Este trabajo fue apoyado por becas de la Asociación de Investigación Neuromuscular CIHR (JNM - 90959, para Jaeb).

Antes de utilizar este modelo, los investigadores deben haber recibido la aprobación para el protocolo quirúrgico del uso de los animales de su institución órgano de gobierno. El modelo es aprobado por la Junta de Ética de la Investigación, Hamilton Health Sciences Corporation, la Universidad McMaster (AUP # 10/04/24) y se lleva a cabo en estricta conformidad con las recomendaciones formuladas por el Consejo Canadiense de los Animales. 1. Ratón Preparación <ol><li> Pesar el ratón. Inducir la anestesia con isoflurano al 5% o 2% de halotano. El circuito utilizado debe garantizar compactación adecuada de la anestesia para proteger el cirujano. Después de 2-3 minutos la respiración del animal se ralentizará. Asegúrese de que el reflejo de parpadeo está ausente y pellizcar los espacios interdigitales de la pata para confirmar la anestesia quirúrgica (es decir, no hay respuesta por el ratón). Aplicar lubricante oftálmica al ojo, para evitar el secado de la córnea durante la cirugía. </li><li> Shave la cara lateral del muslo y la nalga del ciáticoapuntarse a la rodilla y desinfectar con proviodine. Afeitar mantendrá el sitio de la incisión libre de pelo para asegurar una adecuada visualización del campo quirúrgico y para minimizar la interferencia con la disección del nervio y la transección. La escotadura ciática, que es superior y posterior en el fémur, se puede identificar mediante la palpación. </li></ol> 2. Procedimiento Operativo <ol><li> Reducir por inhalación isoflurano al 2% (halotano 1%) y colocar el ratón sobre un lado (el lado destinado a la cirugía hacia arriba), con un microscopio operativo o disección. Alternativamente, la cirugía se puede realizar con lupas quirúrgicas desde ampliación 3.5X es satisfactoria para un adulto (20-25 g) del ratón. </li><li> Ponte los guantes estériles. Identificar la escotadura ciática por palpación. El uso de un escalpelo, incisión de la piel de la cara lateral del muslo de la escotadura ciática a la rodilla (aproximadamente 1 cm). </li><li> Suavemente separa la piel. Identificar el músculo bíceps femoral, que es el músculo superficial plana de la cara lateral del musloinmediatamente debajo de la piel. Con unas tijeras finas, dividir el músculo bíceps femoral a lo largo de las fibras musculares y mantenga abierto con un retractor de primavera para exponer el nervio ciático y sus ramas. </li><li> Identificar el nervio ciático inmediatamente la profundidad del músculo bíceps femoral. Puede ser identificado por su color blanco brillante característico y es de aproximadamente 0,8 mm de diámetro. Se extiende desde la escotadura ciática a la rodilla, se ramifican en los nervios tibiales, peroneo y sural a nivel de la fosa poplítea. </li><li> Separar suavemente el tibial de las ramas del nervio peroneo y sural con fórceps ultrafinas y primavera tijeras microdissecting. El nervio tibial es la rama más grande y suele ser central. Es importante no aplastar el nervio mientras que separa las ramas. Sosteniendo el nervio sólo en la capa adventicial exterior con las pinzas ultrafinas, y mantener la holgura del nervio (no enseñados), evitará aplastamiento del nervio y la lesión por tracción. </li><li> Para obtener información completa y duradera denervatien, cortar el nervio tibial con microdissecting tijeras como distalmente como sea posible, evitando cuidadosamente los vasos poplíteos. Alternativamente, para la denervación temporal con reinervación completa esperada en 2-4 semanas, el nervio tibial puede simplemente ser aplastado con fórceps ultrafinas de 15 segundos en lugar de seccionado. (Nervios periféricos vuelven a crecer después de la lesión y se reinervar músculo deseado.) </li><li> Si se requiere la denervación completa, suturar el extremo del nervio tibial cortado transversalmente a la superficie anterior del músculo bíceps femoral con nylon 10-0 y volver a aproximar el bíceps femoral con Vicryl 5-0 para evitar aberrante de re-inervación de los gastrocnemio y músculos sóleo. </li><li> Cierre la piel con una sutura de Vicryl 5-0 correr. </li></ol> 3. Cuidado operativo del poste <ol><li> Apague la anestesia inhalatoria, pero