Supported by NIH Grants NS14837, R01 NS38537, R24 HD050838 to Dr. Michael E. Selzer; Shriners Research Grant SHC-85220 to Dr. Michael E Selzer; and Shriners Research Grant SHC-85310 to Dr. Michael I. Shifman. Dr. Ant&#243;n Barreiro-Iglesias was supported by the Fundaci&#243;n Barri&#233; (Spain) and the Xunta de Galicia (Galicia, Spain).

Ver Tabla 1 para todos los materiales utilizados en este protocolo. Los experimentos fueron aprobados por el Comité de Cuidado y Uso de Animales Institucional de la Universidad de Temple. 1. Animales <ol><li> Obtener wildtype lampreas marinas larvales (Petromyzon marinus L.), 10 - 14 cm de largo (4-7 años) de los arroyos que alimentan el lago Michigan, a partir de afluentes del río Delaware (Pennsylvania) o arroyos en Maine. </li><li> En el laboratorio, las larvas de mantener en grupos de 50 a 100 animales en tanques de agua dulce de 50 galones a 16 ° C. Línea de los tanques con una pulgada de grava para que las larvas madriguera en, y el agua se filtra el carbón y se acondicionó con piedras de aire durante al menos 48 horas para eliminar el cloro y otras impurezas antes de colocar las lampreas en ellos. No hay necesidad de alimentar a los animales, que reciclan su propio detritus, hasta el día de uso. </li></ol> 2. completa EspinalLa transección del cable <ol><li> Antes de la cirugía de la médula espinal preparar una solución de Ringer lamprea con la siguiente composición: NaCl 110 mM, KCl 2,1 mM, 2,6 mM CaCl2, 1,8 mM de MgCl 2 y 10 mM de tampón Tris; pH 7,4. </li><li> Para realizar la transección de la médula espinal, colocar las larvas en un pequeño recipiente que se anestesiaron con metanosulfonato de tricaína 1% en solución de Ringer enfriada con hielo. </li><li> Una vez anestesiado el lugar de los animales en una placa de Petri llena hasta la mitad con Sylgard (de silicona) y utilizan 4 pins de insectos (0,15 mm de diámetro) para mantener a los animales en posición durante la cirugía (uno se coloca en el hocico del animal, uno en la cola y dos en el nivel de la 5 ª agallas). Llene la caja de Petri casi hasta la parte superior con una solución de Ringer. Coloque el plato con la larva en el hielo mientras se realiza la cirugía bajo el microscopio estereoscópico. </li><li> Para realizar la transección de la médula espinal dorsal, la línea media, hacer una incisión longitudinal con un escalpelo (# 11) a nivel de la 5 ªGill para visualizar la médula espinal. Inicialmente la piel está abierta mediante la inserción de la punta de la cuchilla de escalpelo hacia arriba y entonces el tejido muscular se corta muy suavemente hasta la médula espinal puede ser visto desde arriba. Moda dos ganchos de los pasadores de insectos y los utilizan para sostener las paredes del cuerpo abierto mientras se realiza la transección de la médula espinal. </li><li> Completamente seccionar la médula espinal a nivel de la 5 ª agallas mediante el uso de un par de tijeras (Castroviejo 8 #), insertar las tijeras perpendicularmente a la médula espinal. La médula espinal tiene que ser completamente seccionado con un corte limpio. Visualice los extremos cortados de la médula espinal en el microscopio estereoscópico para confirmar que la médula espinal ha sido completamente seccionado. Entonces, realinear los extremos cortados de la médula espinal después de la transección mediante el uso de un par de pinzas (# 5). </li><li> Después de realizar la transección de la médula espinal a cerrar la herida en la pared dorsal del cuerpo con un par de pinzas finas y poner las larvas en hielo durante 1 hora para permitir que la herida to secar. Ponga un pedazo de papel de filtro entre el hielo y las larvas y remojarlo con solución de Ringer lamprea. La baja temperatura mantiene los animales vivos, al mismo tiempo que permite que la herida se seque al aire y por lo tanto ayudando a prevenir infecciones. </li><li> A continuación, traslado a las larvas de los tanques pequeños (1 larva por tanque) con agua helada durante 24 horas. </li><li> Examine el lesionado larvas de 1 día después de la transección espinal para conductualmente confirmar que no hay movimiento caudal al sitio de la lesión. Un transección de la médula espinal se considera completa si la larva puede moverse sólo su cabeza rostral al sitio de la lesión (en el nivel de la 5 ª agallas). Si este es el caso de las larvas ahora puede ser transferido a los tanques (1 larva por tanque) con agua dulce a temperatura ambiente (23 ° C) para permitir que se recuperen de los puntos de tiempo seleccionados. </li><li> Durante el período de recuperación de cambiar el agua cada 2 o 3 días. </li></ol> 3. Cerebro disección y preparación deCerebro de hibridación in situ <ol><li> En los puntos de tiempo deseados después de la lesión volver a anestesiar las lampreas de mar de larvas y el lugar y el pin en la placa de Petri con solución de Ringer para llevar a cabo la disección del cerebro como anteriormente. </li><li> Para diseccionar el cerebro, en primer lugar hacer una incisión transversal con el bisturí entre la fosa nasal y el órgano pineal. Desde aquí comenzar a cortar el tejido que rodea el cerebro mediante el uso de un par de tijeras Castroviejo mientras la mantiene con un par de fórceps. </li><li> Una vez que el cerebro está expuesto, retire el plexo coroideo mediante el uso de un par de fórceps y el uso de los ganchos para difundir la cabeza del animal y exponer los nervios craneales. Luego, cortar transversalmente la médula espinal con las tijeras de Castroviejo. Mantenga la médula espinal con un par de fórceps durante el uso de otro par de pinzas para cortar los nervios craneales para diseccionar el cerebro fuera. </li><li> Después de la disección, poner el cerebro en un pequeño trozo de silicona y mantenerlo en su posición insertando 2 insect alfileres en los bulbos olfatorios y 1 en la médula espinal. Luego, cortar la parte posterior y comisuras cerebrotectal del cerebro a lo largo de la línea media dorsal con las tijeras y desviar las placas alares lateralmente y el pin plano para la silicona con 4 pins de insectos (Figura 2). </li><li> Transferir la pieza de silicona con el cerebro a un tubo que contiene un 4% de paraformaldehído en tampón fosfato salino (pH 7,4) que se fije en Temparature ambiente durante 3 h en un rotador. </li><li> Después de la fijación utilizar el cerebro para wholemount hibridación in situ como se describe anteriormente (Swain et al., 1994). Los cerebros de los animales de control con operación simulada o se debe ejecutar siempre en paralelo con los cerebros de los animales heridos. El cerebro de larvas wholemounted puede ser estudiada mediante hibridación in situ debido a su forma plana y delgada y también debido a la ausencia de mielina 10, que hace que el cerebro bastante translúcido. </li></ol>

