Este trabajo fue apoyado por la Fundación JB Marshall.

1. Preparar Animal y Equipo para efectuar el procedimiento <ol><li> Antes de comenzar la cirugía, prepare el área quirúrgica y el animal. Hacer que el catéter de la carótida mediante la inserción de una aguja de punta roma de calibre 23-en un extremo de 12 &quot;de tubo de PE50. Cortar un bisel aproximadamente 45 ° en el extremo opuesto del catéter. Esterilizar el equipo antes del procedimiento. Use un capó cabello, máscara quirúrgica y guantes estériles. </li><li> Coloque una almohadilla térmica sobre la superficie donde se realizará la cirugía. Actívalo y deje que se caliente. Cubra el área con una almohadilla absorbente banco. </li><li> Compruebe que tiene 25% de manitol en solución sin cristales. Si hay cristales, que se disuelvan colocando el vial en un baño de agua caliente a 80 ° C y agitando periódicamente. </li><li> Registrar la masa del animal. </li><li> Hacer una dilución de propofol para la entrega a 0,8 mg / kg / min a una velocidad de 0,1 ml / min. </li><li> Coloque la rata en la caja de la inducción durante 3 min. Configuración: 5% de isoflurano, 2 L / minCaudal ventilador. </li><li> En la parte superior de una toalla desechable, afeitarse el cuello y los muslos internos. </li></ol> 2. Intube la Rata <ol><li> Volver a colocar el animal en el cuadro de la inducción durante 3 min. </li><li> Prepare el tubo endotraqueal con un catéter intravenoso. Para este tamaño y raza de ratas, se utiliza un catéter de calibre 18. El tubo debe ser suficientemente grande para permitir la circulación de aire adecuada, pero lo suficientemente pequeño para encajar en la tráquea sin causar daños. Tire de la aguja fuera del catéter plástico con cuidado y romper la aguja aprox. 1 cm de su punta afilada. La aguja tocada será su lápiz. Vuelve a colocar la aguja en el catéter. </li><li> Colgar la rata por los dientes en una superficie inclinada. </li><li> Enciende una luz directamente sobre el cuello del animal y alineados entre sus orejas. </li><li> Inserte una pequeña espátula aprox. 3 cm en la orofaringe. Levante hacia arriba mientras tira suavemente la lengua fuera de la boca. </li><li> Visualizar la apertura de la tráquea. Lo harás síea agujero pequeño abierto y cercano con cada respiración. </li><li> Inserte suavemente catéter en el orificio. A veces se puede sentir el plástico entrar en el cartílago de la tráquea. La tráquea es sensible. No fuerce el catéter. </li><li> Ajuste el ventilador a 1 L / min y 60 lpm y el isoflurano al 2%. </li><li> Conectar el catéter al ventilador y el tubo de cinta a la superficie de operación. </li><li> Verificar que el animal es anestesiado mediante la realización de un sujetador del pie. </li></ol> 3. Establecer anestesia Propofol IV <ol><li> Asegure la rata con cinta adhesiva las cuatro extremidades y la cola a la superficie de operación. </li><li> Frote el cuello afeitado y sitios de la ingle con clorhexidina jabón tres veces. Luego frote con clorhexidina enjuague tres veces. </li><li> Conecte una jeringa de propofol a un conjunto de extensión IV. Monte la jeringa en una bomba de infusión. </li><li> Con un escalpelo, cortar a través de la piel del muslo rasurada. Evite cortar el músculo. </li><li> Abra la incisión con fuerzaps para visualizar la vena femoral. </li><li> Tire el tejido sobre la arteria para exponer el recipiente. </li><li> Inserte un 26 ga Monoject veterinario catéter IV en la vena. Cuando la aguja perfora la pared de la vena se siente que son más fáciles de empujar. Retraer la aguja y empuje el catéter en el vaso. </li><li> Iniciar la infusión de propofol a 0,1 ml / min. </li><li> 3-5 min después de comenzar la infusión de propofol, cambiar el gas de la anestesia a una mezcla de 50% O 2 y 50% N O 2 y apagar el isoflurano. </li></ol> 4. Exponer la bifurcación de la arteria carótida común <ol><li> Hacer una incisión en la línea media del cuello con hoja de bisturí. </li><li> Cortar