The authors would like to acknowledge the support of NIH/NIDDK K12 DK100014 (Lan Lu), the Case Comprehensive Cancer Center (NIH/NCI P30 CA43703), and the Clinical and Translation Science Collaborative of Cleveland (NIH/NCATS UL1 TR000439).

Todos los estudios en animales se realizaron de acuerdo con los protocolos aprobados del Comité de Uso y Cuidado de Animales Institucionales (IACUC) en Case Western Reserve University. La duración del procedimiento quirúrgico descrito a continuación es de aproximadamente 45-60 min. El procedimiento de MRI en sí es de aproximadamente 15 minutos para cada punto de tiempo. 1. Anestesia <ol><li> Anestesiar la rata en una cámara de isoflurano fijada al 2% de isoflurano mezclado con oxígeno para facilitar el manejo y retención de los animales antes de administrar la anestesia inyectable intraperitonealmente. </li><li> Después de 3-5 minutos de exposición al isoflurano, compruebe que el animal está anestesiado y no muestra ninguna respuesta al pellizcado. </li><li> Además, sedar a la rata con una inyección intraperitoneal de una mezcla de xilazina y ketamina: 75 mg / kg de ketamina / 10 mg / kg de xilazina. Cuando realice inyecciones intraperitoneales, retire la aguja para asegurarse de que las porciones del intestino u otros órganos vitales no hayan sido perforadas. </li><li> yoInyectar 2 mg / kg de bupivacaína por vía subcutánea en el sitio de la incisión para proporcionar alivio tópico del dolor. </li></ol> 2. Preparación del área quirúrgica <ol><li> Esterilizar los instrumentos quirúrgicos y los suministros antes de que se usen para la cirugía y colocar en la almohadilla quirúrgica para la esterilidad. La mayoría de los instrumentos y suministros pueden autoclavarse y reutilizarse. </li><li> Use guantes estériles para todos los procedimientos quirúrgicos. </li><li> Use una maquinilla de afeitar eléctrica para afeitar la piel del lado derecho del animal. Afeitar el animal desde el fondo de la caja torácica hasta la parte superior de la pata trasera, proporcionando un gran área sin pelo para la incisión. </li><li> Coloque el animal sobre una almohadilla quirúrgica estéril para aislar el área desinfectada de las áreas circundantes. </li><li> Frote la piel con un desinfectante como povidona yodada o betadina. Comience el lavado en el centro del sitio quirúrgico y muévase al exterior en una manera circular. Repita al menos tres veces con un nuevo trapo de yodo povidona o betadina. </Li <li> Fregar el sitio quirúrgico con algodón con alcohol 70% hasta que la piel está clara, ya que el yodo puede ser tóxico si se absorbe. </li></ol> 3. Procedimiento quirúrgico <ol><li> Mantener este procedimiento bajo condiciones asépticas. </li><li> Coloque el animal anestesiado en un lecho calentador caliente en posición de decúbito lateral izquierdo con el flanco derecho hacia arriba. NOTA: Se debe tener cuidado de mantener la temperatura corporal del animal a 35-37 ° C para prevenir la hipotermia. Esta cama de calentamiento también debe esterilizarse según sea necesario para mantener condiciones asépticas. </li><li> Sentirse por la caja torácica y realizar una pequeña incisión retroperitoneal dorsal derecha de 2-3 cm con una cuchilla de bisturí estéril de tamaño 10 que comienza en la parte inferior de la caja torácica. </li><li> Coloque gasa estéril longitudinalmente a lo largo de ambos lados de la incisión. </li><li> Diseccionar el tejido subcutáneo, la grasa y los músculos para visualizar y acceder a la cavidad abdominal. Utilice las tijeras Mayo de hoja curvada para permitir una penetración más profundaRación en la herida y cortar tejidos gruesos. </li><li> Una vez que el hígado es claramente visible y accesible, use fórceps romos para retraer el hígado hacia arriba. </li><li> Usando otro par de fórceps romos en la otra mano, exponga el riñón derecho para que se sienta justo fuera de la cavidad abdominal. </li><li> Utilice el dedo indicador y el pulgar de la mano izquierda para mantener el riñón en posición. Con la mano derecha, inyectar lenta y firmemente 0,1 ml de solución de E. coli UTI89 (concentración entre 1 x 10 8 -1 x 10 9 ) desde una jeringa estéril hasta la pelvis renal (que aparece como una burbuja blanca) 15 . NOTA: Preparar el título bacteriano como se describe en la referencia 15 . </li><li> Coloque una tira de hemostasis absorbible sobre la aguja para evitar la salida del inóculo al peritoneo. Lentamente jale la aguja de la pelvis renal. NOTA: Debe tenerse