<ol>
	<li>Rodicio, M. C., Barreiro-Iglesias, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lampreys+as+an+animal+model+in+regeneration+studies+after+spinal+cord+injury.">Lampreys as an animal model in regeneration studies after spinal cord injury.</a> Rev Neurol. 55, 157-166 (2012).</li><li>Davis, G. R., McClellan, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extent+and+time+course+of+restoration+of+descending+brainstem+projections+in+spinalcord-transected+lamprey.">Extent and time course of restoration of descending brainstem projections in spinalcord-transected lamprey.</a> J Comp Neurol. 344, 65-82 (1994).</li><li>Jacobs, A. J., Swain, G. P., Snedeker, J. A., Pijak, D. S., Gladstone, L. J., Selzer, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recovery+of+neurofilament+expression+selectively+in+regenerating+reticulospinal+neurons.">Recovery of neurofilament expression selectively in regenerating reticulospinal neurons.</a> J Neurosci. 17, 5206-5220 (1997).</li><li>Shifman, M. I., Selzer, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+the+netrin+receptor+UNC-5+in+lamprey+brain+modulation+by+spinal+cord+transection.">Expression of the netrin receptor UNC-5 in lamprey brain modulation by spinal cord transection.</a> Neurorehabil Neural Repair. 14, 49-58 (2000).</li><li>Barreiro-Iglesias, A., Laramore, C., Shifman, M. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+sea+lamprey+UNC5+receptors+cDNA+cloning,+phylogenetic+analysis+and+expression+in+reticulospinal+neurons+at+larval+and+adult+stages+of+development.">The sea lamprey UNC5 receptors cDNA cloning, phylogenetic analysis and expression in reticulospinal neurons at larval and adult stages of development.</a> J Comp Neurol. 520, 4141-4156 (2012).</li><li>Shifman, M. I., Yumu, l. R. E., Laramore, C., Selzer, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+the+repulsive+guidance+molecule+RGM+and+its+receptor+neogenin+after+spinal+cord+injury+in+sea+lamprey.">Expression of the repulsive guidance molecule RGM and its receptor neogenin after spinal cord injury in sea lamprey.</a> Exp Neurol. 217, 242-251 (2009).</li><li>Busch, D. J., Morgan, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synuclein+accumulation+is+associated+with+cell-specific+neuronal+death+after+spinal+cord+injury.">Synuclein accumulation is associated with cell-specific neuronal death after spinal cord injury.</a> J Comp Neurol. 520, 1751-1771 (2012).</li><li>Shifman, M. I., Zhang, G., Selzer, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Delayed+death+of+identified+reticulospinal+neurons+after+spinal+cord+injury+in+lampreys.">Delayed death of identified reticulospinal neurons after spinal cord injury in lampreys.</a> J Comp Neurol. 510, 269-282 (2008).</li><li>Swain, G. P., Jacobs, A. J., Frei, E., Selzer, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+in+situ+hybridization+in+wholemounted+lamprey+brain+neurofilament+expression+in+larvae+and+adults.">A method for in situ hybridization in wholemounted lamprey brain neurofilament expression in larvae and adults.</a> Exp. Neurol. 126, 256-269 (1994).</li><li>Bullock, T. H., Moore, J. K., Fields, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolution+of+myelin+sheaths:+both+lamprey+and+hagfish+lack+myelin.">Evolution of myelin sheaths: both lamprey and hagfish lack myelin.</a> Neurosci Lett. 48, 145-148 (1984).</li><li>Cohen, A. H., Kiemel, T., Pate, V., Blinder, J., Guan, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature+can+alter+the+function+outcome+of+spinal+cord+regeneration+in+larval+lampreys.">Temperature can alter the function outcome of spinal cord regeneration in larval lampreys.</a> Neuroscience. 90, 957-965 (1999).</li></ol>

The authors declare that they have no competing financial interests.

