Reconhecemos as seguintes fontes de financiamento: NIH NINDS – K08NS101122 (JB), R01NS040337 (JK), R01NS044370 (JK), University of Virginia School of Medicine (JB).

Todos os estudos em animais foram aprovados pelo Comitê Institucional de Cuidados e Uso de Animais (IACUC) da Universidade da Virgínia.
1. Construção de eletrodo/cabo
<ol><li>Use um fio de aço inoxidável isolado unipolar (0,005" de diâmetro nu, 0,008" revestido) para fazer um eletrodo conectado com um conector de soquete feminino (conector de recipiente feminino 0,079).</li>
	<li>Use um cabo feito sob medida para conectar os animais ao amplificador.<ol>
<li>Conecte um conector masculino de 4 pinos (conector masculino de 0,079") à unidade de 4 canais ganha impedância correspondente ao amplificador operacional (op-amp). Conecte um resistor de 10K aos fios que se conectam à bateria de 9 V. Um fio de terra não conectado ao op-amp atua como o ponto médio da bateria.</li>
		<li>Conecte uma extremidade do cabo (AWG, 0,012" OD) ao op-amp e conecte a outra extremidade do cabo ao amplificador.</li>
	</ol>
</li>
</ol>2. Cirurgia de implantação de eletrodos
<ol><li>Anestesiar o filhote (pós-natal dia 9) com isoflurane de 4-5% em um capô de fluxo descendente. Antes do início do procedimento, injete os filhotes com bupivacaína (0,02-0,05 mL, 0,25% de infiltração local subcutânea).</li>
	<li>Uma vez que o animal esteja imóvel, transfira para um estágio estereotático com um cone de nariz. Use o lado inverso da barra de ouvido, pois ela é macia para manter a cabeça firme. Nesta idade, os filhotes não têm um ouvido totalmente desenvolvido para usar a extremidade pontiaguda da barra de ouvido.</li>
	<li>Abaixe o fluxo de isoflurane e mantenha-o em 2,5-3%. Fique de olho na respiração constante do filhote durante todo o procedimento cirúrgico. Aperte a cauda para verificar a resposta à dor e, em seguida, proceda à incisão.</li>
	<li>Esterilize a área de incisão no crânio com betadina e álcool (3 ciclos de iodo alternado e 70% de etanol). Drape a parte do corpo circundante de tal forma que a região de incisão é visível.</li>
	<li>Abra o couro cabeludo anterior-posterior ligeiramente acima dos olhos e retraia aproximadamente 0,5 cm de pele. Reposicione a cabeça do rato no estágio estereotaxico para que a pele puxe para fora expondo o crânio.</li>
	<li>Aplique peróxido de hidrogênio no crânio usando um cotonete e raspe o crânio limpo usando uma lâmina de bisturi. O crânio é muito macio; tenha cuidado ao raspar.</li>
	<li>Aplique uma gota (aproximadamente 50 μL) de adesivo e espalhe-a ao redor da área do crânio exposta usando seu aplicador. Exponha à luz UV por 40 s para definir o adesivo.</li>
	<li>Meça as coordenadas usando o bregma exposto como referência. Implante eletrodos bilateralmente na região ca1 do hipocampo [-3,5 mm Dorsal-Ventral (DV), ±2 mm Medial-Lateral (ML), -1,75 mm De profundidade (D)] e bilateralmente no córtex parietal [-1,22 mm DV, ±0,5 mm ML, -1 mm D] e um eletrodo de referência no cerebelo17. Use uma agulha de 32 G para criar um buraco na região marcada.</li>
	<li>Limpe o sangue da superfície do crânio. Eletrodos inferiores ligados ao conector do soquete feminino no cérebro com a ajuda do braço estereotaxic e fixação no lugar com acrílico dental. Implante o eletrodo no cérebro. O fone de ouvido do conector do soquete fica em cima do crânio colado por acrílico dentário.</li>
	<li>Injete cetoprofeno (5 mg/kg) subcutâneamente na região interescapular quando o eletrodo estiver fixo. Coloque os filhotes de volta com a mãe. NOTA: Introduza metade da ninhada com o fone de ouvido de uma vez para a mãe em vez de apresentá-los um de cada vez. Isso evitará que a mãe prejudique o fone de ouvido do filhote.</li>
</ol>3. Configuração e gravação do EEG (linha de base/pré-lesão)
<ol><li>Após 24 horas de recuperação após a implantação do eletrodo, coloque cada animal em uma câmara plexiglas personalizada (37 °C) para gravação de EEG. Esta câmara também servirá como uma câmara de hipóxia.</li>
