Navegando por Assunto "Isquemia"

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Acidente vascular encefálico isquêmico na exposição crônica ao etanol: estudo pré-clínico da comorbidade e da resposta a minociclina
(Universidade Federal do Pará, 2015-02-27) FONTES JÚNIOR, Enéas de Andrade; MAIA, Cristiane do Socorro Ferraz; http://lattes.cnpq.br/4835820645258101; CRESPO LÓPEZ, Maria Elena; http://lattes.cnpq.br/9900144256348265
Stroke is the second largest cause of death in the world and the leading in Brazil, with 87% of strokes due to ischemic processes. Chronic ethanol consumption, usually beginning in adolescence, is recognized as an independent risk factor for increased morbidity and mortality by stroke. Although cases combining the two diseases are relatively common, there is no data in animals or clinical models demonstrating the quality or mechanisms of interaction between the two morbidities, nor its impact on therapeutic intervention. Considering the recent studies proposing minocycline as a new therapeutic tool for the treatment of stroke, this study aimed to investigate the interaction between the Chronic Alcoholic Intoxication (CAI) started in adolescence and the stroke in motor cortex of adult rats, and the effects of treatment with minocycline on this interaction, using behavioral, cellular and molecular parameters. Female Wistar rats (35 days-old) were chronically exposed to ethanol (6.5 g/kg/day, 22.5% w/v) or water for 55 days. One day after the end of the CAI focal ischemia was induced in motor cortex with the endothelin-1 (ET-1), followed by seven-day treatment with minocycline or saline. After this period, the animals were assayed with open field and rota rod tests. Immediately, animals were sacrificed and cortex was dissected for evaluation of nitrite and lipid peroxidation levels. In all groups, some animals were perfused and the motor cortex subjected to histological analysis to assess the damage, and immunohistochemical labeling to neuronal death (anti-NeuN), microglial/macrophage (anti-ED1) and astrocytes (anti-GFAP) activation. The ethanol intoxication from puberty to adulthood potentiated the damage caused by stroke, causing major losses in capacity to start and running movements as well as the strength and motor coordination compared to ischemic animals pretreated with water. These manifestations were accompanied by increased neuronal loss, reduced ED-1+ and GFAP+ cells and higher levels of nitrite and lipid peroxidation. Treatment with minocycline was effective in preventing/reverse motor deficits and tissue damage induced by focal ischemia, also inhibiting the increase in oxidative stress markers. The CAI either alone with succeeded by focal ischemia, harmed the outcome of treatment with minocycline. Our results indicate that heavy alcohol intoxication during adolescence exacerbates the motor deficit and tissue damage in animals subjected to focal ischemia. This process appears to be associated with microglia/astroglial activation, but mainly with oxidative stress. It also shows that the previous history of CAI started adolescence interferes significantly in the treatment of cerebral ischemia with minocycline.
Acesso aberto (Open Access)
Alterações morfo-funcionais em córtex isquêmico de animais tratados com transplante autólogo de células mononucleares da medula óssea
(Universidade Federal do Pará, 2015-10-08) BARBOSA JUNIOR, Mário Santos; PEREIRA JÚNIOR, Antônio; http://lattes.cnpq.br/1402289786010170; BAHIA, Carlomagno Pacheco; http://lattes.cnpq.br/0910507988777644
Statistical data show stroke as the second leading cause of death and leading cause of disability among all other diseases in the world. The ischemic stroke (ischemic stroke) accounts for about 87% of incidence of strokes. In ischemic stroke, inflammation acts in restraint of infarction caused by ischemic stroke, and on the other hand the intensity of the inflammatory response in neurodegeneration and consequently influence the functional loss. The autologous cell therapy, mononuclear bone marrow cells, promotes modulation in neuroinflammation, being timely during an ischemic event for reduction of tissue loss and functional. In the present study, we used an experimental model of focal ischemic stroke to assess morphological and functional effects of autologous implant mononucleres bone marrow cells (CMMOs) on the morphological and functional changes related to ischemic stroke. We demonstrate in this study that the autologous BM-MNC in acute or acute and subacute periods of ischemic event, promoted neuroprotection and inflammatory modulation able to rebound in preservation and functional recovery in specific activities. We also show that the treatment enhanced in subacute period, the ischemic event, was able to promote increase in morphological and functional improvements promoted by autologous transplantation in acute period.
