This works was supported by funding from a Florida Health grant (Brain and spinal cord injury research fund) (KKW).

Todos los procedimientos se realizaron bajo protocolos # 201207692 aprobado por el Comité de Cuidado y Uso de Animales institucional de la Universidad de Florida y de acuerdo con los Institutos Nacionales de Salud de Guía para el Cuidado y Uso de Animales de Laboratorio. 1. Cuidado de Animales <ol><li> Utilice 3-4 meses de edad de sexo masculino C57BL / 6J. Proporcionar ropa de cama, material de nidificación, alimentación y agua ad libitum. Mantener los ratones en una temperatura ambiente controlada a 20 - 22 ° C, con constantes de 12 horas de luz / 12-hr ciclos de oscuridad. </li></ol> 2. Pre-impactación Preparación <ol><li> Coloque una punta de metal revestida de silicona a medida para un dispositivo de impacto estereotáxica electromagnética. Asegúrese de que la parte inferior plana de la punta es paralela a la superficie de la punta de la sonda (Figura 1A). </li><li> Anestesiar al ratón con 4% de isoflurano seguido de anestesia de mantenimiento de 2,5% de isoflurano. Compruebe la anestesia a través del medidor de flujo. monitor el nivel de la anestesia hasta que el animal alcanza un nivel quirúrgico de anestesia, mostrando la pérdida del reflejo de retirada pedal. </li><li> Ponga el ratón en una posición de decúbito prono sobre una almohadilla térmica. Use un cono de la nariz en forma de embudo para mantener el ratón bajo anestesia. Afeitarse completamente la cabeza utilizando un condensador de ajuste. Utilizar vaselina ungüento oftálmico en los ojos del ratón para evitar la sequedad, mientras que bajo anestesia. </li></ol> 3. Ajuste los parámetros de impacto NOTA: El sistema de impacto incluye una caja de control para ajustar los parámetros de impacto, un actuador para realizar la impactación, y un marco de estereotaxia digital con los ejes 3-movimiento. <ol><li> Pre-establecer la velocidad del dispositivo de impacto a 4 m / s, y el tiempo de permanencia de 240 ms en la caja de control. </li></ol> 4. Colocación del Centro de Impacto <ol><li> Aplique una almohadilla eléctrica suave bajo el cuerpo del animal para mantener la temperatura corporal alrededor de 39 ° C. Montar el ratón en un marco estereotáxico en un pronposición e con las barras de oído sin filo. </li><li> Bajar la punta de impacto cerca de la cabeza del ratón moviendo el Z-conductor. Ajustar la punta de impacto plana (9 mm de diámetro) moviendo los ejes X e Y en los conductores a medio camino a la meta coordina por encima de la sutura sagital. </li><li> Asegúrese de que uno de los bordes de la punta de impacto sea vertical paralelo a una línea horizontal imaginaria trazada entre los dos oídos (Figura 1C). El centro de impacto corresponde a la mitad de camino entre el centro de sutura sagital suturas interfrontal y lamboidea (interaurales 9 mm a interauricular 0 mm, lateral 4,5 mm). </li></ol> 5. Profundidad de impacto Marco <ol><li> Para configurar correctamente la profundidad del impacto, usar punta de la sonda adicional para reemplazar la punta de impacto revestida de silicona con aislamiento. </li><li> Para asegurarse de que no hay un desplazamiento del centro de conmutación de impacto después de consejos, establecer los ejes X e Y del canal en el panel de control estereotáxico digitales a cero antes de cambiar las puntas. </li><li> Mueva el probe punta hasta el centro de la zona de impacto moviendo manualmente los X-e Y unidades. </li><li> sensor de contacto del clip de la cola del ratón. </li><li> Mover el impactador (unidad Z) hacia abajo hasta que la punta de la sonda toca la superficie del lugar del impacto. </li><li> Ajuste el canal Z en el panel de control estereotáxico a cero. </li><li> Mueva la punta de impacto de nuevo a la zona de impacto ajustando manualmente X e Y en los conductores (no con los botones de cero en el panel de control estereotáxica digital) hasta que X e Y son los conductores de cero (donde la punta de impacto anteriormente se ha posicionado). </li><li> Retraer el accionador moviendo el interruptor de retracción en la caja de control. mover manualmente el impactador hacia