, case–control and cohort studies on alcoholism-associated hypovitaminosis, oxidative stress, MBD and ethanol metabolism pathways were admitted as relevant. We highlight that MBD is a poorly described, diagnosed, insidious and progressive condition, for which evidence suggests a synergism between ethanol-induced neurotoxic effects and hypovitaminosis B. Present treatment consists of vitamin B1(thiamine) supplementation. Nonetheless, other strategies such as the inclusion of antidepressants or steroidal anti-inflammatories as add-on therapies have been employed as an attempt to improve the damage. Indeed, both the diagnosis and treatment are difficult, and death occurs within few years.

Neurobehavioral and Antioxidant Effects of Ethanolic Extract of Yellow Propolis

Propolis is a resin produced by bees from raw material collected from plants, salivary secretions, and beeswax. New therapeutic properties for the Central Nervous System have emerged. We explored the neurobehavioral and antioxidant effects of an ethanolic extract of yellow propolis (EEYP) rich in triterpenoids, primarily lupeol and β-amyrin. Male Wistar rats, 3 months old, were intraperitoneally treated with Tween 5% (control), EEYP (1, 3, 10, and 30 mg/kg), or diazepam, fluoxetine, and caffeine (positive controls) 30 min before the assays. Animals were submitted to open field, elevated plus maze, forced swimming, and inhibitory avoidance tests. After behavioral tasks, blood samples were collected through intracardiac pathway, to evaluate the oxidative balance. The results obtained in the open field and in the elevated plus maze assay showed spontaneous locomotion preserved and anxiolytic-like activity. In the forced swimming test, EEYP demonstrated antidepressant-like activity. In the inhibitory avoidance test, EEYP showed mnemonic activity at 30 mg/kg. In the evaluation of oxidative biochemistry, the extract reduced the production of nitric oxide and malondialdehyde without changing level of total antioxidant, catalase, and superoxide dismutase, induced by behavioral stress. Our results highlight that EEYP emerges as a promising anxiolytic, antidepressant, mnemonic, and antioxidant natural product.

Chronic Alcohol Intoxication and Cortical Ischemia: Study of Their Comorbidity and the Protective Effects of Minocycline

Chronic alcohol intoxication (CAI) increases both morbidity and mortality of stroke patients. Despite the high prevalence of CAI and ischemic stroke, studies addressing their comorbidity and/or protective alternatives remain scarce. Thus, the influence of CAI on both stroke outcome and minocycline treatment (recognized for its neuroprotective effect) was investigated. Female Wistar rats (35 days old) were treated with water or ethanol (6.5 g/kg/day, 22.5% w/v) for 55 days. Then, focal ischemia was induced by endothelin-1 in the motor cortex. Two hours later, four doses of 50 mg/kg of minocycline every 12 hours followed by five doses of 25 mg/kg every 24 hours were administered. Behavioral performance (open field and rotarod tests) and immunohistochemical (cellular density, neuronal death, and astrocytic activation) and biochemical (lipid peroxidation and nitrite levels) analyses were performed. CAI increased motor disruption, nitrite and lipid peroxidation levels, and neuronal loss caused by ischemia, whereas it reduced the astrogliosis. Minocycline was effective in preventing the motor and tissue damage caused by stroke. However, these effects were attenuated when CAI preceded stroke. Our data suggest that CAI beginning in adolescence contributes to a worse outcome in ischemic stroke survivors and reduces the benefits of minocycline, possibly requiring adjustments in therapy.

Repeated cycles of binge-like ethanol exposure induce immediate and delayed neurobehavioral changes and hippocampal dysfunction in adolescent female rats

HIGHLIGHTSSingle cycle of ethanol treatment in mid‐adolescence elicits anxiety‐like profile.Adolescent binge multiple cycles impair memory related to GFAP and BDNF alterations.Adolescent repeated binge‐like anxiety persists even in the long‐lasting withdrawal.Memory damage after adolescent binge cycles recovers in the long‐term withdrawal. ABSTRACT Binge‐like ethanol intake (BEI) is a socioeconomical problem among adolescents and increasingly affects women. BEI can leave a long‐term imprint in the brain, but it is unknown if its effect on cognition and anxiety is cumulative on repeated binge‐ethanol episodes. We now submitted female Wistar rats to repeated cycles of binge‐like ethanol treatment by intragastrically administering ethanol (3.0g/kg/day, 20% w/v ethanol; 3 days on/4 days off) starting at postnatal day 35 (PND35). To investigate the short‐term effects of BEI during adolescence, rats underwent 1 or 4 cycles of BEI, being evaluated at PND37 and PND58, respectively: both groups displayed anxiety‐like behavior in the open field and elevated plus‐maze tests, as well as short‐term memory deficits in the object recognition task; this was associated with transient decreases of BDNF levels and increases of GFAP levels in the hippocampus. To evaluate the short‐ and long‐lasting effects of BEI in adulthood, rats were subjected to 8 cycles of BEI and evaluated after 7.5h (PND86) or after 14 days of ethanol withdrawal (PND100). This caused a persistent anxiogenic profile whereas recognition memory was impaired on the short‐term, but not 14 days post‐administration. The reduced BDNF level observed shortly after BEI recovered upon withdrawal, whereas increased GFAP immunoreactivity was persistent up to 14 days post‐administration in adulthood. These findings show that repeated binge‐like ethanol episodes from adolescence to adulthood in female rats cause consistent and long‐term alterations of anxiety and hippocampal astrogliosis, whereas they trigger a recognition memory deficit paralleled by lower hippocampal BDNF levels, both recovering upon ethanol withdrawal.

