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 dish with Sylgard Silicone Elastomer. Sylgard 184 Silicone Elastomer is supplied as a two part liquid component, Part A and Part B. Part A and Part B are mixed in a 10:1 ratio by weight or volume. After the liquid components are mixed, pour the sylgard elastomer into a Petri dish to cover the entire surface of the dish. Some air bubbles may be present that will dissipate during the curing process. Place the Petri dish lid on and allow the elastomer to cure. The elastomer can be cured at room temperature for 24 hr, or at higher temperatures (e.g. 37 &deg;C) for faster curing. Once the liquid components solidify, the dissection dish is ready to use. The dish can be used repeatedly for multiple experiments, provided that it is cleaned well following the procedure.</li>
 <li>Preparation of the micro-capillary pipette (needle). Micro-capillary pipettes are prepared by applying heat and pull using a Narishige PC-10 vertical micropipette puller with the following settings: One step pull; Heater #2 set to 58; 100 g pull weight. The fine tip of the micropipette is carefully snapped off using fine #55 forceps. The resulting average inner diameter of the needle is 85 &mu;m.</li>
 <li>Prepare the aspirator assembly for CSF aspiration. Insert micro-plunger provided with micro-capillary pipettes into the capillary needle. Alternatively, attach a plastic disposable filter to the end of the aspirator tube assembly that is connected to the micro-capillary pipette. Push the needle through the gasket into position on the opposite end of the aspirator assembly.</li>
 <li>Transfer embryo isolated from the litter to a micro-dissection dish prepared with Sylgard.</li>
 <li>Remove the extra-embryonic membranes and tissues so that the embryo is clearly exposed. Each tissue layer-first the uterine wall and then the decidua-can be dissected using fine iridectomy scissors (i.e. Fine Science Tools # 15000-02). At each implantation site, first the uterine wall, then the decidua can be incised parallel to the long axis of the uterus, and the incision can then be opened further using fine forceps. The decidua can be removed after a similar incision, exposing the fetal membranes. Care should be exercised so that the fetal membranes are not incised or punctured.</li>
 <li>Wash with sterile Hanks balanced salt solution (HBSS) and remove excess fluid from the surrounding embryo using a pipette as well as a kimwipe or filter paper cut into triangles.</li>
</ol>
2. Ventricular CSF Collection
<ol>
 <li>Visualize embryo under the dissection microscope: for mouse, the embryo should be laying on its side, such that one has a sagittal view of the developing embryo. With rat embryos E16 or older, position the embryo on its dorsal spinal column, along its longest planar dimension, from a cranial to caudal direction, as if the embryo is lying on its back. In this manner the CSF can be collected from both right and left lateral ventricle.</li>
 <li>Steadily insert the micro-capillary pipette into the lateral ventricle, mesencephalic ventricle, or cisterna magna, attempting not to contact the neuroepithelial cells once the pipette has been inserted. For mouse embryos E14.5 or older, the CSF can be aspirated from the right ventricle and then the needle removed and inserted into the left ventricle. Because of the patency of the ventricles and the neural tube in embryos younger than E14.5, the entire CSF volume can often be aspirated from the lateral ventricles with a single needle insertion. However, this is not always the case as developmental times and patency of the connecting ventricles may vary slightly, and therefore, the micro-capillary pipette can also be inserted into the cisterna magna to collect the maximal CSF volume.</li>
 <li>Once the micro-capillary pipette is inserted into the lateral ventricle, mesencephalic ventricle, or cisterna magna, carefully and gently begin aspirating the CSF into the pipette, using either the micro-plunger to create negative pressure and aspirate the CSF, or by providing a gentle negative pressure created by mouth such that CSF starts to gently flow into the micro-capillary pipette in a slow and controlled fashion. We recommend that the viewer checks with their own local officials regarding institutional policies on these approaches.</li>
 <li>Continue to apply negative pressure and collect the CSF into the micro-capillary pipette. In both mouse and rat embryos of E16.5/E17 or younger, it is possible to observe the ventricle collapse slightly by the appearance of a divot forming on the side of the head that the micro-capillary pipette is in. In older embryos, due to the larger size of the brain, it may not be possible to observe the head collapsing.</li>
 <li>Stop applying pressure and gently remove the micro-capillary pipette from the lateral ventricle.</li>
 <li>Gently expel the CSF sample into an Eppendorf tube that has been chilled on ice.</li>
 <li>Continue collecting the CSF from an entire litter of animals and pool the samples into the same tube.</li>
 <li>Centrifuge at 10,000 x g at 4 &deg;C for 10 min to remove any contaminating cells.</li>