cuidado de no perforar o infectar los tejidos circundantes resultando en infecciones fuera deOns y / o complicaciones. </li><li> Use una jeringa más grande para enjuagar completamente el riñón con solución salina normal antes de volver a colocarla en la cavidad abdominal. </li></ol> 4. Suturas Nota: La sutura que será enterrada en los tejidos debe ser 4-0 suturas trenzadas no absorbibles. Se pueden usar suturas absorbibles o monofilamento para superficies corporales. <ol><li> Coloque las suturas de manera uniforme y tan cerca del borde del tejido como sea posible para evitar la obstrucción del flujo sanguíneo; Típicamente no más de 0,3 cm del borde es necesario. </li><li> Agarre la piel y retírela ligeramente usando un par de fórceps dentados finos, y gire el soporte de la aguja en una posición pronada en preparación para perforar la piel. </li><li> Conduzca la aguja a través del espesor total de la piel supinando la muñeca para girar la aguja y pasarla a través de la piel. </li><li> Repita este proceso para el borde de la piel más cercano al individuo que realiza el procedimiento. </li><li> ApretarLas suturas lo suficiente como para oponerse a los bordes de los tejidos. Cualquier restricción obstruirá el suministro de sangre, cicatrización lenta de la herida y puede resultar en dehiscencia. </li><li> Sujete la sutura con nudos cuadrados, como si fuera una simple puntada interrumpida, excepto que sólo se cortó la hebra corta, dejando alrededor de una cola de 3-4 mm. </li><li> Después de haber atado la primera puntada, prepárese para colocar una segunda puntada a unos 3 mm de distancia de la primera, y continúe con la sutura en marcha. </li><li> Una vez que se ha alcanzado el final de la incisión, no tire completamente de la última puntada. En su lugar, utilice el lazo que se mantiene con el soporte de la aguja aquí como el cordón corto con el fin de amarrar el extremo distal del cierre de la sutura. </li><li> Usando los lazos del instrumento, atar la sutura usando nudos cuadrados. Esto da lugar a 3 hilos que sobresalen del nudo completo en el extremo distal. </li></ol> 5. Recuperación de animales <ol><li> Inyectar 2,1 mg / kg de Yohimbina intraperitonealmente después de la cirugía para revertir la anestesia. UNSe espera que los nimales se recuperen completamente del procedimiento quirúrgico después de 3-5 h. </li><li> Mantenga el animal en una almohadilla de calentamiento (para evitar la hipotermia) y ropa de cama blanda absorbente después de la cirugía. </li><li> Proporcionar rehidratación con líquidos orales o parenterales hasta que pueda volver a la alimentación normal (dentro de las 24 horas). Inyectar aproximadamente 0,6 ml de solución salina normal peritonealmente inmediatamente después de la cirugía para limitar los efectos de la deshidratación. </li><li> Proporcionar analgesia como se describe en el IACUC aprobado Animal Care and Use Protocol. Inyectar 5 mg / kg de carprofeno por vía subcutánea para el tratamiento del dolor. </li><li> Monitorear las incisiones con regularidad por hinchazón, exudado, dolor o dehiscencia. </li></ol> 6. Validación mediante Imágenes de Resonancia Magnética <ol><li> Realización de experimentos de resonancia magnética en vivo en escáneres de RMN de animales pequeños de alto campo. </li><li> Inducir la anestesia con isoflurano al 3% en oxígeno y colocar al animal con el riñón derecho en el isocentro en el escáner de RM y apropiarseBobina de radiofrecuencia. Proporcionar a los animales con 1-2% de anestesia de isoflurano continuamente durante el procedimiento de imagen a través de una nosecone. NOTA: Para las imágenes de IRM in vivo mostradas en la Figura 1 , se utilizó una bobina de volumen de tamaño de rata (diámetro interior = 72 mm). </li><li> Use un sistema de monitoreo y control de animales para mantener la tasa de respiración de cada animal (40-60 respiraciones / min) y la temperatura corporal central (35 ± 1 ° C). </li><li> Utilice una adquisición de resonancia magnética de eco de spin multi-rebanada y multi-eco para obtener imágenes axiales de alta resolución en T2 de los riñones infectados y de control. Los parámetros típicos de adquisición de MRI son el tiempo de repetición = 5.000 ms, el tiempo de eco = 40 ms, el grosor de corte = 2.0 mm, la resolución espacial en el plano = 200 μm, 3 medias de señal y un tiempo de adquisición de 8 min. </li></ol>

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The authors have no other disclosures.

