Este trabajo fue apoyado por la Fundación Lundbeck, la Fundación Carlsberg y Dagmar Marshall Foundation.

1. von Frey mediciones de referencia antes de la cirugía Para el procedimiento de von Frey prueba, por favor refiérase a la sección 5. 2. Anestesia / preparación <ol><li> Anestesiar a los animales (inyección intraperitoneal de una mezcla de ketamina y 100mg/kg 15 xilazina mg / kg). </li><li> Colocar el animal en un lugar tranquilo hasta que esté completamente anestesiado (por ejemplo, cubierta con una toalla de papel). </li><li> Revisar los reflejos pellizcando la punta de la cola y las patas con un par de pinzas. Asegúrese de que los animales no responden antes de proceder. </li><li> Por vía subcutánea inyección (zona posterior del hombro) con 0,5 ml de solución salina isotónica antibióticos, por ejemplo, ampicilina (para evitar la deshidratación y prevenir la infección, aunque este es un procedimiento quirúrgico menor). </li><li> Usando una máquina de afeitar eléctrica, afeitarse el campo operatorio desde ligeramente por debajo del área de la rodilla a la cadera (para las personas diestras la extremidad posterior izquierda es recomendable). </li><li> Aplique un ungüento oftálmico para los ojos con un bastoncillo de algodón. </li><li> Colocar el animal sobre su lado derecho y colocar la extremidad posterior izquierda en una pequeña plataforma para mantenerla elevada. Asegurar la pierna con cinta adhesiva. </li><li> Desinfectar el campo operatorio con la alternancia de matorrales de etanol y betadine de fuera del sitio quirúrgico. </li></ol> 3. Cirugía <ol><li> Localice la rodilla con el pulgar de su mano izquierda y el uso de un bisturí para realizar una aplicación. Incisión de 1 cm en la dirección longitudinal proximal a la rodilla. </li><li> Abrir la piel mediante disección roma con la punta de unas tijeras estériles. </li><li> Separar la capa muscular mediante disección roma justo al lado de los vasos sanguíneos visibles, cerca del hueso del muslo (fémur). Si se hace correctamente, las capas musculares fácilmente por separado sin ningún tipo de hemorragia, dejando al descubierto el nervio ciático derecho debajo de los músculos. Si se produce una hemorragia por ejemplo, por el daño a los vasos sanguíneos cerca de la rodilla, el uso de lana estéril bastoncillos de algodón o pedazos de la mirada para absorber la sangre. Pulse hasta que se detenga el sangrado. </li><li> Coloque el ratón debajo de un microscopio estereoscópico y separar cuidadosamente los músculos con un par de pinzas estériles (n º 2) para visualizar el nervio ciático. Retractores también se puede aplicar. </li><li> Identificar el área donde las ramas del nervio sural del nervio ciático. El nervio sural es el más pequeño de los tres poderes, la ramificación a la derecha en la pierna izquierda. </li><li> Aplicar sutura (6-0 sutura) en torno a las otras dos ramas que todavía están funcionando en paralelo (los nervios peroneo común y tibial), teniendo mucho cuidado de no tocar la rama sural. Este es un paso crítico como el nervio sural tiene que ser dejado intacto. </li><li> Haga un nudo apretado quirúrgica. Si el primer nudo es apretado, las contracciones de las extremidades se observan. </li><li> Coge los nervios a cortar por debajo de la sutura con un par de pinzas (n º 5), y cortar los nervios encima y debajo de las pinzas con un pequeño par de tijeras. En primer lugar, el corte por encima del par de pinzas, halando de los nervios se evita. </li><li> Corte los extremos de sutura con un par de tijeras micro y cierre suavemente la capa muscular. Añadir una gota de lidocaína en la herida y la sutura con nudos quirúrgicos. </li></ol> 4. Después de la cirugía <ol><li> Compruebe si ungüento para los ojos es todavía suficiente. </li><li> Coloque el ratón en una jaula limpia con una toalla de papel en una postura cómoda. Si la habitación es fría, colocar una almohadilla de calor en una parte de la caja (sólo en la parte de la jaula, el animal debe ser capaz de escapar a un área más fría si se prefiere). </li><li> Asegurar que el agua de fácil acceso y comida. </li></ol> 5. prueba de von Frey (línea de base, y desde el día después de la cirugía) <ol><li> Coloque el ratón en rojo cilindros de plástico de color colocados sobre una mesa de malla de alambre de dos días y un día antes de la cirugía. Habituarse durante 15 minutos en los cilindros antes de la prueba. El color rojo de los cilindros de ayuda a los ratones para relajarse rápidamente, ya que no pueden verse entre sí y se encuentran en una zona más oscura. </li><li> Verifique que los ratones son tranquilas y aplicar filamentos de von Frey a la parte lateral de la pata: A partir del filamento de 0,02 g, en primer lugar aplicar la fuerza de la pata izquierda cinco veces durante un período total de 30 segundos (aproximadamente 2 segundos por estímulo) y evaluar la reacción de los ratones después de cada aplicación. Repita el procedimiento con el mismo filamento y la garra izquierda de otros ratones, y luego comenzar de nuevo con la pata derecha del ratón antes de pasar a la siguiente filamento, por ejemplo: <ul><li> 1 del ratón: la pata izquierda 5 veces con filamentos de 0,02 g </li><li> Mouse 2: pata izquierda 5 veces con filamentos de 0,02 g, etc </li><li> 1 del ratón: la pata derecha 5 veces con filamentos de 0,02 g </li><li> Mouse 2: pata derecha 5 veces con filamentos de 0,02 g, etc </li><li> 1 del ratón: la pata izquierda 5 veces con filamentos de 0,04 g </li><li> Mouse 2: pata izquierda 5 veces con filamentos de 0,04 g, etc </li></ul></li><li> Respuesta en tres de los cinco estímulos se considera una reacción positiva. Filamentos por encima de threshold se puede aplicar para verificar el nivel de umbral. Respuesta = retirada de la pata súbita, repentina inmutarse, la pata de repente lamer. </li></ol> 6. Los resultados representativos <img src="/files/ftp_upload/3092/3092fig1.jpg" alt="Figura 1" /> Figura 1. Von Frey prueba en C57BL / 6 ratones de edad 8-10 semanas de edad se realizó un día antes de la operación y en varias ocasiones después de la cirugía. Animales 8.4 se incluyeron en cada grupo. Von Frey prueba en el lado operado está representado por ipsilateral y la parte de control no funciona es representado por contralateral. El día después de la cirugía los animales desarrollan hipersensibilidad significativa en la pata operada, mientras que la no operada es sólo ligeramente afectada en relación con los ratones con operación simulada. (* &lt;0,05, ** &lt;0,01, *** &lt;0,001, en relación ipsilateral a contralateral).

