Name: do's and don'ts in the preparation of muscle cryosections for histological analysis
Uploaded: 2015-05-15T13:00:00.000+00:00
Duration: 10 min 27 s
Description: Watch this Scientific Journal Video about Do's and Don'ts in the Preparation of Muscle Cryosections for Histological Analysis at JoVE.com

We would like to thank Alex Miller for manuscript revisions. This work was supported with the research grants awarded to M.G. from Cure CMD, Struggle Against Muscular Dystrophy (SAM) and Muscular Dystrophy Association (218938).

1. Tejido Cosecha y congelación de los tejidos musculares <ol><li> La eutanasia del ratón con una sobredosis de isoflurano (2-cloro-2- (difluorometoxi) -1,1,1-trifluoro-etano). Realice este paso en una campana de extracción y el uso de un método de contención secundaria, como un secador o una campana de vidrio que contiene un hisopo de algodón empapado en isoflurano. </li><li> Confirmar la muerte apretando firmemente la almohadilla plantar. Use un método secundario de la eutanasia como la dislocación cervical. </li><li> Humedezca la piel con alcohol al 70% para reducir la adherencia de los cabellos sueltos sobre los músculos. Pelar la piel de la extremidad utilizando unas pinzas finas como el # 5. </li><li> Separar cuidadosamente el músculo de interés (tibial anterior (TA) en este caso) de los huesos por debajo, a partir de tendón y quitar. </li><li> Extirpar el músculo, cubrirlo en octubre (compuesto temperatura óptima de corte), y déjelo sobre un molde de congelación desechables etiquetados. Asegúrese de que el músculo está en su orientación fisiológica normal (cabeza para tail) sin estirar. Alternativamente, congelar el músculo en pequeños cuadrados de espuma de poliestireno y el pin con alfileres de insectos para asegurar la longitud correcta de los músculos. </li><li> Chill 2-metilbutano (isopentano) en un vaso de precipitados de acero usando nitrógeno líquido. Esto toma en promedio 3-5 min. Mantener la agitación intermitente hasta precipitados blancos comienzan a formarse en la parte inferior y las paredes del vaso de precipitados. NOTA: Cuando esto ocurre, isopentano ha alcanzado la temperatura óptima de congelación (-150 ° C) </li><li> Sumerja los moldes que contienen músculos en el frío 2-metilbutano. Congele pequeños músculos como el diafragma y el extensor largo del dedo dedos (EDL) durante 6-12 segundos y músculos más grandes como el sóleo gastrocnemio (GS) y tríceps de 15 a 20 seg. No congelar los músculos durante demasiado tiempo ya que esto puede conducir a la rotura. </li><li> Transferir los tejidos congelados sobre hielo seco y dejar que se evapore isopentano (tenga en cuenta que este proceso toma en promedio alrededor de 15 a 20 min). Envuelva los tejidos en papel de aluminio y almacenarlos en ultra baja temperatura (-70 ° C a -80 ° C) hasta el corte. </li></ol> 2. Incorporación de los tejidos en octubre preparar Tissue Bloquear <ol><li> Tejidos Transporte en hielo seco para cyrostat para evitar la descongelación. Transferencia de tejido a criostato cámara (establecido a de -20 a -24 ° C para evitar la descongelación completa de los tejidos) y dejar que se equilibren durante 30 min. </li><li> Gire la bahía Peltier de enfriamiento en. Si el criostato no tiene este enfriamiento, utilice aerosol spray de refrigeración para congelar rápidamente la OCT. No deje que el deshielo del músculo en cualquier momento durante la incrustación ya que esto puede resultar en daños por congelación. </li><li> Añadir una fina capa uniforme de octubre en el disco muestra y dejar enfriar. Cuando la mayoría de la OCT se congela en el fondo mientras que todavía líquido en la parte superior, inserte el tejido en la orientación correcta (perpendicular a octubre para las secciones transversales y paralelas a octubre de secciones longitudinales). Utilice aerosol spray de refrigeración para congelar rápidamente octubre Toque la parte unembeded del tejido con el calor extractor y esperar 45 seg. </li><li> Añadir otra capa delgada de octubre alrededor del músculo, rociar con aerosol spray de enfriamiento y extraer el calor como en el paso anterior. </li><li> Mantenga la adición de octubre en pequeños incrementos y rápidamente congelar el octubre mediante una combinación de aspersión y extractor de calor de refrigeración aerosol hasta que el músculo está cubierto. </li><li> Ponga el extractor de calor en la parte superior del bloque de tejido y esperar 5 min. </li></ol> 3. Preparación de las secciones e identificación de las Secciones de Mid-vientre Región de los músculos <ol><li> Montar la muestra sobre la cabeza de la muestra. Apriete la perilla para asegurar el disco. Asegúrese de que el disco de la muestra se encuentra en buen contacto con la cabeza de la muestra. </li><li> Ajuste la temperatura de la cámara a entre -21 y -24 ° C y espere hasta que se alcanza la temperatura programada. </li><li> Ajuste los valores de espesor (7 micras); recortar el bloque mediante el avance o retroceso del bloque usando ajustes gruesos y finos. </li><li> Recoge las seccionesen pre-calentado portaobjetos cargados positivamente presionando la parte superior de la diapositiva en secciones, con la atracción entre cargas opuestas para facilitar la adherencia de las secciones cortadas a la diapositiva. </li><li> Identificar las secciones mediados de vientre mediante la medición de área de sección transversal (CSA) de las secciones. Para ello, el software de imágenes usando en el equipo que está conectado al microscopio. NOTA: Las imágenes de contraste de fase se toman y la circunferencia de todo el músculo se mide a través de una función de seguimiento del programa de software. Esto producirá tanto CSA así como hurón diámetro mínimo (medida de la fibra de tamaño de sección transversal que se expresa como la distancia más pequeña entre dos tangentes paralelas en lados opuestos de una partícula) mediciones. Nota: Cuando las mediciones CSA y diámetro mínimo hurón comienzan a estabilizarse, se ha llegado a mediados del vientre. </li><li> Inventario y archivar las diapositivas a -80 ° C para la tinción futuro. NOTA: octubre no tiene que ser eliminado antes de staininprocedimientos g. Una vez portaobjetos se cubrieron, que están listos para ser manchado inmediatamente. </li></ol> 4. La tinción NOTA: Si bien los procedimientos detallados paso a paso se pueden encontrar en la hoja de datos del producto y se deben seguir los procedimientos de tinción, la optimización del personal puede ser requerido para obtener la tinción óptima. <ol><li> Debido a que los medios de montaje (véase la tabla) no es miscible con agua, deshidratar diapositivas a través crecientes grados de alcohol (2 min cada uno en 70%, 95%, y 100% de etanol) y claro ellos con xileno (100% durante 5 min) para asegurar diapositivas no se vuelven opacas en el tiempo. </li><li> Cubreobjetos secciones y déjelos secar. Imagen con microscopio equipado con software de imágenes. </li></ol>