La pielonefritis aguda ascendente en roedores (es decir, ratones y ratas) puede ser producida por cateterización transuretral. 16 , 17 , 18 Este método de infección transuretral es ventajoso porque no es invasivo y imita la fisiopatología humana de la infección ascendente. 17 , 18 , 19 , 20</s...

Los modelos de roedores se han utilizado para estudiar numerosas manifestaciones de la enfermedad humana, incluyendo pielonefritis e infecciones del tracto urinario (ITU). Las IU son un problema de salud global y pueden afectar a niños, hombres y mujeres de todas las edades. 1 , 2 , 3 La manifestación inicial de las IU incluye cistitis, y si la infección asciende a lo largo del uréter, puede aparecer una infección renal (pielonefritis). Al mismo tiempo, la prevalencia de la diabetes se aproxima a 400 millones de personas en todo el mundo. 4 , 5 Es importante destacar que la incidencia de UTI puede ser hasta 4 veces mayor en pacientes obesos o con diabetes mellitus tipo 2, lo que aumenta el riesgo de infección recurrente por ITU (rUTI), sepsis, fibrosis renal por pielonefritis y disfunción vesical. 6 , 7 , 8 RoedorLos modelos son importantes en el estudio de las ITU, porque las actuales terapias con antibióticos producen una respuesta sostenida y preventiva sólo en un subconjunto de pacientes con IU. Para mejorar el cuidado clínico de la UTI, los pasos clave son entender el mecanismo de rUTI y sus procesos fisiopatológicos de la infección aguda a la inflamación a la fibrosis, así como el impacto de la diabetes mellitus tipo 2. El objetivo de mejorar los modelos animales es desarrollar técnicas que permitan una evaluación más precisa de la progresión de la enfermedad y las intervenciones terapéuticas. Se han empleado varios enfoques diferentes para inducir pielonefritis en ratas y / o ratones para estudiar la fisiopatología del daño renal, el efecto del tratamiento antibiótico y otros aspectos del curso natural de las ITU. Un enfoque común para establecer UTI retrógrada es el cateterismo transuretral. 10 , 11 , 12 , 13 &lt;Este método introduce bacterias a través de la uretra en la vejiga urinaria de animales anestesiados. Si bien esta técnica simula de cerca la pielonefritis humana, la incidencia real y la magnitud de la infección pielonefritis puede ser muy variable debido a múltiples factores, incluyendo la falta de reflujo ureteral espontáneo o urinario micción durante o inmediatamente después de la inoculación. 11 Como resultado, la variabilidad experimental en la inducción de una infección pielonefritis ascendente puede limitar la utilidad de este modelo para estudiar infecciones de los riñones, así como estrategias terapéuticas. Este informe describe un modelo de rata de pielonefritis quirúrgica donde E. coli se inyecta directamente en el riñón de rata. A pesar de que este modelo de rata es invasivo, la cantidad de E. coli suministrada al riñón puede controlarse eficazmente permitiendo una infección renal robusta e inflamación. 14 Dentro de este procedimiento, también describimosCómo estas infecciones renales inducidas pueden ser monitoreadas longitudinalmente con Imágenes de Resonancia Magnética in vivo (MRI).