<ol>
	<li>Costigan, M., Scholz, J., Woolf, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuropathic+pain:+a+maladaptive+response+of+the+nervous+system+to+damage.">Neuropathic pain: a maladaptive response of the nervous system to damage.</a> Annu. Rev. Neurosci. 32, 1-32 (2009).</li><li>Decosterd, I., Woolf, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spared+nerve+injury:+an+animal+model+of+persistent+peripheral+neuropathic+pain.">Spared nerve injury: an animal model of persistent peripheral neuropathic pain.</a> Pain. 87, 149-158 (2000).</li><li>Bourquin, A. -. F., S&#252;veges, M., Pertin, M., Gilliar, N., Sardy, S., Davidson, A. C., Spahn, D. R., Decosterd, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+and+analysis+of+mechanical+allodynia-like+behavior+induced+by+spared+nerve+injury+(SNI)+in+the+mouse.">Assessment and analysis of mechanical allodynia-like behavior induced by spared nerve injury (SNI) in the mouse.</a> Pain. 122, 14.e1-14.e14 (2006).</li><li>Chaplan, S. R., Bach, F. W., Pogrel, J. W., Chung, J. M., Yaksh, T. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+assessment+of+tactile+allodynia+in+the+rat+paw.">Quantitative assessment of tactile allodynia in the rat paw.</a> J. Neurosci. Methods. 53, 55-63 (1994).</li><li>Bennett, G. J., Xie, Y. -. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+peripheral+mononeuropathy+in+rat+that+produces+disorders+of+pain+sensation+like+those+seen+in+man.">A peripheral mononeuropathy in rat that produces disorders of pain sensation like those seen in man.</a> Pain. 33, 87-107 (1988).</li><li>Seltzer, Z., Dubner, R., Shir, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+behavioral+model+of+neuropathic+pain+disorders+produced+in+rats+by+partial+sciatic+nerve+injury.">A novel behavioral model of neuropathic pain disorders produced in rats by partial sciatic nerve injury.</a> Pain. 43, 205-218 (1990).</li><li>Hargreaves, K., Dubner, R., Brown, F., Flores, C., Joris, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+and+sensitive+method+for+measuring+thermal+nociception+in+cutanous+hyperalgesia.">A new and sensitive method for measuring thermal nociception in cutanous hyperalgesia.</a> Pain. 32, 77-88 (1988).</li><li>Erichsen, H. K., Blackburn-Munro, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacological+characterization+of+the+spared+nerve+injury+model+of+neuropathic+pain.">Pharmacological characterization of the spared nerve injury model of neuropathic pain.</a> Pain. 98, 151-161 (2002).</li></ol>

