1. Preparação 1.1. Anestesia das ratazanas <ol><li> Colocar o rato dentro de uma câmara de pré-preenchido com isoflurano (dependendo do tamanho da câmara de cerca de 3 minutos, de 5%) para anestesiar os ratos. </li><li> Uma vez anestesiados, retire o rato e pesar. </li><li> Colocar o nariz do rato dentro da máscara da anestesia (2-3% de isoflurano em oxigénio de 1 L / min), para manter a anestesia. Durante a anestesia com isoflurano, os batimentos cardíacos de ratos diminuir a 300-340 bpm (380-420 bpm em ratos). </li></ol> 1.2. Inserir uma cânula na veia da cauda <ol><li> Lava-se a cauda do rato com água morna (38 ° C) e o sabão para permitir que os vasos sanguíneos para ser mais facilmente visível. </li><li> Canular ou veia, o que pode ser facilmente visto sobre a face lateral da cauda. Utilizando um cateter IV L 22-24, começam as tentativas de aproximadamente 1/3 da forma da ponta. </li><li> Se os esforços iniciais são mal sucedidos, tente novamente mais proximal. </li><li> Tirar sangue samPLE para análise de hematócrito (necessário para calcular fração de volume extracelular = ECV). </li><li> Fixe o cateter iv com cola de pele e fita. </li></ol> 1.3. Posicionamento dos eletrodos <ol><li> Limpe todos os coxins com algodão embebido em álcool saturado ou com água e sabão. </li><li> Quatro eléctrodos são necessários, um para cada um dos pés. </li><li> Conecte os eletrodos no meio da pata e prenda-os com fita adesiva. </li><li> Torção ou trançar os cabos de ECG em torno de si, para minimizar a formação de laçadas que causariam interferência com o sinal de ECG. </li></ol> 2. Exploração 2.1. Posicionamento do animal e monitorização <ol><li> Colocar o rato na posição supina ou propenso para o tubo de imagem e posição do coração no centro da bobina. </li><li> Dispor o rato de modo que o seu nariz repousa no cone que proporciona anestesia com isoflurano (2-3% em oxigénio de 1 L / min). O rato é permitido respirarlivremente ao longo do procedimento de imagem inteira. </li><li> Coloque o sensor do termômetro no orifício anal e corrigi-lo em cima da mesa com fita adesiva. </li><li> A temperatura do corpo é mantida a 38 ± 1 ° C por um sistema de aquecimento de água quente. A manta de aquecimento é colocada sob o aspecto inferior do animal que se estende para fora da bobina. Por favor, veja a representação esquemática da instalação experimental de ressonância magnética (Figura 2) para mais detalhes. </li><li> Conecte os eletrodos de ECG, uma vez que o sinal de ECG é estável começar imagem. </li></ol> 2.2. Parâmetros de protocolo / Imagem Digitalização <ol><li> Neste estudo Ingenia um sistema de ressonância magnética clínica 3.0T Philips com uma bobina, com 70 mm de diâmetro interno foi usado [requisitos do sistema de RM é um pequeno furo (por exemplo, 16 cm) ou grande diâmetro (tamanho humano, por exemplo, 65 cm) com pequeno animal dedicado bobina, capacidade de propagação de ECG para a freqüência cardíaca de até 500/min, o suprimento de oxigênio e um sistema de remoção de gases anestésicos]. </li><li> Comece com uma pesquisa para localizar o coração no centro do campo de vista de MRI. </li><li> Uma vez que é a posição correcta, prosseguir com duas câmaras e quatro câmaras cine MRI vista a determinar a geometria da pilha de imagens de eixo curto. </li><li> Para SALLI, a posição mid-cavidade fatia eixo curto nos dois e imagens de quatro câmaras (PreSALLI). Uma combinação de 4000 mseg duração de aquisição e 4000 mseg duração do relaxamento permite a recuperação suficiente da magnetização ao longo do eixo z e evita o sobreaquecimento dos gradientes. Para permitir a análise funcional, as fases devem ser definidos para pelo menos 12, com Undersampling temporal do fator 2 para acelerar a aquisição. </li><li> Injectar o agente de contraste à base de gadolínio para o cateter, sem mover o rato. Espere cinco minutos. </li><li> Comece a planejar SALLI como multislice pilha eixo curto, consistindo de pelo menos 7 fatias (fatia de espessura 2,4 milímetros). Posicionar as fatias de modo que o mais distai está abaixo da ponta do coração e tele de nível superior é apenas distal das válvulas cardíacas. Tentar assegurar que os eixos curtos são perpendiculares ao septo. Quase todos os 30 minutos (em torno de três Sallis) injetar outra dose de agente de contraste. </li><li> Quando a aquisição da imagem estiver concluída remover o rato do scanner e permitir que ele se recuperar da anestesia. </li></ol> 3. Reconstrução da Imagem Reconstrução da imagem podem ser realizadas on-line através de parâmetros pré-definidos, de reconstrução ou offline usando uma ferramenta de reconstrução de imagem dedicado: 3.1. Reconstrução online <ol><li> Vários parâmetros podem ser definidos incluindo: </li></ol><ul><li> Para o mapeamento T1: localização e largura da janela de reconstrução no ciclo cardíaco (por exemplo, de 50 a 100 ms para alcançar sistólica mapa T1 no ritmo cardíaco 300/min) </li><li> Para IR-preparados (LGE) Imagens: localização e largura do tempo de inversão (TI) janela e número de imagens a ser wi reconstruídofina que a janela (por exemplo TI 100-300 ms, 5 imagens, para gerar 5 imagens LGE com TIs 100-150-200-250-300 ms). </li></ul> 3.2. Desligada Reconstrução <ol><li> Ao usar um pacote de software dedicado (Gyrotools, Zurique, Suíça) para a reconstrução de imagem, extrair os três conjuntos de dados (cine MR, inversão recuperação e mapas T1) de uma forma mais interativa. </li><li> Ajuste a definição de final da sístole ou no final da diástole para o T1, selecionando a imagem cine correspondente. </li><li> Visualize mapas T1 como mapas de cores. Encontre os valores exatos, passando o mouse sobre uma área de interesse. As imagens podem ser armazenadas em vários formatos de imagem para análise posterior (por exemplo, cálculo de ECV de valores pré-e pós-contraste T1 de miocárdio e de uma acumulação de sangue) 12. </li></ol>