Aquí presentamos un protocolo detallado para realizar un corte transversal de la médula espinal completa y la disección del cerebro posterior en las lampreas marinas larvales. Este procedimiento permite analizar las diferencias en la expresión génica entre identificable de la médula espinal que se proyectan neuronas después de la lesión de la médula espinal por medio de un cerebro todo el montaje hibridación in situ. El paso crítico en el procedimiento es el correcto funcionamiento de una transección complet...

En los mamíferos lesión de la médula espinal (SCI) es una enfermedad devastadora que conduce a la pérdida permanente de la función por debajo del sitio de la lesión, porque los axones lesionados no se regeneran a través de la zona de trauma y se vuelven a conectar a sus objetivos adecuados. En contraste con los mamíferos, lampreas recuperar la locomoción después de una lesión completa de la médula espinal. 1 Curiosamente, lampreas tienen un conjunto de 36 neuronas de la médula espinal que se proyecta que son individualmente identificable en todo el montaje preparaciones cerebrales debido a su gran tamaño 2,3 (Figura 1) . Todas estas neuronas espinales están proyectando axotomizadas por transección de la médula espinal completa de alto nivel. Estudios anteriores de nuestro grupo y otros han demostrado que, incluso en la presencia de la recuperación funcional después de SCI algunas de estas neuronas muestran una capacidad regenerativa muy bajo (se consideran &quot;malos regeneradores&quot;), mientras que otros por lo general se regeneran su axón a través del sitio de la lesión (se consideran &quot;gregeneradores ood &quot;). 2,3 Esta característica hace que las lampreas un modelo vertebrado interesante estudiar las diferencias en la expresión génica entre el bien y el mal regenerador neuronas espinales que se proyecta que a su vez dará lugar a las diferencias en la capacidad regenerativa intrínseca de las neuronas que intentan regenerar sus axones en el mismo entorno extrínseca. 1 El uso de este modelo que hemos demostrado anteriormente que-espinal proyectando las neuronas con baja capacidad regenerativa muestran la expresión de los receptores de moléculas guía axonal como UNC5 4,5 y neogenin, 6 que median la acción inhibitoria de netrina y RGM respectivamente. Además, mediante el uso de este método nuestro grupo ha demostrado también que sólo las buenas regeneradores muestran una recuperación de la expresión de neurofilamentos después de la lesión y durante el proceso de regeneración. Recientemente, Busch y Morgan 7 han demostrado por inmunofluorescencia que los malos regeneradores muestran un increasexpresión ed de sinucleína después de la lesión, que se ha relacionado por los autores sobre el hecho de que las &quot;malas regenerador&quot; neuronas espinales proyectar mueren lentamente después de una médula espinal transección completa 5,7,8. Así, el modelo de la lamprea de una lesión completa de la médula espinal se ha convertido en un modelo muy útil para entender lo que hace que un cable de la proyección de las neuronas de la médula de un &quot;mal regenerador&quot; después de axotomía. Para llevar a cabo nuestros estudios estamos llevando a cabo un protocolo completo de la médula espinal y cirugía transección una disección del cerebro posterior en los momentos deseados después de la lesión para realizar wholemount hibridación in situ. En el presente artículo metodológico se presenta un protocolo detallado para el correcto cumplimiento de la cirugía de lesión medular completa en las lampreas de larvas, el mantenimiento posterior de los animales y la disección del cerebro final y preparación del cerebro para una wholemount hibridación in situ. Un protocolo detallado a performa la wholemount hibridación in situ en el cerebro de las lampreas de larvas ha sido informado previamente. 9 Además, este protocolo para la lesión de la médula espinal y la disección del cerebro puede también ser utilizado entonces para procesar los cerebros de inmunohistoquímica u otros métodos histológicos.