	<li>Conecte filhotes na câmara a um sistema de monitoramento por vídeo-EEG através de um cabo flexível (cabo op-amp personalizado). NOTA: Com o fone de ouvido no lugar, os ratos são livremente móveis e não apresentam diferenças de comportamento. Uma vez fixados nos fios de eletrodo, os fios devem ser ajustados dentro da corda da câmara, a fim de fornecer a quantidade certa de folga para que o filhote possa se mover livremente por toda a câmara.</li>
	<li>Digitalize os dados do EEG a 1000 Hz com ganho de 1K usando um amplificador de grama. Revise o sinal EEG (filtro de passagem de banda entre 3-70 Hz) mais tarde usando software (por exemplo, LabChart Pro).</li>
	<li>Regisso EEG pré-lesão por 30 minutos antes de desconectar animais para procedimento de ligadura da artéria carótida.</li>
</ol>4. Ligamento da artéria carótida esquerda
<ol><li>Anestesiar o filhote (pós-natal dia 10) com isoflurane de 4-5% em um capô de fluxo descendente e colocá-los em configuração especialmente organizada em uma almofada de banho de água. Posicione o supino animal e proteja os membros dianteiros com fita adesiva.<ol>
<li>Reduza o fluxo de isoflurane para 2-3%. Belisque a cauda para obter resposta à dor e monitore a respiração durante todo o procedimento.</li>
	</ol>
</li>
	<li>Esterilizar a área de incisão (entre a mandíbula e a clavícula) no lado esquerdo do pescoço com betadina e álcool (3 ciclos de iodo alternado e 70% de etanol).</li>
	<li>Faça uma incisão de aproximadamente 1 cm de comprimento no lado esquerdo do pescoço usando microscisores. Usando um microscópio dissecando, retraia cuidadosamente o tecido subcutâneo e a pele para expor a artéria carótida. Tome cuidado para identificar o nervo vago (correndo lateralmente para a artéria) e delicadamente separá-lo e retraí-lo da artéria.</li>
	<li>Rosqueie uma sutura de seda estéril de 5 cm de comprimento sob a artéria usando microforceps. Amarre uma sutura dupla ao redor da artéria para ocluir o fluxo.</li>
	<li>Corte o excesso de sutura e feche a artéria exposta puxando para trás o tecido subcutâneo e a pele. Use o vínculo veterinário para selar a incisão.</li>
	<li>Coloque o animal de volta no monitoramento contínuo do EEG em uma câmara em temperatura ambiente, que é colocada em um colchão aquecido. Faça verificações de temperatura infravermelha do núcleo do filhote para evitar abrir a câmara. Deixe o animal se recuperar por 1h antes da hipóxia.</li>
</ol>5. EEG e hipóxia
<ol><li>Monitore continuamente o FiO2 (fração de oxigênio inspirado) dentro da câmara através de um monitor de oxigênio.</li>
	<li>Lave a câmara com 60 L/min de 100% N2 e 0,415 L/min para 100% O2. Uma vez que a saturação de oxigênio na câmara atinja 12%, diminua o fluxo de N2 para 10 L/min, mantendo o fluxo de O2 inalterado. Com pequenos ajustes, mantenha o FiO2 em 8% por 45 min.</li>
	<li>Após 45 min de exposição à hipóxia, retorne fio2 a 21%.</li>
	<li>Que os filhotes se recuperem na câmara e monitorem no EEG por 2h pós-hipóxia.</li>
	<li>Após o término do período de gravação, desconecte os ratos da gravação do EEG e retorne à mãe.</li>
</ol>6. Análise de EEG
<ol><li>Analise o arquivo EEG com vídeo no LabChart Pro. Um pesquisador cego marca o EEG para convulsões e padrões de fundo17. As convulsões são definidas como um evento eletrográfico que dura mais de 10 segundos com descargas de ondas acentuadas rítmica de alta frequência (≥3x de base) com clara evolução17.</li>
	<li>Tenha uma segunda revisão de pesquisador cego marcado eventos aleatoriamente para concordância.</li>
	<li>Revise o vídeo associado para cada evento eletrográfico marcado e analise de acordo com o escore de convulsão comportamental do roedor neonatal16. Resumidamente, essa pontuação varia de 0-6 (imobilidade ao comportamento tônico-clonic grave). Para caracterizar ainda mais a semiologia convulsiva, analise o comportamento de lateralidade (movimentos multifoca/bilaterais versus focal/unilateral versus misto).</li>
	<li>Crie um espectrograma de energia. Use um Fast Fourier Transform com uma janela de dados Cosine-Bell com um tamanho de 1024 pontos de dados. Crie um eixo x liso no espectrograma com a ajuda de uma sobreposição de janela de 87,5%. Expresse a potência como μV218.</li>
</ol>