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T., 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=Equilibrium+contrast+cardiovascular+magnetic+resonance+for+the+measurement+of+diffuse+myocardial+fibrosis:+preliminary+validation+in+humans.">Equilibrium contrast cardiovascular magnetic resonance for the measurement of diffuse myocardial fibrosis: preliminary validation in humans.</a> Circulation. 122 (2), 138-144 (2010).</li><li>Arheden, H., Saed, M., Higgins, C. 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Todos os procedimentos com animais foram conduzidos de acordo com as Diretrizes para o Cuidado e Uso de Animais de Laboratório, e aprovado pelas autoridades locais de cuidados de animais. Não há conflitos de interesse declarados.

Aqui apresentamos um método para gerar multi-modalidade (cine MR, inversão-recuperação e T1 mapas) imagens de RM em pequenos animais. Pesquisa animal pequeno desempenha um papel cada vez mais importante na pesquisa da doença cardiovascular e CMR é uma ferramenta poderosa, permitindo-nos a estudar a composição do miocárdio função, estrutura e tecido. No entanto, pequenos animais CMR tem uma série de desafios únicos devido às altas taxas de coração e de tamanho pequeno coração. Melhores métodos de imagi...

A miocardite é uma causa importante da falha cardíaca aguda, a morte súbita, a cardiomiopatia dilatada crónica 7. CMR foi estabelecido como a técnica padrão ouro para a medida da função e para a análise de tecido vivo. Novas técnicas de imagem e melhorias na imagem pode não só melhorar o diagnóstico de miocardite, mas também auxiliar o estudo da fisiopatologia e identificação de alvos terapêuticos velocidade 8-10. Imagens de pequenos animais é uma importante ferramenta para o estudo de doenças cardiovasculares. Técnicas rotineiramente utilizadas na clínica CMR, como realce pelo gadolínio tardio (LGE), não podem ser facilmente transferidos para pequenas CMR animais devido às altas taxas coração dos animais, mas já pode ser mostrado 11. O pequeno animal Look-Locker recuperação de inversão (SALLI) abordagem gera dados de imagem multi-modais define permitindo a avaliação abrangente de ambos função cardíaca e morfologia (Figuras 1 Aº 3). Aqui vamos mostrar, em detalhes, o procedimento e configuração para imagens de pequenos animais com um protocolo típico SALLI. Em particular, mostramos a reconstrução e análise dos conjuntos T1 de dados de imagem.

