Name: long-term blood pressure measurement in freely moving mice using telemetry
Uploaded: 2016-05-17T14:00:00.000+00:00
Duration: 7 min 54 s
Description: Watch this Scientific Journal Video about Long-term Blood Pressure Measurement in Freely Moving Mice Using Telemetry at JoVE.com

This work was supported by the National Institutes of Health (NIH/NHLBI) [Grant no. HL114869] and the support from UTHSC to SM.

Ética declaración: Todos los animales procedimientos mencionados en este video-artículo fueron revisados ​​y aprobados por el Comité de Cuidado y Uso de Animales (IACUC) de la Universidad de Tennessee Centro de Ciencias de la Salud. Nota: Utilice instrumentos de microcirugía estériles durante todo el procedimiento quirúrgico. Los instrumentos quirúrgicos pueden esterilizarse utilizando un esterilizador de infrarrojos a una temperatura de esterilización óptima de 1500 ° F (815,6 ° C). Telémetros pueden ser reutilizados, sin embargo, antes de insertarla en el animal asegurarse para esterilizar todo el transmisor de acuerdo con las instrucciones del fabricante y que la punta del catéter se ha rellenado con un gel especial proporcionado por el fabricante. 1. Los animales experimentales <ol><li> Obtener una aprobación del IACUC para todos los experimentos que se realizarán. La consulta con IACUC institucional es muy recomendable sobre los requisitos para el uso de analgésicos postoperatorios después de este procedimiento. </li><li> Mantener a los animales en csalas de lima-controlada que tienen una temperatura ambiente de 21 ° C, 60% de humedad relativa y un ciclo de luz-oscuridad de 12 horas con acceso libre a comida y agua. Nota: Debido a que el cuerpo del ratón tiene que acomodar la sonda de telemetría (aproximativamente 1 cm de diámetro x 2 cm de longitud), es preferible utilizar ratones que pesan 20 g o más. </li></ol> 2. Anestesia y preparación Operativo <ol><li> Pesar el ratón usando una balanza de precisión y registrar su peso. Asegúrese de manejar el animal suave y silenciosa. </li><li> Colocar el animal en la cámara de inducción y cerrarla. Ajuste del caudal de oxígeno a 0,5 L / min y la concentración de isoflurano al 4-5%. </li><li> Cuando el ratón se pierde la conciencia, colocarlo en una placa de calentamiento corporal se mantuvo a 36 - 37 ° C. Mantener la anestesia a través del cono de nariz con el conjunto de isoflurano al 2% (mantener el caudal a 0,5 l / min). </li><li> Preparar las regiones de operación mediante la eliminación del pelo de la parte posterior del cuello y tél cara ventral del cuello mediante la aplicación de crema de depilación. </li><li> Se trata el sitio de la incisión con 3 aplicaciones de lavado quirúrgico (solución de betadine) alternando con alcohol isopropílico al 70%. </li></ol> 3. Cirugía <ol><li> Coloque el ratón en una posición supina. Compruebe si hay reflejos pellizcando el pie, y ajustar la anestesia hasta que no haya respuesta. Realiza una de aproximadamente 1 cm de la línea media incisión por debajo del cuello del ratón con un bisturí. En el lado izquierdo de la corte de crear un espacio subcutáneo separando cuidadosamente la piel del tejido conectivo subyacente. </li><li> Da la vuelta al ratón, y el uso de un bisturí para hacer una incisión en la piel de aproximadamente 1,5 cm de la izquierda de la cara dorsal detrás de la escápula. Crear un bolsillo subcutáneo a lo largo del flanco del animal lo suficientemente grande para acomodar el dispositivo. Inserte el transmisor en el bolsillo. </li><li> Inserte una pequeña pinza pinza hemostática en la incisión hacia atrás y maniobrarlo subcutáneamente hacia la parte anteriorabertura del cuello. El uso de la pinza-pinza hemostática insertado, agarre suavemente un tubo de polietileno no tóxico (4 cm de largo x 1 mm de diámetro). <ol><li> Tire de la pinza a través del túnel a cabo la incisión lateral en la parte posterior hasta que el tubo sobresale de ambos incisión abdominal y dorsal, suelte el tubo de la pinza hemostática. Desde la parte posterior, inserte el sensor de catéter en el tubo de túnel de la punta del catéter de detección de presión a través del cuello. Desde la parte anterior del cuello, tirar y sacar el tubo de polietileno y cerrar la incisión dorsal mediante clips metálicos. </li></ol></li><li> separar cuidadosamente las glándulas mandibulares utilizando aplicadores con punta de algodón estéril y retraer la glándula mandibular izquierdo usando un gancho de estancia elástica. El uso de pinzas curvas de punta fina, localizar la arteria carótida a lo largo del lado izquierdo de la tráquea. Mantener el sitio quirúrgico estéril por colocar y asegurar un campo estéril. <ol><li> Con cuidado, aislar el vaso del tejido circundante y suavemente separar elnervio vago (de color blanquecino) que es a lo largo de la arteria carótida lejos de la arteria. Tenga cuidado de no cortar o dañar el nervio o la arteria. </li></ol></li><li> Pasar tres piezas de no absorbible 7-0 sutura debajo de la sección de la arteria carótida aislado. Atar la sutura craneal para cerrar el flujo de sangre. Tirar de la sutura que está más cerca del esternón para ocluir temporalmente el flujo de sangre de la aorta. </li><li> Hacer un nudo flojo usando la sutura media. Esto se utiliza para asegurar el catéter en el vaso. Cortar una pequeña incisión en la arteria entre el cráneo y las suturas del esternón utilizando micro-tijeras. </li><li> Agarrar el catéter con pinzas especiales de canulación buque, teniendo cuidado de no apretar el catéter para evitar la pérdida de gel de la sonda. Suavemente, agarra la arteria con una punta fina curvados fórceps pinzas, recuperar el catéter, y la inserta en el recipiente a través de la pequeña incisión. </li><li> Apretar el nodo de sutura media alrededor de la arteria y avanzar suavemente el gatoheter. liberar suavemente el hilo de sutura que está próximo al esternón y continuar avanzando el catéter hacia la aorta transversal. <ol><li> Observe la marca en el catéter que da un índice aproximado de hasta qué punto es necesario insertar el catéter. Una vez que se alcanza el punto, suavemente apriete tanto el hilo de sutura superior alrededor del catéter e inferior. El catéter se fija a la arteria carótida por los nudos de sutura. </li></ol></li><li> Cerrar la incisión de la piel con no absorbible 5-0 sutura. Una vez cerrado, sellar la incisión con adhesivo tisular. </li></ol> 4. Medidas de recuperación quirúrgicos y BP <ol><li> Vigilar estrechamente los animales para el retorno de posturas y comportamientos normales. Durante la 24 horas después de la cirugía de la analgesia periodo administrar según las indicaciones de un veterinario personal. </li><li> Una vez que los animales se han recuperado (5 - 7 días después de la cirugía), alojarlos individualmente en una jaula rectangular ratón colocado en la parte superior de la placa de receptor de telemetría. </li><li> Gire el tr implantadoansmitters &quot;on&quot; y &quot;off&quot; mediante el uso de un dispositivo magnético posicionados brevemente cerca del animal desde el exterior de la jaula. </li></ol>

