Estamos en deuda con la instalación de pez cebra de la Universidad de Utah para la cría de animales. RID fue apoyado por el NIH R56NS053897 y LKB era un aprendiz predoctoral con el apoyo de la iniciativa del HHMI Med-Into-Grad.

El pez cebra fueron criados y criados según procedimientos estándar; experimentos fueron aprobados por la Universidad de Comité de Cuidado de Animales y el empleo Institucional Utah. 1. Preparación de las placas Cirugía <ol><li> Hacer platos de cirugía usando 60 mm placas de Petri y Sylgard 184 Kit de caucho silicona, siguiendo las instrucciones del fabricante. Llenar los platos no más que medio lleno y deje que se polimeriza. Tienda cubierto a temperatura ambiente. </li></ol> 2. Preparación de Micropipetas <ol><li> Fabrique micropipetas calentando y tirando de pared delgada tubos capilares de borosilicato en un extractor de micropipeta con la misma configuración para la toma de las agujas de microinyección. </li><li> Bajo un microscopio de disección, romper la punta de la micropipeta a aproximadamente 200 m de diámetro con pinzas. </li><li> Bisel borde roto con un microgrinder inicialmente a 35 °, seguido de un segundo biselado a 25 °. Asegúrese de punta está afilada y smooth. Tienda finalizó micropipeta biselada en una placa de Petri en una pequeña cantidad de arcilla. </li></ol> 3. Preparación de Pez cebra larvas <ol><li> 7 días antes de la cirugía, crearon tanques de apareamiento de los peces cebra macho y hembra. </li><li> Recoger los embriones a la mañana siguiente, 3 horas después de que las luces se encienden para garantizar el máximo rendimiento. Si utiliza una línea reportero transgénicos como Tg (elevl3: eGFP) knu3, los embriones fertilizados tipo 100/100 mm de placa en 25 ml de E3 a 28,5 ° C. Si se utiliza de tipo salvaje, especie fertilizado embriones placa 25/100 mm en 25 ml de E3 a 28,5 ° C. </li><li> Si se utiliza una línea de reportero, cribar embriones para la expresión fluorescente a las 48 HPF. Permitir embriones identificados maduren a una densidad de placa 25/100 mm en 25 ml de E3 a 28,5 ° C. </li><li> Cuando las larvas son 5 dpf, preparar la placa de la cirugía, cubriendo Sylgard con E2 + 10 mg / L de sulfato de gentamicina (GS) + tricaína. <ol><li> Preparar el plato de recuperación mediante la adición de 25 ml de E2 + GS a unos 100 mm dis Petrih. </li><li> Preparar bisturí grabando juntos tres hisopos. Esto formará una herramienta triangular con tres ranuras. </li><li> Montar una micropipeta preparado sobre los hisopos con cinta adhesiva en uno de los surcos. </li></ol></li><li> Si vuelve a utilizar micropipetas, enjuague hasta que se aclare con E2 + GS con una jeringa de 1 ml y una aguja de 27 G antes de montar en hisopos. </li></ol> 4. Cirugía <ol><li> Anestesie 1 plato de larvas en un momento (25 peces) con tricaína. Los peces son suficientemente anestesiado cuando ya no muestran respuesta al toque. Es importante que los peces están completamente anestesiados antes de la cirugía, de lo contrario se contracción cuando el bisturí los toca. La cirugía se realiza bajo un microscopio de disección. </li><li> Transfiera las larvas a la placa de la cirugía. <ol><li> Bajo un aumento máximo, girar una larva en un momento de forma que quede en su lado con la espalda lo más cerca de la mano que sostiene el bisturí. </li><li> Posición fórceps, para que estén sobre el Sylgard,ángulo recto sobre la anchura de la larva. </li><li> Refuerzo El escalpelo de vidrio contra una de las ramas de la pinza, cortado en la cara lateral dorsal de la larva a nivel del poro anal, asegurándose de no cortar más allá del borde ventral de la notocorda. Gire el bisturí para cortar la médula espinal. </li><li> Repita con larvas restante. Nota: si una larva sangra, no va a recuperarse de la cirugía. Quitarse de inmediato la larva de la placa de la cirugía y practicar la eutanasia a través de la sobredosis tricaína. </li></ol></li><li> Una vez que la cirugía en el lote de larvas es completa, la transferencia de los animales lesionado a la placa de recuperación. Esto es para apoyar la limpieza de la anestesia. <ol><li> Precaución: al recoger larvas heridos para la transferencia, asegúrese de que se recojan ni pies ni cabeza primero: no insistir en la zona de la lesión, doblando las larvas. Nota: Todos los dispositivos que se utilizan para la cirugía pueden ser reutilizados, incluyendo las micropipetas. </li></ol></li></ol> 5. Recuperación <ol><li> Transfer lesionado larvas de la placa de recuperación a placas de 100 mm rellenas con 25 ml de E2 + GS a una densidad de 25/plato. Permitir a recuperarse en una incubadora de 28.5 ° C. </li><li> Compruebe placas diaria, eliminando los animales enfermos y muertos. No cambie los medios hasta Coleps (protozoos de agua dulce) son visibles en los medios de comunicación. Al cambiar los medios de comunicación, no transfiera el pescado a una nueva placa; en su lugar, eliminar la mayor cantidad posible de medios y la inundación de la misma placa con los nuevos medios. Repita según sea necesario para reducir la población Coleps. </li><li> Diario de alimento con una pequeña cantidad de freír los alimentos en polvo. Nota: El alimento vivo (por ejemplo, los paramecios o rotíferos) no se pueden alimentar a las larvas lesionada hasta después de que se haya recuperado la locomoción. De lo contrario, la comida en vivo será colonizar el lugar de la lesión y matar a las larvas. </li></ol>