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		<tr height="85">
			<td height="85" style="height:85px;width:64px;">Name of the reagent</td>
			<td style="width:83px;">Company</td>
			<td style="width:64px;">Catalogue number</td>
			<td style="width:71px;">Comments (optional)</td>
		</tr>
		<tr height="148">
			<td height="148" style="height:148px;width:64px;">Tricaine methane sulfonate</td>
			<td style="width:83px;">Spectrum</td>
			<td style="width:64px;">TR108</td>
			<td style="width:71px;">Benzocaine saturated solution in PBS for sacrifice</td>
		</tr>
		<tr height="85">
			<td height="85" style="height:85px;width:64px;">Scalpel #3</td>
			<td style="width:83px;">Fine Science Tools (FST)</td>
			<td style="width:64px;">10003-12</td>
			<td style="width:71px;"></td>
		</tr>
		<tr height="85">
			<td height="85" style="height:85px;width:64px;">Blades for scalpel: #11</td>
			<td style="width:83px;">Fine Science Tools&#160;</td>
			<td style="width:64px;">10011-00</td>
			<td style="width:71px;"></td>
		</tr>
		<tr height="85">
			<td height="85" style="height:85px;width:64px;">Castroviejo scissors #8</td>
			<td style="width:83px;">Fine Science Tools&#160;</td>
			<td style="width:64px;">15002-08</td>
			<td style="width:71px;"></td>
		</tr>
		<tr height="190">
			<td height="190" style="height:190px;width:64px;">Forceps #4 &#38; #5</td>
			<td style="width:83px;">Dumont, Switzerland</td>
			<td style="width:64px;">Roboz RS4955</td>
			<td style="width:71px;">#4 for dissection of Spinal cord; #5 for stripping menninges</td>
		</tr>
		<tr height="85">
			<td height="85" style="height:85px;width:64px;">Dissecting Microscope</td>
			<td style="width:83px;">Olympus</td>
			<td style="width:64px;">SZ51</td>
			<td style="width:71px;"></td>
		</tr>
		<tr height="42">
			<td height="63" rowspan="2" style="height:63px;width:64px;">Sylgard</td>
			<td rowspan="2" style="width:83px;">Dow Corning Co.</td>
			<td rowspan="2" style="width:64px;">184</td>
			<td rowspan="2" style="width:71px;"></td>
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		<tr height="21">
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		<tr height="168">
			<td height="189" rowspan="2" style="height:189px;width:64px;">Insect pins 0.15, 0.20 mm</td>
			<td rowspan="2" style="width:83px;">Austerlitz</td>
			<td rowspan="2" style="width:64px;">No catalogue #</td>
			<td rowspan="2" style="width:71px;">0.15 mm for pinning brain and spinal cord; 0.20 mm for the body</td>
		</tr>
		<tr height="21">
		</tr>
		<tr height="127">
			<td height="127" style="height:127px;width:64px;">7 ml HDPE Scintillation Tubes with Caps</td>
			<td style="width:83px;">Fisher Scientific</td>
			<td style="width:64px;">03-337-1</td>
			<td style="width:71px;"></td>
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		<tr height="106">
			<td height="106" style="height:106px;width:64px;">Paraformaldehyde 16%</td>
			<td style="width:83px;">Electron Microscopy Science (EMS)</td>
			<td style="width:64px;">19210</td>
			<td style="width:71px;">Dilute to 4% in PBS</td>
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</table>

complete spinal cord injury and brain dissection protocol for subsequent wholemount in situ hybridization in larval sea lamprey

Después de una lesión completa de la médula espinal, las lampreas de mar en primera están paralizados por debajo del nivel de corte transversal. Sin embargo, se recuperan locomoción después de varias semanas, y esto se acompaña de la regeneración corta distancia (unos pocos mm) de los axones propioespinal y axones-espinales que se proyecta desde el tronco cerebral. Entre los 36 grandes neuronas espinales proyectar identificables, algunos son buenos y otros son regeneradores malas regeneradores. Estas neuronas pueden ser más fáciles de identificar en las preparaciones del SNC wholemount. Con el fin de comprender los mecanismos de las neuronas intrínsecas que favorecen o inhiben la regeneración de axones después de la lesión del SNC en los vertebrados, determinamos diferencias en la expresión génica entre los regeneradores buenas y malas, y cómo la expresión es influenciada por transección de la médula espinal. Este documento ilustra las técnicas de larvas vivienda y recientemente transformado lampreas marinas adultas en depósitos de agua potable, la producción de transección medular completa bajo visión microscópica, y la preparación brain y wholemounts médula espinal para la hibridación in situ. En pocas palabras, los animales se mantienen a 16 &#160; ° C y anestesiado en el 1% de benzocaína en Ringer lamprea. La médula espinal se secciona con tijeras de iridectomía a través de un enfoque dorsal y se permite que el animal pueda recuperarse en depósitos de agua potable a 23 ° C. Para la hibridación in situ, los animales se reanesthetized y el cerebro y el cordón removidos a través de un enfoque dorsal.

Como ejemplo de los resultados que se pueden obtener cuando se utiliza este método, las imágenes representativas de cerebros wholemounted que muestran la expresión de las transcripciones neogenin en neuronas de la médula espinal identificables de proyección del control y 2 semanas después de la lesión de larvas lampreas de mar se muestran en la Figura 2. Los lectores pueden consultar a un estudio previo 6 informar de la relación entre la expresión de neogenin después de una transecc...