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	<li>Danaei, G., 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=The+preventable+causes+of+death+in+the+United+States:+comparative+risk+assessment+of+dietary,+lifestyle,+and+metabolic+risk+factors.">The preventable causes of death in the United States: comparative risk assessment of dietary, lifestyle, and metabolic risk factors.</a> PLoS Med. 6 (4), e1000058 (2009).</li><li>Dornas, W. C., Silva, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+for+the+study+of+arterial+hypertension.">Animal models for the study of arterial hypertension.</a> J Biosci. 36 (4), 731-737 (2011).</li><li>Henze, M., 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=Persistent+alterations+in+heart+rate+variability,+baroreflex+sensitivity,+and+anxiety-like+behaviors+during+development+of+heart+failure+in+the+rat.">Persistent alterations in heart rate variability, baroreflex sensitivity, and anxiety-like behaviors during development of heart failure in the rat.</a> Am J Physiol Heart Circ Physiol. 295 (1), H29-H38 (2008).</li><li>Hoffmann, D. S., 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=Chronic+tempol+prevents+hypertension,+proteinuria,+and+poor+feto-placental+outcomes+in+BPH/5+mouse+model+of+preeclampsia.">Chronic tempol prevents hypertension, proteinuria, and poor feto-placental outcomes in BPH/5 mouse model of preeclampsia.</a> Hypertension. 51 (4), 1058-1065 (2008).</li><li>Lerman, L. O., Chade, A. R., Sica, V., Napoli, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+hypertension:+an+overview.">Animal models of hypertension: an overview.</a> J Lab Clin Med. 146 (3), 160-173 (2005).</li><li>Johns, C., Gavras, I., Handy, D. E., Salomao, A., Gavras, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Models+of+experimental+hypertension+in+mice.">Models of experimental hypertension in mice.</a> Hypertension. 28 (6), 1064-1069 (1996).</li><li>Vatner, S. F., Braunwald, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiovascular+control+mechanisms+in+the+conscious+state.">Cardiovascular control mechanisms in the conscious state.</a> N Engl J Med. 293 (19), 970-976 (1975).</li><li>Zhao, X., 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=Arterial+Pressure+Monitoring+in+Mice.">Arterial Pressure Monitoring in Mice.</a> Curr Protoc Mouse Biol. 1, 105-122 (2011).</li><li>Whitesall, S. E., Hoff, J. B., Vollmer, A. P., D'Alecy, L. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+simultaneous+measurement+of+mouse+systolic+arterial+blood+pressure+by+radiotelemetry+and+tail-cuff+methods.">Comparison of simultaneous measurement of mouse systolic arterial blood pressure by radiotelemetry and tail-cuff methods.</a> Am J Physiol Heart Circ Physiol. 286 (6), H2408-H2415 (2004).</li><li>Kurtz, T. W., 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=Recommendations+for+blood+pressure+measurement+in+humans+and+experimental+animals.+Part+2:+Blood+pressure+measurement+in+experimental+animals:+a+statement+for+professionals+from+the+subcommittee+of+professional+and+public+education+of+the+American+Heart+Association+council+on+high+blood+pressure+research.">Recommendations for blood pressure measurement in humans and experimental animals. Part 2: Blood pressure measurement in experimental animals: a statement for professionals from the subcommittee of professional and public education of the American Heart Association council on high blood pressure research.</a> Hypertension. 45 (2), 299-310 (2005).</li><li>Kurtz, T. W., 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=Recommendations+for+blood+pressure+measurement+in+animals:+summary+of+an+AHA+scientific+statement+from+the+Council+on+High+Blood+Pressure+Research,+Professional+and+Public+Education+Subcommittee.">Recommendations for blood pressure measurement in animals: summary of an AHA scientific statement from the Council on High Blood Pressure Research, Professional and Public Education Subcommittee.</a> Arterioscler Thromb Vasc Biol. 25 (3), 478-479 (2005).</li></ol>

The authors have nothing to disclose.