<ol>
	<li>Houweling, D. A., B&#228;r, P. R., Gispen, W. H., Joosten, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spinal+cord+injury:+bridging+the+lesion+and+the+role+of+neurotrophic+factors+in+repair.">Spinal cord injury: bridging the lesion and the role of neurotrophic factors in repair.</a> Progress in brain research. 117, 455-471 (1998).</li><li>Mikami, Y., 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=Implantation+of+dendritic+cells+in+injured+adult+spinal+cord+results+in+activation+of+endogenous+neural+stem/progenitor+cells+leading+to+de+novo+neurogenesis+and+functional+recovery.">Implantation of dendritic cells in injured adult spinal cord results in activation of endogenous neural stem/progenitor cells leading to de novo neurogenesis and functional recovery.</a> Journal of neuroscience research. 76 (4), 453-465 (2004).</li><li>Chernoff, E. A. G., Sato, K., Corn, A., Karcavich, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spinal+cord+regeneration:+intrinsic+properties+and+emerging+mechanisms.">Spinal cord regeneration: intrinsic properties and emerging mechanisms.</a> Seminars in Cell &amp; Developmental Biology. 13 (5), 361-368 (2002).</li><li>Kuscha, V., Barreiro-Iglesias, A., Becker, C. G., Becker, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasticity+of+tyrosine+hydroxylase+and+serotonergic+systems+in+the+regenerating+spinal+cord+of+adult+zebrafish.">Plasticity of tyrosine hydroxylase and serotonergic systems in the regenerating spinal cord of adult zebrafish.</a> The Journal of comparative neurology. 520 (5), 933-951 (2012).</li><li>Becker, C. G., Lieberoth, B. C., Morellini, F., Feldner, J., Becker, T., Schachner, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=L1.1+is+involved+in+spinal+cord+regeneration+in+adult+zebrafish.">L1.1 is involved in spinal cord regeneration in adult zebrafish.</a> The Journal of Neuroscience: The Official Journal of the Society for Neuroscience. 24 (36), 7837-7842 (2004).</li><li>Hui, S. P., Dutta, A., Ghosh, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+response+after+crush+injury+in+adult+zebrafish+spinal+cord.">Cellular response after crush injury in adult zebrafish spinal cord.</a> Developmental Dynamics: An Official Publication of the American Association of Anatomists. 239 (11), 2962-2979 (2010).</li><li>Goldshmit, Y., Sztal, T. E., Jusuf, P. R., Hall, T. E., Nguyen-Chi, M., Currie, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fgf-dependent+glial+cell+bridges+facilitate+spinal+cord+regeneration+in+zebrafish.">Fgf-dependent glial cell bridges facilitate spinal cord regeneration in zebrafish.</a> The Journal of neuroscience: the official journal of the Society for Neuroscience. 32 (22), 7477-7492 (2012).</li><li>Reimer, M. M., 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=Motor+neuron+regeneration+in+adult+zebrafish.">Motor neuron regeneration in adult zebrafish.</a> The Journal of Neuroscience: The Official Journal of the Society for Neuroscience. 28 (34), 8510-8516 (2008).</li><li>Hale, M. E., Ritter, D. A., Fetcho, 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=A+confocal+study+of+spinal+interneurons+in+living+larval+zebrafish.">A confocal study of spinal interneurons in living larval zebrafish.</a> The Journal of comparative neurology. 437 (1), 1-16 (2001).</li><li>Bhatt, D. H., Otto, S. J., Depoister, B., Fetcho, 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=Cyclic+AMP-induced+repair+of+zebrafish+spinal+circuits.">Cyclic AMP-induced repair of zebrafish spinal circuits.</a> Science. 305 (5681), 254-258 (2004).</li><li>McClenahan, P., Troup, M., Scott, E. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fin-tail+coordination+during+escape+and+predatory+behavior+in+larval+zebrafish.">Fin-tail coordination during escape and predatory behavior in larval zebrafish.</a> PloS one. 7 (2), (2012).</li><li>Kim, C. H., 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=Repressor+activity+of+Headless/Tcf3+is+essential+for+vertebrate+head+formation.">Repressor activity of Headless/Tcf3 is essential for vertebrate head formation.</a> Nature. 407 (6806), 913-916 (2000).</li></ol>