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History, clinical status, muscle strength, and biopsy findings.</a> AMA J Dis Child. 91, 326-338 (1956).</li><li>Platzer, A. C., Chase, W. 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A., Kostek, C. A., Miller, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibition+of+apoptosis+improves+outcome+in+a+model+of+congenital+muscular+dystrophy.">Inhibition of apoptosis improves outcome in a model of congenital muscular dystrophy.</a> The Journal of clinical investigation. 114, 1635-1639 (2004).</li><li>Kumar, A., Yamauchi, J., Girgenrath, T., Girgenrath, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Muscle-specific+expression+of+insulin-like+growth+factor+1+improves+outcome+in+Lama2Dy-w+mice,+a+model+for+congenital+muscular+dystrophy+type+1A.">Muscle-specific expression of insulin-like growth factor 1 improves outcome in Lama2Dy-w mice, a model for congenital muscular dystrophy type 1A.</a> Human molecular genetics. 20, 2333-2343 (2011).</li><li>Mehuron, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dysregulation+of+matricellular+proteins+is+an+early+signature+of+pathology+in+laminin-deficient+muscular+dystrophy.">Dysregulation of matricellular proteins is an early signature of pathology in laminin-deficient muscular dystrophy.</a> Skeletal muscle. 4, 14 (2014).</li><li>Yamauchi, J., Kumar, A., Duarte, L., Mehuron, T., Girgenrath, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Triggering+regeneration+and+tackling+apoptosis:+a+combinatorial+approach+to+treating+congenital+muscular+dystrophy+type+1+A.">Triggering regeneration and tackling apoptosis: a combinatorial approach to treating congenital muscular dystrophy type 1 A.</a> Human molecular genetics. 22, 4306-4317 (2013).</li><li>Sheriffs, I. N., Rampling, D., Smith, V. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Paraffin+wax+embedded+muscle+is+suitable+for+the+diagnosis+of+muscular+dystrophy.">Paraffin wax embedded muscle is suitable for the diagnosis of muscular dystrophy.</a> Journal of clinical pathology. 54, 517-520 (2001).</li><li>Fox, C. H., Johnson, F. B., Whiting, J., Roller, P. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formaldehyde+fixation.">Formaldehyde fixation.</a> Journal of Histochemistry &amp; Cytochemistry. 33, 845-853 (1985).</li><li>Maccarty, W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Diagnostic+Reliability+of+Frozen+Sections.">The Diagnostic Reliability of Frozen Sections.</a> The American journal of pathology. 5, 377-380 (1929).</li><li>Shi, S. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+the+value+of+frozen+tissue+section+used+as+'gold+standard'+for+immunohistochemistry.">Evaluation of the value of frozen tissue section used as 'gold standard' for immunohistochemistry.</a> Am J Clin Pathol. 129, 358-366 (2008).</li><li>Turan, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy+of+frozen+sections+for+intraoperative+diagnosis+of+complex+atypical+endometrial+hyperplasia.">Accuracy of frozen sections for intraoperative diagnosis of complex atypical endometrial hyperplasia.</a> Asian Pacific journal of cancer prevention : APJCP. 13, 1953-1956 (2012).</li></ol>