entre las dos grandes glándulas salivales con tijeras o bisturí. </li><li> Diseccionar tejido lateral a la línea media para exponer la arteria carótida. Utilice unas pinzas para abrir capas de tejido. Usted puede utilizar tijeras para retirar las piezas que lo expongan con las pinzas y determinar que minimally vascular. Controlar el sangrado con una gasa, hisopos de algodón, y cauterización si es necesario. </li><li> Inyectar 3 ml de solución salina IP si ha habido sangrado moderado a fuerte. </li><li> Utilice separadores para extraer el tejido fuera de la carótida. Encuentra la bifurcación. </li><li> Exponer la arteria occipital, justo distal a la bifurcación. Cauterize que entre pinzas y separarlo con un electrocauterio. </li><li> Use pinzas para exponer completamente la bifurcación de la carótida y como mucho de la ECA como sea posible. </li><li> Exponer la arteria tiroidea superior se desvía la ECA distal a la arteria occipital. Cauterize que entre pinzas y separarlo con un electrocauterio. </li></ol> 5. Cateterización de la arteria carótida externa <ol><li> Coloque dos trozos de 4/0 seda bajo el ACA. </li><li> Coge un trozo de sutura con su pinza hemostática y retraer la ECA atrás caudalmente (hacia los pies de la rata). </li><li> Tomar la otra sutura y atar en la medida de cranealmente (hacia la boca de la rata) como sea posible won un nudo de cirujano. Esto forma una ligadura permanente a sacrificar la ECA. </li><li> Retire la pinza hemostática primero (el que se aplica la tensión caudal) y coge la otra sutura (la que se anuda alrededor de la ECA) y aplique una ligera tensión craneal con la pinza hemostática. </li><li> Atar nudo otro cirujano suelta (no aseguran - dejar apenas atado) distal a la bifurcación y proximal a la ligadura permanente. </li><li> Irrigar con lidocaína al 1% para relajar la arteria. </li><li> Llenar el catéter con solución salina heparinizada. </li><li> Colocar una grapa de vaso temporal lo más cerca posible a la bifurcación. Place grapa de vaso en un ángulo para maximizar el espacio para la cateterización. Deslice el nudo flojo hacia el clip. </li><li> Hacer una arteriotomía pequeña (corte) en la CEPA justo proximal a la ligadura usando micro tijeras. No debe haber sangrado y si el clip de ligadura son seguras. </li><li> Utilizando pinzas para controlar las paredes de ECA, alimentar el extremo biselado del catéter en el vaso. </li&gt; <li> Fijar el catéter con el nudo de sutura sueltos. Ate la arteria alrededor del catéter. </li><li> Retire el clip y limpiar la zona con un bastoncillo de algodón. </li><li> Avanzar el catéter a aproximadamente 1 mm distal a la bifurcación. Mantener la arteria con fórceps proximales al nudo para asegurar el recipiente se inmoviliza. </li></ol> 6. Administre Manitol <ol><li> Llenar un 8 &quot;juego de extensión IV y una jeringa de 6 ml con manitol sin crear burbujas de aire en la tienda de esta incubadora a 37 ° C. Nota: el trabajo rápidamente con el manitol -, será fácil de precipitar de la solución a temperatura ambiente.. </li><li> Para visualizar BBBD, puede administrar colorante azul de Evans y verlo entrar en las áreas del cerebro donde se ha interrumpido la barrera. Para ello, dar al animal 2 ml / kg de Evans 2% Blue a través de un nuevo sitio IV en la pierna contralateral a la infusión de propofol. </li><li> Conecte el juego de extensión a un filtro de 5 micras y llenarlo con manitol para eliminar el aire bubbles. A continuación, conecte esta a la llave de paso sin crear burbujas. </li><li> Administrar manitol a 0,09 ml / seg para 25 seg. Reloj para el manitol para alcanzar el equilibrio con el flujo en la carótida común en un punto justo proximal a la ICA. Se debería aparecer a pulso con una frecuencia cardiaca de la rata. Si el manitol simplemente fluye hacia el corazón que hayas superado la presión arterial de la rata. Esto puede causar complicaciones potencialmente mortales y BBBD pobres. </li></ol>