Los autores no tienen nada que revelar.

Cuando se aprende inicialmente esta técnica, se recomienda intentar no más de 50 a 100 transectos en una sola sesión. Después de dominar esta técnica, que son capaces de seccionar hasta 300 embriones por hora; Sin embargo, este nivel de rendimiento requiere de unos meses de práctica semanal. También se recomienda la práctica con un reportero línea y la verificación de la transección completa hasta la incidencia de la transección de la médula espinal incompleta se reduce a menos de 1%. <p class="jove_con...

Mayor trauma en la médula espinal humana a menudo resulta en la parálisis permanente y pérdida de la sensación por debajo del nivel de la lesión, debido a la incapacidad para volver a crecer los axones o reiniciar la neurogénesis 1,2. A diferencia de los mamíferos, sin embargo, anamniotes incluyendo salamandras y el pez cebra (Danio rerio) muestran recuperación robusta, incluso después de la sección completa de la médula espinal 3,4. El pez cebra adultos es un modelo bien establecido para estudiar el proceso de recuperación tras la lesión de la médula espinal 5-7. Después de la transección completa de la médula espinal, restablecimiento de la función sensorial y la locomotora se observa en el pez cebra adultos por 6 semanas después de la lesión 8. Con el fin de examinar el proceso de regeneración in vivo, recurrimos a la larvas de pez cebra transparente 9. Aquí presentamos un método para seccionar la médula espinal de un 5 días después de la fertilización (dpf) larval usi pez cebrang de una pipeta de microinyección biselado como un bisturí, modificado a partir de Bhatt, et al. 10 Este método es compatible con alto rendimiento, baja mortalidad, y la reproducibilidad. Con la práctica, 300 larvas / hr puede secciona, y más de 6 meses de cortes transversales, incluyendo más de 3.600 animales, 98,75% ± 0,72% sobrevivió hasta 7 días después de la lesión (dpi). Nuestros datos muestran una rápida recuperación de la locomoción y sensorial, así: al 1 dpi, todos los movimientos de los peces heridos es impulsado por pectoral sólo locomoción aleta. Sin embargo, las larvas comienzan a responder al tungsteno aguja toque caudal a la transección por 2 dpi, restablecer el movimiento C-doble por 3 dpi, y mostrar la natación predatorias de 5 11 dpi. El uso de la tinción de anticuerpos contra la tubulina acetilada, hemos confirmado que los axones están ausentes en el sitio de la lesión en 1 dpi, pero hemos cruzado el sitio de la lesión por 5 dpi. Creemos que este protocolo proporcionará una técnica valiosa para el estudio de la regeneración axonal y la neurogénesis en la médula espinal después de una lesión. </p&gt;