Acesso aberto (Open Access)
Análise comparativa dos padrões neurodegenerativos da substância cinzenta em diferentes áreas corticais de ratos adultos submetidos à lesão isquêmica focal
(Universidade Federal do Pará, 2012-09-27) SANTOS, Enio Maurício Nery dos; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Stroke can occur in any region of the central nervous system (CNS). The cerebral cortex is one of the most often affected areaby this acute neural disorder, but there are no studies that have compared the damaging pattern in different cortical regions after acomparable focal ischemia. The aim of this investigation was to evaluate the degenerative pattern of different cortical areas after focal ischemic injury. Focal ischemia was induced by stereotaxic microinjections of endothelin-1 (ET-1) into the somatosensory, motor and association cortices of adult rats (N = 45). The control animals were injected with the same volume of sterile saline (N = 27). The animals were perfused 1, 3 and 7 days after the ischemic event. The brain was removed, postfixed, cryoprotected, and sectioned in a cryostat. The general histopathology was evaluated in 50μm sections stained with cresyl violet. 20μm sections were submitted to immunohistochemistry for astrocytes (anti-GFAP), activated microglia / macrophages (anti-ED1) and overall microglial population (anti-Iba1). The damaging patterns werequalitatively evaluated under optical microscopy and quantitatively by counting the number of cells in the ipsilateral and contralateral sides to injury.Descriptive statistics and comparisons within and between groups were performed using analysis of variance with Tukey post-hoc test. Conspicuous ischemic tissue loss, microglial activation and astrocytosis were observed mainly 3 and 7 days after ischemia, which was not observed in control animals. The tissue loss and activation of glial cells were more intense in the somatosensory cortex, followed by the motor cortex. The association cortex displayed less damage compared to other cortical areas, which was confirmed by quantitative analysis. The results suggest that an ischemic lesion of the same intensity induces a differential pattern of tissue loss and neuroinflammation, depending on the cortical area, and that the primary sensory and motor areas are more susceptible to ischemia than association areas.
Acesso aberto (Open Access)
Ativação microglial, lesão da substância branca e expressão de Nogo-A em ratos submetidos à isquemia estriatal
(Universidade Federal do Pará, 2012-05-10) LIMA, Rafael Rodrigues; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
The objective of this investigation was to evaluate the degenerative pattern of several white matter tracts after striatal ischemic injury, correlating degenerative process standards with the microglial activation and expression of Nogo-A. For this purpose, focal ischemia was induced with stereotactic injection of endothelin in striatum of adult rats, and only in the control animals injected with sterile saline. The animals were perfused 3, 7, 14 and 30 days after ischemia. The brain removed, postfixed, cryoprotected, cut into cryostat sections obtained and submitted to immunohistochemical investigation with the following antibodies: anti-GFAP (1:2000, Dako), anti-Tau-1 (1:500, Chemicon), Anti-MBP (1:100, Chemicon International), Anti-Nogo-A (1:100, Invitrogen), Anti-Iba1 (1:1000, WAKO), ED1 (1:500, Serotec) and Anti-MHC II (Abcam 1:100), besides the viewing of the damage pattern with cresyl violet. Slides are marked by different methods were evaluated qualitatively and quantitatively also some (Anti-Nogo A, anti-ED-1, anti-MHC-II and anti-tau-1), counts were carried out in the striatum and in the corpus callosum. The data were tabulated, statistically analyzed by Tukey test (p <0.05) and micrographs taken of the findings more representative. The slides were stained with cresyl violet revealed an increase in cell density by the infiltration of inflammatory cells to the ischemic area, with a significant increase on day 7. The blades immunostained for GFAP was found progressive increase of the population of astrocytes and an increase in cell volume 7 and 14 days. Oligodendrocyte pathology marked with Tau-1 had peak marking the 3rd day in the striatum and the 7th day in the corpus callosum, and loss of myelin compaction identified by MBP was better at 14, in the different treatment. The microglial activation identified by different immunoblots showed a peak on day 7, both in striatum and in the corpus callosum, but in the corpus callosum with a much smaller number compared to the striatum. The morphology of microglial underwent changes, which found the branched phenotype in control animals, as well as in early and late times after ischemia and amoeboid default / phagocytic day 7, coinciding with the largest number of activated cells. The count of Nogo-A + cells peaked at 3 days observed in the striatum, and there were no differences in the corpus callosum expression Nogo-A 3 to 14 days, only a decrease compared to 30 days. Thus, microinjections of ET-1 induced conspicuous striatal tissue loss, concomitant with progressive microglial activation, astrocytosis, loss of immunoreactivity for myelin basic protein and oligodendrocytes damage in various survival times after focal ischemia. These events affect a few SB tracts, as the corpus callosum. The establishment of the temporal evolution of these events is the neuropathological basis for future studies, in which they should handle the inflammatory response in order to minimize these tissue changes.