abajo (controlador Z) a los 4 mm. </li></ol> 6. Impacto <ol><li> Desencadenar el impacto pulsando el interruptor impacto en la caja de control y lograr una profundidad de deformación de 4 mm. </li></ol> 7. Post-impactación <ol><li> Se mide el tiempo desde el impacto hasta primera respiración del ratón utilizando un temporizador. </li><li&gt; Eliminar el animal del instrumento y colocarlos sobre una almohadilla caliente para mantener la temperatura corporal. No dejar al animal sin vigilancia hasta que se haya recuperado el conocimiento suficiente para mantener decúbito esternal. </li><li> Permitir la recuperación antes de volver al animal en una jaula limpia. No devuelva un animal a la compañía de otros animales hasta que esté completamente recuperado. </li><li> Observar y sopesar los ratones diariamente. Si los ratones muestran signos de dolor, por vía intraperitoneal a inyectar con Meloxicam en 1 - 2 mg / kg cada 12 a 24 hr. </li></ol> 8. La impactación repetitivo <ol><li> Dar a los ratones lesiones adicionales en los días 4, 7 y 10 después de la lesión inicial (intervalo de 72 horas entre los impactos). </li></ol> 9. La inmunohistoquímica (IHC) <ol><li> perfusión transcardial <ol><li> Anestesiar a los ratones mediante inyección intraperitoneal con 200 m / kg de pentobarbital. </li><li> Evaluar y asegurar la anestesia quirúrgica placa de circuitos mediante una pizca dedo del pie. SegundoUre el ratón en la posición supina con cinta adhesiva suavemente las patas delanteras y las patas traseras a una superficie de trabajo de espuma de poliestireno dentro de una campana de humos química. </li><li> Hacer una incisión a través de la piel a lo largo de la línea media dorsal desde justo debajo de la apófisis xifoides hasta la clavícula. Hacer dos incisiones adicionales de la piel en el proceso xifoides y proceder a lo largo de la base de la caja torácica ventral lateralmente. </li><li> Abra la cavidad torácica y exponer el corazón cortando a través de la musculatura torácica y la caja torácica. </li><li> Asegure el corazón que late con unas pinzas romas y hacer un 1 - 2 mm incisión en el ventrículo izquierdo. </li><li> Inmediatamente inserte una aguja de mariposa en la aurícula derecha. Comience la infusión de solución salina 20 ml empujando la jeringa lentamente. </li><li> Cambiar de solución salina al 4% de paraformaldehído. Continuar la perfusión con 20 ml de paraformaldehído. </li><li> Decapitar al ratón y quitar la piel con unas tijeras. Aislar el cerebro del cráneo siguiendo un cortador de hueso. </li></ol></li><li> doryostat seccionar <ol><li> tejidos cerebrales incrustar en la formulación temperatura óptima de corte (OCT) y la congelación a -80 ° C. Coloque el cerebro en el criostato en una orientación sagital. secciones de cerebro de corte 5 m de espesor. </li></ol></li><li> tinción <ol><li> Secar las secciones congeladas a temperatura ambiente durante 1 hr. </li><li> Incubar los portaobjetos con 100 l de suero de cabra 2% y 0,1% de Triton X-100 en tampón fosfato salino (PBS) durante 1 hr a RT. </li><li> Se lavan los portas 3 veces con 300 l de PBS. Entonces se incuban los portaobjetos con anti-GFAP (1: 200) o anticuerpo anti-ferritina (1: 200) por separado durante la noche a 4 ° C. </li><li> Se lavan los portas 3 veces con 300 l de PBS. Entonces se incuban los portaobjetos durante 2 hr a temperatura ambiente con anticuerpo secundario conjugado con biotina. </li><li> Se lavan los portas 3 veces con 300 l de PBS. Entonces se incuban los portaobjetos con solución de complejo avidina-biotina (ABC) (1:50) a temperatura ambiente durante 30 min. </li><li>Se lavan los portas 3 veces con 300 l de PBS. A continuación se incuban en 3,3 &#39;-Diaminobencidina solución (DAB) sustrato (50 ml de PBS, 10 l de H 2 O 2, 10 mg pastillas DAB, filtro antes de usar) durante 5 - 8 minutos. Los portaobjetos bajo el microscopio hasta que aparezcan las células positivas. </li><li> Enjuague los portaobjetos en agua del grifo funcionamiento lento durante 5 minutos. diapositivas limpias con un laboratorio de borrado. A continuación, montar las secciones con medio de montaje y cubreobjetos. </li></ol></li></ol>