<table border="0" cellpadding="0" cellspacing="0" style="width:733px;" width="733">
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			<td height="21" style="height:21px;width:269px;">Name of Material/ Equipment</td>
			<td style="width:179px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">60mm petri dish</td>
			<td style="width:179px;">VWR</td>
			<td style="width:119px;">82050-544</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">100mm petri dish</td>
			<td style="width:179px;">VWR</td>
			<td style="width:119px;">89038-968</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">Sylgard 184 Silicone Elastomer Kit</td>
			<td style="width:179px;">Fisher Scientific</td>
			<td style="width:119px;">NC9644388</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:269px;">borosilicate capillary tubing: OD 1.00mm ID 0.78mm</td>
			<td style="width:179px;">Warner Instruments Inc.</td>
			<td style="width:119px;">64-0778</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:269px;">forceps</td>
			<td style="width:179px;">Fine Scientific Tools Inc.</td>
			<td style="width:119px;">11252-30</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">disssection microscope</td>
			<td style="width:179px;">Nikon</td>
			<td style="width:119px;">SMZ6454</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">microgrinder</td>
			<td style="width:179px;">Narishige</td>
			<td style="width:119px;">EG-44</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">Gentamycin Sulfate</td>
			<td style="width:179px;">Amresco Inc.</td>
			<td style="width:119px;">0304-5G</td>
			<td>dissolve in water 10mg/ml, store at -20&#176;C</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:269px;">Tricaine</td>
			<td style="width:179px;">Acros Organics</td>
			<td align="right" style="width:119px;">118000100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">cotton tipped applicator, wood, 6-inch</td>
			<td style="width:179px;">Fisher Scientific</td>
			<td style="width:119px;">23-400-101</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">1ml syringe</td>
			<td style="width:179px;">BD</td>
			<td align="right" style="width:119px;">309625</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">27 ga. needle</td>
			<td style="width:179px;">BD</td>
			<td align="right" style="width:119px;">305109</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">Fry food</td>
			<td style="width:179px;">Argent Labs</td>
			<td style="width:119px;">F-ARGE-PTL-CN</td>
			<td>store at -20&#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">micropipette puller</td>
			<td style="width:179px;">Sutter Instrument Co.</td>
			<td style="width:119px;">Model P-97</td>
			<td>Box Filament FB330B</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;"></td>
			<td style="width:179px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">20x E2 (1L)</td>
			<td style="width:179px;"></td>
			<td style="width:119px;"></td>
			<td>store at RT</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">17.5g NaCl</td>
			<td style="width:179px;">Fisher Scientific</td>
			<td style="width:119px;">S671-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">0.75g KCl</td>
			<td style="width:179px;">Fisher Scientific</td>
			<td style="width:119px;">P217-500</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:269px;">2.90g CaCl2&#183;2H2O</td>
			<td style="width:179px;">Sigma&#160;&#160;&#160;</td>
			<td style="width:119px;">C7902-500G</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:269px;">4.90g MgSO4&#183;7H2O</td>
			<td style="width:179px;">Merck</td>
			<td style="width:119px;">MX0070-1</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:269px;">0.41g KH2PO4</td>
			<td style="width:179px;">Fisher Scientific</td>
			<td style="width:119px;">P285-500</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:269px;">0.12g Na2HPO4</td>
			<td style="width:179px;">Sigma&#160;&#160;&#160;</td>
			<td style="width:119px;">S0876-500G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;"></td>
			<td style="width:179px;"></td>
			<td style="width:119px;"></td>
			<td></td>
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		<tr height="25">
			<td height="25" style="height:25px;width:269px;">500x NaCO3 (10ml)</td>
			<td style="width:179px;"></td>
			<td style="width:119px;"></td>
			<td>make fresh, discard extra</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:269px;">0.35g NaCO3</td>
			<td style="width:179px;">Sigma</td>
			<td style="width:119px;">S5761</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;"></td>
			<td style="width:179px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">1x E2 (1L)</td>
			<td style="width:179px;"></td>
			<td style="width:119px;"></td>
			<td>store at RT</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">50ml 20x E2</td>
			<td style="width:179px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:269px;">2ml fresh 500x NaCO3</td>
			<td style="width:179px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