<ol>
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Childhood outcomes after hypothermia for neonatal encephalopathy.</a> New England Journal of Medicine. 366 (22), 2085-2092 (2012).</li><li>Pappas, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cognitive+outcomes+after+neonatal+encephalopathy.">Cognitive outcomes after neonatal encephalopathy.</a> Pediatrics. 135 (3), 624-634 (2015).</li><li>van Schie, P. 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Apresentamos um modelo para monitoramento contínuo de vídeo-EEG em camundongos neonatais durante convulsões hipoximic-isquêmicas. A análise de vídeo em conjunto com o EEG permite a caracterização da semiologia convulsiva. A análise do EEG permite a extração de espectrogramas de energia e análise de amplitude de fundo.
A colocação correta e cuidadosa de eletrodos é crucial neste protocolo, pois lesões durante a colocação de eletrodos ou colocação imprecisa podem afetar signi...

A encefalopatia isquêmica hipóxica (HIE) é uma condição que afeta 1,5 em 1000 recém-nascidos anualmente e é a causa mais comum de convulsões neonatais1,2. Os bebês que sobrevivem correm risco para várias deficiências neurológicas, como paralisia cerebral, deficiência intelectual e epilepsia3,4,5.
Os modelos animais desempenham um papel fundamental na compreensão e investigação da fisiopatologia da isquemia de hipóxia e convulsões neonatais6,7. Um modelo vannucci modificado é usado para induzir isquemia de hipóxia (OI) no pós-natal dia 10 (p10)7,8. Filhotes de rato dessa idade traduzem neurologicamente aproximadamente para o termo completo neonato humano9.
O monitoramento contínuo da eletroencefalografia por vídeo (EEG) utilizado em conjunto com este modelo de lesão permite maior compreensão e caracterização de convulsões isquêmicas hipoxicas neonatais. Estudos anteriores utilizaram vários métodos para análise de convulsões neonatais em roedores, incluindo gravações de vídeo, gravações limitadas de EEG e gravações de EEG de telemetria10,11,12,13,14,15,16. No manuscrito a seguir, discutimos em profundidade o processo de gravação contínua de EEG de vídeo em filhotes de camundongos durante a hipoxia-isquemia. Esta técnica de monitoramento contínuo de EEG em filhotes de camundongos neonatais pode ser aplicada a uma variedade de modelos de doenças e convulsões.

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continuous video electroencephalogram during hypoxia-ischemia in neonatal mice

A isquemia de hipóxia é a causa mais comum de convulsões neonatais. Modelos animais são cruciais para a compreensão dos mecanismos e fisiologia subjacentes às convulsões neonatais e à isquemia de hipóxia. Este manuscrito descreve um método de monitoramento contínuo de eletroencefalograma de vídeo (EEG) em camundongos neonatais para detectar convulsões e analisar o fundo do EEG durante a isquemia de hipóxia. O uso de vídeo e EEG em conjunto permite a descrição da semiologia da convulsão e a confirmação de convulsões. Este método também permite a análise de espectrogramas de energia e tendências de padrão de fundo EEG durante o período de tempo experimental. Neste modelo de isquemia de hipóxia, o método permite o registro de EEG antes da lesão para obter uma linha de base normativa e durante a lesão e recuperação. O tempo total de monitoramento é limitado pela incapacidade de separar filhotes da mãe por mais de quatro horas. Embora tenhamos utilizado um modelo de convulsões hipoxica-isquêmicas neste manuscrito, este método para monitoramento de vídeo neonatais poderia ser aplicado a diversos modelos de doenças e convulsões em roedores.