The authors have nothing to disclose.

Histología e inmunohistoquímica se han utilizado como herramientas clave en la comprensión de la manifestación y la progresión de la patología en diversos trastornos neuromusculares. Clásicamente, las biopsias musculares se fijaron por primera vez en formaldehído y luego incrustados con cera de parafina. Si bien la fijación de formaldehído conserva la arquitectura del tejido y permite el almacenamiento y transporte del tejido a temperatura ambiente, también inactiva las enzimas y los entrecruzamientos proteí...

El examen de histología muscular juega un papel crítico en la comprensión de los diferentes tipos de trastornos neuromusculares 1-4. Cuando se combina con otras técnicas, permite a los investigadores para obtener una mejor idea de la manifestación y la progresión de la patología y también pueden ser esenciales para evaluar la eficacia de una intervención terapéutica 5-10. Sin embargo, para ser precisos, los tejidos necesitan ser conservado en la manera apropiada a fin de preservar el estado fisiológico inmediatamente antes de la escisión. Esto requiere gran cuidado durante la extracción, preservación, seccionamiento y tinción. Los tejidos pueden prepararse de dos maneras diferentes para estudio microscópico de luz. El primer método, formol fija en parafina (FFPE) secciones, requiere tejidos que se fijaron en formaldehído al 10% tamponada naturales antes de ser integrado con cera de parafina 11,12. La etapa de fijación ayuda a preservar la morfología mejor, pero también vínculos transversales pr endógenaoteins necesitando por lo tanto los procedimientos de recuperación de antígeno intrincada de inmunotinción y eliminando la posibilidad de tinción enzimática en tales secciones 12. Las secciones congeladas, por otra parte, no tienen que ser pre-fijo o procesados; por lo tanto, las proteínas son capaces de retener conformaciones biológicos nativos 13,14. Además, las secciones congeladas también permiten el tiempo de respuesta rápida, que a veces es necesario, por ejemplo en el diagnóstico intraoperatorio de los sarcomas y otros biopsias quirúrgicas 15. Sin embargo, si no se hace correctamente, este método es propenso a los daños por congelación, que introduce cambios en la arquitectura muscular haciendo las secciones no aptos para el examen histológico. En este trabajo se expondrá el método más eficaz para preparar las biopsias musculares para lograr tinción óptimo para examen adecuado.