No hay conflictos de interés declarado.

Los pasos críticos Daño en el nervio sural se debe evitar con el fin de estudiar los cambios patológicos en el intacta lesión del nervio sural siguientes a los nervios peroneo común y tibial. El daño colateral en el nervio sural puede conducir a la parálisis y por lo tanto puede ser visualizado como el arrastre de la extremidad posterior funcionamiento. Sólo la parte lateral de la pata es inervado por el nervio sural ahorrado y, por tanto, sólo que esta zona se desarrolla una neuropatía. Prueba de otras áreas, inervados por los nervios seccionados, puede muy sesgo en la evaluación del umbral de mecánica alterada. Posibles modificaciones Otros tipos de ligaduras pueden ser complementarios en términos de estudio de las condiciones patológicas del dolor después de una lesión de nervios periféricos, tales como la lesión de constricción crónica [5] o la ligadura parcial del nervio [6]. Los resultados de cada procedimiento experimental en distintos cambios fenotípicos que deben ser considerados antes de la prueba después de la cirugía. Además, otras pruebas sensoriales, tales como la hiperalgesia térmica se puede aplicar [7], aunque este fenotipo es menos robusto SNI siguientes. Las futuras aplicaciones Esta técnica puede ser utilizada para las pruebas de drogas que alteran el desarrollo o mantenimiento de la alodinia mecánica [8]. Análisis del nervio ciático, los ganglios de la raíz dorsal (DRG) y / o la médula espinal lumbar permitir la investigación de los mecanismos moleculares responsables del fenotipo inducido. La experimentación con animales se realizó de acuerdo a buenas prácticas de laboratorio en plena conformidad con las normas danesas y europeas. Todos los experimentos fueron aprobados por el danés experimentos con animales de Inspección del Ministerio de Justicia (número de la autorización 2006/561-1206).

<table border="1"><tbody><tr><td> Anestesia: La ketamina y xilazina </td><td> Bisturí </td></tr><tr><td> Oftálmicos pomada </td><td> Pinzas nr. 2 </td></tr><tr><td> Rasuradora eléctrica </td><td> Pinzas nr. 5 </td></tr><tr><td> Guantes </td><td> Par de tijeras para disección roma </td></tr><tr><td> 70% (v / v) de etanol </td><td> Micro tijeras </td></tr><tr><td> Lana de bastoncillos de algodón / la mirada </td><td> 6.0 Prolene sutura no absorbible </td></tr><tr><td> Microscopio estereoscópico </td><td> 2 x porta-agujas </td></tr><tr><td> Cinta adhesiva </td><td> Almohadilla de calor </td></tr><tr><td colspan="2"> filamentos de von Frey (0,02 - 2,0 g para los ratones) (Stoelting) </td></tr></tbody></table>

