This study was funded in part by the IPSEN Foundation. IMV is an American Cancer Society Professor of Molecular Biology, and holds the Irwin and Joan Jacobs Chair in Exemplary Life Sciences. This work was supported in part by grants from the NIH, Leducq Foundation, Meriaux Foundation, Ellison Medical Foundation, Ipsen/Biomeasure, Sanofi Aventis, Prostate Cancer Foundation, and the H.N. and Frances C. Berger Foundation. PAS is funded by McKnight Endowment Fund for Neuroscience and the National Institute on Drug Abuse (R01 DA019022). The authors would like to thank Mark Schmitt. Graphic art was designed by Jamie T. Simon .Sponsorship was kindly provided by Invitrogen.

1. Organotypic Cerebellar Cultures:
<ol>
<li>To successfully generate organotypic cerebellar cultures use mice between P0-P3 or P8-P12. For our experiment we used mice in the P8-P12 range because this developmental stage was more appropriate for our study.</li>
<li>Prepare the dissection and the culture medium:
<ol>
<li>Brain dissection and slice preparation are carried out in low sodium Artificial Cerebrospinal Fluid (ACSF) containing 1mM calcium chloride, 10mM D-Glucose, 4mM potassium chloride, 5mM magnesium chloride, 26mM sodium bicarbonate, 246mM sucrose and phenol red solution (1:1000), pH 7.3. To sterilize the solution, filter it through a .22 &mu;m filter and store at 4 &deg;C.</li>
<li>Cerebellar slices are cultured in 75% Minimum Essential Medium Eagle (MEM), 25% heat-inactivated horse serum, 25mM HEPES, 1mM glutamine, 5mg/ mL glucose, penicillin (100 U/ mL) and streptomycin (100 U/ mL). Filter the medium through a 0.22 &mu;m filter and store at 4 &deg;C for a maximum of two weeks.</li>
</ol>
</li>
<li>Dissect brain in ice-cold ACSF medium previously bubbled with Carbogen (95% oxygen and 5% carbon dioxide) Note, that saturation with Carbogen will change the pH of the solution so it will shift from red to orange. The dissection should be performed in the minimum amount of time possible being careful not to damage the brain structure.</li>
<li>Slice the brain in sagittal sections of 400 &mu;m using a vibratome.
<ol>
<li>Make a sagittal cut with a razor blade in one hemisphere, trying to cut as little as possible of the cerebellum; this will provide a flat surface for slicing. The cortex is used only for support to make the slicing easier but since time is an important issue it is more convenient to cut out the rostral half of the cortex with a razor blade.</li>
<li>Use cyanoacrylate (Superglue) to fix the position of the brain on the metal vibratome plate.
It is important to chill the plate on ice before adding the glue and to spread it well using the tip of the tube to form a thin adhesive layer. If there is an excess of Superglue, it will detach from the plate when it comes in contact with the ACSF and the sample will be lost.</li>
<li>Once the brain is attached to the vibratome plate, add enough ACSF media to cover the brain and put ice below the plate to keep it cold.</li>
<li>Cut 400 &mu;m slices and transfer them with a plastic Pasteur pipette (cut the tip to widen it and avoid damage to the slices) to a 6-well cell culture plate containing ACSF on ice.</li>
<li>Separate the cerebellum from the rest of the brain with the help of two insulin syringes (syringes with small diameter 28-gauge needles) under the dissecting microscope. Some slices will have Superglue attached to the edges: this is the moment to try to remove it as it can affect the viability of the slice. It is important to do it carefully without damaging the cerebellar structure.</li>
</ol>
</li>
<li>Transfer the cerebellar slices to 6-well plates containing 30mm culture plate inserts with 0.4 &mu;m pores. Add 1 mL of culture media per well, that was pre-conditioned by incubation for at least 2 hours at 37&deg;C and 5% CO2 (in the cell culture incubator). Place the inserts on top of the media making sure there are no air bubbles trapped underneath and then place the cerebellar slices (1-3 per insert) on top of the inserts making sure they are fully extended and that no liquid is covering them. Aspirate excess of media if necessary. Incubate at 37&deg;C and 5% CO2 changing the culture media every 2 or 3 days. It is best to replace only a portion of the medium (e.g. &frac12; volume) at once, since used medium contains slice-derived trophic factors that are important for cell survival.</li>
</ol>
2. Fas Treatment and Staining of Cerebellar Slices:
<ol>
