Esta publicación fue apoyada por la Clínica y Traslacional de Investigación (SCTR) Instituto de Carolina del Sur, con un hogar académico de la Universidad Médica de Carolina del Sur, NIH / NCATS subvención Número de UL1 TR000062. Más apoyo fue proporcionado por premio al mérito VA BX002327-01 de DRM. DJH fue apoyado por el NIH / NCATS subvención Número de TL1 TR000061 y por el NIH subvención Número de T32 GM008716. MAR fue apoyado por el NIH subvención Número de T32 HL07260.

Todos los procedimientos que figuran a continuación han sido aprobados por el Comité de Cuidado y Uso de Animales Institucional de la Universidad de Medicina de Carolina del Sur. Los experimentos descritos aquí son experimentos agudos, no de supervivencia. Como tal, no hay uso de la pomada para los ojos y no se requiere un quirófano estéril. La eutanasia se logra por desangrado durante la recolección del corazón. 1. Preparación Experimental <ol><li> Configure sea una presión constante o flujo constante de perfusión Langendorff Aparato 4. </li><li> Preparar 4 L de Krebs Henseleit modificado Buffer (en mM: 112 NaCl, 5 KCl, 1,2 MgSO 4, 1 K 2 HPO 4, 1,25 CaCl 2, 25 NaHCO 3, 11 D-glucosa, 0.2 ácido octanoico, pH = 7,4). <ol><li> Hacer 10x buffers de valores. <ol><li> Disolver NaCl, KCl, MgSO 4, y K 2 HPO 4 en 3 L de agua ultrapura. </li><li> Disolver CaCl 2 en 500 ml de agua ultrapura wiTH 40 ml de HCl 1 N. </li><li> Agregue lentamente solución de CaCl2 al búfer hecho en 1.2.1.1. Agregar suficiente agua ultrapura a un total de 4 L. Permitir agitar durante 1 hora antes de filtrar a través de un filtro de 0,8 micras. Almacenar a 4 ° C. </li><li> Disolver NaHCO3 en 4 L de agua ultrapura. Dejar en agitación durante 1 hr antes de filtrar a través de al 0.8 micras filtro. Almacenar a 4 ° C </li></ol></li><li> Combinar 400 ml de 10x tampón de Krebs Henseleit con NaHCO tampón 400 ml de 10x 3. Agregar suficiente agua ultrapura a un total de 4 L. Disolver la glucosa y ácido octanoico mientras se agita. Filtrar a través de 0,8 micras filtro. </li></ol></li><li> Sistema de Preparación para el corazón. <ol><li> Añadir 2 L de tampón se filtró a una botella de 4 L colocados por encima de 38 en la llave de paso unido a la cánula aórtica. Esto entregar una presión de perfusión de 70-80 mm de Hg para el corazón, que es la presión de perfusión recomendado 4. </li><li> Inserte gas dispersión de burbujeo en el búfer en la botella. </li><li> Ejecutar el tampón a través del sistema, asegurándose de eliminar cualquier burbuja desde el interior de la tubería. </li><li> Encienda gas (95% O 2/5% de CO 2) al menos 30 min antes de corazón se va a colocar en el sistema. Use una sonda de flujo de gas y el analizador de gases en sangre para verificar la saturación de oxígeno. </li></ol></li><li> Preparar material quirúrgico y globo. <ol><li> Para la recolección de corazón, preparar un par de 6.75 &quot;tijeras quirúrgicas, un par de 4.5&quot; tijeras, dos pares de pinzas, dos juegos de pinzas caramalt, dos jeringas con agujas de 27 G, 2 piezas de sutura de seda 0 de calibre (alrededor de 15 cm de longitud), una cánula de púas 1/16 pulgadas, y una cánula traqueal. </li><li> Para el montaje de cánula traqueal, pegar un pequeño trozo de tubo de plástico de diámetro 1/16 pulgada a un conector. </li><li> Para montar un aparato de balón: adjuntar una aguja de sonda a un trozo de tubo de 1/16 pulgadas, a continuación, conecte la tubería a la vivienda transductor de presión. Una pequeña jeringa unida al otro lado de la presión transducer vivienda permitirá la inflación y la deflación del balón. <ol><li> Corte un cuadrado de abrigo y lugar punta de plástico de una aguja sonda en el centro. Envuelva la envoltura de plástico alrededor de la aguja sonda. </li><li> Rellene el globo con solución salina y atar con dos suturas. Inflar el globo para asegurar que no haya fugas. El volumen de solución salina dentro del