<table border="1">
		<tbody>
		 <tr>
			<td>Name of Reagent/Material</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		 </tr>
		 <tr>
			<td>Adhesive Tape (Silkafix)</td>
			<td>Lohmann und Rauscher</td>
			<td>34327</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Gadopentetat-Dimeglumin (Magnevist)</td>
			<td>Bayer</td>
			<td>G-00012163</td>
			<td>2mmol/Kg</td>
		 </tr>
		 <tr>
			<td>Introcan Safety-W (G24)</td>
			<td>B. Braun</td>
			<td>4254503-01</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Red Dot, Neonatal Monitoring Electrode with Pre-Attached Lead Wire</td>
			<td>3M</td>
			<td>2269T</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Skin glue (Histoacryl)</td>
			<td>B. Braun</td>
			<td>1050052</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Scales (Typ 440)</td>
			<td>Kern</td>
			<td>95088</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Skin desinfection (Softasept N)</td>
			<td>B. Braun Petzold</td>
			<td>360250</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Thermometer </td>
			<td>LumaSense Technologies</td>
			<td>Luxtron 812</td>
			<td></td>
		 </tr>
		</tbody>
 </table>

assessment of cardiac function and myocardial morphology using small animal look-locker inversion recovery (salli) mri in rats

Pequeno animal ressonância magnética é uma importante ferramenta para estudar a função cardíaca e alterações no tecido do miocárdio. As altas taxas de coração de animais de pequeno porte (200 a 600 batimentos / min) já limita o papel da CMR imagem. Pequeno animal Look-Locker recuperação de inversão (SALLI) é uma seqüência de mapeamento T1 para pequenos animais para superar este problema 1. Mapas T1 fornecer informações quantitativas sobre alterações teciduais e cinética agente de contraste. Também é possível detectar processos difusa do miocárdio, tais como fibrose intersticial ou edema 1-6. Além disso, a partir de um único conjunto de dados de imagem, é possível examinar a função do coração e cicatrizes do miocárdio através da geração de cine e inversão de recuperação preparados final imagens de RM do tipo realce pelo gadolínio 1. O vídeo apresentado mostra passo-a-passo os procedimentos para realizar pequenos animais CMR imagem. Aqui é apresentado um Sprague-Dawl saudáveley rato, no entanto, naturalmente, pode ser estendida a diferentes modelos de animais pequenos cardíacas.

Aqui vamos demonstrar os resultados de um saudável Sprague Dawley. Com uma configuração de animais bem preparados nós descrito antes, é possível obter um sinal de ECG estável. Semelhante aos protocolos de ressonância magnética cardíaca humanos, começamos com uma pesquisa para localizar o coração. Se a posição do rato na bobina é correcta, continuamos com uma vista de duas câmaras e um de quatro câmaras para detectar a geometria para a pilha SALLI. A técnica SALLI produz tr...

Watch this Scientific Journal Video about Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery SALLI MRI in Rats at JoVE.com

Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery SALLI MRI in Rats

A ressonância magnética cardíaca maior contraste (CMR) permite abrangente<em&gt; In vivo</em&gt; Avaliação do coração em pequenos modelos animais de doença cardiovascular. Aqui detalhamos os procedimentos para realizar CMR imagem, reconstrução e análise usando Pequenos Animais Inversion Recovery Lock-Locker (SALLI) em ratos.