<li>For the apoptotic challenge experiment, we first culture the slices for 5 days changing media on day in vitro 3 (DIV3). On DIV5 cultures are treated with 0.5 &mu;g/ mL of the Fas agonist antibody Jo2 by adding it directly to the media in order to have a clean background of cell death since the changes of media can induce some mortality in the cultures. Half of the wells are left untreated as controls.</li>
<li>After 24 hours remove the media underneath the inserts by suction. To fix the slices, add 1 mL of ice cold 4% PFA beneath and 1 mL above the insert. Incubate for 10 minutes at room temperature.</li>
<li>After 10 minutes remove the PFA and wash briefly with cold PBS.</li>
<li>Next remove the PBS and add 1 mL beneath and 1 mL above the insert of 20% ice-cold methanol in PBS and incubate for 5 minutes at room temperature.</li>
<li>Wash again with PBS and add 1 mL beneath and 1 mL above the insert of 0.5% Triton-X-100 in PBS for permeabilization. Incubate for a minimum of 12 hours at 4&deg;C.</li>
<li>After permeabilization, block with 20% BSA in PBS for a minimum of 4 hours at room temperature or overnight at 4&deg;C. At this stage the slices can be kept in blocking solution for at least 3 days at 4&deg;C.</li>
<li>In order to stain the slices carefully cut the piece of the membrane insert attached to the cerebellar slice and transfer it to 24-well plates containing PBS.</li>
<li>The immunostaining is done sequentially, first with TUNEL reagent for one hour and then with Calbidin antibody overnight.
<ol>
<li>Aspirate the PBS and add 250 &mu;L off TUNEL reagent into each well making sure it covers the entire surface of the slice. Incubate at 37&deg;C for one hour in the dark.</li>
<li>After one hour remove the TUNEL mix and wash with PBS three times for 10 minutes.</li>
<li>After the last wash, remove the PBS and add 250 &mu;L of a 1/1000 dilution of the Calbindin antibody in PBS and incubate overnight at 4&deg;C in the dark.</li>
<li>Remove the primary antibody solution and wash with PBS three times for 10 minutes.</li>
<li>Add 250 &mu;L of secondary antibody diluted 1/500 in PBS and incubate for at least three hours at room temperature in the dark. The TUNEL kit we used is labeled with TMR red, therefore our secondary antibody for Calbindin is conjugated to Alexa-488.</li>
<li>Wash three times for 10 minutes with PBS and mount the slices onto a glass microscope slide using a mounting media that contains DAPI.</li>
<li>Image the slices with a confocal microscope using the 488 nm and 561 nm excitation wavelenght for Calbindin and TUNEL respectively.</li>
</ol>
</li>
</ol>
3. Representative Results:
The main challenge of this protocol is to be able to generate healthy cerebellar slice cultures, especially since our final readout will be cell death. A healthy culture appears as one where the cell body layer is translucent and allows you to see the foliated structure of the cerebellum under the microscope (Figure 1). After few days in culture the slices start to thin and non-neuronal cells can be observed migrating away from the margins of the slice. The dark round cells (most likely macrophages) that cover the slices after few days in culture, will eventually decrease in number after 10-14 days in vitro (Figure 2) 5. The ultimate proof for the viability of the slices is to stain for different cellular markers, such as Calbindin for the Purkinje cells. Figure 3 shows a representative confocal microscope image of the Purkinje cell layer with several TUNEL positive nuclei.
It is important to consider that even if some slices received an apoptotic stimulus, they were only exposed for 24 hours. This allowed sufficient time to observe DNA fragmentation in the dying cells with the TUNEL staining, but a defined Purkinje cell layer was still present. 
<img src="/files/ftp_upload/2564/2564fig1.jpg" alt="Figure 1" /> 
Figure 1. Healthy cerebellar slice at DIV2. This image shows the translucent cell body layer and the foliated cerebellar structure in a healthy slice.
<img src="/files/ftp_upload/2564/2564fig2.jpg" alt="Figure 2" /> 
Figure 2. Healthy cerebellar slice at DIV 7. In this image we can still observe the foliated structure of the cerebellum and the appearance of dark cell bodies.
<img src="/files/ftp_upload/2564/2564fig3.jpg" alt="Figure 3" /> 
Figure 3. Representative image of a Fas-treated cerebellar slice. This confocal image shows the Purkinje cells stained with Calbindin (green) and the apoptotic cells positive for TUNEL staining (red). Purkinje cells do not appear in a single row but are clustered forming a folium-like structure.