spinal cord transection in the larval zebrafish

Mamíferos fallan en la recuperación sensorial y motora después de una lesión de la médula espinal debido a la falta de regeneración axonal por debajo del nivel de la lesión, así como una incapacidad para reiniciar la neurogénesis médula. Sin embargo, algunos anamniotes incluyendo el pez cebra exposición Danio rerio tanto sensorial y la recuperación funcional, incluso después de la transección completa de la médula espinal. El pez cebra adulto es un organismo modelo establecido para el estudio de la regeneración después de una lesión de la médula espinal, con la recuperación motora y sensitiva a las 6 semanas posteriores a la lesión. Para aprovechar las ventajas del análisis in vivo del proceso regenerativo disponible en la larvas de pez cebra transparente, así como herramientas genéticas no son accesibles en el adulto, usamos la larvas de pez cebra para estudiar la regeneración después del corte transversal de la médula espinal. Aquí se demuestra un método para reproducible y verificable transección de la médula espinal de las larvas. Después de transección, nuestros datos muestran principio de recuperación sensorial a los 2 días después de la lesión (ppp), ingenioh del movimiento C-bend detectable por 3 dpi y la reanudación de la natación libre por 5 dpi. Por lo tanto se propone la larvas de pez cebra como una herramienta complementaria para el pez cebra adulto para el estudio de la recuperación después de una lesión de la médula espinal.

Para reducir la gravedad de los daños en los tejidos que rodean el sitio de la lesión, biselado adecuado de la micropipeta es crítica. Figura 1A muestra una punta biselada correctamente. Utilizando una punta que es demasiado amplia (Figura 1B) tiende a provocar víctimas más altas debido a la mayor probabilidad de mellar la aorta dorsal, mientras que el dato de que es demasiado estrecha (Figura 1C) tiende a mirar fuera de la piel en lugar de cortar tejido. <p cl...

Watch this Scientific Journal Video about Spinal Cord Transection in the Larval Zebrafish at JoVE.com

Spinal Cord Transection in the Larval Zebrafish

Después de la transección de la médula, el pez cebra adulto tenga la recuperación funcional a las seis semanas posteriores a la lesión. Para aprovechar las ventajas de la transparencia de las larvas y una recuperación más rápida, se presenta un método para seccionar la médula espinal de las larvas. Después de transección, se observa la recuperación sensorial a partir de los 2 días después de la lesión, y el movimiento C-doble por 3 días después de la lesión.

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 ...

spinal-cord-transection-in-the-larval-zebrafish

Research

JoVE Journal

Neuroscience

11.8K vistas.  University of Utah.  Después de la transección de la médula, el pez cebra adulto tenga la recuperación funcional a las seis semanas posteriores a la lesión. Para aprovechar las ventajas de la transparencia de las larvas y una recuperación más rápida, se presenta un método para seccionar la médula espinal de las larvas. Después de transección, se observa la recuperación sensorial a partir de los 2 días después de la lesión, y el movimiento C-doble por 3 días después de la le...

Video: Spinal Cord Transection in the Larval Zebrafish

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

Spinal Cord Electrophysiology II: Extracellular Suction Electrode Fabrication

Development of neural circuitries and locomotion can be studied using neonatal rodent spinal cord central pattern generator (CPG) behavior. We demonstrate a method to fabricate suction electrodes that are used to examine CPG activity, or fictive locomotion, in dissected rodent spinal cords. The rodent spinal cords are placed in artificial cerebrospinal fluid and the ventral roots are drawn into the suction electrode. The electrode is constructed by modifying a commercially available suction electrode. A heavier silver wire is used instead of the standard wire given by the commercially available electrode. The glass tip on the commercial electrode is replaced with a plastic tip for increased durability. We prepare hand drawn electrodes and electrodes made from specific sizes of tubing, allowing consistency and reproducibility. Data is collected using an amplifier and neurogram acquisition software. Recordings are performed on an air table within a Faraday cage to prevent mechanical and electrical interference, respectively.