Avaliação da função cardíaca e Morfologia do miocárdio Usando Pequenos Animais Inversion Recovery Olha-locker (SALLI) MRI em ratos

Small animal magnetic resonance  imaging is an important tool to study cardiac function and changes in myocardial  tissue. The high heart rates of small ...

assessment-cardiac-function-myocardial-morphology-using-small-animal

Research

JoVE Journal

Medicine

Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery (SALLI) MRI in Rats

12.6K visualizações.  German Heart Institute Berlin. A ressonância magnética cardíaca maior contraste (CMR) permite abrangente In vivo Avaliação do coração em pequenos modelos animais de doença cardiovascular. Aqui detalhamos os procedimentos para realizar CMR imagem, reconstrução e análise usando Pequenos Animais Inversion Recovery Lock-Locker (SALLI) em ratos.

Vídeo: Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery SALLI MRI in Rats

Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy

Bioengineered mouse models have become powerful research tools in determining causal relationships between molecular alterations and models of cardiovascular disease. Although molecular biology is necessary in identifying key changes in the signaling pathway, it is not a surrogate for functional significance. While physiology can provide answers to the question of function, combining physiology with biochemical assessment of metabolites in the intact, beating heart allows for a complete picture of cardiac function and energetics. For years, our laboratory has utilized isolated heart perfusions combined with nuclear magnetic resonance (NMR) spectroscopy to accomplish this task. Left ventricular function is assessed by Langendorff-mode isolated heart perfusions while cardiac energetics is measured by performing 31P magnetic resonance spectroscopy of the perfused hearts. With these techniques, indices of cardiac function in combination with levels of phosphocreatine and ATP can be measured simultaneously in beating hearts. Furthermore, these parameters can be monitored while physiologic or pathologic stressors are instituted. For example, ischemia/reperfusion or high workload challenge protocols can be adopted. The use of aortic banding or other models of cardiac pathology are apt as well. Regardless of the variants within the protocol, the functional and energetic significance of molecular modifications of transgenic mouse models can be adequately described, leading to new insights into the associated enzymatic and metabolic pathways. Therefore, 31P NMR spectroscopy in the isolated perfused heart is a valuable research technique in animal models of cardiovascular disease.

Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy

Langendorff-mode isolated heart perfusion, in conjunction with 31P NMR spectroscopy, combines the fields of biochemistry and physiology into one experiment. The protocol allows for the dynamic measurement of high energy phosphate content and turnover in the heart while concurrently monitoring physiologic function. When performed correctly, this is a valuable technique in the assessment of cardiac energetics.

Avaliação da função cardíaca e Energetics em Corações Isolados rato Usando 31 P NMR Spectroscopy

Bioengineered mouse models have become powerful research tools in determining causal relationships between molecular alterations and models of ...

Medicina

Acute Myocardial Infarction in Rats

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular diseases. Animal models that mimic human cardiac disease, such as myocardial infarction (MI) and ischemia-reperfusion (IR) that induces heart failure as well as pressure-overload (transverse aortic constriction) that induces cardiac hypertrophy and heart failure (Goldman and Tarnavski), are useful models to study cardiovascular disease. In particular, myocardial ischemia (MI) is a leading cause for cardiovascular morbidity and mortality despite controlling certain risk factors such as arteriosclerosis and treatments via surgical intervention (Thygesen). Furthermore, an acute loss of the myocardium following myocardial ischemia (MI) results in increased loading conditions that induces ventricular remodeling of the infarcted border zone and the remote non-infarcted myocardium. Myocyte apoptosis, necrosis and the resultant increased hemodynamic load activate multiple biochemical intracellular signaling that initiates LV dilatation, hypertrophy, ventricular shape distortion, and collagen scar formation. This pathological remodeling and failure to normalize the increased wall stresses results in progressive dilatation, recruitment of the border zone myocardium into the scar, and eventually deterioration in myocardial contractile function (i.e. heart failure). The progression of LV dysfunction and heart failure in rats is similar to that observed in patients who sustain a large myocardial infarction, survive and subsequently develops heart failure (Goldman). The acute myocardial infarction (AMI) model in rats has been used to mimic human cardiovascular disease; specifically used to study cardiac signaling mechanisms associated with heart failure as well as to assess the contribution of therapeutic strategies for the treatment of heart failure. The method described in this report is the rat model of acute myocardial infarction (AMI). This model is also referred to as an acute ischemic cardiomyopathy or ischemia followed by reperfusion (IR); which is induced by an acute 30-minute period of ischemia by ligation of the left anterior descending artery (LAD) followed by reperfusion of the tissue by releasing the LAD ligation (Vasilyev and McConnell). This protocol will focus on assessment of the infarct size and the area-at-risk (AAR) by Evan's blue dye and triphenyl tetrazolium chloride (TTC) following 4-hours of reperfusion; additional comments toward the evaluation of cardiac function and remodeling by modifying the duration of reperfusion, is also presented. Overall, this AMI rat animal model is useful for studying the consequence of a myocardial infarction on cardiac pathophysiological and physiological function.