Watch this Scientific Journal Video about Complete Spinal Cord Injury and Brain Dissection Protocol for Subsequent Wholemount In Situ Hybridization in Larval Sea Lamprey at JoVE.com

Complete Spinal Cord Injury and Brain Dissection Protocol for Subsequent Wholemount In Situ Hybridization in Larval Sea Lamprey

Las lampreas recuperan locomoción después de una lesión completa de la médula espinal. Sin embargo, algunas neuronas espinales-proyectar regeneradores son buenos y otros no lo son. Este documento ilustra las técnicas de larvas de lamprea de mar vivienda (y adultos recientemente transformadas), la producción de transección completa de la médula espinal y la preparación de los cerebros y las médulas espinales wholemount para la hibridación in situ.

Lesiones de la Médula Espinal completo y Protocolo Disección del cerebro por Wholemount posterior<em&gt; In Situ</em&gt; La hibridación en larvas lamprea de mar

After a complete spinal cord injury, sea lampreys at first are paralyzed below the level of transection. However, they recover locomotion after several ...

complete-spinal-cord-injury-brain-dissection-protocol-for-subsequent

Research

JoVE Journal

Neuroscience

Complete Spinal Cord Injury and Brain Dissection Protocol for Subsequent Wholemount In Situ Hybridization in Larval Sea Lamprey

9.8K vistas.  University of Edinburgh.  Las lampreas recuperan locomoción después de una lesión completa de la médula espinal. Sin embargo, algunas neuronas espinales-proyectar regeneradores son buenos y otros no lo son. Este documento ilustra las técnicas de larvas de lamprea de mar vivienda (y adultos recientemente transformadas), la producción de transección completa de la médula espinal y la preparación de los cerebros y las médulas espinales wholemount para la hibridación in situ. 

Video: Complete Spinal Cord Injury and Brain Dissection Protocol for Subsequent Wholemount In Situ Hybridization in Larval Sea Lamprey

Dissection and Culture of Commissural Neurons from Embryonic Spinal Cord

Commissural neurons have been widely used to investigate the mechanisms underlying axon guidance during embryonic spinal cord development. The cell bodies of these neurons are located in the dorsal spinal cord and their axons follow stereotyped trajectories during embryonic development. Commissural axons initially project ventrally towards the floorplate. After crossing the midline, these axons turn anteriorly and project towards the brain. Each of these steps is regulated by the action of several guidance cues. Cultures highly enriched in commissural neurons are ideally suited for many experiments addressing the mechanisms of axon pathfinding, including turning assays, immunochemistry and biochemistry. Here, we describe a method to dissect and culture commissural neurons from E13 rat dorsal spinal cord. First, the spinal cord is isolated and dorsal strips are dissected out. The dorsal tissue is then dissociated into a cell suspension by trypsinization and mechanical disruption. Neurons are plated onto poly-L-lysine-coated glass coverslips or tissue-culture dishes. After 30 hours in vitro, most neurons have extended an axon. The purity of the culture (Yam et al. 2009), typically over 90%, can be assessed by immunolabeling with the commissural neuron markers DCC, LH2 and TAG1 (Helms and Johnson, 1998). This neuronal preparation is a useful tool for in vitro studies of the cellular and molecular mechanisms of commissural axon growth and guidance during spinal cord development.

This video demonstrates a method to dissect and culture commissural neurons from E13 rat dorsal spinal cord. Dissociated commissural neurons are useful to study the cellular and molecular mechanisms of axon growth and guidance.

La disección y la Cultura de las neuronas comisurales de médula espinal embrionaria

Commissural neurons have been widely used to investigate the mechanisms underlying axon guidance during embryonic spinal cord development. The cell bodies ...

Investigación

Neurociencias

Double Fluorescence in situ Hybridization in Fresh Brain Sections

Here we describe a modified version of a double fluorescence in situ hybridization (dFISH) method optimized for detecting two mRNAs of interest in fresh frozen brain sections. Our group has successfully used this approach to study gene co-regulation. More specifically, we have used this dFISH method to explore the anatomical organization, neurochemical properties, and the impact of sensory experience in central sensory circuits, at single cell resolution. This protocol has been validated in brain tissue from mice, rats and songbirds but is expected to be easily adaptable to other vertebrate species, as well as to an array of non-neural tissues. In this film we provide a detailed demonstration of the main steps of this procedure.

Double Fluorescence in situ Hybridization in Fresh Brain Sections

This protocol involves a non-radioactive in-situ hybridization procedure that enables the simultaneous identification of two transcript species, at a single cell resolution, in thin sections of the vertebrate brain.

Doble fluorescencia In situ La hibridación en las secciones del cerebro fresco

Here we describe a modified version of a double fluorescence in situ hybridization (dFISH) method optimized for detecting two mRNAs of interest in fresh ...