Implantable radiotelemetría ha mejorado significativamente en la última década; tamaño de la sonda más pequeño hace que el implante menos traumático para el animal, vida de la batería prolongada ayuda a reducir los costes, y las frecuencias telémetro independientes eliminar la diafonía entre los receptores. La telemetría se considera el método del estado de la técnica para recoger una amplia variedad de parámetros fisiológicos se mueva libremente animales sin los artefactos asociados con el uso de restricción, la interacción humana, o anestesia que son requeridos por otras técnicas 8,9. Sin embargo, algunas de las desventajas de su técnica están asociados con los costes iniciales de instrumento y software. Los transmisores son frágiles y susceptibles a los daños, y la batería finalmente se ejecuta fuera del poder y necesitan ser reemplazados. A pesar de que la empresa ofrece para la renovación de esas sondas dañadas a un menor costo, el costo puede ser todavía prohibitivo para algunos laboratorios.Por otra parte, este procedimiento puede ser técnicamente difícil y se requiere práctica para lograr una medición fiable de BP. Por último, hay algo de post-cirugía mortalidad asociada, que en nuestras manos es de aproximadamente 5%. Esto puede aumentar drásticamente si un tratamiento específico tiene que ser probado o si una manipulación genética en peligro la salud del ratón. Los siguientes factores críticos son esenciales para la ejecución exitosa del procedimiento: mantener la hidratación de los tejidos con solución salina estéril durante todo el procedimiento. Siempre debe sostener el transmisor con gran cuidado; evitar la celebración por el sensor de presión ya que esto puede causar que el gel se escape hacia fuera o dañar el transmisor. Al insertar el catéter, atar la sutura central con un nudo doble, ya que el no hacerlo resultará en el catéter que sale del recipiente. La longitud necesaria del catéter que tiene que ser insertada en la carótida puede cambiar de acuerdo con la cepa de ratón y el peso usado en que particuestudio lar. Por lo tanto, es muy recomendable para ejecutar un experimento preliminar para determinar qué tan profundo que sea insertado para evitar la oclusión de la aorta del catéter. Por último, vigilar el animal al día y asegurarse de que la piel sobre el transmisor no se estira o necrótico. Si se produce la necrosis o infección extendida, la eutanasia a los animales de acuerdo con la política institucional.

La hipertensión es uno de los principales factores de riesgo para enfermedades cardiovasculares, podría decirse que se trata de un importante problema de salud pública tanto en los países desarrollados y en desarrollo 1. Varios modelos animales de hipertensión experimental se han desarrollado para imitar las respuestas hipertensivas como los observados en los seres humanos 2. Entre otros, el ratón ambulatoria representa un modelo excelente para estudiar la génesis y la progresión de la hipertensión que permite en el análisis in vivo de las consecuencias de la exposición crónica a la hipertensión. La presión sanguínea (BP) de vigilancia en ratones ha ayudado a los investigadores a desentrañar varios mecanismos involucrados en la fisiología y la patofisiología de enfermedades tales como la hipertensión y la insuficiencia cardíaca 3, 4. De hecho, la manipulación del genoma de ratón permitió la generación de modelos de genes transgénicos o de orientación adecuado para el estudio de la hipertensión 5, 6. Sin embargo, incluso una manipulación suavede los ratones conscientes induce emociones que potencialmente pueden introducir artefactos durante la adquisición de datos, mientras que el uso de la sedación o tranquilizantes afectan profundamente la presión arterial 7. Estos aspectos son particularmente importantes y deben tenerse en cuenta a la hora de intentar monitorización de la PA a largo plazo. Hay varias maneras de grabar BP en ratones, y una comparación entre las técnicas más comunes disponibles en la actualidad se ha discutido en otra parte 8, 9. Sin embargo, las recomendaciones de la AHA para la medición BP concluyeron que la medición intra-arterial de la presión arterial se prefiere generalmente debido a su capacidad para medir directamente BP durante un período prolongado de tiempo 10. Radiotelemetría junto con la medición directa de la presión arterial es el método del estado de la técnica para el control de las funciones fisiológicas del despierta y se mueve libremente animales de laboratorio y reducir al mínimo el estrés y artefactos asociados con el medio ambiente-9, 11.Radiotelemetría ofrece la posibilidad de recopilar automáticamente la presión arterial, la frecuencia cardíaca, la temperatura corporal y la actividad de los animales de varios animales conscientes. Aunque esta metodología se está volviendo muy popular en muchos laboratorios, la implantación de radio-telemetría en ratones puede ser técnicamente difícil. Aquí se muestra un protocolo de paso a paso que ilustra cómo implantar un transductor de presión en ratones. La técnica implica la inserción subcutánea de la sonda en el cuerpo del ratón, el canal del catéter hasta el cuello y hacia adelante cerca del arco aórtico a través de la arteria carótida izquierda. datos remotamente capturadas se muestran en vivo en el monitor de la computadora. Los datos también se almacenan para su análisis &quot;fuera de línea&quot;.