balón inflado debe ser aproximadamente 200 l, pero puede variar dependiendo del tamaño de la rata. </li><li> También puede utilizar un dedil de látex en lugar de la envoltura de plástico. Coloque la aguja sonda dentro dedil, rellenar con solución salina y atar. </li></ol></li></ol></li></ol> 2. Cosecha el corazón <ol><li> Restringir una rata Sprague Dawley utilizando un decapicone u otro dispositivo de sujeción manual. Pesar rata. </li><li> Administrar ketamina / xilazina mezcla (0,85 mg / kg de ketamina y 0,15 mg / kg de xilazina) mediante inyección intraperitoneal para anestesiar la rata. Esta dosis de anestésico proporcionará suficientes para anestesia20-40 min, pero el procedimiento debe completarse lo antes posible después de que se confirmó la anestesia. </li><li> Confirme grado adecuado de anestesia mediante pruebas toe pizca reflejo. </li><li> Traqueotomía <ol><li> Retire piel desde mediados de pata a la base de la mandíbula, usando pinzas para elevar piel y tijeras para hacer la incisión. Mantenga la piel elevado a separarlo del músculo subyacente, que permite una para cortar a lo largo de la piel y retírela. </li><li> Usando pinzas hemostáticas, levantar el tejido glandular y hacer una incisión horizontal en la fascia inferior al tejido glandular. Utilice pinzas para difundir incisión abierta, teniendo cuidado de no cortar las venas yugulares. </li><li> Usando pinzas hemostáticas, músculo pizca superpuestos tráquea, y el uso de las tijeras hacen una incisión transversal en el músculo justo debajo de la punta de las pinzas hemostáticas. Usando pinzas hemostáticas, se extendió el tejido aparte de revelar tráquea. </li><li> Inserte cuidadosamente hemostatos bajo tráquea, despejando fascia mientras progresa avanzando suavemente y retraer hemostáticos. </li><li>Una vez hemostáticos se colocan con éxito detrás de la tráquea, pellizcar 0-0 sutura de seda con pinzas hemostáticas y hemisect la tráquea con un pequeño par de tijeras afiladas,. </li><li> Insertar cánula traqueal en la tráquea hemiseccionaron, tire de la sutura detrás de la tráquea, y atar la sutura alrededor de la tráquea canulado, el anclaje de la sutura a la Y-ingle de la cánula con un nudo cirujanos. </li><li> Usando una aguja 27 G, inyectar 1.000 U / kg de heparina en la vena yugular y permitir a circular para 30 seg. </li></ol></li><li> La toracotomía <ol><li> Retire piel desde mediados de abdomen a la región a mediados de pata pellizcando con pinzas hemostáticas y cortar con tijeras. </li><li> Hacer una incisión transversal pulgadas ¾ en la pared muscular del abdomen, justo por debajo del diafragma. </li><li> Hacer una incisión vertical hasta la pared y en el pecho de la pared abdominal, el corte a lo largo del esternón. </li><li> Cortar el diafragma hacia atrás de forma bilateral, luego se extendió la caja torácica para revelar el corazón, costillas de sujeción con pinzas hemostáticas para asegurar que sigue siendo propagación. </li&gt; <li> Utilizando pinzas, retire con cuidado el timo, la exposición de la aorta ascendente. </li><li> Tease hemostatos a través del bucle de la aorta, de avance y retroceso hemostáticos y suavemente difusión fascia para permitir punta de pinzas a través. </li><li> Utilice pinzas para tirar de 0-0 sutura de seda detrás de la aorta ascendente, la corbata de sutura en un medio cuadrado nudo flojo. </li><li> Gire la llave de paso para iniciar el flujo de tampón de perfusión, la aorta hemisect e inmediatamente inserte cánula en luz aórtica. Rápidamente cincha un nudo de media plaza y completar el nudo, apretar a fondo. </li><li> Use las tijeras para diseccionar corazón lejos de los grandes vasos, quite el corazón del pecho y adjuntar a la columna de la perfusión. </li><li> Recorte el exceso de tejido pulmonar y permitir que el corazón se equilibre en la columna durante aproximadamente 15 min antes de la inserción del globo. Utilice un caudal