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			<td height="21" style="height:21px;width:216px;">Absorbing Pad</td>
			<td style="width:195px;">Fisher</td>
			<td style="width:168px;">14-127-47</td>
			<td style="width:167px;"></td>
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			<td height="21" style="height:21px;width:216px;">Sterile Cotton Gauze Pad</td>
			<td style="width:195px;">Fisher</td>
			<td style="width:168px;">22-415-469</td>
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			<td height="21" style="height:21px;">Latex Surgical Gloves</td>
			<td>Henry Schein Animal Health</td>
			<td>21540</td>
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			<td height="21" style="height:21px;width:216px;">Curved Mayo Scissors</td>
			<td style="width:195px;">Fisher</td>
			<td style="width:168px;">S17341</td>
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			<td height="21" style="height:21px;width:216px;">Straight Blunt Foreceps</td>
			<td style="width:195px;">Fisher</td>
			<td style="width:168px;">08-895</td>
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			<td height="21" style="height:21px;width:216px;">Scalpel Handle&#160;</td>
			<td style="width:195px;">Fisher</td>
			<td style="width:168px;">08-913-5</td>
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			<td height="21" style="height:21px;width:216px;">Sterile Scalpel Blades</td>
			<td style="width:195px;">Fisher</td>
			<td style="width:168px;">53220</td>
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			<td height="21" style="height:21px;width:216px;">1mL Luer-Lok Syringe</td>
			<td style="width:195px;">BD Biosciences</td>
			<td>309628</td>
			<td>For bacterial injections</td>
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			<td height="21" style="height:21px;">20mL Luer-Lok Syringe&#160;</td>
			<td style="width:195px;">BD Biosciences</td>
			<td>301031</td>
			<td>For saline wash</td>
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			<td height="21" style="height:21px;width:216px;">Hemostat</td>
			<td style="width:195px;">Seneca Medical</td>
			<td style="width:168px;">240267</td>
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			<td height="21" style="height:21px;">23 G 3/4 in. Needle&#160;</td>
			<td style="width:195px;">BD Biosciences</td>
			<td style="width:168px;">305143</td>
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			<td height="21" style="height:21px;">30 G 1 in. Needle&#160;</td>
			<td style="width:195px;">BD Biosciences</td>
			<td style="width:168px;">305128</td>
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			<td height="21" style="height:21px;">U-100 Insulin Syringe</td>
			<td>Exel International&#160;</td>
			<td style="width:168px;">25846</td>
			<td>For medication injections</td>
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			<td height="21" style="height:21px;">Isoflurane</td>
			<td>Henry Schein Animal Health</td>
			<td>050033</td>
			<td></td>
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			<td height="21" style="height:21px;">Xylazine</td>
			<td>Henry Schein Animal Health</td>
			<td>33197</td>
			<td>Inject IP</td>
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			<td height="21" style="height:21px;width:216px;">Ketamine</td>
			<td>Patterson Vetrinary&#160;</td>
			<td>07-881-9413</td>
			<td>Inject IP</td>
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			<td height="21" style="height:21px;width:216px;">Yohimbine (Atipamezole)</td>
			<td style="width:195px;">Patterson Vetrinary&#160;</td>
			<td>07-867-7097</td>
			<td>Inject IP after surgery</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Bupivacaine (Marcaine)</td>
			<td style="width:195px;">Patterson Vetrinary&#160;</td>
			<td>07-890-4584</td>
			<td>Inject SQ at site of incision&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Carprofen (Rimadyl)</td>
			<td style="width:195px;">Patterson Vetrinary&#160;</td>
			<td>07-844-7425</td>
			<td>Should be kept at 4 &#7506;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">4-0 Chromic Gut Suture</td>
			<td style="width:195px;">Ethicon Inc.</td>
			<td>U203H</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">4-0 Braided Vicryl Suture</td>
			<td>Ethicon Inc.</td>
			<td>J304H</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">1mL SubQ Syringe</td>
			<td>BD Biosciences</td>
			<td>309597</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">E. coli&#160; UTI89 or CFT073</td>
			<td style="width:195px;">ATCC</td>
			<td style="width:168px;">700928</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Surgicel Absorbable Hemostat</td>
			<td style="width:195px;">Ethicon Inc.</td>
			<td>ETH1951CS&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Biospec 9.4T MRI&#160;</td>
			<td style="width:195px;">Bruker&#160;</td>
			<td style="width:168px;">94/20 USR</td>
			<td></td>
		</tr>
	</tbody>
</table>

intrarenal injection of escherichia coli in a rat model of pyelonephritis

Pyelonephritis is a bacterial infection of the kidney and is most commonly caused by Escherichia coli. Recurrent infections can cause significant renal inflammation and fibrosis ultimately resulting in declining kidney function. Before improved clinical management and prevention of pyelonephritis can be instituted, a reliable animal model must be established in order to study the mechanisms of progression, recurrence, and therapeutic efficacy. The transurethral infection model closely mimics human pyelonephritis but exhibits considerable variation due to its reliance on urethral reflux to transport the bacteria to the kidney. Herein, a detailed surgical protocol for performing bacterial injections into the rat renal pelvis is provided and confirmed by non-invasive Magnetic Resonance Imaging (MRI). Using this protocol, animals receive direct exposure to a desired concentration of E. coli bacteria and can fully recover from the surgical procedure with adequate post-operative care. This facilitates subsequent longitudinal MRI assessments of the experimental animal models for comparison with saline (sham) controls. Using this direct delivery approach, the severity of infection is controllable and applicable for mechanistic studies of progression as well as development of novel treatment strategies.

Las técnicas de imagen médica ofrecen la oportunidad de evaluar de forma no invasiva la IU y la eficacia terapéutica. Por lo tanto, la resonancia magnética se utilizó para validar la inducción de infección aguda después de la inyección de 1-2 x 10 7 UTI89 E. coli , y para visualizar los cambios en el riñón antes y después de la cirugía. La Figura 1a-b muestra una región progresivamente creciente de la infección renal (flechas amarillas)...