<table><tbody><tr><td>Cryostat</td><td>Leica CM 1850</td><td>Leica Microsystems Inc.</td><td>Buffalo Grove, IL 60089 U.S.A., office phone 1-800-248-0123&lt;br /&gt;Alternative: Richard Allen Scientific</td></tr><tr><td>Microscope</td><td>Nikon Eclipse 50i</td><td>Nikon Instruments Inc.</td><td>1300 Walt Whitman Road, Melville, N.Y. 11747-3064 U.S.A., Phone: 1-631-547-8500&lt;br /&gt;Alternative: Olympus</td></tr><tr><td>Image analysis software</td><td>Nikon Imaging Software Basic Research</td><td>Nikon Instruments Inc.</td><td>1300 Walt Whitman Road, Melville, N.Y. 11747-3064, U.S.A., Phone: 1-631-547-8500&lt;br /&gt;Alternatives: Image J, Metamorph</td></tr><tr><td>Isoflurane</td><td>14043-220-05</td><td>JD Medical Dist. Co., Inc.</td><td>1923 West Peoria Avenue, Phoenix, AZ 85029 U.S.A.</td></tr><tr><td>OCT</td><td>4583</td><td>Sakura Inc.</td><td>Torrence, CA 90501 U.S.A.&lt;br /&gt;Alternative source: Leica Microsystem</td></tr><tr><td>Freeze It</td><td>23-022524</td><td>Thermofisher</td><td>790 Memorial Dr, Cambridge, MA, 02139 U.S.A.&lt;br /&gt;Alternative source: VWR Scientific</td></tr><tr><td>Disposable tissue mold</td><td>22-363-554</td><td>Thermofisher</td><td>790 Memorial Dr, Cambridge, MA 02139 U.S.A.&lt;br /&gt;Alternative source: VWR Scientific</td></tr><tr><td>Colorfrost plus slides</td><td>9991001</td><td>Thermofisher</td><td>790 Memorial Dr, Cambridge, MA 02139 U.S.A.&lt;br /&gt;Alternative source: VWR Scientific</td></tr><tr><td>Acetone</td><td>650501-4L</td><td>Sigma-Aldrich</td><td>3050 Spruce Street, St. Louis, MO 63103 U.S.A.&lt;br /&gt;Alternative source: VWR Scientific</td></tr><tr><td>Ethyl alcohol</td><td>HC-1300-1GL</td><td>Thermofisher</td><td>790 Memorial Dr, Cambridge, MA 02139 U.S.A.&lt;br /&gt;Alternative source: VWR Scientific</td></tr><tr><td>2-methyl butane</td><td>M 32631-SL</td><td>Sigma-Aldrich</td><td>3050 Spruce Street, St. Louis, MO 63103 U.S.A.&lt;br /&gt;Alternative source: VWR Scientific</td></tr><tr><td>Xylene</td><td>HC-7001GA</td><td>Thermofisher</td><td>790 Memorial Dr, Cambridge, MA 02139 U.S.A.&lt;br /&gt;Alternative source: VWR Scientific</td></tr><tr><td>Cytoseal 280</td><td>8311-4</td><td>Thermofisher</td><td>790 Memorial Dr, Cambridge, MA 02139 U.S.A.&lt;br /&gt;Alternative source: VWR Scientific</td></tr><tr><td>Hematoxylin Gill #3</td><td>CS402-1D</td><td>Thermofisher</td><td>790 Memorial Dr, Cambridge, MA 02139 U.S.A.&lt;br /&gt;Alternative source: VWR Scientific</td></tr><tr><td>Eosin</td><td>6766007</td><td>Thermofisher</td><td>790 Memorial Dr, Cambridge, MA 02139 U.S.A.&lt;br /&gt;Alternative source: VWR Scientific</td></tr></tbody></table>

do's and don'ts in the preparation of muscle cryosections for histological analysis

La evaluación histológica de las biopsias musculares ha servido como una herramienta indispensable en la comprensión del desarrollo y la progresión de la patología de los trastornos neuromusculares. Sin embargo, con el fin de hacerlo, el cuidado apropiado debe ser tomado cuando la escisión y la preservación de los tejidos para lograr tinción óptimo. Uno de los métodos de conservación de tejidos implica la fijación de tejidos en formaldehído y luego incrustarlos con cera de parafina. Este método preserva la morfología bien y permite el almacenamiento a largo plazo a temperatura ambiente pero es engorroso y requiere la manipulación de productos químicos tóxicos. Además, los resultados de fijación en formol antígeno entrecruzamiento, lo que requiere protocolos de recuperación de antígeno por inmunotinción eficaz. Por el contrario, seccionado congelado no requiere la fijación y por lo tanto retiene conformación antígeno biológica. Este método también proporciona una clara ventaja en vuelta rápida alrededor del tiempo, por lo que es especialmente útil en situaciones que requieren evaluación histológica rápida como intraoperaTIVE biopsias quirúrgicas. A continuación se describe el método más eficaz de preparar biopsias musculares para la visualización con diferentes tinciones histológicas e inmunológicas.