Acesso aberto (Open Access)
Atividade antiinflamatória e neuroprotetora da Edaravona no córtex sensóriomotor primário de ratos adultos submetidos à isquemia focal experimental
(Universidade Federal do Pará, 2014-02-12) ARAÚJO, Sanderson Corrêa; BORGES, Rosivaldo dos Santos; http://lattes.cnpq.br/4783661132100859; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Stroke is a neural disorder originated from blood flow decreasing or interruption, making inadequate energy supply in the region, thus promoting tissue damage. The stroke can be divided in hemorragic or ischemic. The ischemic stroke is more prevalent and can occur through thrombosis or embolism. The ischemic pathology has multiple interrelated events like excitotoxicity, peri-infarct depolarization, oxidative and nitrosative stress, inflammation and apoptosis. An element of fundamental importance in ischemic pathology is the microglial cell, whose activity is closely linked to the progression of environment harm. A therapeutic alternative in the treatment of stroke is a pyrazolone called Edaravone. This study evaluated the neuroprotective effect of Edaravone dose of 3mg/kg in primary sensorymotor cortex after focal ischemic lesion. Edaravone treated animals (N = 10) and animals treated with saline solution (N = 10) in the survival time of 1 and 7 days after the ischemic event was evaluated. Treatment whith edaravone showed by histopathological analysis with cresyl violet a reduction of 49% and 66% in infarct size in animals in survival time 1 and 7 days respectively. Immunohistochemistry studies for microglia/macrophages assets (ED1+) demonstrated a reduction in the presence of ED1+ cells in 35% and 41% survival times for 1 and 7 days, respectively. Neutrophils (MBS-1+) were reduced to 64% only in animals with survival times a day. Harmful patterns were assessed qualitatively and quantitatively. Data was tested by ANOVA with Tukey post hoc test. Differences were considered significant at p < 0,05.
Acesso aberto (Open Access)
Avaliação neuropatológica da lesão estriatal em ratos machos e fêmeas da linhagem lister hooded induzida experimentalmente por microinjeções de endotelina-1
(Universidade Federal do Pará, 2012-05-30) SANTOS, Ijair Rogerio Costa dos; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
The inflammatory response may exacerbate the process harmful after acute neural disorders. Sexual dimorphism generated by different hormonal attendance between male and female have demonstrated neuroprotective abilities endogenous opposite, showing a better preservation of the integrity of the nervous tissue in female, putatively due to the presence of gynoid hormones. However, there is no research work comparing how this difference might affect the inflammatory response during stroke. In the present study, we investigated the differences in acute inflammatory processes of sexual dimorphism in adult rats of both sexes subjected to acute ischemic injury induced by endothelin (ET1) in the striatum. Six experimental groups were designed: male animals survival 24 hours (n = 8); male survival of 72 hours (n = 8); male survival of 7 days (n = 8) and female 24 hours survival (n = 8), females 72 hours of survival (n = 8); female seven days of survival. Histopathologic analysis was performed in the general sections stained with violet cresila. Macrophages, astrocytes, and neurons were identified by immunohistochemistry with antibodies specific for these inflammatory cells (ED1, anti-GFAP and Anti-NeuN, respectively). We conducted counts activated microglia / macrophages and neuron bodies mentioned in the experimental groups. No difference was observed quantitatively between different sexes, but there was an apparent decrease in the amount of macrophages / microglia at 3 days but in males and in females, presenting apparently some difference in the activation of astrocytes was stronger in males. The results suggest that sex differences, at least in lineage Lister hooded is not enough to cause significant differences in the preservation of nerve tissue and in some aspects of the inflammatory response after induction of cerebral ischemia by ET1.
Acesso aberto (Open Access)
Distribuição tecidual, neuroproteção e efeitos anti-inflamatórios do conjugado LDE/metotrexato após isquemia cortical induzida por microinjeções de endotelina 1 em ratos adultos
(Universidade Federal do Pará, 2017-04-05) PEREIRA, Edmundo Luís Rodrigues; BURBANO, Rommel Mario Rodriguéz; http://lattes.cnpq.br/4362051219348099; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Ischemic stroke is one of the leading causes of morbidity and mortality in adults worldwide. Currently, there is only a single pharmacological therapy available to treat such neural disorder, using a high-cost thrombolytic agent, which must be administered within 4 hours of the onset of symptoms, but with a significant risk of transforming the initially oligoemic area into a catastrophic cerebral haemorrhage. In the last decades, nanoparticles with high affinity for certain types of tissues and specially configured with an enhanced diffusibility through biological barriers, have been employed as vehicles to carry therapeutic agents. Among these, the novel liposomal nanoparticle LDE conjugated to the agent methotrexate (cLDE / MTX) has been successfully tested in several experimental models of inflammation, with promising results. Considering that modulation of the inflammatory process that accompanies cerebral infarction is of prognostic significance, the present study investigated the effects of cLDE / MTX upon an experimental model of cerebral ischemia induced by the vasoconstrictor agent endothelin-1 (ET-1) in the cerebral cortex of adults rats. During the first phase of the study, the behavior of tritiated LDE particles (LDE3H+) concerning the blood-brain barrier (BBB), once injected through the caudal vein, was evaluated in either sham animals (N = 18) and animals submited to ET-1 injection (80pMol / Μl) directly into the frontal cortex (N = 5). Further, the anti-inflammatory and neuroprotective effects of cLDE / MTX (1 mg / kg), also injected by caudal vein, were investigated in ischemic animals (N = 5), with the control group (N = 5) receiving only free LDE. All animals were perfused with 0.9% saline and 4% paraformaldehyde 7 days after ischemic induction. Histopathological findings were evaluated by staining with cresyl violet and immunohistochemistry for adult neuronal bodies (anti-NeuN), astrocytes (anti-GFAP) and microglia (anti-Iba1). The results showed that LDE3H+ positively crosses BBB in both sham animals and ischemic animals, and that cLDE / MTX treatment, despite the fact that it reduces not the total area of primary infarction, was able to considerably reduces microglial activation phenomenon at the center of the lesion, inducing as well a significant neuronal preservation at the periphery of the infarction, when compared to the control animals, injected only with unconjugated LDE (P <0.01). At last, the astrocytosis phenomena usually encountered in cerebral ischemia remained unchanged. The results indicate that cLDE / MTX is a promising anti-inflammatory and neuroprotective agent in such experimental model of ischemic stroke. Future studies are desirable in order to increase knowledge about these outcomes, including in animal models with longer survivals.