Watch this Scientific Journal Video about Intrarenal Injection of Escherichia coli in a Rat Model of Pyelonephritis at JoVE.com

Intrarenal Injection of Escherichia coli in a Rat Model of Pyelonephritis

This manuscript describes a rat surgical model of pyelonephritis using direct intra-renal infection by Escherichia coli into the renal pelvis. The experimental procedure can be utilized to study the pathogenesis of pyelonephritis as well as the associated inflammation and fibrosis.

Intrarrenal Inyección de<em&gt; Escherichia coli</em&gt; En un modelo de rata de pielonefritis

Pyelonephritis is a bacterial infection of the kidney and is most commonly caused by Escherichia coli. Recurrent infections can cause significant renal ...

intrarenal-injection-escherichia-coli-rat-model

Research

JoVE Journal

Medicine

Intrarenal Injection of Escherichia coli in a Rat Model of Pyelonephritis

7.9K vistas.  Case Western Reserve University. This manuscript describes a rat surgical model of pyelonephritis using direct intra-renal infection by Escherichia coli into the renal pelvis. The experimental procedure can be utilized to study the pathogenesis of pyelonephritis as well as the associated inflammation and fibrosis.

Video: Intrarenal Injection of Escherichia coli in a Rat Model of Pyelonephritis

Coronary Artery Ligation and Intramyocardial Injection in a Murine Model of Infarction

Mouse models are a valuable tool for studying acute injury and chronic remodeling of the myocardium in vivo. With the advent of genetic modifications to the whole organism or the myocardium and an array of biological and/or synthetic materials, there is great potential for any combination of these to assuage the extent of acute ischemic injury and impede the onset of heart failure pursuant to myocardial remodeling. 
Here we present the methods and materials used to reliably perform this microsurgery and the modifications involved for temporary (with reperfusion) or permanent coronary artery occlusion studies as well as intramyocardial injections. The effects on the heart that can be seen during the procedure and at the termination of the experiment in addition to histological evaluation will verify efficacy. 
Briefly, surgical preparation involves anesthetizing the mice, removing the fur on the chest, and then disinfecting the surgical area. Intratracheal intubation is achieved by transesophageal illumination using a fiber optic light. The tubing is then connected to a ventilator. An incision made on the chest exposes the pectoral muscles which will be cut to view the ribs. For ischemia/reperfusion studies, a 1 cm piece of PE tubing placed over the heart is used to tie the ligature to so that occlusion/reperfusion can be customized. For intramyocardial injections, a Hamilton syringe with sterile 30gauge beveled needle is used. When the myocardial manipulations are complete, the rib cage, the pectoral muscles, and the skin are closed sequentially. Line block analgesia is effected by 0.25% marcaine in sterile saline which is applied to muscle layer prior to closure of the skin. The mice are given a subcutaneous injection of saline and placed in a warming chamber until they are sternally recumbent. They are then returned to the vivarium and housed under standard conditions until the time of tissue collection. At the time of sacrifice, the mice are anesthetized, the heart is arrested in diastole with KCl or BDM, rinsed with saline, and immersed in fixative. Subsequently, routine procedures for processing, embedding, sectioning, and histological staining are performed. 
Nonsurgical intubation of a mouse and the microsurgical manipulations described make this a technically challenging model to learn and achieve reproducibility. These procedures, combined with the difficulty in performing consistent manipulations of the ligature for timed occlusion(s) and reperfusion or intramyocardial injections, can also affect the survival rate so optimization and consistency are critical.

Numerous genetic manipulations and/or intramyocardial injections of genes, proteins, cells, and/or biomaterials are superimposed upon the dimension of time in studies of acute ischemia/ reperfusion injury and chronic remodeling in mice. This video illustrates the microsurgical procedures for ischemia/reperfusion, permanent coronary artery ligation, and intramyocardial injection studies.

Ligadura de las arterias coronarias y la inyección intramiocárdica en un modelo murino de infarto

Mouse models are a valuable tool for studying acute injury and chronic remodeling of the myocardium in vivo.  With the advent of genetic modifications to ...

