Papers by Gláucia Monteiro de Castro
A esclerose multipla e doenca inflamatoria cronica do sistema nervoso central (SNC), na quallinfo... more A esclerose multipla e doenca inflamatoria cronica do sistema nervoso central (SNC), na quallinfocitos T auto-reativos voltam-se contra os antigenos da mielina. A doenca caracteriza-se por surtos e remissoes, que levam a deficiencias neurologicas irrecuperaveis. A resposta inflamatoria aberrante sugere etiologia autoimune para esclerose multipla, durante a qual, acredita-se que linfocitos T CD4+ ativados contra antigenos da mielina atravessem a barreira hematoencefalica (BHE), iniciando reacao imunologica, seguida de inducao e liberacao de citocinas, producao de anticorpos e ativacao de celulas da microglia e astrocitos. Por apresentar inumeras similaridades com a esclerose multipla, a encefalomielite experimental autoimune (EAE), tem sido usada como modelo experimental para o estudo desta doenca. A EAE pode ser facilmente induzida utilizando-se proteinas da mielina na Inducao Ativa, ou infundindo-se linfocitos T reativos contra estas proteinas na Transferencia Adotiva. Assim como observado na esclerose multipla, linfocitos T CD4+ sao as celulas efetoras na EAE, liberando citocinas e recrutando outras celulas do sistema imunologicopara o ataque ao sistema nervoso central. Neste processo, citocinas tem papel preponderante na modulacao da EAE, fornecendo os sinais necessarios para ativar linfocitosT especificos para auto-antigenos. Dada sua natureza neurotrofica e imunomodulatoria, tem sido proposto o uso de angliosideos na reducao das consequencias deleterias de varias doencas neurodegenerativas e de origem autoimune. Os gangliosideos possuem atividades imunomodulatorias multiplas diminuindo respostas linfoproliferativas e modulando a producao de citocinas. No presente trabalho, utilizando-se ratos da linhagem Lewis no modelo da EAE aguda, foram avaliados os efeitos da administracao de gangliosideos na alteracao do perfil de expressao de citocinas Th1 para Th2/Th3 e na inducao de apoptose em celulas esplenicas e medula espinhal respectivamente, durante os sinais clinicos e apos a recuperacao da doenca. Os resultados demonstram que o grupo tratado com gangliosideos exibe doenca moderada, com a expressao genica de IFN-y diminuida e de TGF-beta elevada, sugerindo que os gangliosideos estudados possam modular a sintese de citocinas Th1, alterando o perfil para o fenotipoTh2/Th3. Por sua vez, esta alteracao do perfil de citocinas pode regular moleculas relacionadas a apoptose, fornecendo evidencias que os gangliosideos diminuam a expressao in vivo de Bcl-2 e Bcl-W, juntamente com o aumento da expressao genica de Fas e FasL Abstract
Behavioural Brain Research, 2013
Background: Optical coherence tomography (OCT) is a novel method of retinal in vivo imaging. In t... more Background: Optical coherence tomography (OCT) is a novel method of retinal in vivo imaging. In this study, we assessed the potential of OCT to yield histology-analogue sections in mouse models of retinal degeneration. Methodology/Principal Findings: We achieved to adapt a commercial 3 rd generation OCT system to obtain and quantify highresolution morphological sections of the mouse retina which so far required in vitro histology. OCT and histology were compared in models with developmental defects, light damage, and inherited retinal degenerations. In conditional knockout mice deficient in retinal retinoblastoma protein Rb, the gradient of Cre expression from center to periphery, leading to a gradual reduction of retinal thickness, was clearly visible and well topographically quantifiable. In Nrl knockout mice, the layer involvement in the formation of rosette-like structures was similarly clear as in histology. OCT examination of focal light damage, well demarcated by the autofluorescence pattern, revealed a practically complete loss of photoreceptors with preservation of inner retinal layers, but also more subtle changes like edema formation. In Crb1 knockout mice (a model for Leber's congenital amaurosis), retinal vessels slipping through the outer nuclear layer towards the retinal pigment epithelium (RPE) due to the lack of adhesion in the subapical region of the photoreceptor inner segments could be well identified. Conclusions/Significance: We found that with the OCT we were able to detect and analyze a wide range of mouse retinal pathology, and the results compared well to histological sections. In addition, the technique allows to follow individual animals over time, thereby reducing the numbers of study animals needed, and to assess dynamic processes like edema formation. The results clearly indicate that OCT has the potential to revolutionize the future design of respective short-and long-term studies, as well as the preclinical assessment of therapeutic strategies.