the spared nerve injury (sni) model of induced mechanical allodynia in mice

El dolor neuropático periférico es una afección grave dolor crónico que puede resultar de un trauma a los nervios sensoriales del sistema nervioso periférico. La lesión del nervio escatimado (SNI) modelo induce los síntomas del dolor neuropático, como la alodinia mecánica es decir, dolor debido a los estímulos táctiles que no suelen provocar una respuesta dolorosa [1]. El modelo de ratón SNI consiste en la ligadura de dos de las tres ramas del nervio ciático (el nervio tibial y el nervio peroneo común), mientras que el nervio sural se deja intacto [2]. Los resultados de la lesión en la hipersensibilidad marcada en la zona lateral de la pata, que es inervado por el nervio sural ahorrado. El lado no operado del ratón se puede usar como control. Las ventajas del modelo de SNI son la solidez de la respuesta y que no requiere conocimientos de expertos de microcirugía. El umbral para la respuesta al dolor mecánico está determinado por las pruebas con filamentos de von Frey de la creciente fuerza de flexión, que son repetidamente presiona contra la zona lateral de la pata [3], [4]. Una reacción positiva del dolor se define como repentina retirada de la pata, acobardarse y / o la pata lamiendo inducida por el filamento. Una respuesta positiva en tres de los cinco estímulos repetitivos se define como el umbral del dolor. Como se demuestra en el protocolo de vídeo, los ratones C57BL / 6 experiencia alodinia profunda tan pronto como al día siguiente de la cirugía y mantener esto durante varias semanas.

Watch this Scientific Journal Video about The Spared Nerve Injury SNI Model of Induced Mechanical Allodynia in Mice at JoVE.com

The Spared Nerve Injury SNI Model of Induced Mechanical Allodynia in Mice

La lesión del nervio Salvados modelo animal es descrito aquí como un modelo de ratón del dolor neuropático periférico después de denervación parcial del nervio ciático por lesionar las ramas tibial y peroneo común del nervio, dejando el nervio sural se mantiene intacta. Modificación de la conducta resultante de la alodinia mecánica se cuantifica por filamentos de von Frey.

La lesión del nervio Salvados (SNI) Modelo de alodinia mecánica inducida en ratones

Peripheral neuropathic pain is a severe chronic pain condition which may result from trauma to sensory nerves in the peripheral nervous system. The spared ...

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Research

JoVE Journal

Medicine

The Spared Nerve Injury (SNI) Model of Induced Mechanical Allodynia in Mice

63.1K vistas.  Aarhus University. La lesión del nervio Salvados modelo animal es descrito aquí como un modelo de ratón del dolor neuropático periférico después de denervación parcial del nervio ciático por lesionar las ramas tibial y peroneo común del nervio, dejando el nervio sural se mantiene intacta. Modificación de la conducta resultante de la alodinia mecánica se cuantifica por filamentos de von Frey.

Video: The Spared Nerve Injury SNI Model of Induced Mechanical Allodynia in Mice

Controlled Cervical Laceration Injury in Mice

Use of genetically modified mice enhances our understanding of molecular mechanisms underlying several neurological disorders such as a spinal cord injury (SCI). Freehand manual control used to produce a laceration model of SCI creates inconsistent injuries often associated with a crush or contusion component and, therefore, a novel technique was developed. Our model of cervical laceration SCI has resolved inherent difficulties with the freehand method by incorporating 1) cervical vertebral stabilization by vertebral facet fixation, 2) enhanced spinal cord exposure, and 3) creation of a reproducible laceration of the spinal cord using an oscillating blade with an accuracy of &plusmn;0.01 mm in depth without associated contusion. Compared to the standard methods of creating a SCI laceration such as freehand use of a scalpel or scissors, our method has produced a consistent lesion. This method is useful for studies on axonal regeneration of corticospinal, rubrospinal, and dorsal ascending tracts.