<table><tbody><tr><td>Small animal anesthesia system</td><td>Kent Scientific Corp, Torrington, Connecticut, USA</td><td></td><td>low-flow small animal anesthesia system</td></tr><tr><td>Pad warmer and mouse termometer</td><td>Kent Scientific Corp, Torrington, Connecticut, USA</td><td></td><td>allows monitoring body temperature, and homeothermic control in small animals</td></tr><tr><td>Binocular Microscope</td><td>Kent Scientific Corp, Torrington, Connecticut, USA</td><td>KSCXTS-1121</td><td>binocular body with boom stand pole and top LED</td></tr><tr><td>Hemostat Forceps</td><td>Kent Scientific Corp, Torrington, Connecticut, USA</td><td>INS750451</td><td>used to clamp blood vessels or tag sutures</td></tr><tr><td>Small metal Clips, 7 mm, Stainless Steel</td><td>Kent Scientific Corp, Torrington, Connecticut, USA</td><td>INS750344</td><td>used for skin closure</td></tr><tr><td>Betadine solution</td><td>Purdue Products L.P., Stamford, CT, USA</td><td>NDC-67618-150-01</td><td>10% povidone iodine topical solution</td></tr><tr><td>Normal saline solution</td><td>Abott Laboratories</td><td>04930-04-10</td><td>needed for preventing tissue from drying.</td></tr><tr><td>Nair (Hair remover lotion)</td><td></td><td></td><td>needed for fur removal from the site of incision/surgery</td></tr><tr><td>Braide silk suture</td><td>Teleflex Medical OEM, Coventry, Connecticut, USA</td><td></td><td>Size 5.0, 6.0, 7.0</td></tr><tr><td>Ethanol</td><td></td><td>2716</td><td>70% ethanol for disinfection</td></tr><tr><td>Spring scissors&amp;nbsp;</td><td>Fine Science Tool</td><td>15000-10</td><td>for minor dissection</td></tr><tr><td>Scissors (angled to side)</td><td>Fine Science Tool</td><td>14063-011</td><td>No. 3 handle</td></tr><tr><td>Scalpel blade</td><td></td><td>2976-0</td><td>No. 10</td></tr><tr><td>Forceps (curved)</td><td>Fine Science Tool</td><td>11150-10</td><td>for holding tissue</td></tr><tr><td>Forceps (straight)</td><td>Fine Science Tool</td><td>11151-10</td><td>for holding tissue</td></tr><tr><td>Needle holder&amp;nbsp;</td><td>Fine Science Tool</td><td>12002-12</td><td>for suturing</td></tr><tr><td>Fine needle nose Forceps</td><td>Fine Science Tool</td><td></td><td></td></tr><tr><td>Isoflurane</td><td>Henry Schein&amp;nbsp;Animal Health, Melville, New York, USA</td><td></td><td>a general inhalation anesthetic agent</td></tr><tr><td>Sterilizer</td><td>Benchmark Scientific, 116 Corporate Blvd, South Plainfield, NJ, USA</td><td>B1000</td><td>sterilize surgical tools&amp;nbsp;in 5-10 seconds using infrared heating</td></tr><tr><td>Gauze Pads</td><td>Johnson &amp;amp; Johnson, New Brunswick, NJ, USA</td><td>JJ8513</td><td>to use for wound cleaning, prepping, scrubbing or dressing</td></tr><tr><td>Telemetry Device</td><td>Data Sciences International, St. Paul, MN, USA</td><td>DSI-PA-C10</td><td>to record blood pressure in freely moving mice</td></tr><tr><td>Telemetry receiver system&amp;nbsp; coumpled with a PC</td><td>Data Sciences International, St. Paul, MN, USA</td><td></td><td></td></tr><tr><td>Tubing</td><td>Instech Laboratories, Plymouth Meeting, PA USA</td><td>BTPE-90</td><td></td></tr><tr><td>Vessel Cannulation Forceps, 13 cm, 0.5 mm OD</td><td>World Precision Instruments</td><td>503374</td><td>special vessel cannulation forceps</td></tr><tr><td>Tissue adhesive</td><td>3M Animal Care Products, St. Paul, MN, USA</td><td>NAC No.:&amp;nbsp;11380041</td><td>use to close minor wounds, often eliminating the need for sutures and/or bandages</td></tr><tr><td>Weighing scale&amp;nbsp;</td><td></td><td>BB300</td><td>precision analytical laboratory balance</td></tr></tbody></table>

long-term blood pressure measurement in freely moving mice using telemetry

Durante el desarrollo de nuevos agentes vasoactivos, control de la presión sanguínea arterial es crucial para evaluar la eficacia de los nuevos fármacos propuestos. De hecho, la investigación se centra en el descubrimiento de nuevas dianas terapéuticas potenciales utilizando ratones alterados genéticamente requiere una evaluación fiable a largo plazo de la variación de la presión arterial sistémica. Actualmente, el estándar de oro para la obtención de mediciones a largo plazo de la presión arterial en ratones ambulatorios utiliza implantables de radio-transmisores, que requieren canulación de la arteria. Esta técnica elimina la necesidad de inmovilización, de restricción, o anestesiar los animales que introducen el estrés y artefactos durante el muestreo de datos. Sin embargo, el seguimiento de la presión arterial en ratones a través de cateterismo puede ser bastante difícil debido al pequeño tamaño de las arterias. Aquí presentamos una guía paso a paso para ilustrar los pasajes claves cruciales para una exitosa implantación subcutánea de radio-transmisores y c arteria carótidaanulación en ratones. También se incluyen ejemplos de la actividad de la presión arterial a largo plazo tomadas de ratones con libertad de movimientos después de un período de recuperación post-cirugía. Después de este procedimiento permitirá que los registros de presión arterial directa fiables de varios animales al mismo tiempo.