<ol>
	<li>Abbott, N. J., Patabendige, A. A. K., Dolman, D. E. M., Yusof, S. R., Begley, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+and+function+of+the+blood-brain+barrier.">Structure and function of the blood-brain barrier.</a> Neurobiology of disease. 37, 13-25 (2010).</li><li>Smith, Q. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Blood-Brain+Barrier.">The Blood-Brain Barrier.</a> 89, 193-208 (2003).</li><li>Kroll, R. A., Neuwelt, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Outwitting+the+blood-brain+barrier+for+therapeutic+purposes:+osmotic+opening+and+other+means.">Outwitting the blood-brain barrier for therapeutic purposes: osmotic opening and other means.</a> Neurosurgery. 42, 1083 (1998).</li><li>Kroll, R. A., Pagel, M. A., Muldoon, L. L., Roman-Goldstein, S., Neuwelt, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increasing+volume+of+distribution+to+the+brain+with+interstitial+infusion:+dose,+rather+than+convection,+might+be+the+most+important+factor.">Increasing volume of distribution to the brain with interstitial infusion: dose, rather than convection, might be the most important factor.</a> Neurosurgery. 38, 746-754 (1996).</li><li>Butt, A. M., Jones, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+histamine+and+antagonists+on+electrical+resistance+across+the+blood-brain+barrier+in+rat+brain-surface+microvessels.">Effect of histamine and antagonists on electrical resistance across the blood-brain barrier in rat brain-surface microvessels.</a> Brain research. 569, 100-105 (1992).</li><li>Inamura, T., Black, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bradykinin+selectively+opens+blood-tumor+barrier+in+experimental+brain+tumors.">Bradykinin selectively opens blood-tumor barrier in experimental brain tumors.</a> Journal of Cerebral Blood Flow &amp; Metabolism. 14, 862-870 (1994).</li><li>Matsukado, K., 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=Enhanced+tumor+uptake+of+carboplatin+and+survival+in+glioma-bearing+rats+by+intracarotid+infusion+of+bradykinin+analog,+RMP-7.">Enhanced tumor uptake of carboplatin and survival in glioma-bearing rats by intracarotid infusion of bradykinin analog, RMP-7.</a> Neurosurgery. 39, 125 (1996).</li><li>Kroll, R. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+drug+delivery+to+intracerebral+tumor+and+surrounding+brain+in+a+rodent+model:+a+comparison+of+osmotic+versus+bradykinin+modification+of+the+blood-brain+and/or+blood-tumor+barriers.">Improving drug delivery to intracerebral tumor and surrounding brain in a rodent model: a comparison of osmotic versus bradykinin modification of the blood-brain and/or blood-tumor barriers.</a> Neurosurgery. 43, 879 (1998).</li><li>Kinoshita, M., McDannold, N., Jolesz, F. A., Hynynen, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+localized+delivery+of+Herceptin+to+the+mouse+brain+by+MRI-guided+focused+ultrasound-induced+blood-brain+barrier+disruption.">Noninvasive localized delivery of Herceptin to the mouse brain by MRI-guided focused ultrasound-induced blood-brain barrier disruption.</a> Proceedings of the National Academy of Sciences. 103, 11719-11723 (2006).</li><li>Neuwelt, E. A., Dahlborg, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemotherapy+administered+in+conjunction+with+osmotic+blood-brain+barrier+modification+in+patients+with+brain+metastases.">Chemotherapy administered in conjunction with osmotic blood-brain barrier modification in patients with brain metastases.</a> Journal of neuro-oncology. 4, 195-207 (1987).</li><li>Doolittle, N. D., 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=Safety+and+efficacy+of+a+multicenter+study+using+intraarterial+chemotherapy+in+conjunction+with+osmotic+opening+of+the+blood-brain+barrier+for+the+treatment+of+patients+with+malignant+brain+tumors.">Safety and efficacy of a multicenter study using intraarterial chemotherapy in conjunction with osmotic opening of the blood-brain barrier for the treatment of patients with malignant brain tumors.</a> Cancer. 88, 637-647 (2000).</li><li>Guillaume, D. J., 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=Intra-arterial+chemotherapy+with+osmotic+blood-brain+barrier+disruption+for+aggressive+oligodendroglial+tumors:+results+of+a+phase+I+study.">Intra-arterial chemotherapy with osmotic blood-brain barrier disruption for aggressive oligodendroglial tumors: results of a phase I study.</a> Neurosurgery. 66, 48 (2010).</li><li>Remsen, L. 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+influence+of+anesthetic+choice,+PaCO2,+and+other+factors+on+osmotic+blood-brain+barrier+disruption+in+rats+with+brain+tumor+xenografts.">The influence of anesthetic choice, PaCO2, and other factors on osmotic blood-brain barrier disruption in rats with brain tumor xenografts.</a> Anesthesia &amp; Analgesia. 88, 559-559 (1999).</li><li>Nilaver, 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=Delivery+of+herpesvirus+and+adenovirus+to+nude+rat+intracerebral+tumors+after+osmotic+blood-brain+barrier+disruption.">Delivery of herpesvirus and adenovirus to nude rat intracerebral tumors after osmotic blood-brain barrier disruption.</a> Proceedings of the National Academy of Sciences. 92, 9829 (1995).</li><li>Fortin, D., McCormick, C. I., Remsen, L. G., Nixon, R., Neuwelt, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unexpected+neurotoxicity+of+etoposide+phosphate+administered+in+combination+with+other+chemotherapeutic+agents+after+blood-brain+barrier+modification+to+enhance+delivery,+using+propofol+for+general+anesthesia,+in+a+rat+model.">Unexpected neurotoxicity of etoposide phosphate administered in combination with other chemotherapeutic agents after blood-brain barrier modification to enhance delivery, using propofol for general anesthesia, in a rat model.</a> Neurosurgery. 47, 199 (2000).</li><li>Neuwelt, E. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+CNS+lymphoma+treated+with+osmotic+blood-brain+barrier+disruption:+prolonged+survival+and+preservation+of+cognitive+function.">Primary CNS lymphoma treated with osmotic blood-brain barrier disruption: prolonged survival and preservation of cognitive function.</a> Journal of clinical oncology. 9, 1580 (1991).</li><li>Remsen, L. G., Trail, P. A., Hellstr&#246;m, I., Hellstr&#246;m, K. E., Neuwelt, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+delivery+improves+the+efficacy+of+a+tumor-specific+doxorubicin+immunoconjugate+in+a+human+brain+tumor+xenograft+model.">Enhanced delivery improves the efficacy of a tumor-specific doxorubicin immunoconjugate in a human brain tumor xenograft model.</a> Neurosurgery. 46, 704 (2000).</li><li>Neuwelt, E. A., Pagel, M. A., Kraemer, D. F., Peterson, D. R., Muldoon, L. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bone+marrow+chemoprotection+without+compromise+of+chemotherapy+efficacy+in+a+rat+brain+tumor+model.">Bone marrow chemoprotection without compromise of chemotherapy efficacy in a rat brain tumor model.</a> Journal of Pharmacology and Experimental Therapeutics. 309, 594-599 (2004).</li></ol>