Investigación

Medicina

Multi-modal Imaging of Angiogenesis in a Nude Rat Model of Breast Cancer Bone Metastasis Using Magnetic Resonance Imaging, Volumetric Computed Tomography and Ultrasound

Angiogenesis is an essential feature of cancer growth and metastasis formation. In bone metastasis, angiogenic factors are pivotal for tumor cell proliferation in the bone marrow cavity as well as for interaction of tumor and bone cells resulting in local bone destruction. Our aim was to develop a model of experimental bone metastasis that allows in vivo assessment of angiogenesis in skeletal lesions using non-invasive imaging techniques.
For this purpose, we injected 105 MDA-MB-231 human breast cancer cells into the superficial epigastric artery, which precludes the growth of metastases in body areas other than the respective hind leg1. Following 25-30 days after tumor cell inoculation, site-specific bone metastases develop, restricted to the distal femur, proximal tibia and proximal fibula1. Morphological and functional aspects of angiogenesis can be investigated longitudinally in bone metastases using magnetic resonance imaging (MRI), volumetric computed tomography (VCT) and ultrasound (US).
MRI displays morphologic information on the soft tissue part of bone metastases that is initially confined to the bone marrow cavity and subsequently exceeds cortical bone while progressing. Using dynamic contrast-enhanced MRI (DCE-MRI) functional data including regional blood volume, perfusion and vessel permeability can be obtained and quantified2-4. Bone destruction is captured in high resolution using morphological VCT imaging. Complementary to MRI findings, osteolytic lesions can be located adjacent to sites of intramedullary tumor growth. After contrast agent application, VCT angiography reveals the macrovessel architecture in bone metastases in high resolution, and DCE-VCT enables insight in the microcirculation of these lesions5,6. US is applicable to assess morphological and functional features from skeletal lesions due to local osteolysis of cortical bone. Using B-mode and Doppler techniques, structure and perfusion of the soft tissue metastases can be evaluated, respectively. DCE-US allows for real-time imaging of vascularization in bone metastases after injection of microbubbles7.
In conclusion, in a model of site-specific breast cancer bone metastases multi-modal imaging techniques including MRI, VCT and US offer complementary information on morphology and functional parameters of angiogenesis in these skeletal lesions.

In the pathogenesis of bone metastasis, angiogenesis is a crucial process and therefore represents a target for imaging and therapy. Here, we present a rat model of site-specific breast cancer bone metastasis and describe strategies to non-invasively image angiogenesis in vivo using magnetic resonance imaging, volumetric computed tomography and ultrasound.

Multimodal de imágenes de la angiogénesis en un modelo de rata desnuda de las metástasis óseas del cáncer de pecho utilizando imágenes de resonancia magnética, tomografía computarizada y la ecografía volumétrica

Angiogenesis is an essential feature of cancer growth and metastasis formation. In bone metastasis, angiogenic factors are pivotal for tumor cell ...

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

Endothelial cells with tight junctions along with the basement membrane and astrocyte end feet surround cerebral blood vessels to form the blood-brain barrier1. The barrier selectively excludes molecules from crossing between the blood and the brain based upon their size and charge. This function can impede the delivery of therapeutics for neurological disorders. A number of chemotherapeutic drugs, for example, will not effectively cross the blood-brain barrier to reach tumor cells2. Thus, improving the delivery of drugs across the blood-brain barrier is an area of interest.
The most prevalent methods for enhancing the delivery of drugs to the brain are direct cerebral infusion and blood-brain barrier disruption3. Direct intracerebral infusion guarantees that therapies reach the brain; however, this method has a limited ability to disperse the drug4. Blood-brain barrier disruption (BBBD) allows drugs to flow directly from the circulatory system into the brain and thus more effectively reach dispersed tumor cells. Three methods of barrier disruption include osmotic barrier disruption, pharmacological barrier disruption, and focused ultrasound with microbubbles. Osmotic disruption, pioneered by Neuwelt, uses a hypertonic solution of 25% mannitol that dehydrates the cells of the blood-brain barrier causing them to shrink and disrupt their tight junctions. Barrier disruption can also be accomplished pharmacologically with vasoactive compounds such as histamine5 and bradykinin6. This method, however, is selective primarily for the brain-tumor barrier7. Additionally, RMP-7, an analog of the peptide bradykinin, was found to be inferior when compared head-to-head with osmotic BBBD with 25% mannitol8. Another method, focused ultrasound (FUS) in conjunction with microbubble ultrasound contrast agents, has also been shown to reversibly open the blood-brain barrier9. In comparison to FUS, though, 25% mannitol has a longer history of safety in human patients that makes it a proven tool for translational research10-12.
In order to accomplish BBBD, mannitol must be delivered at a high rate directly into the brain's arterial circulation. In humans, an endovascular catheter is guided to the brain where rapid, direct flow can be accomplished. This protocol models human BBBD as closely as possible. Following a cut-down to the bifurcation of the common carotid artery, a catheter is inserted retrograde into the ECA and used to deliver mannitol directly into the internal carotid artery (ICA) circulation. Propofol and N2O anesthesia are used for their ability to maximize the effectiveness of barrier disruption13. If executed properly, this procedure has the ability to safely, effectively, and reversibly open the blood-brain barrier and improve the delivery of drugs that do not ordinarily reach the brain 8,13,14.