Semiologia convulsiva
A exposição à hipóxia neonatal resulta em convulsões generalizadas e focais em camundongos (Figura 1A-C). Gravações de EEG de vídeo permitem que achados eletrográficos sejam correlacionados ao comportamento em vídeo. Esses comportamentos foram pontuados utilizando-se um escore de apreensão comportamental de roedores neonatais (BSS)16. Além da BSS, categorizamos eventos com base em ...

Watch this Scientific Journal Video about Continuous Video Electroencephalogram during Hypoxia-Ischemia in Neonatal Mice at JoVE.com

Continuous Video Electroencephalogram during Hypoxia-Ischemia in Neonatal Mice

Este manuscrito descreve um método para gravações contínuas de EEG de vídeo usando eletrodos de profundidade múltiplos em camundongos neonatais submetidos à hipoxia-isquemia.

Eletroencefalograma de vídeo contínuo durante hipoxia-isquemia em camundongos neonatais

Hypoxia ischemia is the most common cause of neonatal seizures. Animal models are crucial for understanding the mechanisms and physiology underlying ...

continuous-video-electroencephalogram-during-hypoxia-ischemia

Universidad de Cartagena UDEC

Research

JoVE Journal

Neuroscience

3.3K visualizações.  University of Virginia. Este manuscrito descreve um método para gravações contínuas de EEG de vídeo usando eletrodos de profundidade múltiplos em camundongos neonatais submetidos à hipoxia-isquemia.

Vídeo: Continuous Video Electroencephalogram during Hypoxia-Ischemia in Neonatal Mice

Delivery of In Vivo Acute Intermittent Hypoxia in Neonatal Rodents to Prime Subventricular Zone-derived Neural Progenitor Cell Cultures

Extended culture of neural stem/progenitor cells facilitates in vitro analyses to understand their biology while enabling expansion of cell populations to adequate numbers prior to transplantation. Identifying approaches to refine this process, to augment the production of all CNS cell types (i.e., neurons), and to possibly contribute to therapeutic cell therapy protocols is a high research priority. This report describes an easily applied in vivo &#8220;pre-conditioning&#8221; stimulus which can be delivered to awake, non-anesthetized animals. Thus, it is a non-invasive and non-stressful procedure. Specifically described are the procedures for exposing mouse or rat pups (aged postnatal day 1-8) to a brief (40-80 min) period of intermittent hypoxia (AIH). The procedures included in this video protocol include calibration of the whole-body plethysmography chamber in which pups are placed during AIH and the technical details of AIH exposure. The efficacy of this approach to elicit tissue-level changes in the awake animal is demonstrated through the enhancement of subsequent in vitro expansion and neuronal differentiation in cells harvested from the subventricular zone (SVZ). These results support the notion that tissue level changes across multiple systems could be observed following AIH, and support the continued optimization and establishment of AIH as a priming or conditioning modality for therapeutic cell populations.

Delivery of In Vivo Acute Intermittent Hypoxia in Neonatal Rodents to Prime Subventricular Zone-derived Neural Progenitor Cell Cultures

This article describes the methodology for administering short periods of intermittent hypoxia to postnatal day 1-8 mouse or rat pups. This approach effectively elicits a robust tissue level &#8220;priming effect&#8221; on cultured neural progenitor cells that are harvested within 30 min of hypoxia exposure.

Entrega de<em&gt; In Vivo</em&gt; Aguda intermitente hipóxia em Neonatal Roedores ao primeiro-subventricular Zona derivados de culturas de células progenitoras neurais

Extended culture of neural stem/progenitor cells facilitates in vitro analyses to understand their biology while enabling expansion of cell populations to ...