Los datos pueden ser adquiridos de forma remota por un receptor; trazas se visualizan en una pantalla de ordenador para el control de calidad (Figura 1a). Los detalles tales como Identificación de los animales, la presión arterial diastólica y la presión arterial sistólica también se muestran (Figura 1b). La PA se puede grabar de forma continua (24/7), o por intervalos programados cortos (es decir, 60 seg adquisición cada hora). Los datos pueden almacenarse automáticamente en un disco duro para su posterior análisis. BP datos promediados de una grabación continua de 3 días se muestran (Figura 2), es posible apreciar la variación del ritmo circadiano entre el ciclo de luz y oscuridad. Promedio de la tasa de variación de la presión y el corazón se calculó y se representó frente al tiempo. <img alt="Figura 1" src="/files/ftp_upload/53991/53991fig1.jpg" /> Figura 1. Los trazados típicos de la presión arterial </strong&gt; de 4 Diferentes ratones implantados con telemétrico de dispositivos. Los trazados (A) que muestra los cambios de presión arterial en tiempo real (mmHg) durante un intervalo de 5 minutos. Los datos se adquieren simultáneamente a partir de cuatro ratones adultos diferentes 5 días después de la implantación. (B) localización en mayor resolución temporal extraída de A, es posible apreciar arterial diastólica de presión sistólica y los valores, la duración del ciclo de BP, y el ritmo cardíaco. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53991/53991fig1large.jpg" target="_blank">Por favor, haga clic aquí para ver una versión más grande de esta figura.</a> <img alt="Figura 2" src="/files/ftp_upload/53991/53991fig2.jpg" /> Presión Figura 2. A largo plazo sangre arterial Muestra de variación del ritmo circadiano. Un promedio de los datos de presión que ilustran los valores de (A) Presión sistólica (SP), (B) la presión diastólica (DP), (C) la presión arterial media (MAP), y (D) ra corazónte expresa en latidos / min. Los datos fueron extraídos de grabaciones continuas tomadas durante el día (ciclo de luz, L) o de la noche (ciclo de oscuridad, D). La grabación comenzó 7 días después de la cirugía. Todos los datos se expresan como media ± SEM (n = 4 ratones). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53991/53991fig2large.jpg" target="_blank">Haga clic aquí para ver una versión más grande de esta figura.</a>

Watch this Scientific Journal Video about Long-term Blood Pressure Measurement in Freely Moving Mice Using Telemetry at JoVE.com

Long-term Blood Pressure Measurement in Freely Moving Mice Using Telemetry

A largo plazo de medida de la presión arterial en ratones con libertad de movimientos mediante telemetría

The goal of this protocol is to assess systemic blood pressure in conscious freely moving mice using implantable radio-telemetry devices.

During the development of new vasoactive agents, arterial blood pressure monitoring is crucial for evaluating the efficacy of the new proposed drugs. ...

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18.6K vistas.  University of Tennessee Health Sciences Center. The goal of this protocol is to assess systemic blood pressure in conscious freely moving mice using implantable radio-telemetry devices.

Video: Long-term Blood Pressure Measurement in Freely Moving Mice Using Telemetry

Implantation of Radiotelemetry Transmitters Yielding Data on ECG, Heart Rate, Core Body Temperature and Activity in Free-moving Laboratory Mice

The laboratory mouse is the animal species of choice for most biomedical research, in both the academic sphere and the pharmaceutical industry. Mice are a manageable size and relatively easy to house. These factors, together with the availability of a wealth of spontaneous and experimentally induced mutants, make laboratory mice ideally suited to a wide variety of research areas.
In cardiovascular, pharmacological and toxicological research, accurate measurement of parameters relating to the circulatory system of laboratory animals is often required. Determination of heart rate, heart rate variability, and duration of PQ and QT intervals are based on electrocardiogram (ECG) recordings. However, obtaining reliable ECG curves as well as physiological data such as core body temperature in mice can be difficult using conventional measurement techniques, which require connecting sensors and lead wires to a restrained, tethered, or even anaesthetized animal. Data obtained in this fashion must be interpreted with caution, as it is well known that restraining and anesthesia can have a major artifactual influence on physiological parameters1, 2.
Radiotelemetry enables data to be collected from conscious and untethered animals. Measurements can be conducted even in freely moving animals, and without requiring the investigator to be in the proximity of the animal. Thus, known sources of artifacts are avoided, and accurate and reliable measurements are assured. This methodology also reduces interanimal variability, thus reducing the number of animals used, rendering this technology the most humane method of monitoring physiological parameters in laboratory animals3, 4. Constant advancements in data acquisition technology and implant miniaturization mean that it is now possible to record physiological parameters and locomotor activity continuously and in realtime over longer periods such as hours, days or even weeks3, 5.
Here, we describe a surgical technique for implantation of a commercially available telemetry transmitter used for continuous measurements of core body temperature, locomotor activity and biopotential (i.e. onelead ECG), from which heart rate, heart rate variability, and PQ and QT intervals can be established in freeroaming, untethered mice. We also present pre-operative procedures and protocols for post-operative intensive care and pain treatment that improve recovery, well-being and survival rates in implanted mice5, 6.

A surgical technique for implantation of commercially available telemetry transmitters used for continuous measurement of biopotential (one-lead ECG), heart rate, core body temperature and locomotor activity in freely moving mice is shown. Recommendations and protocols for post-operative care and pain relief, improving recovery, well being and survival rate are also presented.