No hay conflictos de interés declarado.

Hay unos pocos medios para aumentar al máximo la eficacia de BBBD. Es importante minimizar el sangrado durante la fase de corte hacia abajo. La presión arterial y el ritmo cardíaco puede ser afectada por hemorragia significativa y estos factores se sabe que afectan el grado de BBBD 13. El sangrado puede ser reducido mediante el uso de suturas para ligar vasos importantes, tales como la tiroidea superior y las arterias occipital, que deben ser divididas. Además, la electrocauterización puede ser utilizado...

<table border="1"><tbody><tr><td> Nombre del Material </td><td> Empresa </td><td> Número de catálogo </td><td> Comentario </td></tr><tr><td> Larga rata Evans </td><td> Harlan Laboratories </td><td></td><td> 210-250 g, varón </td></tr><tr><td> PE 50 Tuberías </td><td> Beckton-Dickinson </td><td></td><td></td></tr><tr><td> Calibre 18 x 2,5 &quot;catéter IV </td><td> Terumo </td><td></td><td> Para tubo ET </td></tr><tr><td> 30 &quot;extensión IV se </td><td> Abbott </td><td></td><td></td></tr><tr><td> 26 calibre veterinaria catéter IV </td><td> Monoject </td><td></td><td></td></tr><tr><td> Colorante azul de Evans </td><td> Sigma </td><td> E2129 </td><td></td></tr><tr><td> Bipolar </td><td> Codman </td><td></td><td></td></tr><tr><td> Filtro, 5 m </td><td> Braun </td><td></td><td></td></tr></tbody></table>

rat model of blood-brain barrier disruption to allow targeted neurovascular therapeutics

Células endoteliales con uniones estrechas a lo largo de la membrana basal y los pies de astrocitos finales rodean los vasos sanguíneos cerebrales para formar la barrera sangre-cerebro 1. La barrera selectivamente excluye moléculas de cruce entre la sangre y el cerebro en base a su tamaño y carga. Esta función puede impedir el suministro de agentes terapéuticos para trastornos neurológicos. Una serie de fármacos quimioterapéuticos, por ejemplo, no será efectiva cruzar la barrera sangre-cerebro para alcanzar las células tumorales 2. Por lo tanto, mejorar el suministro de fármacos a través de la barrera sangre-cerebro es un área de interés. Los métodos más frecuentes para intensificar el suministro de fármacos al cerebro son la infusión directa cerebral y la barrera hematoencefálica interrupción 3. Directos garantías infusión intracerebral que las terapias de alcanzar el cerebro, sin embargo, este método tiene una capacidad limitada para dispersar el fármaco 4. Barrera hematoencefálica interrupción (BBBD) allos puntos bajos de medicamentos para fluir directamente desde el sistema circulatorio en el cerebro y así llegar más eficazmente células tumorales dispersas. Tres métodos de alteración de la barrera incluyen alteración de la barrera osmótica, alteración de la barrera farmacológico, y el ultrasonido focalizado con microburbujas. Rotura osmótica, iniciada por Neuwelt, utiliza una solución hipertónica de 25% de manitol que deshidrata las células de la barrera sangre-cerebro, causando que se encojan y alterar sus uniones estrechas. Alteración de la barrera también se puede lograr con compuestos farmacológicamente vasoactivas tales como histamina y bradiquinina 5 6. Este método, sin embargo, es selectiva principalmente para la barrera cerebro-tumor 7. Además, RMP-7, un análogo del péptido bradiquinina, se encontró que era inferior en comparación cabeza a cabeza con BBBD osmótico con 25% de manitol 8. Otro método, ultrasonido focalizado (FUS), en relación con microburbujas agentes de contraste de ultrasonidos, también se ha demostradopara abrir reversiblemente la barrera sangre-cerebro 9. En comparación con FUS, sin embargo, 25% de manitol tiene una larga historia de seguridad en pacientes humanos que hace que sea una herramienta probada para la investigación traslacional 10-12. Con el fin de lograr BBBD, manitol deben ser entregados a una tasa alta directamente en la circulación arterial del cerebro. En los seres humanos, un catéter endovascular es guiado hasta el cerebro donde se puede flujo rápido, directo logrado. Este protocolo modelos BBBD humana tan estrechamente como sea posible. Después de un corte hacia abajo a la bifurcación de la arteria carótida común, se inserta un catéter retrógrado en el TCE y utilizados para entregar el manitol directamente en la arteria carótida interna (ICA) la circulación. Propofol y N 2 O anestesia se utilizan por su capacidad de maximizar la eficacia de la ruptura de la barrera 13. Si se ejecuta correctamente, este procedimiento tiene la capacidad de forma segura, eficaz y reversible abrir la barrera sangre-cerebro y mejorare la administración de fármacos que normalmente no llegan al cerebro 8,13,14.