The rat model of acute myocardial infarction (AMI) is useful to study the consequence of a MI on cardiac pathophysiological and physiological function.

Infarto Agudo do Miocárdio em Ratos

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular ...

MRI and PET in Mouse Models of Myocardial Infarction

Myocardial infarction is one of the leading causes of death in the Western world. The similarity of the mouse heart to the human heart has made it an ideal model for testing novel therapeutic strategies.
In vivo magnetic resonance imaging (MRI) gives excellent views of the heart noninvasively with clear anatomical detail, which can be used for accurate functional assessment. Contrast agents can provide basic measures of tissue viability but these are nonspecific. Positron emission tomography (PET) is a complementary technique that is highly specific for molecular imaging, but lacks the anatomical detail of MRI. Used together, these techniques offer a sensitive, specific and quantitative tool for the assessment of the heart in disease and recovery following treatment.
In this paper we explain how these methods are carried out in mouse models of acute myocardial infarction. The procedures described here were designed for the assessment of putative protective drug treatments. We used MRI to measure systolic function and infarct size with late gadolinium enhancement, and PET with fluorodeoxyglucose (FDG) to assess metabolic function in the infarcted region. The paper focuses on practical aspects such as slice planning, accurate gating, drug delivery, segmentation of images, and multimodal coregistration. The methods presented here achieve good repeatability and accuracy maintaining a high throughput.

We describe how to perform MRI and PET imaging of the mouse heart. The protocol is tailored to assess treatment efficacy in models of myocardial infarction and heart failure.

Ressonância magnética e PET no rato modelos de Infarto do Miocárdio

Myocardial infarction is one of the leading causes of death in the Western world. The similarity of the mouse heart to the human heart has made it an ...

Ascending Aortic Constriction in Rats for Creation of Pressure Overload Cardiac Hypertrophy Model

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart failure. Here, we describe a detailed surgical procedure for creating pressure overload and cardiac hypertrophy in rats by constriction of the ascending aorta using a small metallic clip. After anesthesia, the trachea is intubated by inserting a cannula through a half way incision made between two cartilage rings of trachea. Then a skin incision is made at the level of the second intercostal space on the left chest wall and muscle layers are cleared to locate the ascending portion of aorta. The ascending aorta is constricted to 50&#8211;60% of its original diameter by application of a small sized titanium clip. Following aortic constriction, the second and third ribs are approximated with prolene sutures. The tracheal cannula is removed once spontaneous breathing was re-established. The animal is allowed to recover on the heating pad by gradually lowering anesthesia. The intensity of pressure overload created by constriction of the ascending aorta is determined by recording the pressure gradient using trans-thoracic two dimensional Doppler-echocardiography. Overall this protocol is useful to study the remodeling events and contractile properties of the heart during the gradual onset and progression from compensated cardiac hypertrophy to heart failure stage.

We describe a stepwise procedure for creating pressure overload and left ventricular hypertrophy in Wistar rats by constriction of the ascending aorta using a small metallic clip. This model is extensively used for studying remodeling changes during cardiac hypertrophy and for identifying and evaluating strategies for regression of such changes.

Aorta ascendente constrição em ratos para a criação de sobrecarga de pressão Cardíaca Hipertrofia Modelo

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart ...

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

Avaliação da Estrutura e Função do Ventrículo Direito em modelo de camundongo Pulmonary Artery constrição por Ecocardiografia transtorácica

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, ...