Acesso aberto (Open Access)
Efeito protetor da flavana extraída da espécie Brosimum acutifolium contra danos causados por hipóxia em células retinianas: um estudo in vitro
(Universidade Federal do Pará, 2014-06-14) FONSECA, Susanne Suely Santos da; BAHIA, Carlomagno Pacheco; http://lattes.cnpq.br/0910507988777644; PEREIRA JÚNIOR, Antônio; http://lattes.cnpq.br/1402289786010170
Ischemic stroke causes neuronal death due to excitotocity and oxidative stress. In this work, we investigate the neuroprotective effect of an amazon plant Brosimum acutifolium which is rich in flavanas with antioxidant potential, such as 4',7-dihydroxy-8-(3,3-dimethylallyl) flavana (brosimin b) (Bb), in a experimental model hypoxia in vitro. Neuroprotective effect of Bb was evaluated using cell cultures obtained from chick embryo retinas submitted to hypoxy by deprivation of oxygen and glucose. The antioxidant power of Bb was evaluated by kidnapping of 2,2-diphenyl-1-picryl-hydrazyl (DPPH) molecules. The neuroprotective activity was evaluated through the effects under cell viability, oxidative and antioxidative profile after 3, 6 and 24 hours after hypoxia trough oxygen reactive elements (O2-) analysis and endogenous antioxidant activity power of the catalase enzyme, respectively. We demonstrate that in vitro hypoxia causes time-dependent decreasing of cell viability due to the excessive production of O2-. On the other hands, the Bb treatment (10 μM) significantly preserved the cellular viability after 3 and 6 hours of in vitro hypoxia. This effect contributed to decrease the oxidative stress generated by productions of O2- during the 3 initial hours of hypoxia and also induced the increasing in the power activity of catalase enzyme in all the tested times. Thus, we show that Bb treatment has an antioxidant and neuroprotector effects due to contribute with antioxidant response during the neural hypoxia-induced oxidative stresse in vitro. These results suggest the use of Bb as a potential drug for Ischemic stroke treatment in vivo.
Acesso aberto (Open Access)
Efeitos neuroprotetores e anti-inflamatórios do óleo de copaíba (Copaifera reticulata Ducke) em ratos adultos submetidos a isquemia do córtex motor por microinfecções de Edotelina-1
(Universidade Federal do Pará, 2019-02-15) SILVA, Paulo Rodrigo Oliveira da; FRANCO, Edna Cristina Santos; http://lattes.cnpq.br/5939607544965550; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Stroke is a neural disorder caused by interruption of blood flow in vessels that irrigate the brain (ischemic stroke) or rupture of these (hemorrhagic stroke), causing cognitive, sensory and / or motor deficits. With the exception of thrombolytic use, which has a very narrow therapeutic window and is little used, there are no other pharmacological treatments or cellular therapy available for this pathological condition. Thus, it is necessary to search for new treatments, such as the development of neuroprotective agents. The Amazon is a rich source of natural products, but its therapeutic actions for diseases of the central nervous system (CNS) have been little investigated. In this work, we have investigated the neuroprotective and anti-inflammatory actions of copaiba oil-resin (COR). Adult Wistar rats were submitted to focal ischemia by microinjections (80pMol/μl) of endothelin-1 (ET-1) directly into the motor cortex and were treated with daily doses of COR (400mg / kg) or 5% tween. The animals were perfused at 7 days after the injury. The histopathological analysis was performed by Nissl staining (brain) and hematoxylin-eosin (liver and kidneys). Immunohistochemistry was performed for labeling of neurons (anti-NeuN), astrocytes (anti-S100) and caspase (anti-caspase-3). Morphometry showed a reduction in the lesion size area (copaiba-treated animals (15.96 ± 1.53 mm2); control animals (28.82 ± 2.65 mm2). Histopathological examination of the liver and kidneys did not find changes indicative of toxicity. In the quantitative analysis, neuronal preservation was observed, but no statistical difference was noticed between the groups regarding astrocytes analysis (S100+ cells). The COR-treated group showed an increase in caspase-3 expression. It is concluded that COR may play a neuroprotective role, contributing to neuronal survival in the area of ischemic penumbra, but future work is needed to find out the mechanisms underlying this phenomenon.