mantener el flujo de oxígeno. Administrar buprinorphine (o sustituto) analgésico por vía subcutánea. </li><li> Transferir el ratón a una jaula limpia sinropa de cama, mientras que despierta de la anestesia. Mantener en una manta de calentamiento dentro de la jaula y bajo observación directa hasta deambular. </li><li> Transferencia y la casa en la jaula inferior suave (no cable) con amplia ropa de cama blanda. </li><li> Inspeccionar la extremidad operativa diaria para la condición de la herida quirúrgica y el pie para el desarrollo de las úlceras por decúbito talón o las pruebas de la masticación. Los problemas menores pueden ser tratados con antibióticos o antisépticos tópicos como proviodine. Indicadores de punto final que requieren la eutanasia de animales son la pérdida de peso, la evidencia de autocuidado deficiente (piel rizada) y postura encorvada. Además, los animales con mayor apertura de la herida o úlceras que no se curan en 1-2 semanas con antibióticos tópicos o parece tener dolor deberán ser sacrificados. </li></ol> 4. Gastrocnemius Denervado y cosecha del músculo sóleo <ol><li> En el punto de tiempo después de la operación deseada, pesar el ratón y el sacrificio con sobredosis de CO 2. </li><li> Shave el aspecto medial de tanto laoperativa y las piernas de control contralateral y limpio con alcohol. Coloque el ratón en un microscopio operativo o disección, o alternativamente usar lupas quirúrgicas para la ampliación de visualización. </li><li> En la extremidad operativa, una incisión en la piel pierna medial con un bisturí desde el tobillo hasta la rodilla y circunferencialmente alrededor del tobillo. Tire suavemente la piel con pinzas fuera del músculo y proximalmente hacia el muslo. Esto expone a todos los músculos de la pierna. Identificar el músculo gastrocnemio, que es el músculo de la pantorrilla que se extiende desde la rodilla hasta el tobillo en la cara posterior de la pierna y se encuentra inmediatamente debajo de la piel. Identificar la inserción distal del músculo bíceps femoral, proximal al músculo gastrocnemio en la cara medial de la rodilla. En su inserción distal del bíceps femoral aparece delgada y transparente y se superpone a la porción más proximal del gastrocnemio. Con unas tijeras y disección extremo romo, separar suavemente la inserción distal del bíceps femoral del gasmúsculo gastrocnemio. </li><li> En su inserción distal en el calcáneo, el músculo gastrocnemio se estrecha en el tendón de Aquiles. Identificar el tendón de Aquiles, que aparece blanco y musculoso. Sostenga el tendón de Aquiles con unas pinzas, teniendo cuidado de no agarrar ni triture los músculos gemelos, y dividir el tendón de Aquiles de la inserción del calcáneo con unas tijeras. </li><li> Sin soltar el tendón, levante suavemente el músculo gemelo (rojo claro) fuera el sóleo profundas (más rojo), a partir de la inserción distal a su origen en la rodilla (el sóleo se pueden cosechar por separado). </li><li> Diseccionar el gastrocnemio de la pierna dividiendo el origen de los gastrocnemio de los chondyles fémur medial y lateral con unas tijeras. Tracción muy suave en el músculo facilita este proceso. Tenga cuidado de no aplastar el músculo. </li><li> Los sóleo ahora serán claramente visibles, inmediatamente debajo del sitio de los gastrocnemio. Levante el sóleo de su inserción en el tendón de Aquiles de su oigin en la pantorrilla posterior. Si el sóleo se eleva inadvertidamente con el gastrocnemio, suavemente separarlo de la muestra cosechada. El gastrocnemio (rojo claro) y sóleo (rojo oscuro) siguen siendo fácilmente identificables en la muestra recolectada, debido a sus diferencias de color. </li><li> Pesar los músculos por separado en una balanza de precisión. </li><li> Dividir los músculos verticalmente, un medio para la congelación en nitrógeno líquido a presión (para su posterior proteínas y / o extracción de ARN), y un medio para la histología (es decir, evaluación morfométrica, inmunohistología) que se fijan ya sea en 10% de formalina, o la fijación congelados en isopentano enfriado con nitrógeno líquido , si lo deseas. </li><li> Repita desde el paso 4.3 en el control, no operado, de lado a cosechar gemelo de control y los músculos sóleo. </li></ol>