La puesta a punto para la cosecha y la congelación de los tejidos se puede ver en la Figura 1. Tejidos extirpados se deben almacenar en una gasa empapada en PBS para evitar el secado (Figura 1A). Cuando se seleccionan los tejidos a ser utilizado para el análisis histológico deben ser sumergidos en OCT y se presentarán en molde crio en la orientación adecuada y lo más cerca a la longitud fisiológica como sea posible para asegurar la morfología exacta (Figura 1B)....

Watch this Scientific Journal Video about Do's and Don'ts in the Preparation of Muscle Cryosections for Histological Analysis at JoVE.com

Do's and Don'ts in the Preparation of Muscle Cryosections for Histological Analysis

Here we demonstrate the most efficient methods for freezing, embedding, cryosectioning, and staining of muscle biopsies to avoid freezing artifacts.

Qué hacer y qué no hacer en la preparación de Muscle criosecciones de Análisis histológico

Histological evaluation of muscle biopsies has served as an indispensable tool in the understanding of the development and progression of pathology of ...

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Universidad de Cartagena UDEC

Research

JoVE Journal

Medicine

31.8K vistas.  Boston University. Here we demonstrate the most efficient methods for freezing, embedding, cryosectioning, and staining of muscle biopsies to avoid freezing artifacts.

Video: Do's and Don'ts in the Preparation of Muscle Cryosections for Histological Analysis

Induction of Acute Skeletal Muscle Regeneration by Cardiotoxin Injection

Skeletal muscle regeneration is a physiological process that occurs in adult skeletal muscles in response to injury or disease. Acute injury-induced skeletal muscle regeneration is a widely used, powerful model system to study the events involved in muscle regeneration as well as the mechanisms and different players. Indeed, a detailed knowledge of this process is essential for a better understanding of the pathological conditions that lead to skeletal muscle degeneration, and it aids in identifying new targeted therapeutic strategies. The present work describes a detailed and reproducible protocol to induce acute skeletal muscle regeneration in mice through a single intramuscular injection of cardiotoxin (CTX). CTX belongs to the family of snake venom toxins and causes myolysis of myofibers, which eventually triggers the regeneration events. The dynamics of skeletal muscle regeneration is evaluated by histological analysis of muscle sections. The protocol also illustrates the experimental procedures for dissecting, freezing, and cutting the Tibialis Anterior muscle, as well as the routine Hematoxylin &#38; Eosin staining that is widely used for subsequent morphological and morphometric analysis.

This manuscript describes a detailed protocol to induce acute skeletal muscle regeneration in adult mice and subsequent manipulations of the muscles, such as dissection, freezing, cutting, routine staining, and myofiber cross-sectional area analysis.

La inducción de la regeneración muscular esquelético aguda por inyección Cardiotoxin

Skeletal muscle regeneration is a physiological process that occurs in adult skeletal muscles in response to injury or disease. Acute injury-induced ...

Investigación

Biología del Desarrollo

Preparation of the Rat Vocal Fold for Neuromuscular Analyses

The purpose of this tutorial is to describe the preparation of the rat vocal fold for histochemical neuromuscular study. This protocol outlines procedures for rat laryngeal dissection, flash-freezing, and cryosectioning of the vocal folds. This study describes how to cryosection vocal folds in both longitudinal and cross-sectional planes. A novelty of this protocol is the laryngeal tracking during cryosectioning that ensures accurate identification of the intrinsic laryngeal muscles and reduces the chance of tissue loss. Figures demonstrate the progressive cryosectioning in both planes. Twenty-nine rat hemi-larynges were cryosectioned and tracked from the emergence of the thyroid cartilage to the appearance of the first section that included the full vocal fold. The full vocal fold was visualized for all animals in both planes. There was high variability in the distance from the appearance of the thyroid cartilage to the appearance of the full vocal fold in both planes. Weight was not correlated to depth of laryngeal landmarks, suggesting individual variability and other factors related to tissue preparation may be responsible for the high variability in the appearance of landmarks during sectioning. This study details a methodology and presents morphological data for preparing the rat vocal fold for histochemical neuromuscular investigation. Due to high individual variability, laryngeal landmarks should be closely tracked during cryosectioning to prevent oversectioning tissue and tissue loss. The use of a consistent methodology, including adequate tissue preparation and awareness of landmarks within the rat larynx, will assist with consistent results across studies and aid new researchers interested in using the rat vocal fold as a model to investigate laryngeal neuromuscular mechanisms.

This protocol describes methods used to prepare rat vocal folds for histochemical neuromuscular study.