 <li>Analyze the samples for any signs of contaminating neuroepithelial cells or red blood cells. Signs of contamination are usually indicated by the fluid appearing cloudy or red/pink, or the presence of a pellet with a blood tinged spot. After centrifugation, the CSF can be analyzed microscopically for any evidence of cells or cellular debris. If there are signs of contamination the fluid should be discarded. As an additional control, the pellet content may also be stained for cells. A clean CSF sample can be used for cell culture, cortical culture, spectrometry, western blot, ELISA, and other assays. The clear CSF should be transferred to a new sterile Eppendorf tube. The sample can now be used for analysis, pooled with other samples, or snap frozen with liquid nitrogen and stored at -80 &deg;C. The freezing and thawing of small samples of fluid may result in a small volume decrease and changes in protein concentration. This can be avoided by freeze drying the samples.</li>
</ol>
3. Cortical Explant Dissection
<ol>
 <li>Transfer the E14.5 embryo isolated from the litter onto a micro-dissection dish prepared with Sylgard.</li>
 <li>Remove embryo from extra-embryonic membranes and tissues as described in Step 1.5.</li>
 <li>Wash with sterile Hanks balanced salt solution (HBSS) and remove excess fluid from the surrounding embryo using a pipette.</li>
 <li>Dissect through the cervical region separating the head from the rest of the embryo (Figure 1A).</li>
 <li>Using a fine scalpel (ophthalmic knife), cut down the midline of the scalp. Grasp each side of this incision with fine forceps and remove the skin. Next, use iridectomy scissors to make an incision that runs the length of midline of the developing cranium. Subsequently, make two additional incisions, approximately 1/3 of the distance from the anterior and posterior ends of the developing skull. Use fine forceps to grasp the "flaps" of cranium that result from this part of the dissection, and remove the developing skull tissue, exposing the cortex (Figure 1B).</li>
 <li>Using the scalpel bisect the brain along the midline in the mid-sagital plane, separating the right and left cortical hemispheres (Figures 1B, C). The pia and arachnoid are left attached to the cortex, and the dura is removed together with the developing skull.</li>
 <li>Prepare each cortical hemisphere separately. Place the hemisphere medial side up so that you can see the ganglionic eminence and the developing cortex (Figures 1C, D).</li>
 <li>Using the scalpel, make a coronal incision through the cortical neuroepithelium caudal to the developing olfactory bulb. This incision should begin at the anterior boundary of the lateral and medial ganglionic eminences, and extend through the anterior cingulate region of the developing cortical rudiment (Figure 1E).</li>
 <li>Make another coronal incision just caudal to the posterior boundary of the lateral ganglionic eminence (Figure 1F). This incision should also extend from the lateral boundary of the ganglionic eminence to the medial wall of the developing cortical rudiment.</li>
 <li>Retract the cortical "flap" created by the two incisions made in steps 3.7 and 3.8, using a scalpel or gentle pressure from a stream of HBSS delivered with a 200 &mu;l pipettor to avoid mechanical damage to the cortex. Then make a transverse incision along the boundary separating the lateral ganglionic eminence from the developing cortex (Figures 1G, H). Then, dissect away the developing hippocampus and cortical hem of the medial telencephalon, at the apex of the neocortex where the lateral cortical surface meets the interhemispheric wall.</li>
 <li>Make a transverse incision along the boundary separating the lateral ganglionic eminence from the developing cortex (Figure 1H).</li>
 <li>Remove any extra dissected tissue that is on the Sylgard plate from the dissected cortical explant. One can use gentle pipetting with fresh HBSS buffer to pipette away any extra dissected tissue. The dissected cortex is now with meningeal side facing down (Figure 1I).</li>
</ol>
4. Transferring of Cortical Explant
<ol>
 <li>Prepare a platinum wire loop connected to a glass pipette. Heat the glass pipette with a folded platinum wire inserted in the end of the glass pipette. By twisting the end of the platinum wire loop, the size of the loop can be increased or decreased, and the loop can be shaped to fit the size of the explant desired. (This can be prepared beforehand and reused.)</li>
 <li>Heat the end of the platinum wire to sterilize the loop.</li>
 <li>Isolate the dissected cortical explant and remove the extra HBSS media by gentle pipetting, leaving a small amount to use with the wire loop.</li>
 <li>Place a 1 cm polycarbonate membrane in a 4 cm diameter imaging dish.</li>
 <li>Using the side of the platinum wire loop, gently flip the cortex so that the meningeal side is facing up.</li>
 <li>Lift the cortical explant off the dissection dish, by placing the explant in the middle of the loop and using the intrinsic hydrostatic forces to lift the explant on a flat plane.</li>
 <li>Gently place the explant on the polycarbonate membrane, and lift the platinum wire loop away such that the explant remains on the membrane on a flat plane with the ventricular surface making contact with membrane.</li>
 <li>Gently lift the membrane and pipette 50 &mu;l of CSF or other media under the membrane.</li>
 <li>Cover the imaging dish, place it in a humidified secondary container, and incubate at 37 &deg;C in 5% CO2 for 24 hr to support continued cell proliferation and explant growth. Figure 2 depicts a schematic of the final cortical explant dish preparation.</li>
</ol>