normal de búfer a través del corazón de 10 a 20 ml / min. </li></ol></li></ol> 3. Langendorff de perfusión e isquemia reperfusión <ol><li> La colocación de LV preglobo fisura <ol><li> Desinflar globo mientras rueda en forma de cono y gire la llave de paso para asegurar globo permanece desinflado. </li><li> Impuestos Especiales dejó atrio con un pequeño par de tijeras para exponer el acceso a la válvula mitral. </li><li> Inserte globo a través de la aurícula izquierda y la válvula mitral hacia el ventrículo izquierdo. </li><li> Inicie el software de control de presión (LabChart Pro). </li><li> Inflar el globo con la apertura de la llave de paso y suavemente creciente cantidad de solución salina en el globo hasta que la presión diastólica lectura de micromanómetro supera cero. </li><li> Para comprobar la respuesta longitud-tensión, inflar el globo lentamente a una presión diastólica de 75 mmHg, desinflarse lentamente, repetir una vez. </li><li> Establecer la presión diastólica a 10 mmHg mediante la modulación de la cantidad de solución salina en el globo. Gire la llave de paso para sellar el globo en este nivel de la inflación y mantener el sistema de presión cerrado entre el globo LV y transductor de presión. </li><li> Baja corazón en la cámara de cámara y cubierta climatizada con plástico. </li></ol></li><li> Una dministerio de isquemia reperfusión <ol><li> Enchufe el fondo de la cámara climatizada y permitir que la cámara se llene con tampón derramada. </li><li> Cuando tampón ha sumergido corazón, gire la llave de paso para detener el flujo de tampón en el corazón, la inducción de la isquemia global. El tiempo de isquemia puede variar dependiendo de los objetivos del experimento. </li><li> Después de 30 min de isquemia, gire la llave de paso para restaurar el flujo de tampón en el corazón, iniciando la reperfusión. </li><li> Permitir la reperfusión del corazón durante 1 hora antes de terminar el experimento. Utilice tiempos de reperfusión variables, dependiendo de los objetivos del experimento. </li></ol></li><li> La terminación del experimento y la recolección de Tejidos <ol><li> Uso de puerto lateral de la llave de paso, administrar 10 ml de salina tamponada con fosfato a 4 ° C en el corazón a una velocidad de 10 ml / min para parar el corazón. </li><li> Quite el corazón de la columna de la perfusión, recortar restante tejido auricular. </li><li> Coloque corazón en una matriz de corte de tejido de acero inoxidable, cubrir con Parafilm y lugar a -80 ° C durante 8 minutos, o hasta que el corazón tiene una consistencia como la melcocha. </li><li> Retire el bloque del congelador e insertar hojas de afeitar en la matriz de cortar para cortar corazón en rodajas 2 mm. Bloques de tejidos también pueden ser comprados con tamaños rebanada distintos de 2 mm. </li><li> Retire las rebanadas una a la vez y soltar en nitrógeno líquido para congelar parpadear para estudios bioquímicos. Conserve la tercera rebanada ventricular desde el vértice para la tinción del infarto. </li><li> Retire el tejido de nitrógeno líquido y se almacena a -80 ° C hasta su uso en experimentos bioquímicos. </li></ol></li><li> Infarto de tinción <ol><li> Incubar la tercera rebanada ventricular en 10 ml de 1% w / v de cloruro de trifeniltetrazolio (TTC) a 37 ° C durante 15 min. Nota: La incubación en TTC se puede realizar para 15 o 30 min sin cambio en la eficacia 15. </li><li> Transferencia rebanada de tejido de TTC a 10% de formalina tamponada y se deja incubar a temperatura ambiente durante la noche. Para obtener resultados óptimos, escucharts deben ser sacados de formol y la imagen dentro de 24 horas 4. </li><li> Fotografía manchado software rebanada y el uso como ImageJ para estimar el tamaño del infarto según el protocolo del fabricante. Tome fotografías tan pronto como sea posible después de la fijación, ya que el tinte se desvanecerá con el tiempo. </li></ol></li></ol>