Preparación de la cuerda vocal de la rata para análisis neuromusculares

The purpose of this tutorial is to describe the preparation of the rat vocal fold for histochemical neuromuscular study. This protocol outlines procedures ...

Neurociencias

Tissue Triage and Freezing for Models of Skeletal Muscle Disease

Skeletal muscle is a unique tissue because of its structure and function, which requires specific protocols for tissue collection to obtain optimal results from functional, cellular, molecular, and pathological evaluations. Due to the subtlety of some pathological abnormalities seen in congenital muscle disorders and the potential for fixation to interfere with the recognition of these features, pathological evaluation of frozen muscle is preferable to fixed muscle when evaluating skeletal muscle for congenital muscle disease. Additionally, the potential to produce severe freezing artifacts in muscle requires specific precautions when freezing skeletal muscle for histological examination that are not commonly used when freezing other tissues. This manuscript describes a protocol for rapid freezing of skeletal muscle using isopentane (2-methylbutane) cooled with liquid nitrogen to preserve optimal skeletal muscle morphology. This procedure is also effective for freezing tissue intended for genetic or protein expression studies. Furthermore, we have integrated our freezing protocol into a broader procedure that also describes preferred methods for the short term triage of tissue for (1) single fiber functional studies and (2) myoblast cell culture, with a focus on the minimum effort necessary to collect tissue and transport it to specialized research or reference labs to complete these studies. Overall, this manuscript provides an outline of how fresh tissue can be effectively distributed for a variety of phenotypic studies and thereby provides standard operating procedures (SOPs) for pathological studies related to congenital muscle disease.

The analysis of skeletal muscle tissues to determine structural, functional, and biochemical properties is greatly facilitated by appropriate preparation. This protocol describes appropriate methods to prepare skeletal muscle tissue for a broad range of phenotyping studies.

Triage de tejidos y de congelación para los modelos de la enfermedad del músculo esquelético

Skeletal muscle is a unique tissue because of its structure and function, which requires specific protocols for tissue collection to obtain optimal ...

Biología

Cryosectioning Method for Microdissection of Murine Colonic Mucosa

The colonic mucosal tissue provides a vital barrier to luminal antigens. This barrier is composed of a monolayer of simple columnar epithelial cells. The colonic epithelium is dynamically turned over and epithelial cells are generated in the stem cell containing crypts of Lieberk&#252;hn. Progenitor cells produced in the crypt-bases migrate toward the luminal surface, undergoing a process of cellular differentiation before being shed into the gut lumen. In order to study these processes at the molecular level, we have developed a simple method for the microdissection of two spatially distinct regions of the colonic mucosa; the proliferative crypt zone, and the differentiated surface epithelial cells. Our objective is to isolate specific crypt and surface epithelial cell populations from mouse colonic mucosa for the isolation of RNA and protein.

Here we describe a simple method for the isolation of spatially distinct murine colonic epithelial surface cells from the underlying crypt-base cells.

Método cryosectioning para microdisección de murino mucosa colónica

The colonic mucosal tissue provides a vital barrier to luminal antigens. This barrier is composed of a monolayer of simple columnar epithelial cells. The ...

Fiber Type and Subcellular-Specific Analysis of Lipid Droplet Content in Skeletal Muscle

Skeletal muscle lipid infiltration, known as myosteatosis, increases with obesity and ageing. Myosteatosis has also recently been discovered as a negative prognostic factor for several other disorders such as cardiovascular disease and cancer. Excessive lipid infiltration decreases muscle mass and strength. It also results in lipotoxicity and insulin resistance depending on total intramyocellular lipid content, lipid droplet (LD) morphology, and subcellular distribution. Fiber type (oxidative vs glycolytic) is also important, since oxidative fibers have a greater capacity to utilize lipids. Because of their crucial implications in pathophysiology, in-depth studies on LD dynamics and function in a fiber type-specific manner are warranted.
Herein, a complete protocol is presented for the quantification of intramyocellular lipid content and analysis of LD morphology and subcellular distribution in a fiber type-specific manner. To this end, serial muscle cryosections were stained with the fluorescent dye Bodipy and antibodies against myosin heavy chain isoforms. This protocol enables the simultaneous processing of different muscles, saving time and avoiding possible artifacts and, thanks to a personalized macro created in Fiji, the automatization of LD analysis is also possible.

Increasing evidence indicates that excessive infiltration of lipids inside skeletal muscle results in lipotoxicity and diabetes. Here, we present a complete protocol, including tissue processing, staining with Bodipy, image acquisition, and analysis, to quantify the size, density, and subcellular distribution of lipid droplets in a fiber-type specific manner.