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The authors have no financial interest to disclose.

Para imitar las lesiones cerebrales morfológicamente similares a la condición clínica, se espera que los síntomas post-concusión. síntomas post-concusión generalmente incluyen dolores de cabeza, mareos, vértigo, fatiga, problemas de memoria y de sueño, dificultad para concentrarse, así como la ansiedad y estado de ánimo depresivo. Dado que los síntomas somáticos sin embargo, no pueden ser medibles en modelos animales, los cambios de motor y la función cognitiva y el comportamiento emocional se utilizan com...

Conmoción cerebral, también llamada lesión cerebral traumática leve (LCTL), es la ocurrencia más frecuente de lesión cerebral traumática (TBI) y afecta a millones de personas en los Estados Unidos. Las conmociones cerebrales pueden ser difíciles de diagnosticar y no existe una cura específica para la conmoción cerebral. Hay un creciente reconocimiento y alguna evidencia de que los traumatismos mecánicos leves como consecuencia de lesiones deportivas, combate militar, y otras actividades atractivas físicamente puede tener consecuencias neurológicas crónicas y acumulativas 1,2. Sin embargo, todavía hay una falta de conocimiento sobre las conmociones cerebrales y sus efectos. metodología actual restringe los estudios de patología y el tratamiento en humanos, ya que sólo la valoración neurológica y evaluación de imágenes están disponibles para el diagnóstico clínico. Los modelos animales proporcionan un medio para estudiar conmociones cerebrales de una manera eficiente, riguroso y controlado con la esperanza de diagnóstico y tratamiento de LCTL. Los estudios han adaptado tradicional TBImodelos como el impacto cortical controlado (CCI), el impacto de percusión de fluido (FPI), lesión de caída de peso, y la lesión por estallido para realizar LCTL y estimulan la gravedad de lesiones bajas cambiando los parámetros de lesiones. Estos modelos son beneficiosos de usar debido a su capacidad para replicarse trauma cerebral morfológicamente similar a la situación clínica; sin embargo, también tienen sus propias limitaciones. La gravedad de la lesión inducida por una lesión de aceleración (caída de peso) es a menudo muy variable. Los dos resultados de la ICC leve - hemorragia subaracnoidea y contusión focal - no son comparables con las conmociones cerebrales humanas típicas. CCI y FPI requieren una craneotomía, que no es clínicamente relevante, mientras que la lesión por estallido es un modelo más controvertida en lo que respecta a las diferentes medidas de posición de la exposición y el pico de presión, así como lesión secundaria variable durante la exposición 3-6. Un modelo animal de conmoción actualizado que se puede traducir la investigación preclínica a la clínica setting es necesaria en la investigación. La cuestión clave en el modelado de una LCT leve es definir la gravedad de la lesión experimental, que se replica más de cerca posible de la lesión en un entorno clínico. Recientemente, diferentes grupos de investigación desarrollaron la lesión en la cabeza cerrada o lesión en la cabeza de conmoción (CHI) modelo 7-10. CHI es una modificación del CCI sin una craneotomía, pero todavía utiliza un sistema electrónico de impacto magnética tradicional para generar un impacto de la cabeza. Un CHI puede inducir una conmoción cerebral que van de leves a moderados mediante el ajuste de los parámetros de impacto. La pérdida de conciencia (LOC) se puede observar inmediatamente después de un impacto por la detección de una disminución en la tasa de respiración o la terminación transitoria de la respiración. El período de LOC se usa para determinar la gravedad de la lesión. Este documento incluye una versión ligeramente mejorada y actualizada de un modelo repetitivo CHI (rCHI) en ratones, junto con un protocolo detallado paso a paso y los resultados representativos. El rCHI estrategias de investigación modelo de unare beneficiosa en la determinación de los efectos LCTL y posibles tratamientos, sobre todo porque no existe un modelo animal individual capaz de imitar todos los cambios patológicos de conmoción cerebral inducida.