Biologia do Desenvolvimento

A Swine Model of Neonatal Asphyxia

Annually more than 1 million neonates die worldwide as related to asphyxia. Asphyxiated neonates commonly have multi-organ failure including hypotension, perfusion deficit, hypoxic-ischemic encephalopathy, pulmonary hypertension, vasculopathic enterocolitis, renal failure and thrombo-embolic complications. Animal models are developed to help us understand the patho-physiology and pharmacology of neonatal asphyxia. In comparison to rodents and newborn lambs, the newborn piglet has been proven to be a valuable model. The newborn piglet has several advantages including similar development as that of 36-38 weeks human fetus with comparable body systems, large body size (&tilde;1.5-2 kg at birth) that allows the instrumentation and monitoring of the animal and controls the confounding variables of hypoxia and hemodynamic derangements.
We here describe an experimental protocol to simulate neonatal asphyxia and allow us to examine the systemic and regional hemodynamic changes during the asphyxiating and reoxygenation process as well as the respective effects of interventions. Further, the model has the advantage of studying multi-organ failure or dysfunction simultaneously and the interaction with various body systems. The experimental model is a non-survival procedure that involves the surgical instrumentation of newborn piglets (1-3 day-old and 1.5-2.5 kg weight, mixed breed) to allow the establishment of mechanical ventilation, vascular (arterial and central venous) access and the placement of catheters and flow probes (Transonic Inc.) for the continuously monitoring of intra-vascular pressure and blood flow across different arteries including main pulmonary, common carotid, superior mesenteric and left renal arteries. Using these surgically instrumented piglets, after stabilization for 30-60 minutes as defined by Z&lt;10% variation in hemodynamic parameters and normal blood gases, we commence an experimental protocol of severe hypoxemia which is induced via normocapnic alveolar hypoxia. The piglet is ventilated with 10-15% oxygen by increasing the inhaled concentration of nitrogen gas for 2h, aiming for arterial oxygen saturations of 30-40%. This degree of hypoxemia will produce clinical asphyxia with severe metabolic acidosis, systemic hypotension and cardiogenic shock with hypoperfusion to vital organs. The hypoxia is followed by reoxygenation with 100% oxygen for 0.5h and then 21% oxygen for 3.5h. Pharmacologic interventions can be introduced in due course and their effects investigated in a blinded, block-randomized fashion.

Large animal models have good translational values in the examination of physiology and pharmacology of neonatal asphyxia. Using newborn piglets, we develop an experimental protocol to simulate neonatal asphyxia which has advantages of studying the systemic and regional hemodynamics, oxygen transport with biochemical and pathologic pathways and correlations.

Um Modelo de Suínos de asfixia neonatal

Annually more than 1 million neonates die worldwide as related to asphyxia. Asphyxiated neonates commonly have multi-organ failure including hypotension, ...

Medicina

Simultaneous Video-EEG-ECG Monitoring to Identify Neurocardiac Dysfunction in Mouse Models of Epilepsy

In epilepsy, seizures can evoke cardiac rhythm disturbances such as heart rate changes, conduction blocks, asystoles, and arrhythmias, which can potentially increase risk of sudden unexpected death in epilepsy (SUDEP). Electroencephalography (EEG) and electrocardiography (ECG) are widely used clinical diagnostic tools to monitor for abnormal brain and cardiac rhythms in patients. Here, a technique to simultaneously record video, EEG, and ECG in mice to measure behavior, brain, and cardiac activities, respectively, is described. The technique described herein utilizes a tethered (i.e., wired) recording configuration in which the implanted electrode on the head of the mouse is hard-wired to the recording equipment. Compared to wireless telemetry recording systems, the tethered arrangement possesses several technical advantages such as a greater possible number of channels for recording EEG or other biopotentials; lower electrode costs; and greater frequency bandwidth (i.e., sampling rate) of recordings. The basics of this technique can also be easily modified to accommodate recording other biosignals, such as electromyography (EMG) or plethysmography for assessment of muscle and respiratory activity, respectively. In addition to describing how to perform the EEG-ECG recordings, we also detail methods to quantify the resulting data for seizures, EEG spectral power, cardiac function, and heart rate variability, which we demonstrate in an example experiment using a mouse with epilepsy due to Kcna1 gene deletion. Video-EEG-ECG monitoring in mouse models of epilepsy or other neurological disease provides a powerful tool to identify dysfunction at the level of the brain, heart, or brain-heart interactions.