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No hay conflictos de interés se declaran.

El modelo de transección del nervio tibial de la atrofia del músculo esquelético denervación inducida es un modelo comúnmente empleado y bien validado en ratas. Hemos adaptado este modelo para su uso en los ratones, lo que permite al investigador para tomar ventaja de la existencia de ratones modificados genéticamente y estudiar el proceso de la atrofia muscular in vivo en ausencia de proteínas cruciales para la regulación de la masa muscular 7,8. Los músculos gemelos y sóleo, tanto desnerv...

Denervación del músculo esquelético, debido a una lesión traumática de nervios periféricos, la enfermedad o la intervención farmacológica, resulta en la pérdida inmediata de la función contráctil muscular voluntario. Muscle concomitantemente comienza a atrofiarse y esta atrofia es reversible si reinervación oportuna y de buena calidad produce 1,2. En la ausencia de reinervación, atrofia miofibrilar progresa, y cambios biológicos irreversibles en el músculo se produce con la fibrosis muscular y muerte miofibras. Aquí se demuestra el modelo de transección del nervio tibial, un modelo de la denervación inducida por la atrofia muscular y la fibrosis en los ratones. Este modelo permite a los científicos estudiar los mecanismos biológicos fisiológicos, celulares y moleculares que subyacen a la atrofia muscular in vivo en los músculos gastrocnemio y sóleo. Aunque se han utilizado históricamente predominante en ratas, más reciente aplicación de este modelo a nocaut y las líneas de ratones transgénicos en concreto, permite a los investigadores para evaluar el papel de la, las proteínas (s) de interés en la inducción, el desarrollo y el mantenimiento, o, alternativamente, la resolución de, la atrofia muscular y la fibrosis in vivo. El nervio tibial es un nervio periférico del motor-sensorial mixta en la extremidad posterior de roedores, y es una de las tres ramas terminales del nervio ciático. Transección del nervio tibial desnerva el gastrocnemio, sóleo y plantar (músculos y los tres músculos flexores profundos y pequeños de los pies, incluyendo tibial posterior, flexor largo de los dedos y flexor largo del dedo gordo hallicus), y es un modelo bien estandarizado y validado en ratas 3,4 . Los músculos gastrocnemio y sóleo pueden ser fácilmente diseccionados en puntos de tiempo de serie Publicación de transección del nervio tibial, fijaron y procesaron para la evaluación de la histología muscular y morfometría de la fibra muscular, o el flash congelado para la extracción de ARN y de proteínas musculares para el propósito de estudiar, por ejemplo, las redes de señalización celular que regulan la atrofia muscular. El gamuscular strocnemius es un tipo de fibra muscular mixta (de tipo I y de tipo II, aunque predominantemente de tipo II) y el músculo sóleo se compone de una gran proporción de fibras de tipo I, proporcionando de este modo contracción muscular a la vez rápido y lento para la evaluación de 5,6. El modelo de transección del nervio tibial es adecuado para estudiar el proceso de denervación inducida por la atrofia muscular, tanto a corto plazo (días) 7 y largo plazo (semanas a meses) 4,8. En contraste con el modelo de transección del nervio ciático (un segundo modelo de la denervación inducida por la atrofia muscular comúnmente utilizado en roedores), la transección del nervio tibial induce una menor morbilidad en el animal, por lo que es un modelo más atractivo. Transección del nervio ciático desnerva todos los músculos de la pierna (debajo de la rodilla) y el pie, mermando la capacidad del animal para caminar 2, mientras que la transección del nervio tibial deja las ramas del nervio peroneo y sural del nervio ciático intacto, conservando asísus músculos en cuestión y territorios sensoriales. El ratón es incapaz de flexión plantar o invertir el pie, pero es capaz de deambular fácilmente y el peso lleva igualmente en ambas extremidades traseras, disminuyendo así significativamente la morbilidad del modelo. Estudios de análisis de la marcha que evalúan los patrones de caminar se han realizado en ratas después de lesiones del nervio tibial y ciático y demostrar que la huella y la carga de peso se conserva mejor con una lesión tibial 9,10. Además, en el modelo de transección del nervio tibial, el nervio peroneo puede ser movilizado en un punto de tiempo más tarde y se transfiere como una fuente de reinervación retardada, si el diseño del estudio requiere 3. En contraste, la reinervación retardada en el modelo de transección del nervio ciático hace necesario el uso de un injerto de nervio al déficit nervio ciático, muy significativamente el aumento de la dificultad técnica del modelo y la limitación de su uso para cirujanos expertos. Mientras que el modelo de transección del nervio tibial requires familiaridad del operador con la técnica quirúrgica estéril en cirugía animal, tanto el nervio tibial y los músculos de la pantorrilla que inerva son fácilmente accesibles e identificables para la manipulación, de manera que las personas que no son cirujanos, o una amplia experiencia con la cirugía animal, pueden dominar fácilmente este modelo .

