We are grateful for support from the NIH (Award numbers R00 NS072192 to M.K.L., HD029178 to A-S.L., and 2 RO1 NS032457 to C.A.W.). M.K.L. is the recipient of the Children's Hospital Boston Career Development Fellowship/Harvard Medical School Shore Fellowship and a Fellow of the Alfred P. Sloan Foundation. C.A.W. is an Investigator of the Howard Hughes Medical Institute.

1. Embryo Isolation/Preparation
This technique can be used for mouse or rat. In this protocol we demonstrate the CSF collection technique and cerebral cortical explant dissection with mouse embryonic brain. We will comment on any important differences for rats versus mice that exist within the general techniques. For the embryonic age staging system, E1 is classified as the day of the plug for rats, and E0.5 is classified as the day of the plug for mice.
<ol>
 <li>Prepare a micro-dissection ...

<ol>
	<li>Dziegielewska, K. M., Evans, C. A., Lai, P. C., Lorscheider, F. L., Malinowska, D. H., Mollgard, K., Saunders, N. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteins+in+cerebrospinal+fluid+and+plasma+of+fetal+rats+during+development.">Proteins in cerebrospinal fluid and plasma of fetal rats during development.</a> Developmental Biology. 83 (1), 193-200 (1981).</li><li>Gato, A., Martin, P., Alonso, M. I., Martin, C., Pulgar, M. A., Moro, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+cerebro-spinal+fluid+protein+composition+in+early+developmental+stages+in+chick+embryos.">Analysis of cerebro-spinal fluid protein composition in early developmental stages in chick embryos.</a> Journal of Experimental Zoology. Part A, Comparative Experimental Biology. 301 (4), 280-289 (2004).</li><li>Gato, A., Moro, J. A., Alonso, M. I., Bueno, D., Mano, D. L., Martin, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Embryonic+cerebrospinal+fluid+regulates+neuroepithelial+survival,+proliferation,+and+neurogenesis+in+chick+embryos.">Embryonic cerebrospinal fluid regulates neuroepithelial survival, proliferation, and neurogenesis in chick embryos.</a> The Anatomical Record. Part A, Discoveries in Molecular, Cellular, and Evolutionary Biology. 284 (1), 475-484 (2005).</li><li>Parada, C., Gato, A., Aparicio, M., Bueno, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteome+analysis+of+chick+embryonic+cerebrospinal+fluid.">Proteome analysis of chick embryonic cerebrospinal fluid.</a> Proteomics. 6 (1), 312-320 (2006).</li><li>Parada, C., Gato, A., Bueno, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mammalian+embryonic+cerebrospinal+fluid+proteome+has+greater+apolipoprotein+and+enzyme+pattern+complexity+than+the+avian+proteome.">Mammalian embryonic cerebrospinal fluid proteome has greater apolipoprotein and enzyme pattern complexity than the avian proteome.</a> Journal of Proteome Research. 4 (6), 2420-2428 (2005).</li><li>Zappaterra, M. D., Lisgo, S. N., Lindsay, S., Gygi, S. P., Walsh, C. A., Ballif, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparative+proteomic+analysis+of+human+and+rat+embryonic+cerebrospinal+fluid.">A comparative proteomic analysis of human and rat embryonic cerebrospinal fluid.</a> Journal of Proteome Research. 6 (9), 3537-3548 (2007).</li><li>Desmond, M. E., Jacobson, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Embryonic+brain+enlargement+requires+cerebrospinal+fluid+pressure.">Embryonic brain enlargement requires cerebrospinal fluid pressure.</a> Developmental Biology. 57 (1), 188-198 (1977).</li><li>Lehtinen, M. K., Walsh, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurogenesis+at+the+brain-cerebrospinal+fluid+interface.">Neurogenesis at the brain-cerebrospinal fluid interface.</a> Annual Review of Cell and Developmental Biology. 27, 653-679 (2011).</li><li>Lehtinen, M. K., Zappaterra, M. W., Chen, X., Yang, Y. J., Hill, A. D., Lun, M., Maynard, T., Gonzalez, D., Kim, S., Ye, P., 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=The+cerebrospinal+fluid+provides+a+proliferative+niche+for+neural+progenitor+cells.">The cerebrospinal fluid provides a proliferative niche for neural progenitor cells.</a> Neuron. 69 (5), 893-905 (2011).</li><li>Martin, C., Alonso, M. I., Santiago, C., Moro, J. A., De la Mano, A., Carretero, R., Gato, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+embryonic+brain+development+in+rats+requires+the+trophic+influence+of+cerebrospinal+fluid.">Early embryonic brain development in rats requires the trophic influence of cerebrospinal fluid.</a> International Journal of Developmental Neuroscience: The Official Journal of the International Society for Developmental Neuroscience. 27 (7), 733-7340 (2009).</li><li>Martin, C., Bueno, D., Alonso, M. I., Moro, J. A., Callejo, S., Parada, C., Martin, P., Carnicero, E., Gato, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FGF2+plays+a+key+role+in+embryonic+cerebrospinal+fluid+trophic+properties+over+chick+embryo+neuroepithelial+stem+cells.">FGF2 plays a key role in embryonic cerebrospinal fluid trophic properties over chick embryo neuroepithelial stem cells.</a> Developmental Biology. 297 (2), 402-416 (2006).</li><li>Zappaterra, M. W., Lehtinen, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cerebrospinal+fluid:+regulator+of+neurogenesis,+behavior,+and+beyond.">The cerebrospinal fluid: regulator of neurogenesis, behavior, and beyond.</a> Cellular and Molecular Life Sciences: CMLS. 69 (17), 2863-2878 (2012).</li></ol>

The described method for ventricular CSF collection has yielded relatively pure samples of embryonic CSF with stable protein composition and consistent activity in a number of cellular assays 9 . With a good collection technique and litter size of ten E14.5 mice, one can expect to collect 10-15 &mu;l of CSF, and from a litter of E16 rats, one can expect to collect about 50-90 &mu;l of CSF. This collection technique minimizes contamination from blood and tissue, by careful observation, centrifugation, and...