Here, we present a protocol to record brain and heart bio signals in mice using simultaneous video, electroencephalography (EEG), and electrocardiography (ECG). We also describe methods to analyze the resulting EEG-ECG recordings for seizures, EEG spectral power, cardiac function, and heart rate variability.

Simultânea vídeo-EEG-ECG de monitoramento para identificar a disfunção Neurocardiac em modelos de Mouse de epilepsia

In epilepsy, seizures can evoke cardiac rhythm disturbances such as heart rate changes, conduction blocks, asystoles, and arrhythmias, which can ...

Genética

The Hypoxic Ischemic Encephalopathy Model of Perinatal Ischemia

Hypoxic-Ischemic Encephalopathy (HIE) is the consequence of systemic asphyxia occurring at birth. Twenty five percent of neonates with HIE develop severe and permanent neuropsychological sequelae, including mental retardation, cerebral palsy, and epilepsy. The outcomes of HIE are devastating and permanent, making it critical to identify and develop therapeutic strategies to reduce brain injury in newborns with HIE. To that end, the neonatal rat model for hypoxic-ischemic brain injury has been developed to model this human condition. The HIE model was first validated by Vannucci et al 1 and has since been extensively used to identify mechanisms of brain injury resulting from perinatal hypoxia-ischemia 2 and to test potential therapeutic interventions 3,4. The HIE model is a two step process and involves the ligation of the left common carotid artery followed by exposure to a hypoxic environment. Cerebral blood flow (CBF) in the hemisphere ipsilateral to the ligated carotid artery does not decrease because of the collateral blood flow via the circle of Willis; however with lower oxygen tension, the CBF in the ipsilateral hemisphere decreases significantly and results in unilateral ischemic injury. The use of 2,3,5-triphenyltetrazolium chloride (TTC) to stain and identify ischemic brain tissue was originally developed for adult models of rodent cerebral ischemia 5, and is used to evaluate the extent of cerebral infarctin at early time points up to 72 hours after the ischemic event 6. In this video, we demonstrate the hypoxic-ischemic injury model in postnatal rat brain and the evaluation of the infarct size using TTC staining.

The postnatal rat model for hypoxic-ischemic brain injury is a well-established model of human neonatal hypoxic ischemic encephalopathy (HIE). In this article, we describe the model of HIE in post-natal rat pups.

O Modelo de encefalopatia hipóxico isquêmica Perinatal da Isquemia

Hypoxic-Ischemic Encephalopathy (HIE) is the consequence of systemic asphyxia occurring at birth. Twenty five percent of neonates with HIE develop severe ...

Biologia

A Piglet Model of Neonatal Hypoxic-Ischemic Encephalopathy

Birth asphyxia, which causes hypoxic-ischemic encephalopathy (HIE), accounts for 0.66 million deaths worldwide each year, about a quarter of the world&#8217;s 2.9 million neonatal deaths. Animal models of HIE have contributed to the understanding of the pathophysiology in HIE, and have highlighted the dynamic process that occur in brain injury due to perinatal asphyxia. Thus, animal studies have suggested a time-window for post-insult treatment strategies. Hypothermia has been tested as a treatment for HIE in pdiglet models and subsequently proven effective in clinical trials. Variations of the model have been applied in the study of adjunctive neuroprotective methods and piglet studies of xenon and melatonin have led to clinical phase I and II trials1,2. The piglet HIE model is further used for neonatal resuscitation- and hemodynamic studies as well as in investigations of cerebral hypoxia on a cellular level. However, it is a technically challenging model and variations in the protocol may result in either too mild or too severe brain injury. In this article, we demonstrate the technical procedures necessary for establishing a stable piglet model of neonatal HIE. First, the newborn piglet (&#60; 24 hr old, median weight 1500 g) is anesthetized, intubated, and monitored in a setup comparable to that found in a neonatal intensive care unit. Global hypoxia-ischemia is induced by lowering the inspiratory oxygen fraction to achieve global hypoxia, ischemia through hypotension and a flat trace amplitude integrated EEG (aEEG) indicative of cerebral hypoxia. Survival is promoted by adjusting oxygenation according to the aEEG response and blood pressure. Brain injury is quantified by histopathology and magnetic resonance imaging after 72 hr.