Lateral Fluid Percussion: Model of Traumatic Brain Injury in Mice

Traumatic brain injury (TBI) research has attained renewed momentum due to the increasing awareness of head injuries, which result in morbidity and mortality. Based on the nature of primary injury following TBI, complex and heterogeneous secondary consequences result, which are followed by regenerative processes 1,2. Primary injury can be induced by a direct contusion to the brain from skull fracture or from shearing and stretching of tissue causing displacement of brain due to movement 3,4. The resulting hematomas and lacerations cause a vascular response 3,5, and the morphological and functional damage of the white matter leads to diffuse axonal injury 6-8. Additional secondary changes commonly seen in the brain are edema and increased intracranial pressure 9. Following TBI there are microscopic alterations in biochemical and physiological pathways involving the release of excitotoxic neurotransmitters, immune mediators and oxygen radicals 10-12, which ultimately result in long-term neurological disabilities 13,14. Thus choosing appropriate animal models of TBI that present similar cellular and molecular events in human and rodent TBI is critical for studying the mechanisms underlying injury and repair.
Various experimental models of TBI have been developed to reproduce aspects of TBI observed in humans, among them three specific models are widely adapted for rodents: fluid percussion, cortical impact and weight drop/impact acceleration 1. The fluid percussion device produces an injury through a craniectomy by applying a brief fluid pressure pulse on to the intact dura. The pulse is created by a pendulum striking the piston of a reservoir of fluid. The percussion produces brief displacement and deformation of neural tissue 1,15. Conversely, cortical impact injury delivers mechanical energy to the intact dura via a rigid impactor under pneumatic pressure 16,17. The weight drop/impact model is characterized by the fall of a rod with a specific mass on the closed skull 18. Among the TBI models, LFP is the most established and commonly used model to evaluate mixed focal and diffuse brain injury 19. It is reproducible and is standardized to allow for the manipulation of injury parameters. LFP recapitulates injuries observed in humans, thus rendering it clinically relevant, and allows for exploration of novel therapeutics for clinical translation 20.
We describe the detailed protocol to perform LFP procedure in mice. The injury inflicted is mild to moderate, with brain regions such as cortex, hippocampus and corpus callosum being most vulnerable. Hippocampal and motor learning tasks are explored following LFP.

Lateral fluid percussion (LFP), an established model of traumatic brain injury in mice, is demonstrated. LFP fulfills three major criteria for animal models: validity, reliability and clinical relevance. The procedure, consisting of surgical craniotomy, fixation of hub followed by induction of injury, resulting in focal and diffuse injuries, is described.

Percusión fluido lateral: Modelo de Lesión Cerebral Traumática en ratones

Traumatic brain injury (TBI) research has attained renewed momentum due to the increasing awareness of head injuries, which result in morbidity and ...

Spinal Cord Transection in the Larval Zebrafish

Mammals fail in sensory and motor recovery following spinal cord injury due to lack of axonal regrowth below the level of injury as well as an inability to reinitiate spinal neurogenesis. However, some anamniotes including the zebrafish Danio rerio exhibit both sensory and functional recovery even after complete transection of the spinal cord. The adult zebrafish is an established model organism for studying regeneration following spinal cord injury, with sensory and motor recovery by 6&#160;weeks post-injury. To take advantage of in vivo analysis of the regenerative process available in the transparent larval zebrafish as well as genetic tools not accessible in the adult, we use the larval zebrafish to study regeneration after spinal cord transection. Here we demonstrate a method for reproducibly and verifiably transecting the larval spinal cord. After transection, our data shows sensory recovery beginning at 2&#160;days post-injury (dpi), with the C-bend movement detectable by 3 dpi and resumption of free swimming by 5 dpi. Thus we propose the larval zebrafish as a companion tool to the adult zebrafish for the study of recovery after spinal cord injury.

After spinal transection, adult zebrafish have functional recovery by six weeks post-injury. To take advantage of larval transparency and faster recovery, we present a method for transecting the larval spinal cord. After transection, we observe sensory recovery beginning at 2&#160;days post-injury, and C-bend movement by 3 days post-injury.

La transección de la médula espinal en el pez cebra larval

Mammals fail in sensory and motor recovery following spinal cord injury due to lack of axonal regrowth below the level of injury as well as an inability ...

An Ex Vivo Laser-induced Spinal Cord Injury Model to Assess Mechanisms of Axonal Degeneration in Real-time

Injured CNS axons fail to regenerate and often retract away from the injury site. Axons spared from the initial injury may later undergo secondary axonal degeneration. Lack of growth cone formation, regeneration, and loss of additional myelinated axonal projections within the spinal cord greatly limits neurological recovery following injury. To assess how central myelinated axons of the spinal cord respond to injury, we developed an ex vivo living spinal cord model utilizing transgenic mice that express yellow fluorescent protein in axons and a focal and highly reproducible laser-induced spinal cord injury to document the fate of axons and myelin (lipophilic fluorescent dye Nile Red) over time using two-photon excitation time-lapse microscopy. Dynamic processes such as acute axonal injury, axonal retraction, and myelin degeneration are best studied in real-time. However, the non-focal nature of contusion-based injuries and movement artifacts encountered during in vivo spinal cord imaging make differentiating primary and secondary axonal injury responses using high resolution microscopy challenging. The ex vivo spinal cord model described here mimics several aspects of clinically relevant contusion/compression-induced axonal pathologies including axonal swelling, spheroid formation, axonal transection, and peri-axonal swelling providing a useful model to study these dynamic processes in real-time. Major advantages of this model are excellent spatiotemporal resolution that allows differentiation between the primary insult that directly injures axons and secondary injury mechanisms; controlled infusion of reagents directly to the perfusate bathing the cord; precise alterations of the environmental milieu (e.g., calcium, sodium ions, known contributors to axonal injury, but near impossible to manipulate in vivo); and murine models also offer an advantage as they provide an opportunity to visualize and manipulate genetically identified cell populations and subcellular structures. Here, we describe how to isolate and image the living spinal cord from mice to capture dynamics of acute axonal injury.