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			<td height="21" style="height:21px;width:216px;">anesthesia machine</td>
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			<td>perform impaction</td>
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			<td>mount mouse and positioning tips</td>
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			<td height="42" style="height:42px;width:216px;">Sicilone rubber-coated metal tip</td>
			<td style="width:188px;">Precision Tool &#38; Engineering, Gainesvill FL</td>
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			<td>impact tip</td>
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			<td height="21" style="height:21px;width:216px;">Lithium Ion All-in-One Trimmer</td>
			<td style="width:188px;">WAHL Home Products</td>
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			<td>shave mouse hair</td>
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			<td style="width:188px;">custom-made</td>
			<td style="width:137px;"></td>
			<td>probe tip</td>
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			<td height="21" style="height:21px;width:216px;">Cotton tipped applicators</td>
			<td style="width:188px;">MEDLINE</td>
			<td style="width:137px;">MDS202055</td>
			<td>scrub head with saline</td>
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			<td style="width:188px;">ASKURA FINETEK USA INC</td>
			<td style="width:137px;">4583</td>
			<td>tissue embedding</td>
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			<td height="21" style="height:21px;width:216px;">anti-GFAP</td>
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			<td>antibody for IHC</td>
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			<td>IHC detection system</td>
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			<td height="21" style="height:21px;width:216px;">Permount Mounting Medium</td>
			<td style="width:188px;">Fisher Scientific</td>
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			<td></td>
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			<td height="21" style="height:21px;width:216px;">Aperio XT ScanScope scanner</td>
			<td style="width:188px;">Leica Microsystems Inc,</td>
			<td style="width:137px;"></td>
			<td>slides scanning</td>
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			<td height="42" style="height:42px;width:216px;">Leica AutoStainer XL</td>
			<td style="width:188px;">Leica the pathology Company</td>
			<td style="width:137px;">ST2010</td>
			<td>H&#38;E staining</td>
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			<td height="21" style="height:21px;width:216px;">DAB&#160;</td>
			<td style="width:188px;">sigma</td>
			<td style="width:137px;">D3939</td>
			<td>IHC detection system</td>
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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.

En este modelo (Figura 1 AC), hubo breves períodos de jadeos y respiraciones superficiales. Una pérdida de la conciencia (inconsciente) se define como una disminución en el ritmo de la respiración o la terminación transitoria de la respiración antes de reanudar una respiración normal. Un impacto en el centro de la cabeza causado inconsciencia a corto plazo (7,5 ± 4,7, 7,8 ± 5,5, 10,2 ± 8,8, 9,5 ± 8,0 seg en cada impacto por separado, la Figura 1D).</st...

Watch this Scientific Journal Video about A Repetitive Concussive Head Injury Model in Mice at JoVE.com

A Repetitive Concussive Head Injury Model in Mice

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 ...

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11.8K vistas.  University of Florida. 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.