Acesso aberto (Open Access)
Fenótipos microgliais e tratamento com minociclina após isquemia focal induzida por microinjeções de endotelina-1 no córtex motor de ratos adultos
(Universidade Federal do Pará, 2016-12-23) DIAS, Michelle Nerissa Coelho; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Microglial cells are fundamental components of the innate immune system that continually make a complete scan of the neural parenchyma in search of subtle tissue changes for the preservation of tissue integrity. These resident macrophages of the central nervous system (CNS) correspond to about 20% of the encephalic cell population. In acute and chronic neural disorders, including brain and spinal cord injury, experimental stroke, Alzheimer's, Parkinson's and Huntington's disease, microglial cells are activated, which is reflected in morphological and biochemical changes. In these diseases, it is believed that microglial activation contributes to both neuroprotection and exacerbation of the injury process. Several experimental evidences suggest that excessive microglial activation may contribute to the increase of the injury process after experimental stroke. However, our previous studies suggest that microglial cells may release trophic factors after experimental stroke in anatomically distinct regions of the microglial population with deleterious phenotypes. There are no studies that have described the reactivity patterns of the different microglial phenotypes after experimental ischemia. In the present project, we will investigate the patterns of activation of microglial cells presenting beneficial and harmful phenotypes, evaluating which microglial populations are inhibited by tetracycline minocycline after focal cortical ischemia. The animals were submitted to focal ischemia in the motor cortex by microinjections of 80 pMol of endothelin-1 (ET- 1). They were sacrificed 7, 14 and 30 days after ischemic induction. The immunohistochemistry technique for the observation of neuronal loss (NeuN +) and double immunofluorescence to evaluate the density of M1 and M2 microglial cells in the lesioned area was used. Statistical analysis of NeuN+ cell density was performed by the Student's t-test from the 7-day of control and treated groups while the analysis of the M1 and M2 microglial cells were done by the analysis of variance in the 07, 14 and 30 control groups, adopting in all tests the level of significance P <0.05. A preservation in the number of neurons in the injured parenchyma of the animals treated with minocycline was confirmed. A decrease in the number of M1 microglial cells in minocycline-treated animals was observed, suggesting that the drug may present effects on expression pathways of M1 microglial phenotypes. However, when the animals of the control group of 07, 14 and 30 are compared, there is an increase in the number of this M1 phenotype that extends from day 7 to day 30. We conclude that there is a neuroprotective effect of the drug minocycline when associated to stroke, suggesting that this drug may be involved in the modulation of microglial phenotypes requiring further studies on its function in the pathways of expression of these phenotypes.
Acesso aberto (Open Access)
Imunoreatividade para os receptores de neurotrofinas P75NTR e TrkA na zona subventricular de ratos adultos após isquemia estriatal
(Universidade Federal do Pará, 2015-08-21) TAVARES, Patrycy Assis Noronha; LIMA, Rafael Rodrigues; http://lattes.cnpq.br/3512648574555468; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Neurotrophins are growth factors expressed by cells of the nervous system both during development and in adulthood. The Nerve Growth Factor (NGF, the English- Nerve Growth Factor), brain-derived neurotrophic factor (English- BDNF- of Brain-Derived Neurotrophic Factor), Neurotrophin-3 (NT-3), Neurotrophin-4/5 ( NT-4/5), have many functions related to aging and response of nervous tissue to the pathology such as vascular accident (CVA). In this pathology, the increase of the neurotrophin expression can interfere with the degree of neurogenesis in the sub-ventricular zone (SVZ) and redirect the rostral migratory flow of Adult Neural Stem Cells (CTNAs) to the ischemic region. The presence of neurotrophin receptors TrkA and p75NTR in the CTNAs of SVZ indicates that they may participate in the regulation of neurogenesis in this region. Here we describe the influence of an experimental ischemia by microinjection of a vasconstritor Endothelin-1 peptide, which is restricted to the striatum adjacent SVZ; on the pattern of immunoreactivity for TrkA and p75NTR receptors in different survival times. The histopathological pattern of ischemic striatum and the cytoarchitecture of the SVZ, followed by immunohistochemical analysis to the receptors were analyzed. Numerous p75NTR + cells were found in the ipsilateral SVZ and against the injection site, with had a reduction in immunoreactivity at first and third day after ischemia. Few TrkA + cells were found in SVZ of both groups, however, many TrkA + axonal terminals were saw in the ischemic ipsilateral SVZ. Soon after the ischemic process, there was thickening of the SVZ, the concomitant reduction in immunoreactivity for p75NTR and TrkA + arisings of axonal terminals.