A novel technique to create a reproducible in vivo model of cervical spinal cord laceration injury in the mouse is described. This technique is based on spine stabilization by fixation of the cervical facets and laceration of the spinal cord using an oscillating blade with an accuracy of &plusmn;0.01 mm.

Controlado lesiones laceración cervical en ratones

Use of genetically modified mice enhances our  understanding of molecular mechanisms underlying several neurological disorders  such as a spinal cord ...

Investigación

Medicina

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

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

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

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

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

Tibial Nerve Transection - A Standardized Model for Denervation-induced Skeletal Muscle Atrophy in Mice

The tibial nerve transection model is a well-tolerated, validated, and reproducible model of denervation-induced skeletal muscle atrophy in rodents. Although originally developed and used extensively in the rat due to its larger size, the tibial nerve in mice is big enough that it can be easily manipulated with either crush or transection, leaving the peroneal and sural nerve branches of the sciatic nerve intact and thereby preserving their target muscles. Thus, this model offers the advantages of inducing less morbidity and impediment of ambulation than the sciatic nerve transection model and also allows investigators to study the physiologic, cellular and molecular biologic mechanisms regulating the process of muscle atrophy in genetically engineered mice. The tibial nerve supplies the gastrocnemius, soleus and plantaris muscles, so its transection permits the study of denervated skeletal muscle composed of fast twitch type II fibers and/or slow twitch type I fibers. Here we demonstrate the tibial nerve transection model in the C57Black6 mouse. We assess the atrophy of the gastrocnemius muscle, as a representative muscle, at 1, 2, and 4 weeks post-denervation by measuring muscle weights and fiber type specific cross-sectional area on paraffin-embedded histologic sections immunostained for fast twitch myosin.

The tibial nerve transection model is a well-tolerated, validated, and reproducible model of skeletal muscle atrophy. The model surgical protocol is described and demonstrated in C57Black6 mice. &#160;

Transección del nervio tibial - Un modelo normalizado para la atrofia del músculo esquelético denervación inducida en ratones

The tibial nerve transection model is a well-tolerated, validated, and reproducible model of denervation-induced skeletal muscle atrophy in rodents. ...

The Sciatic Nerve Cuffing Model of Neuropathic Pain in Mice

Neuropathic pain arises as a consequence of a lesion or a disease affecting the somatosensory system. This syndrome results from maladaptive changes in injured sensory neurons and along the entire nociceptive pathway within the central nervous system. It is usually chronic and challenging to treat. In order to study neuropathic pain and its treatments, different models have been developed in rodents. These models derive from known etiologies, thus reproducing peripheral nerve injuries, central injuries, and metabolic-, infectious- or chemotherapy-related neuropathies. Murine models of peripheral nerve injury often target the sciatic nerve which is easy to access and allows nociceptive tests on the hind paw. These models rely on a compression and/or a section. Here, the detailed surgery procedure for the &#34;cuff model&#34; of neuropathic pain in mice is described. In this model, a cuff of PE-20 polyethylene tubing of standardized length (2 mm) is unilaterally implanted around the main branch of the sciatic nerve. It induces a long-lasting mechanical allodynia, i.e., a nociceptive response to a normally non-nociceptive stimulus that can be evaluated by using von Frey filaments. Besides the detailed surgery and testing procedures, the interest of this model for the study of neuropathic pain mechanism, for the study of neuropathic pain sensory and anxiodepressive aspects, and for the study of neuropathic pain treatments are also discussed.

Neuropathic pain is a consequence of a lesion or disease affecting the somatosensory system. The &#8220;cuff model&#8221; of neuropathic pain in mice consists of the implantation of a polyethylene cuff around the main branch of the sciatic nerve. Mechanical allodynia is tested using von Frey filaments.

El nervio ciático esposar modelo de dolor neuropático en ratones

Neuropathic pain arises as a consequence of a lesion or a disease affecting the somatosensory system. This syndrome results from maladaptive changes in ...