<img alt="Figura 1" src="/files/ftp_upload/50019/50019fig1.jpg" /> Figura 1. Visualización de sangre-cerebro alteración de la barrera a través de la extravasación de azul de Evans colorante. Colorante azul de Evans es un pigmento que se une a la albúmina y no es extravasada en el cerebro en condiciones fisiológicas. La interrupción de la barrera sangre-cerebro en un lado del cerebro permite azul de Evans para entrar y mancha el azul hemisferio interrumpi...

Watch this Scientific Journal Video about Rat Model of Blood-brain Barrier Disruption to Allow Targeted Neurovascular Therapeutics at JoVE.com

Rat Model of Blood-brain Barrier Disruption to Allow Targeted Neurovascular Therapeutics

Hematoencefálica interrupción de la barrera ayuda a la entrega de ciertos medicamentos para el cerebro. Manitol entregado intraarterial células se contrae los vasos sanguíneos circundantes con el fin de perturbar físicamente la barrera.

Modelo de rata de ruptura de la barrera sangre-cerebro para permitir dirigida Therapeutics neurovascular

Endothelial cells with tight junctions along with the basement membrane and astrocyte end feet surround cerebral blood vessels to form the blood-brain ...

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JoVE Journal

Medicine

19.3K vistas.  Vanderbilt University School of Medicine. Hematoencefálica interrupción de la barrera ayuda a la entrega de ciertos medicamentos para el cerebro. Manitol entregado intraarterial células se contrae los vasos sanguíneos circundantes con el fin de perturbar físicamente la barrera.

Video: Rat Model of Blood-brain Barrier Disruption to Allow Targeted Neurovascular Therapeutics

MRI-guided Disruption of the Blood-brain Barrier using Transcranial Focused Ultrasound in a Rat Model

Focused ultrasound (FUS) disruption of the blood-brain barrier (BBB) is an increasingly investigated technique for circumventing the BBB1-5. The BBB is a significant obstacle to pharmaceutical treatments of brain disorders as it limits the passage of molecules from the vasculature into the brain tissue to molecules less than approximately 500 Da in size6. FUS induced BBB disruption (BBBD) is temporary and reversible4 and has an advantage over chemical means of inducing BBBD by being highly localized. FUS induced BBBD provides a means for investigating the effects of a wide range of therapeutic agents on the brain, which would not otherwise be deliverable to the tissue in sufficient concentration. While a wide range of ultrasound parameters have proven successful at disrupting the BBB2,5,7, there are several critical steps in the experimental procedure to ensure successful disruption with accurate targeting. This protocol outlines how to achieve MRI-guided FUS induced BBBD in a rat model, with a focus on the critical animal preparation and microbubble handling steps of the experiment.

Microbubble-mediated focused ultrasound disruption of the blood-brain barrier (BBB) is a promising technique for non-invasive targeted drug delivery in the brain1-3. This protocol outlines the experimental procedure for MRI-guided transcranial BBB disruption in a rat model.

Resonancia magnética guiada por disrupción de la barrera sangre-cerebro con ultrasonido transcraneal Enfocado en un modelo de rata

Focused ultrasound (FUS) disruption of the blood-brain barrier (BBB) is an increasingly investigated technique for circumventing the BBB1-5. The BBB is a ...

Investigación

Medicina

Stretch in Brain Microvascular Endothelial Cells (cEND) as an In Vitro Traumatic Brain Injury Model of the Blood Brain Barrier

Due to the high mortality incident brought about by traumatic brain injury (TBI), methods that would enable one to better understand the underlying mechanisms involved in it are useful for treatment. There are both in vivo and in vitro methods available for this purpose. In vivo models can mimic actual head injury as it occurs during TBI. However, in vivo techniques may not be exploited for studies at the cell physiology level. Hence, in vitro methods are more advantageous for this purpose since they provide easier access to the cells and the extracellular environment for manipulation.
Our protocol presents an in vitro model of TBI using stretch injury in brain microvascular endothelial cells. It utilizes pressure applied to the cells cultured in flexible-bottomed wells. The pressure applied may easily be controlled and can produce injury that ranges from low to severe. The murine brain microvascular endothelial cells (cEND) generated in our laboratory is a well-suited model for the blood brain barrier (BBB) thus providing an advantage to other systems that employ a similar technique. In addition, due to the simplicity of the method, experimental set-ups are easily duplicated. Thus, this model can be used in studying the cellular and molecular mechanisms involved in TBI at the BBB.