A demonstration of the fabrication and use of an extracellular suction electrode used to measure electrophysiological recordings of neonatal rodent spinal cords in vitro

Médula Espinal Electrofisiología II: Fabricación de electrodos de aspiración extracelular

Development of neural circuitries and locomotion can be studied using neonatal rodent spinal cord central pattern generator (CPG) behavior. We demonstrate ...

Forebrain Electrophysiological Recording in Larval Zebrafish

Epilepsy affects nearly 3 million people in the United States and up to 50 million people worldwide. Defined as the occurrence of spontaneous unprovoked seizures, epilepsy can be acquired as a result of an insult to the brain or a genetic mutation. Efforts to model seizures in animals have primarily utilized acquired insults (convulsant drugs, stimulation or brain injury) and genetic manipulations (antisense knockdown, homologous recombination or transgenesis) in rodents. Zebrafish are a vertebrate model system1-3 that could provide a valuable alternative to rodent-based epilepsy research. Zebrafish are used extensively in the study of vertebrate genetics or development, exhibit a high degree of genetic similarity to mammals and express homologs for ~85% of known human single-gene epilepsy mutations. Because of their small size (4-6 mm in length), zebrafish larvae can be maintained in fluid volumes as low as 100 &mu;l during early development and arrayed in multi-well plates. Reagents can be added directly to the solution in which embryos develop, simplifying drug administration and enabling rapid in vivo screening of test compounds4. Synthetic oligonucleotides (morpholinos), mutagenesis, zinc finger nuclease and transgenic approaches can be used to rapidly generate gene knockdown or mutation in zebrafish5-7. These properties afford zebrafish studies an unprecedented statistical power analysis advantage over rodents in the study of neurological disorders such as epilepsy. Because the "gold standard" for epilepsy research is to monitor and analyze the abnormal electrical discharges that originate in a central brain structure (i.e., seizures), a method to efficiently record brain activity in larval zebrafish is described here. This method is an adaptation of conventional extracellular recording techniques and allows for stable long-term monitoring of brain activity in intact zebrafish larvae. Sample recordings are shown for acute seizures induced by bath application of convulsant drugs and spontaneous seizures recorded in a genetically modified fish.

A simple method to record extracellular field potentials in the larval zebrafish forebrain is described. The method provides a robust in vivo read-out of seizure-like activity. This technique can be used with genetically modified zebrafish larvae carrying epilepsy-related genes or seizures evoked by administration of convulsant drugs.

Prosencéfalo electrofisiológico de grabación en larvas de pez cebra

Epilepsy affects nearly 3 million people in the United States and up to 50 million people worldwide. Defined as the occurrence of spontaneous unprovoked ...

Dissection and Lateral Mounting of Zebrafish Embryos: Analysis of Spinal Cord Development

The zebrafish spinal cord is an effective investigative model for nervous system research for several reasons. First, genetic, transgenic and gene knockdown approaches can be utilized to examine the molecular mechanisms underlying nervous system development. Second, large clutches of developmentally synchronized embryos provide large experimental sample sizes. Third, the optical clarity of the zebrafish embryo permits researchers to visualize progenitor, glial, and neuronal populations. Although zebrafish embryos are transparent, specimen thickness can impede effective microscopic visualization. One reason for this is the tandem development of the spinal cord and overlying somite tissue. Another reason is the large yolk ball, which is still present during periods of early neurogenesis. In this article, we demonstrate microdissection and removal of the yolk in fixed embryos, which allows microscopic visualization while preserving surrounding somite tissue. We also demonstrate semipermanent mounting of zebrafish embryos. This permits observation of neurodevelopment in the dorso-ventral and anterior-posterior axes, as it preserves the three-dimensionality of the tissue.

Developmental processes such as proliferation, patterning, differentiation, and axon guidance can be readily modeled in the zebrafish spinal cord. In this article, we describe a mounting procedure for zebrafish embryos, which optimizes visualization of these events.