Facial Nerve Axotomy in Mice: A Model to Study Motoneuron Response to Injury

The goal of this surgical protocol is to expose the facial nerve, which innervates the facial musculature, at its exit from the stylomastoid foramen and either cut or crush it to induce peripheral nerve injury. Advantages of this surgery are its simplicity, high reproducibility, and the lack of effect on vital functions or mobility from the subsequent facial paralysis, thus resulting in a relatively mild surgical outcome compared to other nerve injury models. A major advantage of using a cranial nerve injury model is that the motoneurons reside in a relatively homogenous population in the facial motor nucleus in the pons, simplifying the study of the motoneuron cell bodies. Because of the symmetrical nature of facial nerve innervation and the lack of crosstalk between the facial motor nuclei, the operation can be performed unilaterally with the unaxotomized side serving as a paired internal control. A variety of analyses can be performed postoperatively to assess the physiologic response, details of which are beyond the scope of this article. For example, recovery of muscle function can serve as a behavioral marker for reinnervation, or the motoneurons can be quantified to measure cell survival. Additionally, the motoneurons can be accurately captured using laser microdissection for molecular analysis. Because the facial nerve axotomy is minimally invasive and well tolerated, it can be utilized on a wide variety of genetically modified mice. Also, this surgery model can be used to analyze the effectiveness of peripheral nerve injury treatments. Facial nerve injury provides a means for investigating not only motoneurons, but also the responses of the central and peripheral glial microenvironment, immune system, and target musculature. The facial nerve injury model is a widely accepted peripheral nerve injury model that serves as a powerful tool for studying nerve injury and regeneration.

We present a surgical protocol detailing how to perform a cut or crush axotomy on the facial nerve in the mouse. The facial nerve axotomy can be employed to study the physiological response to nerve injury and test therapeutic techniques.

Axotomía nervio facial en ratones: un modelo para estudiar las motoneuronas respuesta a la lesión

The goal of this surgical protocol is to expose the facial nerve, which innervates the facial musculature, at its exit from the stylomastoid foramen and ...

Photothrombosis-induced Focal Ischemia as a Model of Spinal Cord Injury in Mice

Spinal cord injury (SCI) is a devastating clinical condition causing permanent changes in sensorimotor and autonomic functions of the spinal cord (SC) below the site of injury. The secondary ischemia that develops following the initial mechanical insult is a serious complication of the SCI and severely impairs the function and viability of surviving neuronal and non-neuronal cells in the SC. In addition, ischemia is also responsible for the growth of lesion during chronic phase of injury and interferes with the cellular repair and healing processes. Thus there is a need to develop a spinal cord ischemia model for studying the mechanisms of ischemia-induced pathology. Focal ischemia induced by photothrombosis (PT) is a minimally invasive and very well established procedure used to investigate the pathology of ischemia-induced cell death in the brain. Here, we describe the use of PT to induce an ischemic lesion in the spinal cord of mice. Following retro-orbital sinus injection of Rose Bengal, the posterior spinal vein and other capillaries on the dorsal surface of SC were irradiated with a green light resulting in the formation of a thrombus and thus ischemia in the affected region. Results from histology and immunochemistry studies show that PT-induced ischemia caused spinal cord infarction, loss of neurons and reactive gliosis. Using this technique a highly reproducible and relatively easy model of SCI in mice can be achieved that would serve the purpose of scientific investigations into the mechanisms of ischemia induced cell death as well as the efficacy of neuroprotective drugs. This model will also allow exploration of the pathological changes that occur following SCI in live mice like axonal degeneration and regeneration, neuronal and astrocytic Ca2+ signaling using two-photon microscopy.

Photothrombosis is a minimally invasive and highly reproducible procedure to induce focal ischemia in the spinal cord and serves as a model of spinal cord injury in mice.

Photothrombosis inducida por isquemia focal como un modelo de lesión de médula espinal en ratones

Spinal cord injury (SCI) is a devastating clinical condition causing permanent changes in sensorimotor and autonomic functions of the spinal cord (SC) ...