Stretch in Brain Microvascular Endothelial Cells cEND as an In Vitro Traumatic Brain Injury Model of the Blood Brain Barrier

In vitro traumatic brain injury models are being developed to reproduce in vivo brain deformation. Stretch-induced injury has been employed for astrocytes, neurons, glial cells, aortic, and brain endothelial cells. However, our system uses a blood brain barrier (BBB) model that possesses properties constituting a legitimate model of the BBB to establish an in vitro&#160;TBI model.

Estirar en Brain células endoteliales microvasculares (CEND) como<em&gt; In Vitro</em&gt; Lesión cerebral traumática Modelo de la barrera hematoencefálica

Due to the high mortality incident brought about by traumatic brain injury (TBI), methods that would enable one to better understand the underlying ...

Setting-up an In Vitro Model of Rat Blood-brain Barrier (BBB): A Focus on BBB Impermeability and Receptor-mediated Transport

The blood brain barrier (BBB) specifically regulates molecular and cellular flux between the blood and the nervous tissue. Our aim was to develop and characterize a highly reproducible rat syngeneic in vitro model of the BBB using co-cultures of primary rat brain endothelial cells (RBEC) and astrocytes to study receptors involved in transcytosis across the endothelial cell monolayer. Astrocytes were isolated by mechanical dissection following trypsin digestion and were frozen for later co-culture. RBEC were isolated from 5-week-old rat cortices. The brains were cleaned of meninges and white matter, and mechanically dissociated following enzymatic digestion. Thereafter, the tissue homogenate was centrifuged in bovine serum albumin to separate vessel fragments from nervous tissue. The vessel fragments underwent a second enzymatic digestion to free endothelial cells from their extracellular matrix. The remaining contaminating cells such as pericytes were further eliminated by plating the microvessel fragments in puromycin-containing medium. They were then passaged onto filters for co-culture with astrocytes grown on the bottom of the wells. RBEC expressed high levels of tight junction (TJ) proteins such as occludin, claudin-5 and ZO-1 with a typical localization at the cell borders. The transendothelial electrical resistance (TEER) of brain endothelial monolayers, indicating the tightness of TJs reached 300 ohm&#183;cm2 on average. The endothelial permeability coefficients (Pe) for lucifer yellow (LY) was highly reproducible with an average of 0.26 &#177;&#160;0.11 x 10-3 cm/min. Brain endothelial cells organized in monolayers expressed the efflux transporter P-glycoprotein (P-gp), showed a polarized transport of rhodamine 123, a ligand for P-gp, and showed specific transport of transferrin-Cy3 and DiILDL across the endothelial cell monolayer. In conclusion, we provide a protocol for setting up an in vitro BBB model that is highly reproducible due to the quality assurance methods, and that is suitable for research on BBB transporters and receptors.

Setting-up an In Vitro Model of Rat Blood-brain Barrier BBB: A Focus on BBB Impermeability and Receptor-mediated Transport

The aim of the present study was to validate the reproducibility of an in vitro BBB model involving a rat syngeneic co-culture of endothelial cells and astrocytes. The endothelial cell monolayer presented high TEER and low LY permeability. Expression of specific TJ proteins, functional responses to inflammation and functionality of transporters and receptors were assessed.

Establecimiento de un<em&gt; In Vitro</em&gt; Modelo de Rata barrera hematoencefálica (BBB): Un Enfoque en la acreditación Impermeabilidad y transporte mediado por los receptores

The blood brain barrier (BBB) specifically regulates molecular and cellular flux between the blood and the nervous tissue. Our aim was to develop and ...

Oxygen-Glucose Deprivation and Reoxygenation as an In Vitro Ischemia-Reperfusion Injury Model for Studying Blood-Brain Barrier Dysfunction

Ischemia-Reperfusion (IR) injury is known to contribute significantly to the morbidity and mortality associated with ischemic strokes. Ischemic cerebrovascular accidents account for 80% of all strokes. A common cause of IR injury is the rapid inflow of fluids following an acute/chronic occlusion of blood, nutrients, oxygen to the tissue triggering the formation of free radicals.
Ischemic stroke is followed by blood-brain barrier (BBB) dysfunction and vasogenic brain edema. Structurally, tight junctions (TJs) between the endothelial cells play an important role in maintaining the integrity of the blood-brain barrier (BBB). IR injury is an early secondary injury leading to a non-specific, inflammatory response. Oxidative and metabolic stress following inflammation triggers secondary brain damage including BBB permeability and disruption of tight junction (TJ) integrity.
Our protocol presents an in vitro example of oxygen-glucose deprivation and reoxygenation (OGD-R) on rat brain endothelial cell TJ integrity and stress fiber formation. Currently, several experimental in vivo models are used to study the effects of IR injury; however they have several limitations, such as the technical challenges in performing surgeries, gene dependent molecular influences and difficulty in studying mechanistic relationships. However, in vitro models may aid in overcoming many of those limitations. The presented protocol can be used to study the various molecular mechanisms and mechanistic relationships to provide potential therapeutic strategies. However, the results of in vitro studies may differ from standard in vivo studies and should be interpreted with caution.