Tipo de fibra y análisis subcelular específico del contenido de gotas lipídicas en el músculo esquelético

Skeletal muscle lipid infiltration, known as myosteatosis, increases with obesity and ageing. Myosteatosis has also recently been discovered as a negative ...

Medicina

High-Throughput, Multi-Image Cryohistology of Mineralized Tissues

There is an increasing need for efficient phenotyping and histopathology of a variety of tissues. This phenotyping need is evident with the ambitious projects to disrupt every gene in the mouse genome. The research community needs rapid and inexpensive means to phenotype tissues via histology. Histological analyses of skeletal tissues are often time consuming and semi-quantitative at best, regularly requiring subjective interpretation of slides from trained individuals. Here, we present a cryohistological paradigm for efficient and inexpensive phenotyping of mineralized tissues. First, we present a novel method of tape-stabilized cryosectioning that preserves the morphology of mineralized tissues. These sections are then adhered rigidly to glass slides and imaged repeatedly over several rounds of staining. The resultant images are then aligned either manually or via computer software to yield composite stacks of several layered images. The protocol allows for co-localization of numerous molecular signals to specific cells within a given section. In addition, these fluorescent signals can be quantified objectively via computer software. This protocol overcomes many of the shortcomings associated with histology of mineralized tissues and can serve as a platform for high-throughput, high-content phenotyping of musculoskeletal tissues moving forward.

In this manuscript, we present a high-throughput, semi-automated cryohistology platform to produce aligned composite images of multiple response measures from several rounds of fluorescent imaging on frozen sections of mineralized tissues.

De alto rendimiento, de múltiples imágenes Cryohistology de tejidos mineralizados

There is an increasing need for efficient phenotyping and histopathology of a variety of tissues. This phenotyping need is evident with the ambitious ...

Cryosectioning of Contiguous Regions of a Single Mouse Skeletal Muscle for Gene Expression and Histological Analyses

With this method, consecutive cryosections are collected to enable both microscopy applications for tissue histology and enrichment of RNA for gene expression using adjacent regions from a single mouse skeletal muscle. Typically, it is challenging to achieve adequate homogenization of small skeletal muscle samples because buffer volumes may be too low for efficient grinding applications, yet without sufficient mechanical disruption, the dense tissue architecture of muscle limits penetration of buffer reagents, ultimately causing low RNA yield. By following the protocol reported here, 30 &#956;m sections are collected and pooled allowing cryosectioning and subsequent needle homogenization to mechanically disrupt the muscle, increasing the surface area exposed for buffer penetration. The primary limitations of the technique are that it requires a cryostat, and it is relatively low throughput. However, high-quality RNA can be obtained from small samples of pooled muscle cryosections, making this method accessible for many different skeletal muscles and other tissues. Furthermore, this technique enables matched analyses (e.g., tissue histopathology and gene expression) from adjacent regions of a single skeletal muscle so that measurements can be directly compared across applications to reduce experimental uncertainty and to reduce replicative animal experiments necessary to source a small tissue for multiple applications.

Consecutive cryo-sections are collected to enable histological applications and enrichment of RNA for gene expression measurements using adjacent regions from a single mouse skeletal muscle. High-quality RNA is obtained from 20 - 30 mg of pooled cryosections and measurements are directly compared across applications.

Cryosectioning de regiones contiguas de un músculo esquelético solo ratón para la expresión de genes y análisis histológicos

With this method, consecutive cryosections are collected to enable both microscopy applications for tissue histology and enrichment of RNA for gene ...

A Multi-hole Cryovial Eliminates Freezing Artifacts when Muscle Tissues are Directly Immersed in Liquid Nitrogen