Video: A Repetitive Concussive Head Injury Model in Mice

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

Peripheral neuropathic pain is a severe chronic pain condition which may result from trauma to sensory nerves in the peripheral nervous system. The spared nerve injury (SNI) model induces symptoms of neuropathic pain such as mechanical allodynia i.e. pain due to tactile stimuli that do not normally provoke a painful response [1]. 
The SNI mouse model involves ligation of two of the three branches of the sciatic nerve (the tibial nerve and the common peroneal nerve), while the sural nerve is left intact [2]. The lesion results in marked hypersensitivity in the lateral area of the paw, which is innervated by the spared sural nerve. The non-operated side of the mouse can be used as a control. The advantages of the SNI model are the robustness of the response and that it doesn&#x2019;t require expert microsurgical skills.
The threshold for mechanical pain response is determined by testing with von Frey filaments of increasing bending force, which are repetitively pressed against the lateral area of the paw [3], [4]. A positive pain reaction is defined as sudden paw withdrawal, flinching and/or paw licking induced by the filament. A positive response in three out of five repetitive stimuli is defined as the pain threshold. 
As demonstrated in the video protocol, C57BL/6 mice experience profound allodynia as early as the day following surgery and maintain this for several weeks.

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

The Spared Nerve Injury animal model is described here as a mouse model of peripheral neuropathic pain following partial denervation of the sciatic nerve by lesioning the tibial and common peroneal nerve branches, leaving the remaining sural nerve intact. Behavioral modification resulting from mechanical allodynia is quantified by von Frey filaments.

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 ...

Investigación

Medicina

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 ...

A Contusion Model of Severe Spinal Cord Injury in Rats

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is described to obtain a consistent model of severe SCI. Use of a stereotactic frame and computer controlled impactor allows for creation of reproducible injury. Hypothermia and urinary tract infection pose significant challenges in the post-operative period. Careful monitoring of animals with daily weight recording and bladder expression allows for early detection of post-operative complications. The functional results of this contusion model are equivalent to transection models. The contusion model can be utilized to evaluate the efficacy of both neuroprotective and neuroregenerative approaches.

A contusion model of severe spinal cord injury is described. Detailed pre-operative, operative and post-operative steps are described to obtain a consistent model.

Un modelo Contusión de la lesión de la médula espinal severa en ratas

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is ...

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 ...

Renal Ischaemia Reperfusion Injury: A Mouse Model of Injury and Regeneration

Renal ischaemia reperfusion injury (IRI) is a common cause of acute kidney injury (AKI) in patients and occlusion of renal blood flow is unavoidable during renal transplantation. Experimental models that accurately and reproducibly recapitulate renal IRI are crucial in dissecting the pathophysiology of AKI and the development of novel therapeutic agents. Presented here is a mouse model of renal IRI that results in reproducible AKI. This is achieved by a midline laparotomy approach for the surgery with one incision allowing both a right nephrectomy that provides control tissue and clamping of the left renal pedicle to induce ischaemia of the left kidney. By careful monitoring of the clamp position and body temperature during the period of ischaemia this model achieves reproducible functional and structural injury. Mice sacrificed 24 hr&#160;following surgery demonstrate loss of renal function with elevation of the serum or plasma creatinine level as well as structural kidney damage with acute tubular necrosis evident. Renal function improves and the acute tissue injury resolves during the course of 7 days following renal IRI such that this model may be used to study renal regeneration. This model of renal IRI has been utilized to study the molecular and cellular pathophysiology of AKI as well as analysis of the subsequent renal regeneration.

The mouse model of renal ischaemia reperfusion injury described here comprises of a right nephrectomy that provides control tissue and clamping of the left renal pedicle to induce ischaemia that results in acute kidney injury. This model uses a midline laparotomy approach with all steps performed via one incision.

La isquemia reperfusión renal: un modelo de ratón de la lesión y regeneración

Renal ischaemia reperfusion injury (IRI) is a common cause of acute kidney injury (AKI) in patients and occlusion of renal blood flow is unavoidable ...