Echocardiographic and Histological Examination of Cardiac Morphology in the Mouse

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed in mice is high. Phenotypic characterization of these mouse models also requires the examination of cardiac function and morphology. Echocardiography and magnetic resonance imaging (MRI) are commonly used approaches to characterize cardiac function and morphology in mice. Echocardiographic and MRI equipment specialized for use in small rodents is&#160;expensive and requires a dedicated space. This protocol describes cardiac measurements in mice using a clinical echocardiographic system with a 15 MHz human vascular probe. Measurements are performed on anesthetized adult mice. At least three image sequences are recorded and analyzed for each animal in M-mode in the parasternal short-axis view. Afterwards, cardiac histological examination is performed, and cardiomyocyte diameters are determined on hematoxylin-eosin- or wheat germ agglutinin (WGA)-stained paraffin sections. Vessel density is determined morphometrically after Pecam-1 immunostaining. The protocol has been applied successfully to pharmacological studies and different genetic animal models under baseline conditions, as well as after experimental myocardial infarction by the permanent ligation of the left anterior descending coronary artery (LAD). In our experience, echocardiographic investigation is limited to anesthetized animals and is feasible in adult mice weighing at least 25 g.

Echocardiographic examination is frequently used in mice. Expensive high-resolution ultrasound devices have been developed for this purpose. This protocol describes an affordable echocardiographic procedure combined with histological morphometric analyses to determine cardiac morphology.

Exame ecocardiográfico e histológico da morfologia cardíaca no Mouse

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed ...

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The amount of the different tissues in the callus provides important information on the fracture healing progress. Available in vivo techniques to longitudinally monitor the callus tissue development in preclinical fracture-healing studies using small animals include digital radiography and &#181;CT imaging. However, both techniques are only able to distinguish between mineralized and non-mineralized tissue. Consequently, it is impossible to discriminate cartilage from fibrous tissue. In contrast, magnetic resonance imaging (MRI) visualizes anatomical structures based on their water content and might therefore be able to noninvasively identify soft tissue and cartilage in the fracture callus. Here, we report the use of an MRI-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice. The experiments demonstrated that the fixator and a custom-made mounting device allow repetitive MRI scans, thus enabling longitudinal analysis of fracture-callus tissue development.

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

The evaluation of tissue development in the fracture callus during endochondral bone healing is essential to monitor the healing process. Here, we report the use of a magnetic resonance imaging (MRI)-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice.

Na Vivo Avaliação do desenvolvimento de calo de fratura durante a consolidação óssea em ratos usando um dispositivo de osteossíntese compatível com MRI para o fêmur de Mouse

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The ...

Normothermic Ex Situ Heart Perfusion in Working Mode: Assessment of Cardiac Function and Metabolism

The current standard method for organ preservation (cold storage, CS), exposes the heart to a period of cold ischemia that limits the safe preservation time and increases the risk of adverse post-transplantation outcomes. Moreover, the static nature of CS does not allow for organ evaluation or intervention during the preservation interval. Normothermic ex situ heart perfusion (ESHP) is a novel method for preservation of the donated heart that minimizes cold ischemia by providing oxygenated, nutrient-rich perfusate to the heart. ESHP has been shown to be non-inferior to CS in the preservation of standard-criteria donor hearts and has also facilitated the clinical transplantation of the hearts donated after the circulatory determination of death. Currently, the only available clinical ESHP device perfuses the heart in an unloaded, non-working state, limiting assessments of myocardial performance. Conversely, ESHP in working mode provides the opportunity for comprehensive evaluation of cardiac performance by assessment of functional and metabolic parameters under physiologic conditions. Moreover, earlier experimental studies have suggested that ESHP in working mode may result in improved functional preservation. Here, we describe the protocol for ex situ perfusion of the heart in a large mammal (porcine) model, which is reproducible for different animal models and heart sizes. The software program in this ESHP apparatus allows for real-time and automated control of the pump speed to maintain desired aortic and left atrial pressure and evaluates a variety of functional and electrophysiological parameters with minimal need for supervision/manipulation.