Petiveria alliacea exerts mnemonic and learning effects on rats.

ETHNOPHARMACOLOGICAL RELEVANCE Petiveria alliacea L. (Phytolaccaceae) is a perennial shrub native to the Amazon region and other tropical areas such as Central America and the Caribbean. Popularly known as mucuracaá, P. alliacea is used in the folk medicine for a broad variety of therapeutic purpose and also in religious ceremonies by slaves as a sedative, which highlights its properties on the Central Nervous System (CNS). AIM OF THE STUDY The present study evaluated the effects of the P. alliacea leaves hydroalcoholic extract (PaLHE) on the cognition, including learning and memory. MATERIAL AND METHODS Three-month-old male and female Wistar rats (n=8-10/group) were administered with 900mg/kg of PaLHE. The behavioral assays included Step-down Inhibitory avoidance (IA) and Morris Water Maze (MWM) tests. RESULTS Consistent with our previous reports, P. alliacea improved long-term memory. It also exerted previously unreported effects on short-term and spatial memory improvement, and increased learning in the tasks. CONCLUSIONS The P. alliacea extract elicited mnemonic effects and improved the learning process in both IA and MWM tests. Our results highlight the importance of further studies in order to identify the active substances of the PaLHE and investigate the pharmacological mechanisms that underlies the reported effects.

Anti-Inflammatory and Antinociceptive Studies of Hydroalcoholic Extract from the Leaves of Phyllanthus brasiliensis (Aubl.) Poir. and Isolation of 5-O-β-d-Glucopyranosyljusticidin B and Six Other Lignans

The aim of this study was to investigate the chemical composition and the antiinflammatory/antinociceptive properties of the hydroalcoholic extract derived from the leaves of Phyllanthus brasiliensis (HEPB) in rodents. A new arylnaphthalene lignan glycoside, 5-O-β-d-glucopyranosyljusticidin B, together with six known lignans, were isolated from HEPB. 1D and 2D NMR experiments and HRMS were used to elucidate the structure of the new compound. HEPB toxicity and antinociceptive activity were evaluated through acute oral toxicity and formalin models in mice, respectively. The anti-inflammatory effects of HEPB were assessed using carrageenan- and dextran-induced paw edema models in rats. HEPB showed low toxicity. Oral administration of HEPB reduced paw edema induced by carrageenan, but not by dextran. HEPB and its fractions from FR6 to FR10 (FR6-10) inhibited the neurogenic and inflammatory phases of formalin-induced linking, demonstrating its antinociceptive activity. These results indicated that lignans from Phyllanthus brasiliensis exerted antinociceptive/anti-inflammatory effects not related to the histaminergic pathway.

Heavy Chronic Ethanol Exposure From Adolescence to Adulthood Induces Cerebellar Neuronal Loss and Motor Function Damage in Female Rats

Over the last years, heavy ethanol consumption by teenagers/younger adults has increased considerably among females. However, few studies have addressed the long-term impact on brain structures’ morphology and function of chronic exposure to high ethanol doses from adolescence to adulthood in females. In line with this idea, in the current study we investigated whether heavy chronic ethanol exposure during adolescence to adulthood may induce motor impairments and morphological and cellular alterations in the cerebellum of female rats. Adolescent female Wistar rats (35 days old) were treated with distilled water or ethanol (6.5 g/kg/day, 22.5% w/v) during 55 days by gavage. At 90 days of age, motor function of animals was assessed using open field (OF), pole, beam walking and rotarod tests. Following completion of behavioral tests, morphological and immunohistochemical analyses of the cerebellum were performed. Chronic ethanol exposure impaired significantly motor performance of female rats, inducing spontaneous locomotor activity deficits, bradykinesia, incoordination and motor learning disruption. Moreover, histological analysis revealed that ethanol exposure induced atrophy and neuronal loss in the cerebellum. These findings indicate that heavy ethanol exposure during adolescence is associated with long-lasting cerebellar degeneration and motor impairments in female rats.