Blood-brain barrier disruption aids the delivery of certain drugs to the brain. Mannitol delivered intra-arterially shrinks cells surrounding blood vessels in order to physically disrupt the barrier.

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 ...

A Model of Chronic Nutrient Infusion in the Rat

Chronic exposure to excessive levels of nutrients is postulated to affect the function of several organs and tissues and to contribute to the development of the many complications associated with obesity and the metabolic syndrome, including type 2 diabetes. To study the mechanisms by which excessive levels of glucose and fatty acids affect the pancreatic beta-cell and the secretion of insulin, we have established a chronic nutrient infusion model in the rat. The procedure consists of catheterizing the right jugular vein and left carotid artery under general anesthesia; allowing a 7-day recuperation period; connecting the catheters to the pumps using a swivel and counterweight system that enables the animal to move freely in the cage; and infusing glucose and/or Intralipid (a soybean oil emulsion which generates a mixture of approximately 80% unsaturated/20% saturated fatty acids when infused with heparin) for 72 hr. This model offers several advantages, including the possibility to finely modulate the target levels of circulating glucose and fatty acids; the option to co-infuse pharmacological compounds; and the relatively short time frame as opposed to dietary models. It can be used to examine the mechanisms of nutrient-induced dysfunction in a variety of organs and to test the effectiveness of drugs in this context.

A protocol for chronic infusions of glucose and Intralipid in rats is described. This model can be used to study the impact of nutrient excess on organ function and physiological parameters.

Un modelo de infusión de nutrientes crónica en la rata

Chronic exposure to excessive levels of nutrients is postulated to  affect the function of several organs and tissues and to contribute to the  ...

Development of an Alpha-synuclein Based Rat Model for Parkinson's Disease via Stereotactic Injection of a Recombinant Adeno-associated Viral Vector

In order to study the molecular pathways of Parkinson&#39;s disease (PD) and to develop novel therapeutic strategies, scientific investigators rely on animal models. The identification of PD-associated genes has led to the development of genetic PD models. Most transgenic &#945;-SYN mouse models develop gradual &#945;-SYN pathology but fail to display clear dopaminergic cell loss and dopamine-dependent behavioral deficits. This hurdle was overcome by direct targeting of the substantia nigra with viral vectors overexpressing PD-associated genes. Local gene delivery using viral vectors provides an attractive way to express transgenes in the central nervous system. Specific brain regions can be targeted (e.g. the substantia nigra), expression can be induced in the adult setting and high expression levels can be achieved. Further, different vector systems based on various viruses can be used. The protocol outlines all crucial steps to perform a viral vector injection in the substantia nigra of the rat to develop a viral vector-based alpha-synuclein animal model for Parkinson&#39;s disease.

This manuscript describes how viral vector-mediated local gene delivery provides an attractive way to express transgenes in the central nervous system. The protocol outlines all crucial steps to perform a viral vector injection in the substantia nigra of the rat to develop a viral vector-based animal model for Parkinson's disease.

Desarrollo de un modelo basado en la rata alfa-sinucleína para la enfermedad de Parkinson mediante inyección estereotáctica de un vector viral adeno-asociado recombinante

In order to study the molecular pathways of Parkinson&#39;s disease (PD) and to develop novel therapeutic strategies, scientific investigators rely on ...

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 ...

Acupuncture in a Rat Model of Asthma

A high platform can fix rats without restriction and completely expose the acupoints on the back during acupuncture manipulation. This article describes methods for the fabrication of the high platform, establishes a rat model of asthma and measures changes in respiratory function using a noninvasive and real-time whole-body plethysmography (WBP) system.

Acupuntura en un modelo de rata de asma

A high platform can fix rats without restriction and completely expose the acupoints on the back during acupuncture manipulation. This article describes ...

Retinal Pathophysiological Evaluation in a Rat Model

A posterior segment eye disease like diabetic retinopathy alters the physiology of the retina. Diabetic retinopathy is characterized by a retinal detachment, breakdown of the blood-retinal barrier (BRB), and retinal angiogenesis. An in vivo rat model is a valuable experimental tool to examine the changes in the structure and function of the retina. We propose three different experimental techniques in the rat model to identify morphological changes of retinal cells, retinal vasculature, and compromised BRB. Retinal histology is used to study the morphology of various retinal cells. Also, quantitative measurement is performed by retinal cell count and thickness measurement of different retinal layers. A BRB breakdown assay is used to determine the leakage of extraocular proteins from the plasma to vitreous tissue due to the breakdown of BRB. Fluorescence angiography is used to study angiogenesis and leakage of blood vessels by visualizing retinal vasculature using FITC-dextran dye.