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The authors declare that they have no competing financial interests.

El corazón aislado y perfundido de rata puede ser utilizado con éxito para estudiar el efecto de la intervención farmacológica en el precondicionamiento cardíaco en la isquemia reperfusión 9. Sin embargo, hay algunos pasos esenciales para el procedimiento que debe ser estandarizada con el fin de asegurar resultados reproducibles. El mantenimiento de una temperatura de 37,4 ° C dentro del sistema es crítica, ya que incluso la hipotermia leve y la hipertermia pueden causar preacondicionamiento cardíaco...

La elucidación de los hechos que subyacen a la respuesta cardiaca tanto la isquemia y la reperfusión es esencial para mejorar el tratamiento del infarto de 1 y cardíacas procedimientos quirúrgicos miocardio que requieren pinzamiento aórtico 2. Mientras que los modelos in vivo de la lesión de reperfusión de isquemia permiten el análisis de punto final muy útiles, no son tan eficaces para el estudio de los efectos funcionales de la lesión de reperfusión de isquemia aguda en tiempo real. Además, en modelos de isquemia reperfusión in vivo generalmente producen variabilidad significativa en el tamaño del infarto, y la entrega directa de medicamento para el corazón en el momento de la reperfusión es un reto. La utilización de un sistema de corazón Langendorff aislados para el estudio de la lesión de reperfusión de isquemia permite una evaluación funcional en tiempo real de los tratamientos farmacológicos, área uniforme de tejido infartado, y la entrega instantánea del fármaco directamente al miocardio. En primer lugar se describe by Oscar Langendorff en 1895 3, el corazón Langendorff aislado es un modelo robusto para el estudio de la lesión por isquemia-reperfusión, después de haber sido utilizado en la investigación de isquemia reperfusión durante los últimos 40 años 4,5. Aquí, se hacen algunas modificaciones para optimizar el corazón aislado para el análisis funcional. En la canulación situ de la aorta mientras el corazón está latiendo asegura que el corazón no experimenta precondicionamiento isquémico que pudieran alterar los resultados de los ensayos de reperfusión isquemia 6. Para facilitar esto, se realiza una traqueotomía, lo que permite la ventilación y garantizar la estabilidad fisiológica de la rata durante la cirugía. El corazón luego se une a una columna con camisa de agua espiral de vidrio a través del cual tampón de Krebs Henseleit se entrega a través de perfusión retrógrada directamente en la aorta. Un globo lleno de solución salina se inserta en el ventrículo izquierdo y unido a un transductor de presión, que permite la medición en tiempo real de las presiones desde dentro de la una ventrículod cálculo de varios parámetros funcionales. A la conclusión del experimento, el corazón se lava con solución salina fría para detener la contracción y flash congelado en nitrógeno líquido para permitir el análisis aguas abajo de los niveles de ADN, ARN y proteínas. Por lo tanto modificado, el corazón Langendorff perfundidos sirve como un sistema eficaz para la supervisión directa del efecto fisiológico de las intervenciones farmacológicas en cualquier momento de forma aguda durante la lesión por isquemia y reperfusión.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Sodium Chloride</td>
			<td>Sigma Aldrich</td>
			<td>S3014</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium Chloride</td>
			<td>Sigma Aldrich</td>
			<td>P9541</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium Sulfate</td>
			<td>Sigma Aldrich</td>
			<td align="right">203726</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium Phosphate Dibasic</td>
			<td>Sigma Aldrich</td>
			<td>RES20765-A7</td>
			<td></td>
		</tr>
		<tr>
			<td>Calcium Chloride Dihydrate</td>
			<td>Sigma Aldrich</td>
			<td>C8106</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Bicarbonate</td>
			<td>Sigma Aldrich</td>
			<td>S5761</td>
			<td></td>
		</tr>
		<tr>
			<td>D-Glucose</td>
			<td>Sigma Aldrich</td>
			<td>G8270</td>
			<td></td>
		</tr>
		<tr>
			<td>Octanoic Acid</td>
			<td>Sigma Aldrich</td>
			<td>C2875</td>
			<td></td>
		</tr>
		<tr>
			<td>2,3,5-triphenyltetrazolium chloride</td>
			<td>Sigma Aldrich</td>
			<td>T8877</td>
			<td></td>
		</tr>
		<tr>
			<td>Medical Pressure Transducer</td>
			<td>MEMSCAP</td>
			<td>SP844</td>
			<td></td>
		</tr>
		<tr>
			<td>Masterflex Peristaltic Pump</td>
			<td>Cole Parmer</td>
			<td>EW-07521-40</td>
			<td></td>
		</tr>
		<tr>
			<td>Masterflex Easy Load Pump Head</td>
			<td>Cole Parmer</td>
			<td>EW-07518-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Heated circulating water bath</td>
			<td>Lauda</td>
			<td>M3</td>
			<td></td>
		</tr>
		<tr>
			<td>Tubing Flow Module</td>
			<td>Transonic</td>
			<td>TS410</td>
			<td></td>
		</tr>
		<tr>
			<td>Modular Research Console</td>
			<td>Transonic</td>
			<td>T402</td>
			<td></td>
		</tr>
		<tr>
			<td>Inline flow sensor</td>
			<td>Transonic</td>
			<td>ME2PXN</td>
			<td></td>
		</tr>
		<tr>
			<td>PowerLab Data Acquisition Device</td>
			<td>AD Instruments</td>
			<td>PL3508</td>
			<td></td>
		</tr>
		<tr>
			<td>LabChart data acquisition software</td>
			<td>AD Instruments</td>
			<td>MLU60/8</td>
			<td></td>
		</tr>
	</tbody>
</table>

induction and assessment of ischemia-reperfusion injury in langendorff-perfused rat hearts

The biochemical events surrounding ischemia reperfusion injury in the acute setting are of great importance to furthering novel treatment options for myocardial infarction and cardiac complications of thoracic surgery. The ability of certain drugs to precondition the myocardium against ischemia reperfusion injury has led to multiple clinical trials, with little success. The isolated heart model allows acute observation of the functional effects of ischemia reperfusion injury in real time, including the effects of various pharmacological interventions administered at any time-point before or within the ischemia-reperfusion injury window. Since brief periods of ischemia can precondition the heart against ischemic injury, in situ aortic cannulation is performed to allow for functional assessment of non-preconditioned myocardium. A saline filled balloon is placed into the left ventricle to allow for real-time measurement of pressure generation. Ischemic injury is simulated by the cessation of perfusion buffer flow, followed by reperfusion. The duration of both ischemia and reperfusion can be modulated to examine biochemical events at any given time-point. Although the Langendorff isolated heart model does not allow for the consideration of systemic events affecting ischemia and reperfusion, it is an excellent model for the examination of acute functional and biochemical events within the window of ischemia reperfusion injury as well as the effect of pharmacological intervention on cardiac pre- and postconditioning. The goal of this protocol is to demonstrate how to perform in situ aortic cannulation and heart excision followed by ischemia/reperfusion injury in the Langendorff model.