Oxygen-Glucose Deprivation and Reoxygenation as an In Vitro Ischemia-Reperfusion Injury Model for Studying Blood-Brain Barrier Dysfunction

Ischemia-Reperfusion (IR) injury is associated with a high rate of morbidity and mortality. The goal of the in vitro model of oxygen-glucose deprivation and reoxygenation (OGD-R) described here is to assess the effects of ischemia reperfusion injury on a variety of cells, particularly in blood-brain barrier (BBB) endothelial cells.

Oxígeno-Glucosa Privación y Reoxigenación como<em&gt; In Vitro</em&gt; La isquemia-reperfusión modelo para el estudio de la disfunción barrera hematoencefálica

Ischemia-Reperfusion (IR) injury is known to contribute significantly to the morbidity and mortality associated with ischemic strokes. Ischemic ...

A Rat Carotid Balloon Injury Model to Test Anti-vascular Remodeling Therapeutics

The rat carotid balloon injury is a well-established surgical model that has been used to study arterial remodeling and vascular cell proliferation. It is also a valuable model system to test, and to evaluate therapeutics and drugs that negate maladaptive remodeling in the vessel. The injury, or barotrauma, in the vessel lumen caused by an inflated balloon via an inserted catheter induces subsequent neointimal growth, often leading to hyperplasia or thickening of the vessel wall that narrows, or obstructs the lumen. The method described here is sufficiently sensitive, and the results can be obtained in relatively short time (2 weeks after the surgery). The efficacy of the drug or therapeutic against the induced-remodeling can be evaluated either by the post-mortem pathological and histomorphological analysis, or by ultrasound sonography in live animals. In addition, this model system has also been used to determine the therapeutic window or the time course of the administered drug. These studies can leadto the development of a better administrative strategy and a better therapeutic outcome. The procedure described here provides a tool for translational studies that bring drug and therapeutic candidates from bench research to clinical applications.

The rat carotid balloon injury model described below allows researchers to evaluate drugs or therapeutics that negate injury-induced arterial hyperplasia. Detailed pre-surgical preparation, surgical procedure, and post-surgical cares of the animal are described.

Una rata carótida lesión con el balón modelo para probar Terapéutica Remodelación Anti-vasculares

The rat carotid balloon injury is a well-established surgical model that has been used to study arterial remodeling and vascular cell proliferation. It is ...

Retroductal Submandibular Gland Instillation and Localized Fractionated Irradiation in a Rat Model of Salivary Hypofunction

Normal tissues that lie within the portals of radiation are inadvertently damaged. Salivary glands are often injured during head and neck radiotherapy. Irreparable cell damage results in a chronic loss of salivary function that impairs basic oral activities, and increases the risk of oral infections and dental caries. Salivary hypofunction and its complications gravely impact a patient's comfort. Current symptomatic management of the condition is ineffective, and newer therapies to assuage the condition are needed. 
Salivary glands are exocrine glands, which expel their secretions into the mouth via excretory ducts. Cannulation of these ducts provides direct access to the glands. Retroductal delivery of a contrast agent to major salivary glands is a routine out-patient procedure for diagnostic imaging. Using a similar procedure, localized treatment of the glands is feasible. However, performing this technique in preclinical studies with small animals poses unique challenges. In this study we describe the technique of retroductal administration in rat submandibular glands, a procedure that was refined in Dr. Bruce Baum's laboratory (NIH)1, and lay out a procedure for local gland irradiation.

Salivary gland hypofunction, a major adverse effect of head and neck radiotherapy diminishes a patient's quality of life. The demonstration of efficacy of new therapies in animal models is a prerequisite before clinical transition. This protocol describes retroductal administration and local irradiation of rat submandibular glands.

Retroductal submandibular Glándula instilación y con localización fraccionado irradiación en un modelo de rata de hipofunción salival

Normal tissues that lie within the portals of radiation are inadvertently damaged. Salivary glands are often injured during head and neck radiotherapy. ...

In Vitro Assays to Assess Blood-brain Barrier Mesh-like Vessel Formation and Disruption

Blood-brain barrier (BBB) coverage plays a central role in the homeostasis of the central nervous system (CNS). The BBB is dynamically maintained by astrocytes, pericytes and brain endothelial cells (BECs). Here, we detail methods to assess BBB coverage using single cultures of immortalized human BECs, single cultures of primary mouse BECs, and a humanized triple culture model (BECs, astrocytes and pericytes) of the BBB. To highlight the applicability of the assays to disease states, we describe the effect of oligomeric amyloid-&#946; (oA&#946;), which is an important contributor to Alzheimer&#39;s disease (AD) progression, on BBB coverage. Further, we utilize the epidermal growth factor (EGF) to illuminate the drug screening potential of the techniques. Our results show that single and triple cultured BECs form meshwork-like structures under basal conditions, and that oA&#946; disrupts this cell meshwork formation and degenerates the preformed mesh structures, but EGF blocks this disruption. Thus, the techniques described are important for dissecting fundamental and disease-relevant processes that modulate BBB coverage.