Diabetic retinopathy is one of the leading causes of blindness. Histology, blood-retinal barrier breakdown assay, and fluorescence angiography are valuable techniques to understand the pathophysiology of the retina, which could further enhance the efficient drug screening against diabetic retinopathy.

Evaluación fisiopatológica de la retina en un modelo de rata

A posterior segment eye disease like diabetic retinopathy alters the physiology of the retina. Diabetic retinopathy is characterized by a retinal ...

Development of a Uterosacral Ligament Suspension Rat Model

Pelvic organ prolapse (POP) is a common pelvic floor disorder (PFD) with the potential to significantly impact a woman's quality of life. Approximately 10%-20% of women undergo pelvic floor repair surgery to treat prolapse in the United States. PFD cases result in an overall $26.3 billion annual cost in the United States alone. This multifactorial condition has a negative impact on the quality of life and yet the treatment options have only dwindled in the recent past. One common surgical option is uterosacral ligament suspension (USLS), which is typically performed by affixing the vaginal vault to the uterosacral ligament in the pelvis. This repair has a lower incidence of complications compared to those with mesh augmentation, but is notable for a relatively high failure rate of up to 40%. Considering the lack of standard animal models to study pelvic floor dysfunction, there is an urgent clinical need for innovation in this field with a focus on developing cost-effective and accessible animal models. In this manuscript, we describe a rat model of USLS involving a complete hysterectomy followed by fixation of the remaining vaginal vault to the uterosacral ligament. The goal of this model is to mimic the procedure performed on women to be able to use the model to then investigate reparative strategies that improve the mechanical integrity of the ligament attachment. Importantly, we also describe the development of an in situ tensile testing procedure to characterize interface integrity at chosen time points following surgical intervention. Overall, this model will be a useful tool for future studies that investigate treatment options for POP repair via USLS.

Pelvic organ prolapse affects millions of women worldwide and yet some common surgical interventions have failure rates as high as 40%. The lack of standard animal models to investigate this condition impedes progress. We propose the following protocol as a model for uterosacral ligament suspension and in vivo tensile testing.

Desarrollo de un modelo de rata con suspensión del ligamento uterosacro

Pelvic organ prolapse (POP) is a common pelvic floor disorder (PFD) with the potential to significantly impact a woman's quality of life. Approximately ...

A Model of Long-Term Ventricular Fibrillation in Isolated Rat Hearts

Ventricular fibrillation (VF) is a fatal arrhythmia with a high incidence in cardiac patients, but VF arrest under perfusion is a neglected method of intraoperative arrest in the field of cardiac surgery. With recent advances in cardiac surgery, the demand for prolonged VF studies under perfusion has increased. However, the field lacks simple, reliable, and reproducible animal models of chronic ventricular fibrillation. This protocol induces long-term VF through alternating current (AC) electrical stimulation of the epicardium. Different conditions were used to induce VF, including continuous stimulation with a low or high voltage to induce long-term VF and stimulation for 5 min with a low or high voltage to induce spontaneous long-term VF. The success rates of the different conditions, as well as the rates of myocardial injury and recovery of cardiac function, were compared. The results showed that continuous low-voltage stimulation induced long-term VF and that 5 min of low-voltage stimulation induced spontaneous long-term VF with mild myocardial injury and a high rate of recovery of cardiac function. However, the low-voltage, continuously stimulated long-term VF model had a higher success rate. High-voltage stimulation provided a higher rate of VF induction but showed a low defibrillation success rate, poor recovery of cardiac function, and severe myocardial injury. On the basis of these results, continuous low-voltage epicardial AC stimulation is recommended for its high success rate, stability, reliability, reproducibility, low impact on cardiac function, and mild myocardial injury.

This protocol presents a model of long-term ventricular fibrillation in rat hearts induced by continuous stimulation with low-voltage alternating current. This model has a high success rate, is stable, reliable, and reproducible, has a low impact on cardiac function, and causes only mild myocardial injury.

Un modelo de fibrilación ventricular a largo plazo en corazones de rata aislados

Ventricular fibrillation (VF) is a fatal arrhythmia with a high incidence in cardiac patients, but VF arrest under perfusion is a neglected method of ...

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