Hypoxic-ischemic encephalopathy following perinatal asphyxia can be studied using animal models. We demonstrate the procedures necessary for establishing a piglet model of neonatal hypoxic-ischemic encephalopathy.

Um Modelo de Leitão Neonatal encefalopatia hipóxico-isquêmica

Birth asphyxia, which causes hypoxic-ischemic encephalopathy (HIE), accounts for 0.66 million deaths worldwide each year, about a quarter of the ...

Neurobehavioral Assessments in a Mouse Model of Neonatal Hypoxic-ischemic Brain Injury

We performed unilateral carotid artery occlusion on CD-1 mice to create a neonatal hypoxic-ischemic (HI) model and investigated the effects of neonatal HI brain injury by studying neurobehavioral functions in these mice compared to non-operated (i.e., normal) mice. During the study, Rice-Vannucci&#39;s method was used to induce neonatal HI brain damage in postnatal day 7-10 (P7-10) mice. The HI operation was performed on the pups by unilateral carotid artery ligation and exposure to hypoxia (8% O2 and 92% N2 for 90 min). One week after the operation, the damaged brains were evaluated with the naked eye through the semi-transparent skull and were categorized into subgroups based on the absence (&#34;no cortical injury&#34; group) or presence (&#34;cortical injury&#34; group) of cortical injury, such as a lesion in the right hemisphere. On week 6, the following neurobehavioral tests were performed to evaluate the cognitive and motor functions: passive avoidance task (PAT), ladder walking test, and grip strength test. These behavioral tests are helpful in determining the effects of neonatal HI brain injury and are used in other mouse models of neurodegenerative diseases. In this study, neonatal HI brain injury mice showed motor deficits that corresponded to right hemisphere damage. The behavioral test results are relevant to the deficits observed in human neonatal HI patients, such as cerebral palsy or neonatal stroke patients. In this study, a mouse model of neonatal HI brain injury was established and showed different degrees of motor deficits and cognitive impairment compared to non-operated mice. This work provides basic information on the HI mouse model. MRI images demonstrate the different phenotypes, separated according to the severity of brain damage by motor and cognitive tests.

We performed unilateral carotid artery occlusion on postnatal day 7-10 CD-1 mouse pups to create a neonatal hypoxic-ischemic (HI) model and investigated the effects of HI brain injury. We studied neurobehavioral functions in these mice compared to non-operated normal mice.

Neurocomportamentais avaliações em um modelo do rato de lesão cerebral hipóxica-isquêmica Neonatal

We performed unilateral carotid artery occlusion on CD-1 mice to create a neonatal hypoxic-ischemic (HI) model and investigated the effects of neonatal HI ...

Neurociência

Noninvasive Electrocardiography in the Perinatal Mouse

Electrocardiography (ECG) has long been relied upon as an effective and reliable method of assessing cardiovascular (and cardiopulmonary) function in both human and animal models of disease. Individual heart rate, rhythm, and regularity, combined with quantitative parameters collected from ECG, serve to assess the integrity of the cardiac conduction system as well as the integrated physiology of the cardiac cycle. This article provides a comprehensive description of the methods and techniques used to perform a noninvasive ECG on perinatal and neonatal mouse pups as early as the first postnatal day, without requiring the use of anesthetics. This protocol was designed to directly address a need for a standardized and repeatable method for obtaining ECG in newborn mice. From a translational perspective, this protocol proves to be entirely effective for characterization of congenital cardiopulmonary defects generated using transgenic mouse lines, and particularly for analysis of defects causing lethality at or during the first postnatal days. This protocol also aims to directly address a gap in the scientific literature to characterize and provide normative data associated with maturation of the early postnatal cardiac conduction system. This method is not limited to a specific postnatal timepoint, but rather allows for ECG data collection in neonatal mouse pups from birth to postnatal day 10 (P10), a window that is of critical importance for modeling human diseases in vivo, with particular emphasis on congenital heart disease (CHD).

Here, we present a noninvasive electrocardiography (ECG) protocol, optimized for early postnatal mice, that does not require the use of anesthetics.