A encefalomielite experimental autoimune (EAE) e uma doenca mediada por linfocitos T CD4, que pen... more A encefalomielite experimental autoimune (EAE) e uma doenca mediada por linfocitos T CD4, que penetram atraves da barreira hematoencefalica promovendo uma reacao inflamatoria local e edema, responsaveis pela ocorrencia das deficiencias neurologicas da doenca. Como modelo da esclerose multipla, a EAE tem sido usada na avaliacao de estrategias terapeuticas. No presente trabalho, nos investigamos o efeito do tratamento com gangliosideos na evolucao da encefalomielite experimental autoimune. Para tanto foi realizado estudo morfologicojmorfometrico, imunoistoquimico, ensaio de linfoproliferacao e dosagem de fator de necrose tumorala (TNF-a) e fator transformador de crescimento-p (TGF- ?). OS resultados mostram que a administracao de gangliosideos na fase efetora leva a supressao parcial ou total dos sinais clinicos, refletindo-se na contagem de infiltrados, onde o numero destes foi significativamente menor no cerebro. A avaliacao imunologica demonstrou que os animais tratados com gangliosideos apresentam niveis significativamente menores de TNF-a, uma das principais citocinas envolvidas na genese da EAE. Estes resultados comprovam a acao imunomoduladora dos gangliosideos na evolucao da EAE, relacionada com a provavel inibicao na producao do TNF-a devido a supressao na proliferacao de linfocitos Th1, o que leva a propor a possibilidade de um novo agente terapeutico para o tratamento da esclerose multipla Abstract
The Journal of Neuroscience
We thank Daniel Morrison and Mike Peacock for help with electron microscopy. We also thank Dr. Em... more We thank Daniel Morrison and Mike Peacock for help with electron microscopy. We also thank Dr. Emily Harrington for advice in mouse oligodendrocyte progenitor cell isolation. As well, we thank the following individuals for providing the transgenic mouse lines used in this study: Dr. Silvia Nicolis for floxed Sox2 mouse line; Drs. Ryan Driskell and Fiona Watts for help and advice in rederivation; Professor William D. Richardson for Pdgfra-creER T2 and Sox10-icreER T2 mouse lines; and Dr. Frank Kirchhoff for Gfap-creER T2 : Rosa26floxedSTOP-YFP line. The Rosa26floxedSTOP-fGFP was a gift from Dr. Emma Rawlins. We also thank Dr. Michael Wegner for his gift of plasmids for making cRNA probes for detecting Sox protein transcripts by in situ hybridization.
Biological Trace Element Research
Frontiers in Neurology
The maintenance of blood-brain barrier (BBB) integrity is essential for providing a suitable envi... more The maintenance of blood-brain barrier (BBB) integrity is essential for providing a suitable environment for nervous tissue function. BBB disruption is involved in many central nervous system diseases, including epilepsy. Evidence demonstrates that BBB breakdown may induce epileptic seizures, and conversely, seizure-induced BBB disruption may cause further epileptic episodes. This study was conducted based on the premise that the impairment of brain tissue during the triggering event may determine the organization and functioning of the brain during epileptogenesis, and that BBB may have a key role in this process. Our purpose was to investigate in rats the relationship between pilocarpine-induced status epilepticus (SE), and BBB integrity by determining the time course of the BBB opening and its subsequent recovery during the acute phase of the pilocarpine model. BBB integrity was assessed by quantitative and morphological methods, using sodium fluorescein and Evans blue (EB) dyes as markers of the increased permeability to micromolecules and macromolecules, respectively. Different time-points of the pilocarpine model were analyzed: 30 min after pilocarpine injection and then 1, 5, and 24 h after the SE onset. Our results show that BBB breakdown is a dynamic phenomenon and time-dependent, i.e., it happens at specific time-points of the acute phase of pilocarpine model of epilepsy, recovering in part its integrity afterwards. Pilocarpine-induced changes on brain tissue initially increases the BBB permeability to micromolecules, and subsequently, around 5 h after SE, the BBB breakdown to macromolecules occurs. After BBB breakdown, EB dye is captured by damaged cells, especially neurons, astrocytes, and oligodendrocytes. Although the BBB permeability to macromolecules is restored 24 h after the start of SE, the leakage of micromolecules persists and the consequences of BBB degradation are widely disseminated in the brain. Our findings reveal the existence of a temporal window of BBB dysfunction in the acute phase of the pilocarpine model that is important for the development of therapeutic strategies that could prevent the epileptogenesis.