<table border="1">
	<tbody>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Reagents and Materials</td>
		</tr>
		<tr>
			<td>10-0 Nylon suture</td>
			<td>Ethicon</td>
			<td>2850G</td>
			<td></td>
		</tr>
		<tr>
			<td>5-0 Vicryl suture</td>
			<td>Ethicon</td>
			<td>J553G</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Spring microdissecting scissors</td>
			<td>Fine Surgical Tools</td>
			<td>15021-15</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultra fine forceps</td>
			<td>Fine Surgical Tools</td>
			<td>11370-40</td>
			<td></td>
		</tr>
		<tr>
			<td>Non locking micro needle holder (driver)</td>
			<td>Fine Surgical Tools</td>
			<td>12076-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Spring retractor</td>
			<td>Fine Surgical Tools</td>
			<td>17000-02</td>
			<td></td>
		</tr>
	</tbody>
</table>

tibial nerve transection - a standardized model for denervation-induced skeletal muscle atrophy in mice

El modelo de transección del nervio tibial es un bien tolerado, validado, y reproducible modelo de atrofia del músculo esquelético inducida por desnervación en roedores. Aunque originalmente desarrollado y utilizado ampliamente en la rata, debido a su tamaño más grande, el nervio tibial en ratones es lo suficientemente grande que pueda ser manipulado fácilmente, ya sea con aplastamiento o transección, dejando las ramas del nervio peroneal y sural del nervio ciático intacta y preservando así sus músculos en cuestión. Por lo tanto, este modelo ofrece las ventajas de la inducción de una menor morbilidad y impedimento de la deambulación que el modelo de transección del nervio ciático y también permite a los investigadores estudiar los mecanismos biológicos fisiológicos, celulares y moleculares que regulan el proceso de la atrofia muscular en ratones diseñados genéticamente. El nervio tibial suministra el gastrocnemio, sóleo y plantar los músculos, por lo que su corte transversal permite el estudio de los músculos esqueléticos desnervado compuesto por fibras de contracción rápida de tipo II y / o de tipo I de contracción lentafibras. Aquí se demuestra el modelo de transección del nervio tibial en el C57Black6 ratón. Evaluamos la atrofia del músculo gastrocnemio, como representante de un músculo, en 1, 2, y 4 semanas después de la denervación mediante la medición de los pesos musculares y del tipo de área de la sección transversal de la fibra específica en parafina secciones histológicas immunostained para la miosina rápida contracción.