<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. 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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 authors declare that they have no competing financial interests.

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>
 <tr>
 <td>Name of Reagent/Material</td>
 <td>Company</td>
 <td>Catalog Number</td>
 <td>Comments</td>
 </tr>
 <tr>
 <td>Wiretrop II capillary needles</td>
 <td>Drummond Scientific</td>
 <td>#5-000-2020</td>
 <td></td>
 </tr>
 <tr>
 <td>Sylgard</td>
 <td>Ellsworth Adhesives</td>
 <td>#184 SIL ELAST kit</td>
 <td></td>
 </tr>
 <tr>
 <td>Aspirator tube assembly</td>
 <td>Sigma</td>
 <td>#A5177-5EA</td>
 <td></td>
 </tr>
 <tr>
 <td>Disposable filter</td>
 <td>Venturi or local pharmacy</td>
 <td>not available</td>
 <td>Standard cigarette filter</td>
 </tr>
 <tr>
 <td>Roundstock opthalmic knife (15 degree stab knife)</td>
 <td>World Precision Instruments, Inc.</td>
 <td>#500250</td>
 <td></td>
 </tr>
 <tr>
 <td>35mm glass bottomed culture dish</td>
 <td>MatTek Corp.</td>
 <td>#P35G-1.5-14-C</td>
 <td></td>
 </tr>
 <tr>
 <td>Platinum-iridium wire</td>
 <td>Tritech Research</td>
 <td>#PT-9010-010-3FT</td>
 <td></td>
 </tr>
 <tr>
 <td>Nuclepore Track-Etch Membrane</td>
 <td>Whatman</td>
 <td>#09-300-57</td>
 <td></td>
 </tr>
 <tr>
 <td>Hanks Balanced Salt Solution</td>
 <td>Fisher Scientific</td>
 <td>#SH30031.FS</td>
 <td></td>
 </tr>
 <tr>
 <td>Iridectomy Scissors</td>
 <td>Fine Science Tools</td>
 <td>#15000-02</td>
 <td></td>
 </tr>
 </tbody>
</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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22.9K 次观看.  VA Greater Los Angeles Healthcare System. 心室脑脊液（CSF）沐浴在早期的大脑发育在胚胎神经上皮和大脑皮质祖细胞。在这里，我们描述的方法，从不同年龄层的啮齿动物胚胎隔离室CSF，为了研究其生物学功能。此外，我们展示了我们的脑皮质外植体的解剖和文化的技术，可以为外植体生长的培养基或CSF以最小的体积。

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

Isolation and Culture of Mouse Cortical Astrocytes

Astrocytes are an abundant cell type in the mammalian brain, yet much remains to be learned about their molecular and functional characteristics. In vitro astrocyte cell culture systems can be used to study the biological functions of these glial cells in detail. This video protocol shows how to obtain pure astrocytes by isolation and culture of mixed cortical cells of mouse pups. The method is based on the absence of viable neurons and the separation of astrocytes, oligodendrocytes and microglia, the three main glial cell populations of the central nervous system, in culture. Representative images during the first days of culture demonstrate the presence of a mixed cell population and indicate the timepoint, when astrocytes become confluent and should be separated from microglia and oligodendrocytes. Moreover, we demonstrate purity and astrocytic morphology of cultured astrocytes using immunocytochemical stainings for well established and newly described astrocyte markers. This culture system can be easily used to obtain pure mouse astrocytes and astrocyte-conditioned medium for studying various aspects of astrocyte biology.