Journal of Photochemistry and Photobiology B: Biology
Lasers in medical science, 2016
The aim of this study was to evaluate the in vivo response of different fluences of low-level las... more The aim of this study was to evaluate the in vivo response of different fluences of low-level laser therapy (LLLT) on the area of the injury, inflammatory markers, and functional recovery using an experimental model of traumatic spinal cord injury (SCI). Thirty two rats were randomly divided into four experimental groups: control group (CG), laser-treated group 500 J/cm(2) (L-500), laser-treated group 750 J/cm(2) (L-750), and laser-treated group 1000 J/cm(2) (L-1000). SCI was performed by an impactor equipment (between the ninth and tenth thoracic vertebrae), with a pressure of 150 kdyn. Afterwards, the injured region was irradiated daily for seven consecutive sessions, using an 808-nm laser, at the respective fluence of each experimental groups. Motor function and tactile sensitivity were performed on days 1 and 7 post-surgery. Animals were euthanized on the eighth day after injury, and the samples were retrieved for histological and immunohistochemistry analyses. Functional evalua...
The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 19, 2015
The Sox family of transcription factors have been widely studied in the context of oligodendrocyt... more The Sox family of transcription factors have been widely studied in the context of oligodendrocyte development. However, comparatively little is known about the role of Sox2, especially during CNS remyelination. Here we show that the expression of Sox2 occurs in oligodendrocyte progenitor cells (OPCs) in rodent models during myelination and in activated adult OPCs responding to demyelination, and is also detected in multiple sclerosis lesions. In normal adult white matter of both mice and rats, it is neither expressed by adult OPCs nor by oligodendrocytes (although it is expressed by a subpopulation of adult astrocytes). Overexpression of Sox2 in rat OPCs in vitro maintains the cells in a proliferative state and inhibits differentiation, while Sox2 knockout results in decreased OPC proliferation and survival, suggesting that Sox2 contributes to the expansion of OPCs during the recruitment phase of remyelination. Loss of function in cultured mouse OPCs also results in an impaired abi...
The American Journal of Pathology, 2015
Remyelination within the central nervous system (CNS) most often is the result of oligodendrocyte... more Remyelination within the central nervous system (CNS) most often is the result of oligodendrocyte progenitor cells differentiating into myelin-forming oligodendrocytes. In some cases, however, Schwann cells, the peripheral nervous system myelinating glia, are found remyelinating demyelinated regions of the CNS. The reason for this peripheral type of remyelination in the CNS and what governs it is unknown. Here, we used a conditional astrocytic phosphorylated signal transducer and activator of transcription 3 knockout mouse model to investigate the effect of abrogating astrocyte activation on remyelination after lysolecithin-induced demyelination of spinal cord white matter. We show that oligodendrocyte-mediated remyelination decreases and Schwann cell remyelination increases in lesioned knockout mice in comparison with lesioned controls. Our study shows that astrocyte activation plays a crucial role in the balance between Schwann cell and oligodendrocyte remyelination in the CNS, and provides further insight into remyelination of CNS axons by Schwann cells.
Behavioural brain research, Jan 2, 2015
Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating disease of the central nervous ... more Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating disease of the central nervous system (CNS). Further to the symptoms resulting from demyelination, new studies point to the involvement of neuroinflammation and white matter abnormalities in psychiatric disorders and neurodegenerative diseases. Cuprizone, a model of MS, produces consistent demyelination and elicits behavioural, morphological and inflammatory changes in animals that share some similarities with those observed in humans. In this study, we used the cuprizone model in Lewis Rats to evaluate clinical signs triggered by the demyelination process which could be comparable with the symptoms seen in white matter abnormalities in human beings. To induce the demyelination process, 0.6% cuprizone was added to the Lewis Rats' diet for four weeks. We proceeded with behavioural, morphological and immunological analyses. Animals fed with cuprizone exhibited behavioural changes: higher scores in the neurotoxicity ...
Brazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas / Sociedade Brasileira de Biofísica ... [et al.], 2011
It is known that chronic high levels of corticosterone (CORT) enhance aversive responses such as ... more It is known that chronic high levels of corticosterone (CORT) enhance aversive responses such as avoidance and contextual freezing. In contrast, chronic CORT does not alter defensive behavior induced by the exposure to a predator odor. Since different defense-related responses have been associated with specific anxiety disorders found in clinical settings, the observation that chronic CORT alters some defensive behaviors but not others might be relevant to the understanding of the neurobiology of anxiety. In the present study, we investigated the effects of chronic CORT administration (through surgical implantation of a 21-day release 200 mg pellet) on avoidance acquisition and escape expression by male Wistar rats (200 g in weight at the beginning of the experiments, N = 6-10/group) tested in the elevated T-maze (ETM). These defensive behaviors have been associated with generalized anxiety and panic disorder, respectively. Since the tricyclic antidepressant imipramine is successful...
The American Journal of Pathology, 2012
Brazilian Archives of Biology and Technology
The aim of this study was to evaluate the effectiveness of 3 different fluences of low-level lase... more The aim of this study was to evaluate the effectiveness of 3 different fluences of low-level laser therapy (LLLT) in intermediate period of spinal cord repair using an experimental model in rats. Thirty two rats were randomly divided into four experimental groups: Control Group (CG); Laser treated group 500 J/cm² (L-500); Laser treated group 750 J/cm² (L-750) and Laser treated group 1000 J/cm² (L-1000). Spinal cord injury (SCI) was performed by an impactor equipment (between 9th and 10th thoracic vertebrae), with a pressure of 150 kdyn. Afterwards, the injured region was irradiated daily for 14 consecutive sessions, using an 808 nm laser, at the respective fluence of each experimental groups. Locomotor function and tactile sensitivity were performed on days 1 and 15 post-surgery. Animals were euthanized 15 days post-surgery and samples were retrieved for histological and immunohistochemistry analysis. Functional behavior and tactile sensitivity were improved after laser irradiation. Moreover, higher fluencies of LLLT reduced the volume of injury. Additionally, LLLT produced a decreased CD-68 expression. These results demonstrated that, for an intermediate period of SCI repair, LLLT at higher fluences, was effective in promoting functional recovery and modulating the inflammatory process in the spinal cord of rats after traumatic SCI.
Brazilian Journal of Medical and Biological Research, 2002
Insulin-dependent diabetes mellitus is caused by autoimmune destruction of pancreatic ß cells. No... more Insulin-dependent diabetes mellitus is caused by autoimmune destruction of pancreatic ß cells. Non-obese diabetic (NOD) mice spontaneously develop diabetes similar to the human disease. Cytokines produced by islet-infiltrating mononuclear cells may be directly cytotoxic and can be involved in islet destruction coordinated by CD4+ and CD8+ cells. We utilized a semiquantitative RT-PCR assay to analyze in vitro the mRNA expression of TNF-a and IFN-g cytokine genes in isolated islets (N = 100) and spleen cells (5 x 10 5 cells) from female NOD mice during the development of diabetes and from female CBA-j mice as a related control strain that does not develop diabetes. Cytokine mRNAs were measured at 2, 4, 8, 14 and 28 weeks of age from the onset of insulitis to the development of overt diabetes. An increase in IFN-g expression in islets was observed for females aged 28 weeks (149 ± 29 arbitrary units (AU), P<0.05, Student t-test) with advanced destructive insulitis when compared with CBA-j mice, while TNF-a was expressed in both NOD and CBA-j female islets at the same level at all ages studied. In contrast, TNF-a in spleen was expressed at higher levels in NOD females at 14 weeks (99 ± 8 AU, P<0.05) and 28 weeks (144 ± 17 AU, P<0.05) of age when compared to CBA-j mice. The data suggest that IFN-g and TNF-a expression in pancreatic islets of female NOD mice is associated with ß cell destruction and overt diabetes.
Uploads
Papers by Gláucia Monteiro de Castro