<html> Transección del nervio tibial desnerva el gastrocnemio, sóleo y plantar los músculos de la pantorrilla. Aquí se evalúa el desarrollo de la atrofia en los músculos gemelos, como un músculo representativo. Músculo gastrocnemio fue cosechada de 2-3 meses de edad C57Black 6 ratones (Jackson Laboratories) denervado para 1, 2, o 4 semanas. Pesos musculares disminuyen progresivamente (Figura 1), al igual que el área de sección transversal de las fibras de tipo II musculares de contracción ráp...

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

El modelo de transección del nervio tibial es un bien tolerado, validado, y reproducible modelo de atrofia del músculo esquelético. El modelo de protocolo quirúrgico se describe y se demuestra en C57Black6 ratones.

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. ...

tibial-nerve-transection-standardized-model-for-denervation-induced

Research

JoVE Journal

Medicine

24.2K vistas.  St Michaels Hospital.  El modelo de transección del nervio tibial es un bien tolerado, validado, y reproducible modelo de atrofia del músculo esquelético. El modelo de protocolo quirúrgico se describe y se demuestra en C57Black6 ratones. 

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

Skeletal Muscle Gender Dimorphism from Proteomics

Gross contraction in skeletal muscle is primarily determined by a relatively small number of contractile proteins, however this tissue is also remarkably adaptable to environmental factors1 such as hypertrophy by resistance exercise and atrophy by disuse. It thereby exhibits remodeling and adaptations to stressors (heat, ischemia, heavy metals, etc.)2,3. Damage can occur to muscle by a muscle exerting force while lengthening, the so-called eccentric contraction4. The contractile proteins can be damaged in such exertions and need to be repaired, degraded and/or resynthesized; these functions are not part of the contractile proteins, but of other much less abundant proteins in the cell. To determine what subset of proteins is involved in the amelioration of this type of damage, a global proteome must be established prior to exercise5 and then followed subsequent to the exercise to determine the differential protein expression and thereby highlight candidate proteins in the adaptations to damage and its repair. Furthermore, most studies of skeletal muscle have been conducted on the male of the species and hence may not be representative of female muscle. 
In this article we present a method for extracting proteins reproducibly from male and female muscles, and separating them by two-dimensional gel electrophoresis followed by high resolution digital imaging6. This provides a protocol for spots (and subsequently identified proteins) that show a statistically significant (p &lt; 0.05) two-fold increase or decrease, appear or disappear from the control state. These are then excised, digested with trypsin and separated by high-pressure liquid chromatography coupled to a mass spectrometer (LC/MS) for protein identification (LC/MS/MS)5. This methodology (Figure 1) can be used on many tissues with little to no modification (liver, brain, heart etc.).

A straight-forward set of methods to isolate and determine the identity of the most abundant proteins expressed in skeletal muscle. About 800 spots are discerned on a two-dimensional gel from 10 mg muscle; this allows for the determination of gender-specific protein expression. These methods will give equivalent results in most tissues.

Músculo Esquelético dimorfismo de género de Proteómica

Gross contraction in skeletal muscle is primarily determined by a relatively small number of contractile proteins, however this tissue is also remarkably ...

Investigación

Medicina

Utility of Dissociated Intrinsic Hand Muscle Atrophy in the Diagnosis of Amyotrophic Lateral Sclerosis

The split hand phenomenon refers to predominant wasting of thenar muscles and is an early and specific feature of amyotrophic lateral sclerosis (ALS). A novel split hand index (SI) was developed to quantify the split hand phenomenon, and its diagnostic utility was assessed in ALS patients. The split hand index was derived by dividing the product of the compound muscle action potential (CMAP) amplitude recorded over the abductor pollicis brevis and first dorsal interosseous muscles by the CMAP amplitude recorded over the abductor digiti minimi muscle. In order to assess the diagnostic utility of the split hand index, ALS patients were prospectively assessed and their results were compared to neuromuscular disorder patients. The split hand index was significantly reduced in ALS when compared to neuromuscular disorder patients (P&#60;0.0001). Limb-onset ALS patients exhibited the greatest reduction in the split&#160;hand index, and a value of 5.2 or less reliably differentiated ALS from other neuromuscular disorders. Consequently, the split&#160;hand index appears to be a novel diagnostic biomarker for ALS, perhaps facilitating an earlier diagnosis.