Astrocytes have been recognized to be versatile cells participating in fundamental biological processes that are essential for normal brain development and function, and central nervous system repair. Here we present a rapid procedure to obtain pure mouse astrocyte cultures to study the biology of this major class of central nervous system cells.

Astrocytes  are an abundant cell type in the mammalian brain, yet much remains to be  learned about their molecular and functional characteristics. In ...

Ex utero Electroporation and Whole Hemisphere Explants: A Simple Experimental Method for Studies of Early Cortical Development

Cortical development involves complex interactions between neurons and non-neuronal elements including precursor cells, blood vessels, meninges and associated extracellular matrix. Because they provide a suitable organotypic environment, cortical slice explants are often used to investigate those interactions that control neuronal differentiation and development. Although beneficial, the slice explant model can suffer from drawbacks including aberrant cellular lamination and migration. Here we report a whole cerebral hemisphere explant system for studies of early cortical development that is easier to prepare than cortical slices and shows consistent organotypic migration and lamination. In this model system, early lamination and migration patterns proceed normally for a period of two days in vitro, including the period of preplate splitting, during which prospective cortical layer six forms. We then developed an ex utero electroporation (EUEP) approach that achieves ~80% success in targeting GFP expression to neurons developing in the dorsal medial cortex.
The whole hemisphere explant model makes early cortical development accessible for electroporation, pharmacological intervention and live imaging approaches. This method avoids the survival surgery required of in utero electroporation (IUEP) approaches while improving both transfection and areal targeting consistency. This method will facilitate experimental studies of neuronal proliferation, migration and differentiation.

Ex utero Electroporation and Whole Hemisphere Explants: A Simple Experimental Method for Studies of Early Cortical Development

This protocol describes an improved explant procedure that involves ex utero electroporation, dissection and culture of entire cerebral hemispheres from the embryonic mouse. The preparation facilitates pharmacological studies and assays of gene function during early cortical development.

Cortical development involves complex interactions between neurons and non-neuronal elements including precursor cells, blood vessels, meninges and ...

Isolation and Culture of Dissociated Sensory Neurons From Chick Embryos

Neurons are multifaceted cells that carry information essential for a variety of functions including sensation, motor movement, learning, and memory. Studying neurons in vivo can be challenging due to their complexity, their varied and dynamic environments, and technical limitations. For these reasons, studying neurons in vitro can prove beneficial to unravel the complex mysteries of neurons. The well-defined nature of cell culture models provides detailed control over environmental conditions and variables. Here we describe how to isolate, dissociate, and culture primary neurons from chick embryos. This technique is rapid, inexpensive, and generates robustly growing sensory neurons. The procedure consistently produces cultures that are highly enriched for neurons and has very few non-neuronal cells (less than 5%). Primary neurons do not adhere well to untreated glass or tissue culture plastic, therefore detailed procedures to create two distinct, well-defined laminin-containing substrata for neuronal plating are described. Cultured neurons are highly amenable to multiple cellular and molecular techniques, including co-immunoprecipitation, live cell imagining, RNAi, and immunocytochemistry. Procedures for double immunocytochemistry on these cultured neurons have been optimized and described here.

Cell culture models provide detailed control over environmental conditions and thus provide a powerful platform to elucidate numerous aspects of neuronal cell biology. We describe a rapid, inexpensive, and reliable method to isolate, dissociate, and culture sensory neurons from chick embryos. Details of substrata preparation and immunocytochemistry are also provided.

Neurons are multifaceted cells that carry information essential for a variety of functions including sensation, motor movement, learning, and memory. ...