La disección y de montaje lateral de embriones de pez cebra: Análisis para el Desarrollo de la médula espinal

The zebrafish spinal cord is an effective investigative model for nervous system research for several reasons. First, genetic, transgenic and gene ...

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

After a complete spinal cord injury, sea lampreys at first are paralyzed below the level of transection. However, they recover locomotion after several weeks, and this is accompanied by short distance regeneration (a few mm) of propriospinal axons and spinal-projecting axons from the brainstem. Among the 36 large identifiable spinal-projecting neurons, some are good regenerators and others are bad regenerators. These neurons can most easily be identified in wholemount CNS preparations. In order to understand the neuron-intrinsic mechanisms that favor or inhibit axon regeneration after injury in the vertebrates CNS, we determine differences in gene expression between the good and bad regenerators, and how expression is influenced by spinal cord transection. This paper illustrates the techniques for housing larval and recently transformed adult sea lampreys in fresh water tanks, producing complete spinal cord transections under microscopic vision, and preparing brain and spinal cord wholemounts for in situ hybridization. Briefly, animals are kept at 16&#160;&#176;C and anesthetized in 1% Benzocaine in lamprey Ringer. The spinal cord is transected with iridectomy scissors via a dorsal approach and the animal is allowed to recover in fresh water tanks at 23 &#176;C. For in situ hybridization, animals are reanesthetized and the brain and cord removed via a dorsal approach.

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

Lampreys recover locomotion after a complete spinal cord injury. However, some spinal-projecting neurons are good regenerators and others are not. This paper illustrates the techniques for housing sea lamprey larvae (and recently transformed adults), producing complete spinal cord transections and preparing wholemount brains and spinal cords for in situ hybridization.

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 ...

Diffusion Imaging in the Rat Cervical Spinal Cord

Magnetic resonance imaging (MRI) is the state of the art approach for assessing the status of the spinal cord noninvasively, and can be used as a diagnostic and prognostic tool in cases of disease or injury. Diffusion weighted imaging (DWI), is sensitive to the thermal motion of water molecules and allows for inferences of tissue microstructure. This report describes a protocol to acquire and analyze DWI of the rat cervical spinal cord on a small-bore animal system. It demonstrates an imaging setup for the live anesthetized animal and recommends a DWI acquisition protocol for high-quality imaging, which includes stabilization of the cord and control of respiratory motion. Measurements with diffusion weighting along different directions and magnitudes (b-values) are used. Finally, several mathematical models of the resulting signal are used to derive maps of the diffusion processes within the spinal cord tissue that provide insight into the normal cord and can be used to monitor injury or disease processes noninvasively.

The goal of this protocol is to obtain high-quality diffusion weighted magnetic resonance imaging (DWI) of the rat spinal cord for noninvasive characterization of tissue microstructure. This protocol describes optimizations of the MRI sequence, radiofrequency coil, and analysis methods to enable DWI images free from artifacts.

Imágenes de difusión en la médula espinal de rata Cervical

Magnetic resonance imaging (MRI) is the state of the art approach for assessing the status of the spinal cord noninvasively, and can be used as a ...

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 ...

Laminectomy and Spinal Cord Window Implantation in the Mouse

This protocol describes a method for spinal cord laminectomy and glass window implantation for in vivo imaging of the mouse spinal cord. An integrated digital vaporizer is utilized to achieve a stable plane of anesthesia at a low-flow rate of isoflurane. A single vertebral spine is removed, and a commercially available cover-glass is overlaid on a thin agarose bed. A 3D-printed plastic backplate is then affixed to the adjacent vertebral spines using tissue adhesive and dental cement. A stabilization platform is used to reduce motion artifact from respiration and heartbeat. This rapid and clamp-free method is well-suited for acute multi-photon fluorescence microscopy. Representative data are included for an application of this technique to two-photon microscopy of the spinal cord vasculature in transgenic mice expressing eGFP:Claudin-5 &#8212; a tight junction protein.

This protocol describes implantation of a glass window onto the spinal cord of a mouse to facilitate visualization by intravital microscopy.

Laminectomía e implantación de la ventana de la médula espinal en el ratón

This protocol describes a method for spinal cord laminectomy and glass window implantation for in vivo imaging of the mouse spinal cord. An integrated ...

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 ...