An Ex Vivo Laser-induced Spinal Cord Injury Model to Assess Mechanisms of Axonal Degeneration in Real-time

We present a protocol utilizing two-photon excitation time-lapse microscopy to simultaneously visualize the dynamics of axon and myelin injuries in real time. This proposed protocol permits studies of both intrinsic and extrinsic factors which can influence central myelinated axon fate after injury and contribute to permanent clinical disability.

Una<em&gt; Ex Vivo</em&gt; Médula espinal inducida por láser Lesiones modelo para evaluar los mecanismos de degeneración axonal en tiempo real

Injured CNS axons fail to regenerate and often retract away from the injury site. Axons spared from the initial injury may later undergo secondary axonal ...

Zebrafish In Situ Spinal Cord Preparation for Electrophysiological Recordings from Spinal Sensory and Motor Neurons

Zebrafish, first introduced as a developmental model, have gained popularity in many other fields. The ease of rearing large numbers of rapidly developing organisms, combined with the embryonic optical clarity, served as initial compelling attributes of this model. Over the past two decades, the success of this model has been further propelled by its amenability to large-scale mutagenesis screens and by the ease of transgenesis. More recently, gene-editing approaches have extended the power of the model.
For neurodevelopmental studies, the zebrafish embryo and larva provide a model to which multiple methods can be applied. Here, we focus on methods that allow the study of an essential property of neurons, electrical excitability. Our preparation for the electrophysiological study of zebrafish spinal neurons involves the use of veterinarian suture glue to secure the preparation to a recording chamber. Alternative methods for recording from zebrafish embryos and larvae involve the attachment of the preparation to the chamber using a fine tungsten pin1,2,3,4,5. A tungsten pin is most often used to mount the preparation in a lateral orientation, although it has been used to mount larvae dorsal-side up4. The suture glue has been used to mount embryos and larvae in both orientations. Using the glue, a minimal dissection can be performed, allowing access to spinal neurons without the use of an enzymatic treatment, thereby avoiding any resultant damage. However, for larvae, it is necessary to apply a brief enzyme treatment to remove the muscle tissue surrounding the spinal cord. The methods described here have been used to study the intrinsic electrical properties of motor neurons, interneurons, and sensory neurons at several developmental stages6,7,8,9.

Zebrafish In Situ Spinal Cord Preparation for Electrophysiological Recordings from Spinal Sensory and Motor Neurons

This manuscript describes methods for electrophysiological recordings from spinal neurons of zebrafish embryos and larvae. The preparation maintains neurons in situ and often involves minimum dissection. These methods allow for the electrophysiological study of a variety of spinal neurons, from the initial electrical excitability acquisition through the early larval stages.

El pez cebra<em&gt; In Situ</em&gt; Médula Espinal Preparación para Registros electrofisiológicos de Spinal Sensory y neuronas motoras

Zebrafish, first introduced as a developmental model, have gained popularity in many other fields. The ease of rearing large numbers of rapidly developing ...

Imaging Neural Activity in the Primary Somatosensory Cortex Using Thy1-GCaMP6s Transgenic Mice

The mammalian brain exhibits marked symmetry across the sagittal plane. However, detailed description of neural dynamics in symmetric brain regions in adult mammalian animals remains elusive. In this study, we describe an experimental procedure for measuring calcium dynamics through dual optical windows above bilateral primary somatosensory corticies (S1) in Thy1-GCaMP6s transgenic mice using 2-photon (2P) microscopy. This method enables recordings and quantifications of neural activity in bilateral mouse brain regions one at a time in the same experiment for a prolonged period in vivo. Key aspects of this method, which can be completed within an hour, include minimally invasive surgery procedures for creating dual optical windows, and the use of 2P imaging. Although we only demonstrate the technique in the S1 area, the method can be applied to other regions of the living brain facilitating the elucidation of structural and functional complexities of brain neural networks.

Imaging Neural Activity in the Primary Somatosensory Cortex Using Thy1-GCaMP6s Transgenic Mice

We describe an experimental procedure for measuring neuronal activity through dual optical windows above bilateral primary somatosensory corticies (S1) in Thy1-GCaMP6s transgenic mice using 2-photon (2P) microscopy in vivo.

Imágenes de la actividad neuronal en la corteza somatosensorial primaria usando Thy1-ratones transgénicos GCaMP6s

The mammalian brain exhibits marked symmetry across the sagittal plane. However, detailed description of neural dynamics in symmetric brain regions in ...