Implantación de transmisores de radiotelemetría Ceder los datos en el ECG, frecuencia cardiaca, la temperatura corporal y la actividad en ratones de laboratorio de movimiento libre

The laboratory mouse is the animal species of choice for most biomedical research, in both the academic sphere and the pharmaceutical industry. Mice are a ...

Investigación

Medicina

Measuring Blood Pressure in Mice using Volume Pressure Recording, a Tail-cuff Method

The CODA 8-Channel High Throughput Non-Invasive Blood Pressure system measures the blood pressure in up to 8 mice or rats simultaneously. The CODA tail-cuff system uses Volume Pressure Recording (VPR) to measure the blood pressure by determining the tail blood volume. A specially designed differential pressure transducer and an occlusion tail-cuff measure the total blood volume in the tail without the need to obtain the individual pulse signal. Special attention is afforded to the length of the occlusion cuff in order to derive the most accurate blood pressure readings. VPR can easily obtain readings on dark-skinned rodents, such as C57BL6 mice and is MRI compatible. The CODA system provides you with measurements of six (6) different blood pressure parameters; systolic and diastolic blood pressure, heart rate, mean blood pressure, tail blood flow, and tail blood volume. Measurements can be made on either awake or anesthetized mice or rats. The CODA system includes a controller, laptop computer, software, cuffs, animal holders, infrared warming pads, and an infrared thermometer. There are seven different holder sizes for mice as small as 8 grams to rats as large as 900 grams.

The CODA 8-Channel High Throughput Non-Invasive Blood Pressure system measures the blood pressure in up to 8 mice or rats simultaneously. This tail-cuff system uses Volume Pressure Recording (VPR) to measure the blood pressure by determining the tail blood volume.

Medición de la presión arterial en ratones con registro del volumen de presión, un método de la cola del manguito

The CODA 8-Channel High Throughput Non-Invasive Blood Pressure system measures the blood pressure in up to 8 mice or rats simultaneously. The CODA ...

Biología

Monitoring of Systemic and Hepatic Hemodynamic Parameters in Mice

The use of mouse models in experimental research is of enormous importance for the study of hepatic physiology and pathophysiological disturbances. However, due to the small size of the mouse, technical details of the intraoperative monitoring procedure suitable for the mouse were rarely described. Previously we have reported a monitoring procedure to obtain hemodynamic parameters for rats. Now, we adapted the procedure to acquire systemic and hepatic hemodynamic parameters in mice, a species ten-fold smaller than rats. This film demonstrates the instrumentation of the animals as well as the data acquisition process needed to assess systemic and hepatic hemodynamics in mice. Vital parameters, including body temperature, respiratory&#160;rate&#160;and heart&#160;rate were recorded throughout the whole procedure. Systemic hemodynamic parameters consist of carotid artery pressure (CAP) and central venous pressure (CVP). Hepatic perfusion parameters include portal vein pressure (PVP), portal flow rate as well as the flow rate of the common hepatic artery (table 1). Instrumentation and data acquisition to record the normal values was completed within 1.5 h. Systemic and hepatic hemodynamic parameters remained within normal ranges during this procedure.
This procedure is challenging but feasible. We have already applied this procedure to assess hepatic hemodynamics in normal mice as well as during 70% partial hepatectomy and in liver lobe clamping experiments. Mean PVP after resection (n= 20), was 11.41&#177;2.94 cmH2O which was significantly higher (P&#60;0.05) than before resection (6.87&#177;2.39 cmH2O). The results of liver lobe clamping experiment indicated that this monitoring procedure is sensitive and suitable for detecting small changes in portal pressure and portal flow rate. In conclusion, this procedure is reliable in the hands of an experienced micro-surgeon but should be limited to experiments where mice are absolutely needed.

This film demonstrates how to acquire systemic and hepatic hemodynamics in mice. The whole monitoring includes acquisition of vital parameters, systemic blood pressure, central venous pressure, common hepatic artery flow rate, and portal vein pressure as well as the portal flow rate in mice.

Monitoreo de Parámetros sistémicos y hemodinámicos hepática en ratones

The use of mouse models in experimental research is of enormous importance for the study of hepatic physiology and pathophysiological disturbances. ...

Intrauterine Telemetry to Measure Mouse Contractile Pressure In Vivo

A complex integration of molecular and electrical signals is needed to transform a quiescent uterus into a contractile organ at the end of pregnancy. Despite the discovery of key regulators of uterine contractility, this process is still not fully understood. Transgenic mice provide an ideal model in which to study parturition. Previously, the only method to study uterine contractility in the mouse was ex vivo isometric tension recordings, which are suboptimal for several reasons. The uterus must be removed from its physiological environment, a limited time course of investigation is possible, and the mice must be sacrificed. The recent development of radiometric telemetry has allowed for longitudinal, real-time measurements of in vivo intrauterine pressure in mice. Here, the implantation of an intrauterine telemeter to measure pressure changes in the mouse uterus from mid-pregnancy until delivery is described. By comparing differences in pressures between wild type and transgenic mice, the physiological impact of a gene of interest can be elucidated. This technique should expedite the development of therapeutics used to treat myometrial disorders during pregnancy, including preterm labor.

Intrauterine Telemetry to Measure Mouse Contractile Pressure In Vivo

This manuscript provides a protocol for implanting telemeters in the mouse for the purpose of measuring intrauterine pressures during pregnancy.

Telemetría intrauterina para medir la presión del ratón contráctil<em&gt; En Vivo</em

A complex integration of molecular and electrical signals is needed to transform a quiescent uterus into a contractile organ at the end of pregnancy. ...