Isolation and Cannulation of Cerebral Parenchymal Arterioles

Intracerebral parenchymal arterioles (PAs), which include parenchymal arterioles, penetrating arterioles and pre-capillary arterioles, are high resistance blood vessels branching out from pial arteries and arterioles and diving into the brain parenchyma. Individual PA perfuse a discrete cylindrical territory of the parenchyma and the neurons contained within. These arterioles are a central player in the regulation of cerebral blood flow both globally (cerebrovascular autoregulation) and locally (functional hyperemia). PAs are part of the neurovascular unit, a structure that matches regional blood flow to metabolic activity within the brain and also includes neurons, interneurons, and astrocytes. Perfusion through PAs is directly linked to the activity of neurons in that particular territory and increases in neuronal metabolism lead to an augmentation in local perfusion caused by dilation of the feed PA. Regulation of PAs differs from that of better-characterized pial arteries. Pressure-induced vasoconstriction is greater in PAs and vasodilatory mechanisms vary. In addition, PAs do not receive extrinsic innervation from perivascular nerves &#8212; innervation is intrinsic and indirect in nature through contact with astrocytic endfeet. Thus, data regarding contractile regulation accumulated by studies using pial arteries does not directly translate to understanding PA function. Further, it remains undetermined how pathological states, such as hypertension and diabetes, affect PA structure and reactivity. This knowledge gap is in part a consequence of the technical difficulties pertaining to PA isolation and cannulation. In this manuscript we present a protocol for isolation and cannulation of rodent PAs. Further, we show examples of experiments that can be performed with these arterioles, including agonist-induced constriction and myogenic reactivity. Although the focus of this manuscript is on PA cannulation and pressure myography, isolated PAs can also be used for biochemical, biophysical, molecular, and imaging studies.

This manuscript describes a simple and reproducible protocol for isolation of intracerebral arterioles (a group of blood vessels encompassing parenchymal arterioles, penetrating arterioles and pre-capillary arterioles) from mice, to be used in pressure myography, immunofluorescence, biochemistry, and molecular studies.

Intracerebral parenchymal arterioles (PAs), which include parenchymal arterioles, penetrating arterioles and pre-capillary arterioles, are high resistance ...

Sample Preparation for Endopeptidomic Analysis in Human Cerebrospinal Fluid

This protocol describes a method developed to identify endogenous peptides in human cerebrospinal fluid (CSF). For this purpose, a previously developed method based on molecular weight cut-off (MWCO) filtration and mass spectrometric analysis was combined with an offline high-pH reverse phase HPLC pre-fractionation step.
Secretion into CSF is the main pathway for removal of molecules shed by cells of the central nervous system. Thus, many processes in the central nervous system are reflected in the CSF, rendering it a valuable diagnostic fluid. CSF has a complex composition, containing proteins that span a concentration range of 8 - 9 orders of magnitude. Besides proteins, previous studies have also demonstrated the presence of a large number of endogenous peptides. While less extensively studied than proteins, these may also hold potential interest as biomarkers.
Endogenous peptides were separated from the CSF protein content through MWCO filtration. By removing a majority of the protein content from the sample, it is possible to increase the sample volume studied and thereby also the total amount of the endogenous peptides. The complexity of the filtrated peptide mixture was addressed by including a reverse phase (RP) HPLC pre-fractionation step at alkaline pH prior to LC-MS analysis. The fractionation was combined with a simple concatenation scheme where 60 fractions were pooled into 12, analysis time consumption could thereby be reduced while still largely avoiding co-elution.
Automated peptide identification was performed by using three different peptide/protein identification software programs and subsequently combining the results. The different programs were complementary rather than comparable with less than 15% of the identifications overlapped between the three.

A method for mass spectrometric analysis of endogenous peptides in human cerebrospinal fluid (CSF) is presented. By employing molecular weight cut-off filtration, chromatographic pre-fractionation, mass spectrometric analysis and a subsequent combination of peptide identification strategies, it was possible to expand the known CSF peptidome nearly ten-fold compared to previous studies.

This protocol describes a method developed to identify endogenous peptides in human cerebrospinal fluid (CSF). For this purpose, a previously developed ...