El aparato de balón del ventrículo izquierdo permite la monitorización en tiempo real de la presión desarrollada por la contratación del ventrículo izquierdo (Figura 1). Como se ha descrito previamente 7, esta traza de presión puede ser usada para calcular muchos de los parámetros de la función ventricular. Estos cálculos pueden realizarse en la fase de línea de base, así como la fase de reperfusión, promediados sobre múltiples trazas dentro de cada grupo, y se compararon con el...

Watch this Scientific Journal Video about Induction and Assessment of Ischemia-reperfusion Injury in Langendorff-perfused Rat Hearts at JoVE.com

Induction and Assessment of Ischemia-reperfusion Injury in Langendorff-perfused Rat Hearts

The isolated rat heart is an enduring model for ischemia reperfusion injury. Here, we describe the process of harvesting the beating heart from a rat via in situ aortic cannulation, Langendorff perfusion of the heart, simulated ischemia-reperfusion injury, and infarct staining to confirm the extent of ischemic insult.

Inducción y Evaluación de la isquemia-reperfusión en perfundidos Langendorff corazones de ratas

The biochemical events surrounding ischemia reperfusion injury in the acute setting are of great importance to furthering novel treatment options for ...

induction-assessment-ischemia-reperfusion-injury-langendorff-perfused

Research

JoVE Journal

Medicine

22.6K vistas.  Medical University of South Carolina. The isolated rat heart is an enduring model for ischemia reperfusion injury. Here, we describe the process of harvesting the beating heart from a rat via in situ aortic cannulation, Langendorff perfusion of the heart, simulated ischemia-reperfusion injury, and infarct staining to confirm the extent of ischemic insult.

Video: Induction and Assessment of Ischemia-reperfusion Injury in Langendorff-perfused Rat Hearts

Real-time Digital Imaging of Leukocyte-endothelial Interaction in Ischemia-reperfusion Injury (IRI) of the Rat Cremaster Muscle

Ischemia-reperfusion injury (IRI) has been implicated in a large array of pathological conditions such as cerebral stroke, myocardial infarction, intestinal ischemia as well as following transplant and cardiovascular surgery.1 Reperfusion of previously ischemic tissue, while essential for the prevention of irreversible tissue injury, elicits excessive inflammation of the affected tissue. Adjacent to the production of reactive oxygen species, activation of the complement system and increased microvascular permeability, the activation of leukocytes is one of the principle actors in the pathological cascade of inflammatory tissue damage during reperfusion.2, 3 Leukocyte activation is a multistep process consisting of rolling, firm adhesion and transmigration and is mediated by a complex interaction between adhesion molecules in response to chemoattractants such as complement factors, chemokines, or platelet-activating factor.4
While leukocyte rolling in postcapillary venules is predominantly mediated by the interaction of selectins5 with their counter ligands, firm adhesion of leukocytes to the endothelium is selectin-controlled via binding to intercellular adhesion molecules (ICAM) and vascular cellular adhesion molecules (VCAM).6, 7 
Gold standard for the in vivo observation of leukocyte-endothelial interaction is the technique of intravital microscopy, first described in 1968.8
Though various models of IRI (ischemia-reperfusion injury) have been described for various organs, 9-12 only few are suitable for direct visualization of leukocyte recruitment in the microvascular bed on a high level of image quality.8 
We here promote the digital intravital epifluorescence microscopy of the postcapillary venule in the cremasteric microcirculation of the rat 13 as a convenient method to qualitatively and quantitatively analyze leukocyte recruitment for IRI-research in striated muscle tissue and provide a detailed manual for accomplishing the technique. We further illustrate common pitfalls and provide useful tips which should enable the reader to truly appreciate, and safely perform the method.
In a step by step protocol we depict how to get started with respiration controlled anesthesia under sufficient monitoring to keep the animal firmly anesthetized for longer periods of time. We then describe the cremasteric preparation as a thin flat sheet for outstanding optical resolution and provide a protocol for leukocyte imaging in IRI that has been well established in our laboratories.

Real-time Digital Imaging of Leukocyte-endothelial Interaction in Ischemia-reperfusion Injury IRI of the Rat Cremaster Muscle

Digital intravital epifluorescence microscopy of postcapillary venules in the cremasteric microcirculation is a convenient method to gain insights into leukocyte-endothelial interaction in vivo in ischemia-reperfusion injury (IRI) of striated muscle tissue. We here provide a detailed protocol to safely perform the technique and discuss its applications and limitations.

En tiempo real de imágenes digitales de los leucocitos del endotelio interacción en el daño por isquemia-reperfusión (IRI) del músculo cremáster Rata

Ischemia-reperfusion injury (IRI) has been implicated in a large array of pathological conditions such as cerebral stroke, myocardial infarction, ...