In Vitro Assays to Assess Blood-brain Barrier Mesh-like Vessel Formation and Disruption

Maintaining blood-brain barrier coverage is key for the homeostasis of the central nervous system. This protocol describes in vitro techniques to delineate the fundamental and pathological processes that modulate blood-brain barrier coverage.

Ensayos in vitro para evaluar la formación y la interrupción de los vasos sanguíneos de barrera hematoencefálica

Blood-brain barrier (BBB) coverage plays a central role in the homeostasis of the central nervous system (CNS). The BBB is dynamically maintained by ...

Improved Method for the Establishment of an In Vitro Blood-Brain Barrier Model Based on Porcine Brain Endothelial Cells

The aim of this protocol presents an optimized procedure for the purification and cultivation of pBECs and to establish in vitro blood-brain barrier (BBB) models based on pBECs in mono-culture (MC), MC with astrocyte-conditioned medium (ACM), and non-contact co-culture (NCC) with astrocytes of porcine or rat origin. pBECs were isolated and cultured from fragments of capillaries from the brain cortices of domestic pigs 5-6 months old. These fragments were purified by careful removal of meninges, isolation and homogenization of grey matter, filtration, enzymatic digestion, and centrifugation. To further eliminate contaminating cells, the capillary fragments were cultured with puromycin-containing medium. When 60-95% confluent, pBECs growing from the capillary fragments were passaged to permeable membrane filter inserts and established in the models. To increase barrier tightness and BBB characteristic phenotype of pBECs, the cells were treated with the following differentiation factors: membrane permeant 8-CPT-cAMP (here abbreviated cAMP), hydrocortisone, and a phosphodiesterase inhibitor, RO-20-1724 (RO). The procedure was carried out over a period of 9-11 days, and when establishing the NCC model, the astrocytes were cultured 2-8 weeks in advance. Adherence to the described procedures in the protocol has allowed the establishment of endothelial layers with highly restricted paracellular permeability, with the NCC model showing an average transendothelial electrical resistance (TEER) of 1249 &#177; 80 &#937; cm2, and paracellular permeability (Papp) for Lucifer Yellow of 0.90 10-6 &#177; 0.13 10-6 cm sec-1 (mean &#177; SEM, n=55). Further evaluation of this pBEC phenotype showed good expression of the tight junctional proteins claudin 5, ZO-1, occludin and adherens junction protein p120 catenin. The model presented can be used for a range of studies of the BBB in health and disease and, with the highly restrictive paracellular permeability, this model is suitable for studies of transport and intracellular trafficking.

Improved Method for the Establishment of an In Vitro Blood-Brain Barrier Model Based on Porcine Brain Endothelial Cells

The aim of the protocol is to present an optimized procedure for the establishment of an in vitro blood-brain barrier (BBB) model based on primary porcine brain endothelial cells (pBECs). The model shows high reproducibility, high tightness, and is suitable for studies of transport and intracellular trafficking in drug discovery.

Mejor método para el establecimiento de un In Vitro Barrera Blood - Brain modelo basado en las células endoteliales de cerebro porcino

The aim of this protocol presents an optimized procedure for the purification and cultivation of pBECs and to establish in vitro blood-brain barrier (BBB) ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

Medición de la contractilidad isométrica de la arteria mesentérica de ratón con cable miografía

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...

Delivery of Cardioactive Therapeutics in a Porcine Myocardial Infarction Model

Myocardial infarction is one of the leading causes of death and disability worldwide, and there is an urgent need for novel cardioprotective or regenerative strategies. An essential component of drug development is determining how a novel therapeutic is to be administered. Physiologically relevant large animal models are of critical importance in assessing the feasibility and efficacy of various therapeutic delivery strategies. Due to their similarities to humans in cardiovascular physiology, coronary vascular anatomy, and heart weight to body weight ratio, swine is one of the preferred species in the preclinical evaluation of new therapies for myocardial infarction. The present protocol describes three methods of administering cardioactive therapeutic agents in a porcine model. After percutaneously induced myocardial infarction, female landrace swine received treatment with novel agents through either: (1) thoracotomy and transepicardial injection, (2) catheter-based transendocardial injection, or (3) intravenous infusion via jugular vein osmotic minipump. The procedures employed for each technique are reproducible, resulting in reliable cardioactive drug delivery. These models can be easily adapted to suit individual study designs, and each of these delivery techniques can be used to investigate a variety of possible interventions. Therefore, these methods are a useful tool for translational scientists pursuing novel biological approaches in cardiac repair following myocardial infarction.

The present protocol describes three methods of administering cardioactive therapeutic agents in a porcine model. Female landrace swine received treatment through either: (1) thoracotomy and transepicardial injection, (2) catheter-based transendocardial injection, or (3) intravenous infusion via jugular vein osmotic minipump.