Dissociated atrophy of intrinsic hand muscles, termed the split hand, appears to be a specific feature of amyotrophic lateral sclerosis (ALS).&#160;Consequently, a novel neurodiagnostic test, termed the split hand&#160;index, was developed to quantify the clinical phenomenon of the split hand, which differentiated ALS from mimic disorders.

Utilidad de la disociada intrínseca Mano Atrofia muscular en el diagnóstico de la esclerosis lateral amiotrófica

The split hand phenomenon refers to predominant wasting of thenar muscles and is an early and specific feature of amyotrophic lateral sclerosis (ALS). A ...

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 ...

Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow reserve (CFR) in humans. Reduced CFR is accompanied by marked intramyocardial and pericoronary fibrosis and is used as an indication of the severity of dysfunction. This study explores, step-by-step, the real-time changes measured in the coronary flow velocity, CFR and systolic to diastolic peak velocity (S/D) ratio in the setting of an aortic banding model in mice. By using a Doppler transthoracic imaging technique that yields reproducible and reliable data, the method assesses changes in flow in the septal coronary artery (SCA), for a period of over two weeks in mice, that previously either underwent aortic banding or thoracotomy. 
During imaging, hyperemia in all mice was induced by isoflurane, an anesthetic that increased coronary flow velocity when compared with resting flow. All images were acquired by a single imager. Two ratios, (1) CFR, the ratio between hyperemic and baseline flow velocities, and (2) systolic (S) to diastolic (D) flow were determined, using a proprietary software and by two independent observers. Importantly, the observed changes in coronary flow preceded LV dysfunction as evidenced by normal LV mass and fractional shortening (FS). 
The method was benchmarked against the current gold standard of coronary assessment, histopathology. The latter technique showed clear pathologic changes in the coronary artery in the form of peri-coronary fibrosis that correlated to the flow changes as assessed by echocardiography. 
The study underscores the value of using a non-invasive technique to monitor coronary circulation in mouse hearts. The method minimizes redundant use of research animals and demonstrates that advanced ultrasound-based indices, such as CFR and S/D ratios, can serve as viable diagnostic tools in a variety of investigational protocols including drug studies and the study of genetically modified strains.

Coronary flow reserve (CFR) is useful for assessment of myocardial oxygen demand and evaluation of cardiovascular risk. This study establishes a step-by-step transthoracic Doppler echocardiographic (TTDE) method for longitudinal monitoring of the changes in CFR, as measured from coronary artery in mice, under the experimental pressure overload of aortic banding.

Evaluación Ultrasonido base de la arteria coronaria de flujo y la reserva coronaria Utilizando la sobrecarga Modelo Presión en ratones

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow ...

Human Vastus Lateralis Skeletal Muscle Biopsy Using the Weil-Blakesley Conchotome

Percutaneous muscle biopsy using the Weil-Blakesley conchotome is well established in both clinical and research practice. It is a safe, effective and well tolerated technique. The Weil-Blakesley conchotome has a sharp biting tip with a 4 - 6 mm wide hollow. It is inserted through a 5 - 10 mm skin incision and can be maneuvered for controlled tissue penetration. The tip is opened and closed within the tissue and then rotated through 90 -180&#176; to cut the muscle. The amount of muscle obtained following repeated sampling can vary from 20 mg to 290 mg which can be processed for both histology and molecular studies. The wound needs to be kept dry and vigorous physical activity kept to a minimum for approximately 72 hr although normal levels of activity can restart immediately following the procedure. This procedure is safe and effective when close attention is paid to the selection of subjects, full asepsis and post procedure care. &#160;Both right and left vastus lateralis are suitable for biopsy dependent on participant preference.