Normothermic ex situ heart perfusion (ESHP), preserves the heart in a beating, semi-physiologic state. When performed in a working mode, ESHP provides the opportunity to perform sophisticated assessments of donor heart function and organ viability. Here, we describe our method for myocardial performance evaluation during ESHP.

Normotérmica Ex Situ coração perfusão na modalidade de trabalho: avaliação da função cardíaca e metabolismo

The current standard method for organ preservation (cold storage, CS), exposes the heart to a period of cold ischemia that limits the safe preservation ...

Continuous Blood Sampling in Small Animal Positron Emission Tomography/Computed Tomography Enables the Measurement of the Arterial Input Function

For quantitative analysis and bio-kinetic modeling of positron emission tomography/computed tomography (PET/CT) data, the determination of the temporal blood time-activity concentration also known as arterial input function (AIF) is a key point, especially for the characterization of animal disease models and the introduction of newly developed radiotracers. The knowledge of radiotracer availability in the blood helps to interpret PET/CT-derived data of tissue activity. For this purpose, online blood sampling during the PET/CT imaging is advisable to measure the AIF. In contrast to manual blood sampling and image-derived approaches, continuous online blood sampling has several advantages. Besides the minimized blood loss, there is an improved resolution and a superior accuracy for the blood activity measurement. However, the major drawback of online blood sampling is the costly and time-consuming preparation to catheterize the femoral vessels of the animal. Here, we describe an easy and complete workflow for catheterization and continuous blood sampling during small animal PET/CT imaging and compared it to manual blood sampling and an image-derived approach. Using this highly-standardized workflow, the determination of the fluorodeoxyglucose ([18F]FDG) AIF is demonstrated. Further, this procedure can be applied to any radiotracer in combination with different animal models to create fundamental knowledge of tracer kinetic and model characteristics. This allows a more precise evaluation of the behavior of pharmaceuticals, both for diagnostic and therapeutic approaches in the preclinical research of oncological, neurodegenerative and myocardial diseases.

Here a protocol for continuous blood sampling during PET/CT imaging of rats to measure the arterial input function (AIF) is described. The catheterization, the calibration and setup of the system and the data analysis of the blood radioactivity are demonstrated. The generated data provide input parameters for subsequent bio-kinetic modeling.

A amostragem contínua do sangue no tomography de emissão de Positron animal pequeno/tomography computado permite a medida da função de entrada arterial

For quantitative analysis and bio-kinetic modeling of positron emission tomography/computed tomography (PET/CT) data, the determination of the temporal ...

Echocardiographic Assessment of Cardiac Anatomy and Function in Adult Rats

The use of experimental animal models has become crucial in cardiovascular science. Most studies using rodent models are focused on two-dimensional imaging to study the cardiac anatomy of the left ventricle and M-mode echo to assess its dimensions. However, this could limit a comprehensive study. Herein, we describe a protocol that allows an assessment of the heart chamber size, left ventricular function (systolic and diastolic) and valvular function. A conventional medical ultrasound machine was used in this protocol and different echo views were obtained through left parasternal, apical and suprasternal windows. In the left parasternal window, the long and short axis were acquired to analyze left chamber dimensions, right ventricle and pulmonary artery dimensions, and mitral, pulmonary and aortic valve function. The apical window allows the measurement of heart chamber dimensions and evaluation of systolic and diastolic parameters. It also allows Doppler assessment with detection and quantification of heart valve disturbances (regurgitation or stenosis). Different segments and walls of the left ventricle are visualized throughout all views. Finally, the ascending aorta, aortic arch, and descending aorta can be imaged through the suprasternal window. A combination of ultrasound imaging, Doppler flow and tissue Doppler assessment have been obtained to study cardiac morphology and function. This represents an important contribution to improve the assessment of cardiac function in adult rats with impact for research using these animal models.

A non-invasive protocol for transthoracic echocardiography assessment of cardiac anatomy and function for adult rats is presented in the current study. The heart valves, all four cardiac chambers and the ascending aorta, aortic arch and descending aorta are studied in detail.

Avaliação ecocardiográfica da anatomia e função cardíaca em ratos adultos

The use of experimental animal models has become crucial in cardiovascular science. Most studies using rodent models are focused on two-dimensional ...