Studies on skeletal muscle physiology face the technical challenge of appropriately processing the specimens to obtain sections with clearly visible cytoplasmic compartments. Another hurdle is the tight apposition of myofibers to the surrounding tissues. Because the process of tissue fixation and paraffin embedding leads to the shrinkage of muscle fibers, freezing is an optimal means of hardening muscle tissue for sectioning. However, a commonly encountered issue, the formation of ice crystals, occurs during the preparation of frozen sections because of the high water content of muscle. The protocol presented here first describes a simple and efficient method for properly freezing muscle tissues by immersing them in liquid nitrogen. The problem with using liquid nitrogen alone is that it causes the formation of a nitrogen gas barrier next to the tissue, which acts as an insulator and inhibits the cooling of the tissues. To avoid this "vapor blanket" effect, a new cryovial was designed to increase the speed of liquid flow around the tissue surface. This was achieved by punching a total of 14 inlet holes in the wall of the vial. According to bubble dynamics, a higher rate of liquid flow results in smaller bubbles and fewer chances to form a gas barrier. When liquid nitrogen flows into the cryovial through the inlet holes, the flow velocity around the tissue is fast enough to eliminate the gas barrier. Compared to the method of freezing muscle tissues using pre-chilled isopentane, this protocol is simpler and more efficient and can be used to freeze muscle in a throughput manner. Furthermore, this method is optimal for institutions that do not have access to isopentane, which is extremely flammable at room temperature.

This protocol describes a procedure to freeze muscle tissues by plunging them directly into liquid nitrogen. This protocol also highlights a new cryovial that can avoid the &#34;blanket effect&#34; of nitrogen gas when liquid nitrogen contacts the tissue surface of a specimen.

A Multi-agujero criovial Elimina congelación Artifacts cuando los tejidos musculares se sumergen directamente en nitrógeno líquido

Studies on skeletal muscle physiology face the technical challenge of appropriately processing the specimens to obtain sections with clearly visible ...

In Situ Immunofluorescent Staining of Autophagy in Muscle Stem Cells

Increasing evidence points to autophagy as a crucial regulatory process to preserve tissue homeostasis. It is known that autophagy is involved in skeletal muscle development and regeneration, and the autophagic process has been described in several muscular pathologies and age-related muscle disorders. A recently described block of the autophagic process that correlates with the functional exhaustion of satellite cells during muscle repair supports the notion that active autophagy is coupled with productive muscle regeneration. These data uncover the crucial role of autophagy in satellite cell activation during muscle regeneration in both normal and pathological conditions, such as muscular dystrophies. Here, we provide a protocol to monitor the autophagic process in the adult Muscle Stem Cell (MuSC) compartment during muscle regenerative conditions. This protocol describes the setup methodology to perform in situ immunofluorescence imaging of LC3, an autophagy marker, and MyoD, a myogenic lineage marker, in muscle tissue sections from control and injured mice. The methodology reported allows for monitoring the autophagic process in one specific cell compartment, the MuSC compartment, which plays a central role in orchestrating muscle regeneration.

In Situ Immunofluorescent Staining of Autophagy in Muscle Stem Cells

Active autophagy is associated with productive muscle regeneration, which is essential for Muscle Stem Cell (MuSC) activation. Here, we provide a protocol for the in situ detection of LC3, an autophagy marker in MyoD-positive MuSCs of muscle tissue sections from control and injured mice.

Tinción Inmunofluorescente In Situ de Autofagia en Células Madre Musculares

Increasing evidence points to autophagy as a crucial regulatory process to preserve tissue homeostasis. It is known that autophagy is involved in skeletal ...

Immunolabelling Myofiber Degeneration in Muscle Biopsies

The necrosis of muscle fibres (myonecrosis) plays a central role in the pathogenesis of several muscle conditions, including muscular dystrophies. Therapeutic options addressing the causes of muscular dystrophy pathogenesis are expected to alleviate muscle degeneration. Therefore, a method to assay and quantify the extent of cell death in muscle biopsies is needed. Conventional methods to observe myofiber degeneration in situ are either poorly quantitative or rely on the injection of vital dyes. In this article, an immunofluorescence protocol is described that stains necrotic myofibers by targeting immunoglobulin G (IgG) uptake by myofibers. The IgG uptake method is based on cell features characterizing the necrotic demise, including 1) the loss of plasma membrane integrity with the release of damage-associated molecular patterns and 2) the uptake of plasmatic proteins. In murine cross-sections, the co-immunolabelling of myofibers, extracellular matrix proteins, and mouse IgG allows clean and straightforward identification of myofibers with necrotic fate. This simple method is suitable for quantitative analysis and applicable to all species, including human samples, and does not require the injection of vital dye. The staining of necrotic myofibers by IgG uptake can also be paired with other co-immunolabelling.

Described here is a protocol for direct immunolabelling of necrotic myofibers in muscle cryosections. Necrotic cells are permeable to serum proteins, including immunoglobulin G (IgG). Revealing the uptake of IgG by myofibers allows the identification and quantification of myofibers that undergo necrosis regardless of muscle condition.