Novel Approach for Simultaneous Recording of Renal Sympathetic Nerve Activity and Blood Pressure with Intravenous Infusion in Conscious, Unrestrained Mice.

Renal sympathetic nerves contribute significantly to both physiological and pathophysiological phenomena. Evaluating renal sympathetic nerve activity (RSNA) is of great interest in many areas of research such as chronic kidney disease, hypertension, heart failure, diabetes and obesity. Unequivocal assessment of the role of the sympathetic nervous system is thus imperative for proper interpretation of experimental results and understanding of disease processes. RSNA has been traditionally measured in anesthetized rodents, including mice. However, mice usually exhibit very low systemic blood pressure and hemodynamic instability for several hours during anesthesia and surgery. Meaningful interpretation of RSNA is confounded by this non-physiological state, given the intimate relationship between sympathetic nervous tone and cardiovascular status. To address this limitation of traditional approaches, we developed a new method for measuring RSNA in conscious, freely-moving mice. Mice were chronically instrumented with radio-telemeters for continuous monitoring of blood pressure as well as a jugular venous infusion catheter and custom-designed bipolar electrode for direct recording of RSNA. Following a 48-72 hour recovery period, survival rate was 100% and all mice behaved normally. At this time-point, RSNA was successfully recorded in 80% of mice, with viable signals acquired up to 4 and 5 days post-surgery in 70% and 50% of mice, respectively. Physiological blood pressures were recorded in all mice (116&plusmn;2 mmHg; n=10). Recorded RSNA increased with eating and grooming, as well-established in the literature. Furthermore, RSNA was validated by ganglionic blockade and modulation of blood pressure with pharmacological agents. Herein, an effective and manageable method for clear recording of RSNA in conscious, freely-moving mice is described.

Anesthetized mice exhibit non-physiological systemic blood pressure, which precludes meaningful assessment of autonomic tone given the intimate relationship between blood pressure and the autonomic nervous system. Thus, a novel method to simultaneously record renal sympathetic nerve activity and blood pressure with intravenous infusion in conscious mice is outlined.

Nuevo enfoque para la grabación simultánea de la actividad nerviosa simpática Renal y presión arterial con la infusión intravenosa en consciente, libre de ratones.

Renal sympathetic nerves contribute significantly to both physiological and pathophysiological phenomena. Evaluating renal sympathetic nerve activity ...

Simultaneous Electrocardiography Recording and Invasive Blood Pressure Measurement in Rats

For studies related to cardiovascular physiology or pathophysiology, blood pressure (BP) and electrocardiography are basic observational parameters. Research focusing on cardiovascular disease models, potential cardiovascular therapeutic targets or pharmaceutical agents requires assessment of systemic arterial pressure and heart rhythm changes. In situations where radio telemetry systems are not available or affordable, the technique of femoral artery cannulation is an alternative way to obtain intra-arterial pressure waveform recordings and systemic BP measurements. This technique is economical and can be performed with standard equipment in animal facilities. However, invasive arterial pressure recording requires cannulation of small arteries, which can be a challenging surgical skill. Here, we present step-by-step protocols for femoral artery cannulation procedures. Key procedures include the calibration of the data acquisition system, tissue dissection and femoral artery cannulation, and setup of the arterial cannulation system for pressure recording. Surface electrocardiography recording procedures are also included. We also present examples of BP recordings from normotensive and hypertensive rats. This protocol allows reliable direct recordings of systemic BP with simultaneous electrocardiography.

Here, we describe a setup for simultaneous recording of electrocardiography and intra-arterial blood pressure (BP) in experimental rats, which can be done with standard equipment in animal facilities and can be applied to physiological or pharmacological studies to investigate pathogenic or therapeutic mechanisms in cardiovascular medicine.

Grabación simultánea de electrocardiografía y sangre invasiva presión medida en ratas

For studies related to cardiovascular physiology or pathophysiology, blood pressure (BP) and electrocardiography are basic observational parameters. ...

Implantation of Combined Telemetric ECG and Blood Pressure Transmitters to Determine Spontaneous Baroreflex Sensitivity in Conscious Mice

Blood pressure (BP) and heart rate (HR) are both controlled by the autonomic nervous system (ANS) and are closely intertwined due to reflex mechanisms. The baroreflex is a key homeostatic mechanism to counteract acute, short-term changes in arterial BP and to maintain BP in a relatively narrow physiological range. BP is sensed by baroreceptors located in the aortic arch and carotid sinus. When BP changes, signals are transmitted to the central nervous system and are then communicated to the parasympathetic and sympathetic branches of the autonomic nervous system to adjust HR. A rise in BP causes a reflex decrease in HR, a drop in BP causes a reflex increase in HR.
Baroreflex sensitivity (BRS) is the quantitative relationship between changes in arterial BP and corresponding changes in HR. Cardiovascular diseases are often associated with impaired baroreflex function. In various studies reduced BRS has been reported in e.g., heart failure, myocardial infarction, or coronary artery disease. 
Determination of BRS requires information from both BP and HR, which can be recorded simultaneously using telemetric devices. The surgical procedure is described beginning with the insertion of the pressure sensor into the left carotid artery and positioning of its tip in the aortic arch to monitor arterial pressure followed by the subcutaneous placement of the transmitter and ECG electrodes. We also describe postoperative intensive care and analgesic management. After a two-week period of post-surgery recovery long-term ECG and BP recordings are performed in conscious and unrestrained mice. Finally, we include examples of high-quality recordings and the analysis of spontaneous baroreceptor sensitivity using the sequence method.