Human Vastus Lateralis Skeletal Muscle Biopsy Using the Weil-Blakesley Conchotome

This video demonstrates the technique of percutaneous muscle biopsy of the human vastus lateralis using the Weil-Blakesley conchotome.

Humano<em&gt; vasto externo</em&gt; Esquelético biopsia muscular utilizando el Weil-Blakesley Conchotome

Percutaneous muscle biopsy using the Weil-Blakesley conchotome is well established in both clinical and research practice. It is a safe, effective and ...

Surgical Angiogenesis in Porcine Tibial Allotransplantation: A New Large Animal Bone Vascularized Composite Allotransplantation Model

Segmental bone loss resulting from trauma, infection malignancy and congenital anomaly remains a major reconstructive challenge. Current therapeutic options have significant risk of failure and substantial morbidity.
Use of bone vascularized composite allotransplantation (VCA) would offer both a close match of resected bone size and shape and the healing and remodeling potential of living bone. At present, life-long drug immunosuppression (IS) is required. Organ toxicity, opportunistic infection and neoplasm risks are of concern to treat such non-lethal indications.
We have previously demonstrated that bone and joint VCA viability may be maintained in rats and rabbits without the need of long-term-immunosuppression by implantation of recipient derived vessels within the VCA. It generates an autogenous, neoangiogenic circulation with measurable flow and active bone remodeling, requiring only 2 weeks of IS. As small animals differ from man substantially in anatomy, bone physiology and immunology, we have developed a porcine bone VCA model to evaluate this technique before clinical application is undertaken. Miniature swine are currently widely used for allotransplantation research, given their immunologic, anatomic, physiologic and size similarities to man. Here, we describe a new porcine orthotopic tibial bone VCA model to test the role of autogenous surgical angiogenesis to maintain VCA viability.
The model reconstructs segmental tibial bone defects using size- and shape-matched allogeneic tibial bone segments, transplanted across a major swine leukocyte antigen (SLA) mismatch in Yucatan miniature swine. Nutrient vessel repair and implantation of recipient derived autogenous vessels into the medullary canal of allogeneic tibial bone segments is performed in combination with simultaneous short-term IS. This permits a neoangiogenic autogenous circulation to develop from the implanted tissue, maintaining flow through the allogeneic nutrient vessels for a short time. Once established, the new autogenous circulation maintains bone viability following cessation of drug therapy and subsequent nutrient vessel thrombosis.

Currently any kind of vascularized composite allotransplantation depends on long-term-immunosuppression, difficult to support for non-life-critical indications. We present a new porcine tibial VCA model that can be used to study bone VCA and demonstrate the use of surgical angiogenesis to maintain bone viability without the need of long-term immune-modulation.

Angiogénesis quirúrgica en porcino Allotransplantation Tibial: un hueso de Animal grande nuevo vascularizado compuesto Allotransplantation modelo

Segmental bone loss resulting from trauma, infection malignancy and congenital anomaly remains a major reconstructive challenge. Current therapeutic ...

Semi-automated Analysis of Mouse Skeletal Muscle Morphology and Fiber-type Composition

For years, distinctions between skeletal muscle fiber types were best visualized by myosin-ATPase staining. More recently, immunohistochemical staining of myosin heavy chain (MyHC) isoforms has emerged as a finer discriminator of fiber-type. Type I, type IIA, type IIX and type IIB fibers can now be identified with precision based on their MyHC profile; however, manual analysis of these data can be slow and down-right tedious. In this regard, rapid, accurate assessment of fiber-type composition and morphology is a very desirable tool. Here, we present a protocol for state-of-the-art immunohistochemical staining of MyHCs in frozen sections obtained from mouse hindlimb muscle in concert with a novel semi-automated algorithm that accelerates analysis of fiber-type and fiber morphology. As expected, the soleus muscle displayed staining for type I and type IIA fibers, but not for type IIX or type IIB fibers. On the other hand, the tibialis anterior muscle was composed predominantly of type IIX and type IIB fibers, a small fraction of type IIA fibers and little or no type I fibers. Several image transformations were used to generate probability maps for the purpose of measuring different aspects of fiber morphology (i.e., cross-sectional area (CSA), maximal and minimal Feret diameter). The values obtained for these parameters were then compared with manually-obtained values. No significant differences were observed between either mode of analysis with regards to CSA, maximal or minimal Feret diameter (all p &#62; 0.05), indicating the accuracy of our method. Thus, our immunostaining analysis protocol may be applied to the investigation of effects on muscle composition in many models of aging and myopathy.