Acesso aberto (Open Access)
Intestinal intraluminal injection of glutamine increases trolox total equivalent antioxidant capacity (TEAC) in hepatic ischemia-reperfusion
(Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia, 2006) SALOMÃO, Alberto Bicudo; NASCIMENTO, José Eduardo de Aguilar Siqueira do; PERCÁRIO, Sandro; GARCIA, Victor Cezar Sano; MARQUES, Nicole Ribeiro; DIAS, Claudia Cristina Gomes de Oliveira
PURPOSE: To evaluate the effects of intraluminal injection of glutamine on the serum trolox equivalent antioxidant capacity in an experimental model of ischemia-reperfusion of the liver observing the applicability of modifications on the original assay method. METHODS: Thirty Wistar rats underwent laparotomy to perform a 20 cm blind sac of small bowel and occlusion of the hepatic hilo for 30 minutes and reperfusion for 5 minutes. Into the gut sac it was injected glutamine (glutamine group, n=10) or distilled water (control group, n=10). Ten other animals (sham group) underwent laparotomy without artery occlusion. Blood samples were collected for trolox equivalent antioxidant capacity assays in different temperature conditions, reagent quantities and time for spectrophotometer readings. RESULTS: Total antioxidant capacity was significantly greater in glutamine group than in both control group (1,60[1,55-1,77] vs 1,44[1,27-1,53]) and sham group (1,60[1,55-1,77] vs 1,48[1,45-1,59]). CONCLUSION: Glutamine enhanced serum antioxidant capacity. The assay technique consistently reflected the changes in the antioxidant defenses in this experimental model.
Acesso aberto (Open Access)
Lesão intestinal após isquemia-reperfusão: estudo comparativo usando sal tetrazólico (MTT) e histologia
(Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia, 2001-03) BRITO, Marcus Vinicius Henriques; ARAÚJO, Marialva Tereza Ferreira de; ACÁCIO, Glayce June Sasaki; ACÁCIO, Glayce Josy Sasaki; REIS, José Maciel Caldas dos
Many methods are used to evaluate ischemia reperfusion injury, but the most employed one is the histological study. However, it only demonstrates on mucosal tunic, the index of lesion and morphologic preserved cells, but not the index of viable functional cells, present in the sample. With this purpose, a colorimetric method was used, employing Methyl Thiazolyl Blue (MTT). The experiment was conducted in 30 Wistar male rats, distributed in 3 groups: Group Control (GC), Group ischemia and reperfusion-1 (GIR-1) and Group ischemia and reperfusion-3 (GIR-3), with 10 animals each. The Groups GIR-1 and GIR-3 were submitted to intestinal ischemia for 30 minutes by a false ligature of superior mesenteric artery, and submitted to euthanasia after 1 and 3 days of reperfusion, when material was picked for absorbency and histological procedures. It was observed a smaller proportion of viable cells and a larger degree of mucosal lesion in GIR-3 group (p<0.05), while GC group was the one with the larger proportion of viable cells and smaller degree of the mucosal injury (p<0.05). This way we concluded that MTT is as effective and reliable as the histological study at evaluating alterations produced by intestinal ischemia-reperfusion.
Acesso aberto (Open Access)
Minociclina atenua os prejuízos motores em ratos submetidos à isquemia focal no córtex motor e expostos cronicamente ao etanol da adolescência à fase adulta
(Universidade Federal do Pará, 2012-08-30) OLIVEIRA, Gedeão Batista de; MAIA, Cristiane do Socorro Ferraz; http://lattes.cnpq.br/4835820645258101
According to World Health Organization, alcohol consumption in the world has become a public health problem. In this context, Brazil is at 63th position in the world in per capita alcohol consumption for people aged 15 or older. In addition to its socio-economic effects, ethanol is an important risk factor in the occurrence of cerebral ischemia. Exacerbated consumption of this drug contributes to the poor prognosis, as well as possible treatment for health problems related to stroke. The objective of this study was to evaluate neuromotor changes after blocking micróglial activation with minocycline in rats subjected to focal ischemia in the motor cortex, when treated chronically with ethanol from adolescence to adulthood. Rats were given for 55 days by gavage ethanol (6.5 g/kg/dia, 22.5 w/v). At the end of 55 days the animals were microinjected with the vasoconstrictor peptide endothelin-1 (40 pmol) for induction of focal ischemic lesion. The ischemic animals were treated with minocycline receiving two daily doses of 50 mg/kg in the first two days, and five daily applications of single 25mg/kg, intraperitoneally, by the seventh day post-ischemic induction. Behavioral tests consisted of open field, inclined plane and rota-rod. The results showed that the animals were exposed to ethanol showed motor deficits in all behavioral tests. However, treatment with minocycline was able to reverse them, enabling better performance on all tests. The results suggest that minocycline was able to reverse damage caused by motors stroke, even in the presence of ethanol. The exact mechanism involved in this process need to be investigated in future research.