Investigación

Medicina

In situ Transverse Rectus Abdominis Myocutaneous Flap: A Rat Model of Myocutaneous Ischemia Reperfusion Injury

Free tissue transfer is the gold standard of reconstructive surgery to repair complex defects not amenable to local options or those requiring composite tissue. Ischemia reperfusion injury (IRI) is a known cause of partial free flap failure and has no effective treatment. Establishing a laboratory model of this injury can prove costly both financially as larger mammals are conventionally used and in the expertise required by the technical difficulty of these procedures typically requires employing an experienced microsurgeon. This publication and video demonstrate the effective use of a model of IRI in rats which does not require microsurgical expertise. This procedure is an in situ model of a transverse abdominis myocutaneous (TRAM) flap where atraumatic clamps are utilized to reproduce the ischemia-reperfusion injury associated with this surgery. A laser Doppler Imaging (LDI) scanner is employed to assess flap perfusion and the image processing software, Image J to assess percentage area skin survival as a primary outcome measure of injury.

In situ Transverse Rectus Abdominis Myocutaneous Flap: A Rat Model of Myocutaneous Ischemia Reperfusion Injury

Free tissue transfer is widely employed in reconstructive surgery to restore form and function following oncological resection and trauma. Preconditioning this tissue prior to surgery may improve outcome. This article describes an in situ transverse rectus abdominis myocutaneous flap (TRAM) in rats as a means for testing preconditioning strategies.

In situ recto abdominal transverso colgajo miocutáneo: un modelo de rata de miocutáneo isquemia reperfusión

Free tissue transfer is the gold standard of reconstructive surgery to repair complex defects not amenable to local options or those requiring composite ...

Ischemia-reperfusion Model of Acute Kidney Injury and Post Injury Fibrosis in Mice

Ischemia-reperfusion induced acute kidney injury (IR-AKI) is widely used as a model of AKI in mice, but results are often quite variable with high, often unreported mortality rates that may confound analyses. Bilateral renal pedicle clamping is commonly used to induce IR-AKI, but differences between effective clamp pressures and/or renal responses to ischemia between kidneys often lead to more variable results. In addition, shorter clamp times are known to induce more variable tubular injury, and while mice undergoing bilateral injury with longer clamp times develop more consistent tubular injury, they often die within the first 3 days after injury due to severe renal insufficiency. To improve post-injury survival and obtain more consistent and predictable results, we have developed two models of unilateral ischemia-reperfusion injury followed by contralateral nephrectomy. Both surgeries are performed using a dorsal approach, reducing surgical stress resulting from ventral laparotomy, commonly used for mouse IR-AKI surgeries. For induction of moderate injury BALB/c mice undergo unilateral clamping of the renal pedicle for 26 min and also undergo simultaneous contralateral nephrectomy. Using this approach, 50-60% of mice develop moderate AKI 24 hr after injury but 90-100% of mice survive. To induce more severe AKI, BALB/c mice undergo renal pedicle clamping for 30 min followed by contralateral nephrectomy 8 days after injury. This allows functional assessment of renal recovery after injury with 90-100% survival. Early post-injury tubular damage as well as post injury fibrosis are highly consistent using this model.

We describe models of moderate and severe ischemia-reperfusion-induced kidney injury in which the mice undergo unilateral renal pedicle clamping followed by simultaneous or delayed contralateral nephrectomy, respectively. These models consistently give rise to renal dysfunction and post-injury fibrosis, but injury severity and survival are dependent on mouse background, age and surgical equipment.

La isquemia-reperfusión modelo de lesión renal aguda y post lesión fibrosis en ratones

Ischemia-reperfusion induced acute kidney injury (IR-AKI) is widely used as a model of AKI in mice, but results are often quite variable with high, often ...

Murine Model of Intestinal Ischemia-reperfusion Injury

Intestinal ischemia is a life-threatening condition associated with a broad range of clinical conditions including atherosclerosis, thrombosis, hypotension, necrotizing enterocolitis, bowel transplantation, trauma and chronic inflammation. Intestinal ischemia-reperfusion (IR) injury is a consequence of acute mesenteric ischemia, caused by inadequate blood flow through the mesenteric vessels, resulting in intestinal damage. Reperfusion following ischemia can further exacerbate damage of the intestine. The mechanisms of IR injury are complex and poorly understood. Therefore, experimental small animal models are critical for understanding the pathophysiology of IR injury and the development of novel therapies.
Here we describe a mouse model of acute intestinal IR injury that provides reproducible injury of the small intestine without mortality. This is achieved by inducing ischemia in the region of the distal ileum by temporally occluding the peripheral and terminal collateral branches of the superior mesenteric artery for 60 min using microvascular clips. Reperfusion for 1 hr, or 2 hr after injury results in reproducible injury of the intestine examined by histological analysis. Proper position of the microvascular clips is critical for the procedure. Therefore the video clip provides a detailed visual step-by-step description of this technique. This model of intestinal IR injury can be utilized to study the cellular and molecular mechanisms of injury and regeneration.

Here we describe the detailed procedure of intestinal ischemia-reperfusion in mice which results in reproducible injury without mortality to encourage the standardization of this technique across the field. This model of intestinal ischemia-reperfusion injury can be utilized to study the cellular and molecular mechanisms of injury and regeneration.

Modelo murino de isquemia-reperfusión intestinal Lesiones

Intestinal ischemia is a life-threatening condition associated with a broad range of clinical conditions including atherosclerosis, thrombosis, ...