An In Vivo Duo-color Method for Imaging Vascular Dynamics Following Contusive Spinal Cord Injury

Spinal cord injury (SCI) causes significant vascular disruption at the site of injury. Vascular pathology occurs immediately after SCI and continues throughout the acute injury phase. In fact, endothelial cells appear to be the first to die after a contusive SCI. The early vascular events, including increased permeability of the blood-spinal cord barrier (BSCB), induce vasogenic edema and contribute to detrimental secondary injury events caused by complex injury mechanisms. Targeting the vascular disruption, therefore, could be a key strategy to reduce secondary injury cascades that contribute to histological and functional impairments after SCI. Previous studies were mostly performed on postmortem samples and were unable to capture the dynamic changes of the vascular network. In this study, we have developed an in vivo duo-color two-photon imaging method to monitor acute vascular dynamic changes following contusive SCI. This approach allows detecting blood flow, vessel diameter, and other vascular pathologies at various sites of the same rat pre- and post-injury. Overall, this method provides an excellent venue for investigating vascular dynamics.

An In Vivo Duo-color Method for Imaging Vascular Dynamics Following Contusive Spinal Cord Injury

We introduce an in vivo imaging method using two different fluorescent dyes to track dynamic spinal vascular changes following a contusive spinal cord injury in adult Sprague-Dawley rats.

Un en Vivo Dúo color método de proyección de imagen dinámica Vascular tras lesión medular contundente

Spinal cord injury (SCI) causes significant vascular disruption at the site of injury. Vascular pathology occurs immediately after SCI and continues ...

Intra-Arterial Delivery of Neural Stem Cells to the Rat and Mouse Brain: Application to Cerebral Ischemia

Neural stem cell (NSC) therapy is an emerging innovative treatment for stroke, traumatic brain injury and neurodegenerative disorders. As compared to intracranial delivery, intra-arterial administration of NSCs is less invasive and produces a more diffuse distribution of NSCs within the brain parenchyma. Further, intra-arterial delivery allows the first-pass effect in the brain circulation, lessening the potential for trapping of cells in peripheral organs, such as liver and spleen, a complication associated with peripheral injections. Here, we detail the methodology, in both mice and rats, for delivery of NSCs through the common carotid artery (mouse) or external carotid artery (rat) to the ipsilateral hemisphere after an ischemic stroke. Using GFP-labeled NSCs, we illustrate the widespread distribution achieved throughout the rodent ipsilateral hemisphere at 1 d, 1 week and 4 weeks after postischemic delivery, with a higher density in or near the ischemic injury site. In addition to long-term survival, we show evidence of differentiation of GFP-labeled cells at 4 weeks. The intra-arterial delivery approach described here for NSCs can also be used for administration of therapeutic compounds, and thus has broad applicability to varied CNS injury and disease models across multiple species.

A method for delivering neural stem cells, adaptable for injecting solutions or suspensions, through the common carotid artery (mouse) or external carotid artery (rat) after ischemic stroke is reported. Injected cells are distributed broadly throughout the brain parenchyma and can be detected up to 30 d after delivery.

Entrega intra-arterial de células madre neuronales a la rata y el cerebro del ratón: aplicación a la isquemia cerebral

Neural stem cell (NSC) therapy is an emerging innovative treatment for stroke, traumatic brain injury and neurodegenerative disorders. As compared to ...

Induction of Complete Transection-Type Spinal Cord Injury in Mice

Spinal cord injury (SCI) largely leads to irreversible and permanent loss of function, most commonly as a result of trauma. Several treatment options, such as cell transplantation methods, are being researched to overcome the debilitating disabilities arising from SCI. Most pre-clinical animal trials are conducted in rodent models of SCI. While rat models of SCI have been widely used, mouse models have received less attention, even though mouse models can have significant advantages over rat models. The small size of mice equates to lower animal maintenance costs than for rats, and the availability of numerous transgenic mouse models is advantageous for many types of studies. Inducing repeatable and precise injury in the animals is the primary challenge for SCI research, which in small rodents requires high-precision surgery. The transection-type injury model has been a commonly used injury model over the last decade for transplantation-based therapeutic research, however a standardized method for inducing a complete transection-type injury in mice does not exist. We have developed a surgical protocol for inducing a complete transection type injury in C57BL/6 mice at thoracic vertebral level 10 (T10). The procedure uses a small tip drill instead of rongeurs to precisely remove the lamina, after which a thin blade with rounded cutting edge is used to induce the spinal cord transection. This method leads to reproducible transection-type injury in small rodents with minimal collateral muscle and bone damage and therefore minimizes confounding factors, specifically where behavioral functional outcomes are analyzed.

This protocol describes how to create a precise laminectomy for induction of stable transection-type spinal cord injury in the mouse model, with minimal collateral damage for spinal cord injury research.

Inducción de lesiones completas de la médula espinal de tipo transección en ratones

Spinal cord injury (SCI) largely leads to irreversible and permanent loss of function, most commonly as a result of trauma. Several treatment options, ...