A Repetitive Concussive Head Injury Model in Mice

Despite the concussion/ mild traumatic brain injury (mTBI) being the most frequent occurrence of traumatic brain injury, there is still a lack of knowledge on the injury and its effects. To develop a better understanding of concussions, animals are often used because they provide a controlled, rigorous, and efficient model. Studies have adapted traditional animal models to perform mTBI to stimulate mild injury severity by changing the injury parameters. These models have been used because they can produce morphologically similar brain injuries to the clinical condition and provide a spectrum of injury severities. However, they are limited in their ability to present the identical features of injuries in patients. Using a traditional impact system, a repetitive concussive injury (rCHI) model can induce mild to moderate human-like concussion. The injury degree can be determined by measuring the period of loss of consciousness (LOC) with a sign of a transient termination of breathing. The rCHI model is beneficial to use for its accuracy and simplicity in determining mTBI effects and potential treatments.

Concussion presents the most common type of traumatic brain injury. Therefore, a repetitive concussive animal model, which replicates the important features of an injury in patients, may provide a means to study concussion in a rigorous, controlled, and efficient manner.

Un modelo de lesión en la cabeza repetidos de conmoción en ratones

Despite the concussion/ mild traumatic brain injury (mTBI) being the most frequent occurrence of traumatic brain injury, there is still a lack of ...

Induction of Accelerated Atherosclerosis in Mice: The "Wire-Injury" Model

Atherosclerosis is a proliferative fibro-inflammatory disease developing in the arterial wall, inducing a deficient blood flow or a lack of blood flow. Moreover, by rupture of the defective vascular wall, atherosclerosis induces occlusive thrombus formation, which represents the main cause of myocardial infarction or stroke and the most frequent cause of death. Despite the advances in the cardiovascular field, many questions remain unanswered, and additional basic research is essential to improve our understanding of the molecular mechanisms during atherosclerosis and its effects. Due to limited clinical studies, there is a need for representative animal models recreating atherosclerotic conditions such as neointima formation after stent implantation, balloon angioplasty, or endarterectomy. Since the mouse presents many advantages and is the most frequently used model for studying molecular processes, the current study proposes an invasive procedure of endothelial denudation, also known as the wire-injury model, which is representative of the human condition of neointima formation in arteries after revascularization procedures.

This study describes an invasive procedure for the induction of accelerated atherosclerosis in mice. In comparison to other methods using electric- or cryo-induced injury, mechanical-induced injury mimics the human condition of restenosis after revascularization therapies and is ideal for the study of the molecular mechanisms involved.

Inducción de la Aterosclerosis Acelerada en Ratones: El Modelo de "Lesiones por Alambre"

Atherosclerosis is a proliferative fibro-inflammatory disease developing in the arterial wall, inducing a deficient blood flow or a lack of blood flow. ...

A Tissue Displacement-based Contusive Spinal Cord Injury Model in Mice

Producing a consistent and reproducible contusive spinal cord injury (SCI) is critical to minimizing behavioral and histological variabilities between experimental animals. Several contusive SCI models have been developed to produce injuries using different mechanisms. The severity of the SCI is based on the height that a given weight is dropped, the injury force, or the spinal cord displacement. In the current study, we introduce a novel mouse contusive SCI device, the Louisville Injury System Apparatus (LISA) impactor, which can create a displacement-based SCI with high injury velocity and accuracy. This system utilizes laser distance sensors combined with advanced software to produce graded and highly-reproducible injuries. We performed a contusive SCI at the 10th thoracic vertebral (T10) level in mice to demonstrate the step-by-step procedure. The model can also be applied to the cervical and lumbar spinal levels.

We introduce a tissue displacement-based contusive spinal cord injury model that can produce a consistent contusive spinal cord injury in adult mice.

Un modelo de lesión de la médula espinal contundente basado en el desplazamiento de tejidos en ratones

Producing a consistent and reproducible contusive spinal cord injury (SCI) is critical to minimizing behavioral and histological variabilities between ...

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 ...