Acesso aberto (Open Access)
Modulação da neuroinflamação celular e neuroproteção induzidas por tratamento com betacariofileno em um modelo experimental de isquemia estriatal em ratos adultos
(Universidade Federal do Pará, 2016-10-11) LOPES, Rosana Telma Santos; SANTOS, Enio Maurício Nery dos; http://lattes.cnpq.br/7789458294239924; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Stroke results from the transitory or permanent reduction of cerebral blood flow. It can be classified as hemorrhagic or ischemic. Ischemic stroke is responsible for around 87% of all cases. This acute neural disorder is the second cause of mortality and disability around the world and the main cause of death in Brazil. Since ischemic stroke in patients usually results from a thrombotic or embolic occlusion of the middle cerebral artery (MCA), experimental models of ischemia have been developed to mimic human stroke. There are no neuroprotective drugs available for human stroke. It follows that research on development of alternative neuroprotective drugs are of important clinical relevance. In this study, we investigated the effects of betacaryophyllene, the main sesquiterpene present in about 40% of the copaiba oil-resin composition, on microglial activation, astrocytic reactivity and neuronal preservation following experimental MCAO in adult rats. Animals were submitted to experimental stroke by microinjections of endothelin-1 (ET-1) and treated (i.p) with betacaryophillene (N=4) or vehicle control (N=4) and perfused at 3 days or 7 days post-MCAO. Gross histopathology was performed using cresyl violet staining. Immunohistochemistry was used to assess neuronal loss (anti-NeuN), microglial activation (anti-ED1) and astrocytosis (anti-GFAP). Numbers of NeuN+ and GFAP+ cells were quantified in the ischemic striatum. Betacaryophyllene treatment reduced microglial activation, increased neuronal preservation and decreased astrocytic reactivity at 7 days post-MCAO. These results suggest that betacaryophylene modulates neuroinflammation and is neuroprotective following experimental striatal. Considering that betacaryophyllene is a natural dietetic extract already used in non-neural human diseases with antiinflammatory, anti-microbial and anti-carcinogenic properties, its use as a neuroprotective agent is a promising future therapy for human stroke.
Acesso aberto (Open Access)
Neurogênese endógena induzida por acidente vascular encefálico experimental após inibição da ativação microglial/macrofágica com o anti-inflamatório indometacina
(Universidade Federal do Pará, 2011-05-16) LOPES, Rosana Telma Santos; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Stroke results from the transitory or permanent reduction of cerebral blood flow. It can be classified as hemorrhagic or ischemic. Ischemic stroke is responsible for around 87% of all cases. This acute neural disorder is the second cause of mortality and disability around the world and the main cause of death in Brazil. It has been shown that neuroblasts migrate to the ischemic striatum following middle cerebral artery occlusion (MCAO) and partially replace neurons lost during ischemia. Nevertheless, most of the migrating neuroblasts die in the first weeks following MCAO and inflammatory events, mainly microglia activation, may underlie neuroblast death. In this study, we investigated the effects of the nonsteroidal anti-inflammatory indomethacin on microglial activation, neuronal preservation and adult neurogenesis following experimental MCAO in adult rats. Animals were submitted to endothelin-1 induced- MCAO and treated (i.p) with indomethacin (N=8) or sterile saline (N=8) for 7 days and perfused at 8 or 14 days. Immunohistochemistry was performed to assess neuronal loss (anti-NeuN), microglial activation (anti-Iba1 and ED1) and migrating neuroblasts (anti-DCX). The numbers of NeuN, ED1 and DCX positive cells per field were counted in the ischemic striatum or subventricular zone. Indomethacin treatment reduced microglial activation in general and the number of ED1+ cells at both 8 and 14 days (±6,9 and ±3,0 cells respectively) postinjury, compared to control (±7,9 or ±6,5 cells, p<0.001, ANOVA-Tukey). There was an increase in the number of DCX+ cells in both subventricular zone (SVZ) and striatum at the same survival times. There was no difference in the number of NeuN positive cells between groups in all investigated survival times. The results show that indomethacin treatment induces inhibition of microglial activation concomitant with increased neuroblast proliferation and migration following MCAO. This is a promising outcome, considering that indomethacin is already used in non-neural human diseases and that adult neurogenesis may underlie functional recovery following stroke.