The CSF is a complex fluid that bathes the developing neuroepithelium 1-6 and provides essential pressure 7 and growth promoting cues for the developing brain 8-12. To study the CSF over the course of brain development, we developed techniques to isolate ventricular CSF from developing rat or mouse embryos during various stages of development 6,9. Previous methods of isolation included using a glass micro-needle and isolating the CSF using a micro-injector 1,2. Our method utilizes a glass micro-capillary pipette whose tip has been pulled to create an ultrafine point for improved tissue penetration. The glass micro-capillary pipette is connected to an aspirator so that ventricular CSF collection can be controlled with gentle changes in pressure. To investigate the stem cell influences of CSF signals, we dissect cerebral cortical explants, place them on polycarbonate membranes, and float them on appropriate culture medium supplemented with CSF samples 9. With this technique, reduced volumes of media are sufficient to culture the tissue, allowing for an efficient use of CSF 9.

<table border="1">
 <tbody>
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 <td>Name of Reagent/Material</td>
 <td>Company</td>
 <td>Catalog Number</td>
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 <tr>
 <td>Wiretrop II capillary needles</td>
 <td>Drummond Scientific</td>
 <td>#5-000-2020</td>
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 <td>Sylgard</td>
 <td>Ellsworth Adhesives</td>
 <td>#184 SIL ELAST kit</td>
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 <td>Aspirator tube assembly</td>
 <td>Sigma</td>
 <td>#A5177-5EA</td>
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 <td>Disposable filter</td>
 <td>Venturi or local pharmacy</td>
 <td>not available</td>
 <td>Standard cigarette filter</td>
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 <td>Roundstock opthalmic knife (15 degree stab knife)</td>
 <td>World Precision Instruments, Inc.</td>
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 <td>35mm glass bottomed culture dish</td>
 <td>MatTek Corp.</td>
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 <td>Platinum-iridium wire</td>
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 <td>Hanks Balanced Salt Solution</td>
 <td>Fisher Scientific</td>
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 <td>Iridectomy Scissors</td>
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</table>

isolation of cerebrospinal fluid from rodent embryos for use with dissected cerebral cortical explants

The CSF is a complex fluid with a dynamically varying proteome throughout development and in adulthood. During embryonic development, the nascent CSF differentiates from the amniotic fluid upon closure of the anterior neural tube. CSF volume then increases over subsequent days as the neuroepithelial progenitor cells lining the ventricles and the choroid plexus generate CSF. The embryonic CSF contacts the apical, ventricular surface of the neural stem cells of the developing brain and spinal cord. CSF provides crucial fluid pressure for the expansion of the developing brain and distributes important growth promoting factors to neural progenitor cells in a temporally-specific manner. To investigate the function of the CSF, it is important to isolate pure samples of embryonic CSF without contamination from blood or the developing telencephalic tissue. Here, we describe a technique to isolate relatively pure samples of ventricular embryonic CSF that can be used for a wide range of experimental assays including mass spectrometry, protein electrophoresis, and cell and primary explant culture. We demonstrate how to dissect and culture cortical explants on porous polycarbonate membranes in order to grow developing cortical tissue with reduced volumes of media or CSF. With this method, experiments can be performed using CSF from varying ages or conditions to investigate the biological activity of the CSF proteome on target cells.

The CSF collection should yield a clear, transparent fluid. There should be no evidence of contamination from blood, as demonstrated by a red or yellow tinged fluid in the aspirate and in the Eppendorf tube. There should also be no evidence of tissue in the aspirate and Eppendorf tube. When the CSF is centrifuged, one can also assess the CSF microscopically to ensure that there is no contamination. If there are signs of contamination, the CSF should be discarded. From one E14.5 mouse litter, one can anticipate co...

Watch this Scientific Journal Video about Isolation of Cerebrospinal Fluid from Rodent Embryos for use with Dissected Cerebral Cortical Explants at JoVE.com

Isolation of Cerebrospinal Fluid from Rodent Embryos for use with Dissected Cerebral Cortical Explants

The ventricular cerebrospinal fluid (CSF) bathes the neuroepithelial and cerebral cortical progenitor cells during early brain development in the embryo. Here we describe the method developed to isolate ventricular CSF from rodent embryos of different ages in order to investigate its biological function. In addition, we demonstrate our cerebral cortical explant dissection and culture technique that allows for explant growth with minimal volumes of culture medium or CSF.

The CSF is a complex fluid with a dynamically varying proteome throughout development and in adulthood. During embryonic development, the nascent CSF ...

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Neuroscience

22.8K vistas.  VA Greater Los Angeles Healthcare System. El líquido ventricular cefalorraquídeo (LCR) baña las células de la corteza cerebral y neuroepitelial progenitoras durante el desarrollo temprano del cerebro del embrión. Aquí se describe el método desarrollado para aislar CSF ventricular de embriones de roedores de diferentes edades con el fin de investigar su función biológica. Además, demostramos nuestra disección cerebral cortical explantes y técnica de cultivo que permita el crecimiento de explantes con v...