An Improved Method for Collection of Cerebrospinal Fluid from Anesthetized Mice

The cerebrospinal fluid (CSF) is a valuable body fluid for analysis in neuroscience research. It is one of the fluids in closest contact with the central nervous system and thus, can be used to analyze the diseased state of the brain or spinal cord without directly accessing these tissues. However, in mice it is difficult to obtain from the cisterna magna due to its closeness to blood vessels, which often contaminate samples. The area for CSF collection in mice is also difficult to dissect to and often only small samples are obtained (maximum of 5-7 &#181;L or less). This protocol describes in detail a technique that improves on current methods of collection to minimize contamination from blood and allow for the abundant collection of CSF (on average 10-15 &#181;L can be collected). This technique can be used with other dissection methods for tissue collection from mice, as it does not impact any tissues during CSF extraction. Thus, the brain and spinal cord are not affected with this technique and remain intact. With greater CSF sample collection and purity, more analyses can be used with this fluid to further aid neuroscience research and better understand diseases affecting the brain and spinal cord.

This protocol describes an improved technique for the abundant collection of cerebrospinal fluid (CSF) with no contamination from blood. With greater sample collection and purity, more analyses can be performed using CSF to further our understanding of diseases that affect the brain and spinal cord.

The cerebrospinal fluid (CSF) is a valuable body fluid for analysis in neuroscience research. It is one of the fluids in closest contact with the central ...

Isolation of Cerebral Capillaries from Fresh Human Brain Tissue

Understanding blood-brain barrier function under physiological and pathophysiological conditions is critical for the development of new therapeutic strategies that hold the promise to enhance brain drug delivery, improve brain protection, and treat brain disorders. However, studying the human blood-brain barrier function is challenging. Thus, there is a critical need for appropriate models. In this regard, brain capillaries isolated from human brain tissue represent a unique tool to study barrier function as close to the human in vivo situation as possible. Here, we describe an optimized protocol to isolate capillaries from human brain tissue at a high yield and with consistent quality and purity. Capillaries are isolated from fresh human brain tissue using mechanical homogenization, density-gradient centrifugation, and filtration. After the isolation, the human brain capillaries can be used for various applications including leakage assays, live cell imaging, and immune-based assays to study protein expression and function, enzyme activity, or intracellular signaling. Isolated human brain capillaries are a unique model to elucidate the regulation of the human blood-brain barrier function. This model can provide insights into central nervous system (CNS) pathogenesis, which will help the development of therapeutic strategies for treating CNS disorders.

Isolated brain capillaries from human brain tissue can be used as a preclinical model to study barrier function under physiological and pathophysiological conditions. Here, we present an optimized protocol to isolate brain capillaries from fresh human brain tissue.

Understanding blood-brain barrier function under physiological and pathophysiological conditions is critical for the development of new therapeutic ...

Rat Model of Widespread Cerebral Cortical Demyelination Induced by an Intracerebral Injection of Pro-Inflammatory Cytokines

Multiple sclerosis (MS) is the most common immune-mediated disease of the central nervous system (CNS) and progressively leads to physical disability and death, caused by white matter lesions in the spinal cord and cerebellum, as well as by demyelination in grey matter. Whilst conventional models of experimental allergic encephalomyelitis are suitable for the investigation of the cell-mediated inflammation in the spinal and cerebellar white matter, they fail to address grey matter pathologies. Here, we present the experimental protocol for a novel rat model of cortical demyelination allowing the investigation of the pathological and molecular mechanisms leading to cortical lesions. The demyelination is induced by an immunization with low-dose myelin oligodendrocyte glycoprotein (MOG) in an incomplete Freund&#39;s adjuvant followed by a catheter-mediated intracerebral delivery of pro-inflammatory cytokines. The catheter, moreover, enables multiple rounds of demyelination without causing injection-induced trauma, as well as the intracerebral delivery of potential therapeutic drugs undergoing a preclinical investigation. The method is also ethically favorable as animal pain and distress or disability are controlled and relatively minimal. The expected timeframe for the implementation of the entire protocol is around 8 - 10 weeks.

The protocol presented here allows the reproduction of a widespread grey matter demyelination of both cortical hemispheres in adult male Dark Agouti rats. The method comprises of intracerebral implantation of a catheter, subclinical immunization against myelin oligodendrocyte glycoprotein, and intracerebral injection of a pro-inflammatory cytokine mixture through the implanted catheter.