A Simple Critical-sized Femoral Defect Model in Mice

While bone has a remarkable capacity for regeneration, serious bone trauma often results in damage that does not properly heal. In fact, one tenth of all limb bone fractures fail to heal completely due to the extent of the trauma, disease, or age of the patient. Our ability to improve bone regenerative strategies is critically dependent on the ability to mimic serious bone trauma in test animals, but the generation and stabilization of large bone lesions is technically challenging. In most cases, serious long bone trauma is mimicked experimentally by establishing a defect that will not naturally heal. This is achieved by complete removal of a bone segment that is larger than 1.5 times the diameter of the bone cross-section. The bone is then stabilized with a metal implant to maintain proper orientation of the fracture edges and allow for mobility. 
Due to their small size and the fragility of their long bones, establishment of such lesions in mice are beyond the capabilities of most research groups. As such, long bone defect models are confined to rats and larger animals. Nevertheless, mice afford significant research advantages in that they can be genetically modified and bred as immune-compromised strains that do not reject human cells and tissue.
Herein, we demonstrate a technique that facilitates the generation of a segmental defect in mouse femora using standard laboratory and veterinary equipment. With practice, fabrication of the fixation device and surgical implantation is feasible for the majority of trained veterinarians and animal research personnel. Using example data, we also provide methodologies for the quantitative analysis of bone healing for the model.

Animal models are frequently employed to mimic serious bone injury in biomedical research. Due to their small size, establishment of stabilized bone lesions in mice are beyond the capabilities of most research groups. Herein, we describe a simple method for establishing and analyzing experimental femoral defects in mice.

A-crítico tamaño femoral Defecto sencillo modelo en ratones

While bone has a remarkable capacity for regeneration, serious bone trauma often results in damage that does not properly heal. In fact, one tenth of all ...

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 ...

Quantification of Neurovascular Protection Following Repetitive Hypoxic Preconditioning and Transient Middle Cerebral Artery Occlusion in Mice

Experimental animal models of stroke are invaluable tools for understanding stroke pathology and developing more effective treatment strategies. A 2 week protocol for repetitive hypoxic preconditioning (RHP) induces long-term protection against central nervous system (CNS) injury in a mouse model of focal ischemic stroke. RHP consists of 9 stochastic exposures to hypoxia that vary in both duration (2 or 4 hr) and intensity (8% and 11% O2). RHP reduces infarct volumes, blood-brain barrier (BBB) disruption, and the post-stroke inflammatory response for weeks following the last exposure to hypoxia, suggesting a long-term induction of an endogenous CNS-protective phenotype. The methodology for the dual quantification of infarct volume and BBB disruption is effective in assessing neurovascular protection in mice with RHP or other putative neuroprotectants. Adult male Swiss Webster mice were preconditioned by RHP or duration-equivalent exposures to 21% O2 (i.e. room air). A 60 min transient middle cerebral artery occlusion (tMCAo) was induced 2 weeks following the last hypoxic exposure. Both the occlusion and reperfusion were confirmed by transcranial laser Doppler flowmetry. Twenty-two hr after reperfusion, Evans Blue (EB) was intravenously administered through a tail vein injection. 2 hr later, animals were sacrificed by isoflurane overdose and brain sections were stained with 2,3,5- triphenyltetrazolium chloride (TTC). Infarcts volumes were then quantified. Next, EB was extracted from the tissue over 48 hr to determine BBB disruption after tMCAo. In summary, RHP is a simple protocol that can be replicated, with minimal cost, to induce long-term endogenous neurovascular protection from stroke injury in mice, with the translational potential for other CNS-based and systemic pro-inflammatory disease states.

This protocol describes repetitive hypoxic preconditioning, or brief exposures to systemic hypoxia that reduce infarct volumes and blood-brain barrier disruption following transient middle cerebral artery occlusion in mice. It also details dual quantification of infarct volume and blood-brain barrier disruption after stroke to assess the efficacy of neurovascular protection.

Cuantificación de Protección neurovascular Siguiendo repetitivo hipóxico Precondicionamiento y transitoria cerebral media oclusión de la arteria en ratones

Experimental animal models of stroke are invaluable tools for understanding stroke pathology and developing more effective treatment strategies. A 2 week ...

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) ...

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. ...