Evaluation of Coronary Flow Reserve After Myocardial Ischemia Reperfusion in Rats

Coronary artery disease is the leading cause of death worldwide. After an acute myocardial infarction, early and successful myocardial intervention via recanalization of the coronary artery is the most effective strategy for reducing the size of ischemic myocardium. The coronary microvasculature cannot be visualized and imaged&#160;in vivo, but there are several invasive and noninvasive techniques that can be used to assess parameters which depend directly on coronary microvascular function. The endothelial function after ischemia reperfusion can be assessed also at the level of the coronary circulation via the coronary flow reserve (CFR).&#160;In this study, peak velocity of left anterior descending (LAD) coronary arteries was measured in rats in vivo via Transthoracic Doppler Echocardiography during resting and stress challenge (induced by Dobutamine). A normal heart can increase its coronary blood flow up to four times above the resting values during stress induction. Following ischemia reperfusion, we found a significantly diminished CFR, which can be used as a marker of coronary microvascular dysfunction. CFR has opened a window on the importance of microvascular dysfunction and has been shown to predict cardiovascular risk independent of whether the severe obstructive disease is present.

Coronary flow reserve (CFR), is defined as the ratio of maximal coronary blood flow to the resting coronary blood flow. We present a protocol for evaluating CFR in rats via ultrasound, which offers the opportunity to predict cardiovascular risk factors in the absence of obstructive coronary disease.

Evaluación de la Reserva de Flujo Coronario Después de la Reperfusión de Isquemia Miocárdica en Ratas

Coronary artery disease is the leading cause of death worldwide. After an acute myocardial infarction, early and successful myocardial intervention via ...

A Pre-clinical Rat Model for the Study of Ischemia-reperfusion Injury in Reconstructive Microsurgery

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many areas of biomedical research due to its cost-effectiveness and its translation to humans. This protocol describes a method to create a preclinical free skin flap model in rats with ischemia-reperfusion injury. The described 3 cm x 6 cm rat free skin flap model is easily obtained after the placement of several vascular ligatures and the section of the vascular pedicle. Then, 8 h after the ischemic insult and completion of the microsurgical anastomosis, the free skin flap develops the tissue damage. These ischemia-reperfusion injury-related damages can be studied in this model, making it a suitable model for evaluating therapeutic agents to address this pathophysiological process. Furthermore, two main monitoring techniques are described in the protocol for the assessment of this animal model: transit-time ultrasound technology and laser speckle contrast analysis.

Here, we describe a pre-clinical animal model for studying the pathophysiology of ischemia-reperfusion injury in reconstructive microsurgery. This free skin flap model based on the superficial caudal epigastric vessels in the rat may also allow for the evaluation of different therapies and compounds to counteract ischemia-reperfusion injury-related damage.

Un modelo preclínico de rata para el estudio de la lesión por isquemia-reperfusión en microcirugía reconstructiva

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many ...

Optocardiography and Electrophysiology Studies of Ex Vivo Langendorff-perfused Hearts

Small animal models are most commonly used in cardiovascular research due to the availability of genetically modified species and lower cost compared to larger animals. Yet, larger mammals are better suited for translational research questions related to normal cardiac physiology, pathophysiology, and preclinical testing of therapeutic agents. To overcome the technical barriers associated with employing a larger animal model in cardiac research, we describe an approach to measure physiological parameters in an isolated, Langendorff-perfused piglet heart. This approach combines two powerful experimental tools to evaluate the state of the heart: electrophysiology (EP) study and simultaneous optical mapping of transmembrane voltage and intracellular calcium using parameter sensitive dyes (RH237, Rhod2-AM). The described methodologies are well suited for translational studies investigating the cardiac conduction system, alterations in action potential morphology, calcium handling, excitation-contraction coupling and the incidence of cardiac alternans or arrhythmias.

The objective of this study was to establish a method for investigating cardiac dynamics using a translational animal model. The described experimental approach incorporates dual-emission optocardiography in conjunction with an electrophysiological study to assess electrical activity in an isolated, intact porcine heart model.

Estudios de Optocardiografía y Electrofisiología de Corazones Perfundidos Ex Vivo Langendorff

Small animal models are most commonly used in cardiovascular research due to the availability of genetically modified species and lower cost compared to ...