The baroreflex is a heart-rate regulation mechanism by the autonomic nervous system in response to blood-pressure changes. We describe a surgical technique to implant telemetry transmitters for continuous and simultaneous measurement of electrocardiogram and blood pressure in mice. This can determine spontaneous baroreflex sensitivity, an important prognostic marker for cardiovascular disease.

Implantación de ECG telemétrico combinado y transmisores de presión arterial para determinar la sensibilidad barorrefleja espontánea en ratones conscientes

Blood pressure (BP) and heart rate (HR) are both controlled by the autonomic nervous system (ANS) and are closely intertwined due to reflex mechanisms. ...

Long-Term Continuous Measurement of Renal Blood Flow in Conscious Rats

The kidneys play a crucial role in maintaining the homeostasis of body fluids. The regulation of renal blood flow (RBF) is essential to the vital functions of filtration and metabolism in kidney function. Many acute studies have been carried out in anesthetized animals to measure RBF under various conditions to determine mechanisms responsible for the regulation of kidney perfusion. However, for technical reasons, it has not been possible to measure RBF continuously (24 h/day) in unrestrained unanesthetized rats over prolonged periods. These methods allow the continuous determination of RBF over many weeks while also simultaneously recording blood pressure (BP) with implanted catheters (fluid-filled or by telemetry). RBF monitoring is carried out with rats placed in a circular servo-controlled rat cage that enables the unrestrained movement of the rat throughout the study. At the same time, the tangling of cables from the flow probe and arterial catheters is prevented. Rats are first instrumented with an ultrasonic flow probe placement on the left renal artery and an arterial catheter implanted in the right femoral artery. These are routed subcutaneously to the nape of the neck, and connected to the flowmeter and pressure transducer, respectively, to measure RBF and BP. Following surgical implantation, rats are immediately placed in the cage to recover for at least one week and stabilize the ultrasonic probe recordings. Urine collection is also feasible in this system. The surgical and post-surgical procedures for continuous monitoring are demonstrated in this protocol.

The present protocol describes a long-term continuous measurement of renal blood flow in conscious rats and simultaneously recording blood pressure with implanted catheters (fluid-filled or by telemetry).

Medición continua a largo plazo del flujo sanguíneo renal en ratas conscientes

The kidneys play a crucial role in maintaining the homeostasis of body fluids. The regulation of renal blood flow (RBF) is essential to the vital ...

Multiple Intravenous Bolus Dosing and Invasive Hemodynamic Assessment in a Hypoxia-Induced Mouse Pulmonary Artery Hypertension Model

Pulmonary arterial hypertension (PAH) is a progressive life-threatening disease, primarily affecting small pulmonary arterioles of the lung. Currently, there is no cure for PAH. It is important to discover new compounds that can be used to treat PAH. The mouse hypoxia-induced PAH model is a widely used model for PAH research. This model recapitulates human clinical manifestations of PAH Group 3 disease and is an important research tool to evaluate the effectiveness of new experimental therapies for PAH. Research using this model often requires the administration of compounds in mice. For a compound that needs to be given directly into the bloodstream, optimizing intravenous (IV) administration is a key part of the experimental procedures. Ideally, the IV injection system should permit multiple injections over a set time course. Although the mouse hypoxia-induced PAH model is very popular in many laboratories, it is technically challenging to perform multiple IV bolus dosing and invasive hemodynamic assessment in this model. In this protocol, we present step-by-step instructions on how to carry out multiple IV bolus dosing via mouse jugular vein and perform arterial and right ventricle catheterization for hemodynamic assessment in mouse hypoxia-induced PAH model.

This protocol provides a step-by-step procedure for executing multiple intravenous bolus dose administration and invasive hemodynamic monitoring in mice. Investigators can use this protocol for future therapeutic compound screening for pulmonary artery hypertension.

Dosificación múltiple en bolo intravenoso y evaluación hemodinámica invasiva en un modelo de hipertensión de la arteria pulmonar de ratón inducida por hipoxia

Pulmonary arterial hypertension (PAH) is a progressive life-threatening disease, primarily affecting small pulmonary arterioles of the lung. Currently, ...

Simple Continuous Glucose Monitoring in Freely Moving Mice

Mice are a common model organism used to study metabolic diseases such as diabetes mellitus. Glucose levels are typically measured by tail-bleeding, which requires handling the mice, causes stress, and does not provide data on freely behaving mice during the dark cycle. State-of-the-art continuous glucose measurement in mice requires inserting a probe into the aortic arch of the mouse, as well as a specialized telemetry system. This challenging and expensive method has not been adopted by most labs. Here, we present a simple protocol involving the utilization of commercially available continuous glucose monitors used by millions of patients to measure glucose continuously in mice as a part of basic research. The glucose-sensing probe is inserted into the subcutaneous space in the back of the mouse through a small incision to the skin and is held in place tightly using a couple of sutures. The device is sutured to the mouse skin to ensure it remains in place. The device can measure glucose levels for up to 2 weeks and sends the data to a nearby receiver without any need to handle the mice. Scripts for the basic data analysis of glucose levels recorded are provided. This method, from surgery to computational analysis, is cost-effective and potentially very useful in metabolic research.

Here, we describe a simple method to implant a commercial continuous glucose monitor designed for patients onto mice and provide the scripts to analyze the results.

Monitoreo continuo simple de glucosa en ratones que se mueven libremente

Mice are a common model organism used to study metabolic diseases such as diabetes mellitus. Glucose levels are typically measured by tail-bleeding, which ...