Immunohistochemical staining of myosin heavy chain isoforms has emerged as the state-of-the-art discriminator of skeletal muscle fiber-type (i.e., type I, type IIA, type IIX, type IIB). Here, we present a staining protocol along with a novel semi-automated algorithm that facilitates rapid assessment of fiber-type and fiber morphology.

Análisis semi-automatizado de fibra tipo composición y morfología del músculo esquelético de ratón

For years, distinctions between skeletal muscle fiber types were best visualized by myosin-ATPase staining. More recently, immunohistochemical staining of ...

A Minimally Invasive Model to Analyze Endochondral Fracture Healing in Mice Under Standardized Biomechanical Conditions

Bone healing models are necessary to analyze the complex mechanisms of fracture healing to improve clinical fracture treatment. During the last decade, an increased use of mouse models in orthopedic research was noted, most probably because mouse models offer a large number of genetically-modified strains and special antibodies for the analysis of molecular mechanisms of fracture healing. To control the biomechanical conditions, well-characterized osteosynthesis techniques are mandatory, also in mice. Here, we report on the design and use of a closed bone healing model to stabilize femur fractures in mice. The intramedullary screw, made of medical-grade stainless steel, provides through fracture compression an axial and rotational stability compared to the mostly used simple intramedullary pins, which show a complete lack of axial and rotational stability. The stability achieved by the intramedullary screw allows the analysis of endochondral healing. A large amount of callus tissue, received after stabilization with the screw, offers ideal conditions to harvest tissue for biochemical and molecular analyses. A further advantage of the use of the screw is the fact that the screw can be inserted into the femur with a minimally invasive technique without inducing damage to the soft tissue. In conclusion, the screw is a unique implant that can ideally be used in closed fracture healing models offering standardized biomechanical conditions.

This protocol describes a minimally invasive osteosynthesis technique using an intramedullary screw for standardized stabilization of femur fractures, which can be used to analyze endochondral bone healing in mice.

Un modelo mínimamente invasivo para analizar la fractura endocondral en ratones en condiciones biomecánicas estandarizadas

Bone healing models are necessary to analyze the complex mechanisms of fracture healing to improve clinical fracture treatment. During the last decade, an ...

Non-invasive Assessment of Dorsiflexor Muscle Function in Mice

Assessment of skeletal muscle contractile function is an important measurement for both clinical and research purposes. Numerous conditions can negatively affect skeletal muscle. This can result in a loss of muscle mass (atrophy) and/or loss of muscle quality (reduced force per unit of muscle mass), both of which are prevalent in chronic disease, muscle-specific disease, immobilization, and aging (sarcopenia). Skeletal muscle function in animals can be evaluated by a range of different tests. All tests have limitations related to the physiological testing environment, and the selection of a specific test often depends on the nature of the experiments. Here, we describe an in vivo, non-invasive technique involving a helpful and easy assessment of force frequency-curve (FFC) in mice that can be performed on the same animal over time. This permits monitoring of disease progression and/or efficacy&#160;of a potential therapeutic treatment.

Measurement of rodent skeletal muscle contractile function is a useful tool that can be used to track disease progression as well as efficacy of therapeutic intervention. We describe here the non-invasive, in vivo assessment of the dorsiflexor muscles that can be repeated over time in the same mouse.

Evaluación no invasiva de la función muscular de los dorsiflexores en ratones

Assessment of skeletal muscle contractile function is an important measurement for both clinical and research purposes. Numerous conditions can negatively ...