Delayed Intramyocardial Delivery of Stem Cells after Ischemia Reperfusion Injury in a Murine Model

There is significant interest in the use of stem cells (SCs) for the recovery of cardiac function in individuals with myocardial injuries. Most commonly, cardiac stem cell therapy is studied by delivering SCs concurrently with the induction of myocardial injury. However, this approach presents two significant limitations: the early hostile pro-inflammatory ischemic environment may affect the survival of transplanted SCs, and it does not represent the subacute infarction scenario where SCs will likely be used. Here we describe a two-part series of surgical procedures for the induction of ischemia-reperfusion injury and delivery of mesenchymal stem cells (MSCs). This method of stem cell administration may allow for the longer viability and retention around damaged tissue by circumventing the initial immune response. A model of ischemia reperfusion injury was induced in mice accompanied by the delivery of mesenchymal stem cells (3.0 x 105), stably expressing the reporter gene firefly luciferase under the constitutively expressed CMV promoter, intramyocardially 7 days later. The animals were imaged via ultrasound and bioluminescent imaging for confirmation of injury and injection of cells, respectively. Importantly, there was no added complication rate when performing this two-procedure approach for SC delivery. This method of stem cell administration, collectively with the utilization of state-of-the-art reporter genes, may allow for the in vivo study of viability and retention of transplanted SCs in a situation of chronic ischemia commonly seen clinically, while also circumventing the initial pro-inflammatory response. In summary, we established a protocol for the delayed delivery of stem cells into the myocardium, which can be used as a potential new approach in promoting regeneration of the damaged tissue.

Stems cells are continuously investigated as potential treatments for individuals with myocardial damage, however, their decreased viability and retention within injured tissue can impact their long-term efficacy. In this manuscript we describe an alternative method for stem cell delivery in a murine model of ischemia reperfusion injury.

Retraso en la administración intramiocardio de células madre después de la lesión por reperfusión de isquemia en un modelo murino

There is significant interest in the use of stem cells (SCs) for the recovery of cardiac function in individuals with myocardial injuries. Most commonly, ...

Organ Ischemia-Reperfusion Injury by Simulating Hemodynamic Changes in Rat Liver Transplant Model

Orthotopic liver transplantation (OLT) in rats is a tried and proven animal model used for preoperative, intraoperative, and postoperative studies, including ischemia-reperfusion injury (IRI) of extrahepatic organs. This model requires numerous experiments and devices. The duration of anhepatic phase is closely related to the time to develop IRI after transplantation. In this experiment, we used hemodynamic changes to induce extrahepatic organ damage in rats and determined the maximum tolerance time. The time until the most severe organ injury varied for different organs. This method can easily be replicated and can also be used to study IRI of the extrahepatic organs after liver transplantation.

This paper provides a detailed description of how to build an animal model of the anhepatic phase (liver ischemia) in rats to facilitate basic research into ischemia-reperfusion injury after liver transplantation.

Lesión de isquemia-reperfusión de órganos mediante la simulación de cambios hemodinámicos en el modelo de trasplante de hígado de rata

Orthotopic liver transplantation (OLT) in rats is a tried and proven animal model used for preoperative, intraoperative, and postoperative studies, ...

Real-Time Assessment of Spinal Cord Microperfusion in a Porcine Model of Ischemia/Reperfusion

Spinal cord injury is a devastating complication of aortic repair. Despite developments for the prevention and treatment of spinal cord injury, its incidence is still considerably high and therefore, influences patient outcome. Microcirculation plays a key role in tissue perfusion and oxygen supply and is often dissociated from macrohemodynamics. Thus, direct evaluation of spinal cord microcirculation is essential for the development of microcirculation-targeted therapies and the evaluation of existing approaches in regard to spinal cord microcirculation. However, most of the methods do not provide real-time assessment of spinal cord microcirculation. The aim of this study is to describe a standardized protocol for real-time spinal cord microcirculatory evaluation using laser-Doppler needle probes directly inserted in the spinal cord. We used a porcine model of ischemia/reperfusion to induce deterioration of the spinal cord microcirculation. In addition, a fluorescent microsphere injection technique was used. Initially, animals were anesthetized and mechanically ventilated. Thereafter, laser-Doppler needle probe insertion was performed, followed by the placement of cerebrospinal fluid drainage. A median sternotomy was performed for exposure of the descending aorta to perform aortic cross-clamping. Ischemia/reperfusion was induced by supra-celiac aortic cross-clamping for a total of 48 min, followed by reperfusion and hemodynamic stabilization. Laser-Doppler Flux was performed in parallel with macrohemodynamic evaluation. In addition, automated cerebrospinal fluid drainage was used to maintain a stable cerebrospinal pressure. After completion of the protocol, animals were sacrificed, and the spinal cord was harvested for histopathological and microsphere analysis. The protocol reveals the feasibility of spinal cord microperfusion measurements using laser-Doppler probes and shows a marked decrease during ischemia as well as recovery after reperfusion. Results showed comparable behavior to fluorescent microsphere evaluation. In conclusion, this new protocol might provide a useful large animal model for future studies using real-time spinal cord microperfusion assessment in ischemia/reperfusion conditions.

Spinal cord microcirculation plays a pivotal role in spinal cord injury. Most methods do not allow real-time assessment of spinal cord microcirculation, which is essential for the development of microcirculation-targeted therapies. Here, we propose a protocol using Laser-Doppler-Flow Needle probes in a large animal model of ischemia/reperfusion.

Evaluación en tiempo real de la microperfusión de la médula espinal en un modelo porcino de isquemia/reperfusión

Spinal cord injury is a devastating complication of aortic repair. Despite developments for the prevention and treatment of spinal cord injury, its ...