Multiple sclerosis (MS) is the most common immune-mediated disease of the central nervous system (CNS) and progressively leads to physical disability and ...

Effects of Blast-induced Neurotrauma on Pressurized Rodent Middle Cerebral Arteries

Though there have been studies on the histopathological and behavioral effects of blast exposure, fewer have been dedicated to blast&#39;s cerebral vascular effects. Impact (i.e., non-blast) traumatic brain injury (TBI) is known to decrease pressure autoregulation in the cerebral vasculature in both humans and experimental animals. The hypothesis that blast-induced traumatic brain injury (bTBI), like impact TBI, results in impaired cerebral vascular reactivity was tested by measuring myogenic dilatory responses to reduced intravascular pressure in rodent middle cerebral arterial (MCA) segments from rats subjected to mild bTBI using an Advanced Blast Simulator (ABS) shock tube. Adult, male Sprague-Dawley rats were anesthetized, intubated, ventilated and prepared for Sham bTBI (identical manipulation and anesthesia except for blast injury) or mild bTBI. Rats were randomly assigned to receive Sham bTBI or mild bTBI followed by sacrifice 30 or 60 min post-injury. Immediately after bTBI, righting reflex (RR) suppression times were assessed, euthanasia at the time points post-injury was completed, the brain was harvested and the individual MCA segments were collected, mounted and pressurized. As the intraluminal pressure perfused through the arterial segments was reduced in 20 mmHg increments from 100 to 20 mmHg, MCA diameters were measured and recorded. With decreasing intraluminal pressure, MCA diameters steadily increased significantly above baseline in the Sham bTBI groups while MCA dilator responses were significantly reduced (p &#60; 0.05) in both bTBI groups as evidenced by the impaired, smaller MCA diameters recorded for the bTBI groups. In addition, RR suppression in the bTBI groups was significantly (p &#60; 0.05) higher than in the Sham bTBI groups. MCA&#39;s collected from the Sham bTBI groups exhibited typical vasodilatory properties to decreases in intraluminal pressure while MCA&#39;s collected following bTBI exhibited significantly impaired myogenic vasodilatory responses to reduced pressure that persisted for at least 60 min after bTBI.

Here, we present a protocol to describe methods for ex vivo vascular reactivity determination following a primary blast traumatic brain injury (bTBI) using isolated, pressurized, rodent middle cerebral arterial (MCA) segments. bTBI induction is accomplished using a shock tube, also known as an Advanced Blast Simulator (ABS) device.

Though there have been studies on the histopathological and behavioral effects of blast exposure, fewer have been dedicated to blast&#39;s cerebral ...

In Vivo Imaging of Cerebrospinal Fluid Transport through the Intact Mouse Skull using Fluorescence Macroscopy

Cerebrospinal fluid (CSF) flow in rodents has largely been studied using ex vivo quantification of tracers. Techniques such as two-photon microscopy and magnetic resonance imaging (MRI) have enabled in vivo quantification of CSF flow but they are limited by reduced imaging volumes and low spatial resolution, respectively. Recent work has found that CSF enters the brain parenchyma through a network of perivascular spaces surrounding the pial and penetrating arteries of the rodent cortex. This perivascular entry of CSF is a primary driver of the glymphatic system, a pathway implicated in the clearance of toxic metabolic solutes (e.g., amyloid-&#946;). Here, we illustrate a new macroscopic imaging technique that allows real-time, mesoscopic imaging of fluorescent CSF tracers through the intact skull of live mice. This minimally-invasive method facilitates a multitude of experimental designs and enables single or repeated testing of CSF dynamics. Macroscopes have high spatial and temporal resolution and their large gantry and working distance allow for imaging while performing tasks on behavioral devices. This imaging approach has been validated using two-photon imaging and fluorescence measurements obtained from this technique strongly correlate with ex vivo fluorescence and quantification of radio-labeled tracers. In this protocol, we describe how transcranial macroscopic imaging can be used to evaluate glymphatic transport in live mice, offering an accessible alternative to more costly imaging modalities.

Transcranial optical imaging allows wide-field imaging of cerebrospinal fluid transport in the cortex of live mice through an intact skull.

Cerebrospinal fluid (CSF) flow in rodents has largely been studied using ex vivo quantification of tracers. Techniques such as two-photon microscopy and ...