Acesso aberto (Open Access)
Perda neuronal, ativação glial, neurogênese e alterações sensório-motoras após isquemia focal no córtex somestésico de ratos adultos
(Universidade Federal do Pará, 2012-09-26) CORRÊA, Vania Castro; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Stroke is considered one of the most important causes of death and functional deficits in the world. Few neurological conditions are so complex and devastating, resulting in severe neurological deficits and death in the survivors. The cortical regions are commonly affected by stroke, resulting in sensory and motor loss. The establishment of neuropathological patterns in cortical regions, including the somatosensory area, is critical for the investigation of possible therapeutic interventions. In the present study, we investigated the patterns of neuronal loss, microgliosis, astrocytosis, neurogenesis and functional deficits in the primary somatosensory cortex of adult rats submitted to focal ischemia induced by microinjections of 40 pmol of endothelin-1 (ET-1). A total of 30 young adult Wistar rats (Rattus norvegicus) of Wistar, weighing between 250-280g were used in the study. The animals were divided into ischemic (N = 21) and control (N = 9) groups. They were perfused at survival times of 1, 3 and 7 days. The 7 days animals were submitted to behavioral tests to evaluate sensorimotor impairment. Sections were stained with cresyl violet, cytochrome oxidase and immunostained to identify neurons (anti-NeuN), activated and non-activated microglia (Iba-1), activated macrophages/microglia (ED-1), astrocytes (GFAP) and neuroblasts (DCX ). Statistical comparisons between groups were made by one analysis of variance (ANOVA) with Tukey post-hoc test. The animals showed ischemic sensorimotor deficits revealed by Bederson Neurological Scale, Paw Placement and corner tests. Microinjections of ET-1 induced focal ischemic lesion in the primary somatosensory cortex with neuronal loss and progressive astrocytosis and microgliosis mainly in the late survival times. The cytochrome oxidase histochemistry revealed the barrel fields, but unexpectedly marked a population of inflammatory cells with macrophage characteristics in the ischemic region. Increased numbers of SVZ neuroblasts were observed mainly in late survival times of ipsilateral hemisphere in comparison to contralateral side and control animals. There was no significant migration of neuroblasts to the ischemic cortex. The results show that microinjections of ET-1 are an effective method for inducing tissue loss and sensorymotor deficits in the primary somatosensory cortex of adult rats. It was evident that the SVZ is influenced by distant ischemic events distant and that macrophage populations seem to increase the cytochrome oxidase expression. The implemented experimental model can be used in future studies, in which potential neuroprotective drugs can be tested to minimize the described neuropathological alterations.
Acesso aberto (Open Access)
Prevenção do estresse oxidativo na síndrome de isquemia e reperfusão renal em ratos com suplementação nutricional com antioxidantes
(2010-04) PERCÁRIO, Sandro
OBJECTIVE: The objective of this study was to verify the potential protective effect of antioxidant vitamin supplementation in a model of renal ischemic-reperfusion injury in rats. METHODS: Twenty-nine Wistar rats were divided into three groups: groups I and II (n=10 each), were submitted to 60 minutes of renal ischemia, followed by 10 minutes of reperfusion; additionally, animals of group II were treated for twelve days with antioxidant vitamins (vitamin C 11.43mg/kg and vitamin E 28.5 mg/kg) before being submitted to ischemia; In group III (n=9), the animals were treated like the other groups but not submitted to ischemic-reperfusion injury and not given antioxidant supplements. Subsequently, blood samples and the kidneys were collected for assessment of malondialdehyde, uric acid and total antioxidant capacity. RESULTS: The malondialdehyde and uric acid of group I was significantly higher than those of group III (p<0.01), which in turn did not differ from group II. The levels of total antioxidant capacity of the animals of group I was lower than those of groups II and III (p<0.01). CONCLUSION: These data confirmed the effective participation of oxidative stress in this model of renal ischemia-reperfusion syndrome in rats and showed that the use of antioxidant supplementation can protect the animals from oxidative changes.
Acesso aberto (Open Access)
Sobrevivência e dispersão de células da fração mononuclear da medula óssea transplantadas heterologamente no estriado após isquemia experimental
(Universidade Federal do Pará, 2015-02-27) CARDOSO, Marcelo Marques; SAUNIER, Ghislain; http://lattes.cnpq.br/6254015055212071; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
The studies show the promising potential of bone marrow mononuclear cells (BMMC) for the treatment of stroke models. It is known that the BMMC are sensitive to environmental changes, like those induced by ischemia, such as events associated with inflammation. However, little is known about the biodistribution and survival of these cells in the post-injury nerve tissue. Aims to investigate whether the survival and spread of BMMC are influenced by the inflammatory response after striatum stroke. Heterologous transplantation (5x105 BMMC) in the striatum of rats clustered among untreated controls (CNT) and sham (SHM) and treated (STBC) perfused at 1, 3, 7 and 28 days. BMMC were impregnated with Qdot nanocrystals for identification by fluorescence microscopy in the host tissue. Staining for cresyl violet, and basic immunohistochemistry (IBA1 and ED1) were applied for histopathological analysis of tissue by light microscopy. Neurobehavioral tests (adhesive removal test and cylinder test) were performed to assess the response of groups for interventions. The results show the effectiveness of the experimental model of ischemic induction to reproduce the injury in the dorsolateral striatum. The cell infiltrate in the CNT group shows the inflammatory response, later confirmed by immunohistochemistry for ED1 and IBA1; the cellular infiltrate in STBM group, shows the BMMC of stay in all studied survival. The loss profile for death of BMMC transplanted into the injury site is similar between STBM and SHM groups, however, shows that inflammatory response of the receptor causes more decay of cell amount in STBM group. More refined or automated cell infusion procedures can improve the sensitivity of behavioral tests to discriminate the evolution between groups. To summarize the change of post-ischemic microenvironment creates conditions that determine the distribution and survival of BMMC. Other immunohistochemical procedures may point to the results presented as microglial profile and the degree of the immunomodulation study of the dynamics of inflammatory cytokines produced.