Eletrocardiografia não invasiva no Rato Perinatal

Electrocardiography (ECG) has long been relied upon as an effective and reliable method of assessing cardiovascular (and cardiopulmonary) function in both ...

Echocardiographic Characterization of Left Ventricular Structure, Function, and Coronary Flow in Neonate Mice

Echocardiography is a non-invasive procedure that enables the evaluation of structural and functional parameters in animal models of cardiovascular disease and is used to assess the impact of potential treatments in preclinical studies. Echocardiographic studies are usually conducted in young adult mice (i.e., 4-6 weeks of age). The evaluation of early neonatal cardiovascular function is not usually performed because of the small size of the mouse pups and the associated technical difficulties. One of the most important challenges is that the short length of the pups&#39; limbs prevents them from reaching the electrodes in the echocardiography platform. Body temperature is the other challenge, as pups are very susceptible to changes in temperature. Therefore, it is important to establish a practical guide for performing echocardiographic studies in small mouse pups to help researchers detect early pathological changes and study the progression of cardiovascular disease over time. The current work describes a protocol for performing echocardiography in mouse pups at the early age of 7 days old. The echocardiographic characterization of cardiac morphology, function, and coronary flow in neonatal mice is also described.

The present protocol describes the echocardiographic assessment of left ventricular morphology, function, and coronary blood flow in 7-day old neonate mice.

Caracterização ecocardiográfica da estrutura, função e fluxo coronariano do ventrículo esquerdo em camundongos recém-nascidos

Echocardiography is a non-invasive procedure that enables the evaluation of structural and functional parameters in animal models of cardiovascular ...

Early Pathological and Magnetic Resonance Detection of Cerebral Injury Using a Rat Model of Neonatal Hypoxic Ischemic Encephalopathy

Perinatal hypoxic-ischemic encephalopathy (HIE) is an acute disease that may afflict newborns, resulting in variable long- and short-term neurodevelopmental outcomes. Early diagnosis is critical to identifying infants who may benefit from intervention; however, early diagnosis relies heavily on clinical criteria. No molecular or radiological tests have shown promise in detecting early cerebral injury. Studies have shown that magnetic resonance imaging (MRI) can show changes in both blood flow/ischemia and metabolic disruption. However, they have all been used to evaluate the secondary phase of the disease (&gt;12 h) after the onset of the injury. Early diagnosis is critical to rapidly starting therapeutic hypothermia in eligible infants, which is currently recommended to be initiated within 6 h of birth. The rat model of hypoxic-ischemic injury was developed in 1981 and has been validated and used extensively to study changes in brain perfusion, cerebral injury markers, and morphology. However, it has primarily been used as a "late model", evaluating injury several days after the initial ischemic insult. The model has been known to have poor sensitivity in evaluating reliable and reproducible early cerebral changes. The objective of this study was to develop a reliable model to study early gross morphological and radiological markers of HIE using pathological staining and cerebral magnetic resonance imaging/magnetic resonance spectroscopy.

The present protocol describes a rodent model of newborn hypoxic-ischemic injury for identifying early changes in cerebral tissue by gross morphology and magnetic resonance imaging. This has benefits over existing models, which can be used to study late injury but do not allow the evaluation of reproducible early changes.

Perinatal hypoxic-ischemic encephalopathy (HIE) is an acute disease that may afflict newborns, resulting in variable long- and short-term ...

Establishing a Mouse Model of Neonatal Hypoxic-Ischemic Brain Injury

Source: Kim, M., et al. <a href="https://appjove.unicartagenaproxy.elogim.com/v/55838">Neurobehavioral Assessments in a Mouse Model of Neonatal Hypoxic-ischemic Brain Injury.</a> J. Vis. Exp. (2017).
The video demonstrates the procedure for creating a mouse model to study neonatal hypoxic-ischemic brain injury. It outlines the steps for surgically inducing ischemia and subjecting the animal to hypoxia to exacerbate brain damage. Finally, it shows how to assess the resulting brain lesions, ensuring the mouse model is prepared for further scientific investigation.

Eletroencefalograma de vídeo contínuo durante hipoxia-isquemia em camundongos neonatais

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