<ol>
	<li>Hogue, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+fetal+ependymal+cells+in+tissue+cultures.">Human fetal ependymal cells in tissue cultures.</a> Anat Rec. 99, 523-529 (1947).</li><li>Hogue, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+of+studies+of+human+fetal+brain+cells+in+tissue+cultures.">Review of studies of human fetal brain cells in tissue cultures.</a> Etudes Neonatales. 1, 1-13 (1952).</li><li>Gogolla, N., Galimberti, I., DePaola, V., Caroni, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Staining+protocol+for+organotypic+hippocampal+slice+cultures.">Staining protocol for organotypic hippocampal slice cultures.</a> Nat Protoc. 1, 2452-2456 (2006).</li><li>Stoppini, L., Buchs, P. A., Muller, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+method+for+organotypic+cultures+of+nervous+tissue.">A simple method for organotypic cultures of nervous tissue.</a> J Neurosci Methods. 37, 173-182 (1991).</li><li>Beat, H., G&#228;hwiler, S. M. T., McKinney, R. A., Debanne, D., Robertson, R. T., Banker, G., Goslin, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Organotypic Slice Cultures of Neural Tissue in Culturing Nerve Cells. , 461-498 (1998).</li></ol>

All animal work conducted was done in accordance with policies established by the IACUC. The Salk Institute is an AAALAC accredited facility.

This method describes one of the many possible applications of neuronal organotypic cultures and it has allowed us to study the effect of apoptotic stimuli in wild type and mutant cerebellar slices.
The most critical part of this experiment is to be able to consistently generate healthy cerebellar slice cultures. The key factors are dissection and slicing technique and the ability to perform the protocol in the least time possible, but at the same time being careful not to damage the slices. Another crucial factor is the preparation and composition of the culture media, these cultures are very sensitive, so we had to test several recipes and brands of media. Even different batches of serum or any other components of the media could affect the viability of the slices. We got the best results with the Horse Serum from Invitrogen Lot # 480116.
Once the cerebellar slices are generated one can study cerebellar development, electrophysiology, cell survival alone or in response to apoptotic stimuli, excitotoxicity or oxygen deprivation. Comparative studies using wild type and mutant cerebellar slices have been very insightful in many aspects of cerebellar function and development.

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>MEM</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>11090</td>
<td>&nbsp;</td>
<tr>
<td>Horse Serum</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>16050</td>
<td>&nbsp;</td>
<tr>
<td>Hepes</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>15630</td>
<td>&nbsp;</td>
<tr>
<td>Glutamine</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>25030</td>
<td>&nbsp;</td>
<tr>
<td>Penicillin/ Streptomycin</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>15140</td>
<td>&nbsp;</td>
<tr>
<td>Superglue</td>
<td>&nbsp;</td>
<td>Krazy Glue</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>6 well / 24 well cell culture plates</td>
<td>&nbsp;</td>
<td>Corning Incorporated</td>
<td>3506/ 3527</td>
<td>&nbsp;</td>
<tr>
<td>30mm culture plate inserts (0.4-&mu;m pore)</td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>PICM03050</td>
<td>&nbsp;</td>
<tr>
<td>Purified NA/LE Hamster anti-mouse CD95 (Jo2)</td>
<td>&nbsp;</td>
<td>BD Pharmingen</td>
<td>554254</td>
<td>&nbsp;</td>
<tr>
<td>In situ cell death detection kit, TMR red</td>
<td>&nbsp;</td>
<td>Roche</td>
<td>12 156 792 910</td>
<td>&nbsp;</td>
<tr>
<td>Rabbit anti-Calbindin D-28k antibody</td>
<td>&nbsp;</td>
<td>Swant</td>
<td>CB-38a</td>
<td>&nbsp;</td>
<tr>
<td>Alexa 488-goat anti-rabbit IgG secondary antibody</td>
<td>&nbsp;</td>
<td>Invitrogen (Molecular probes)</td>
<td>A-11008</td>
<td>&nbsp;</td>
<tr>
<td>Vectashield Mounting Medium with DAPI</td>
<td>&nbsp;</td>
<td>Vector labs</td>
<td>H-1200</td>
<td>&nbsp;</td>
<tr>
<td>Dissecting Microscope</td>
<td>&nbsp;</td>
<td>Zeiss Stemi SV 11</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Vibratome</td>
<td>&nbsp;</td>
<td>Leica</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Confocal Microscope</td>
<td>&nbsp;</td>
<td>Leica TCS SP2 AOBS</td>
<td>&nbsp;</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

organotypic cerebellar cultures: apoptotic challenges and detection

Organotypic cultures of neuronal tissue were first introduced by Hogue in 1947 1,2 and have constituted a major breakthrough in the field of neuroscience. Since then, the technique was developed further and currently there are many different ways to prepare organotypic cultures. The method presented here was adapted from the one described by Stoppini et al. for the preparation of the slices and from Gogolla et al. for the staining procedure 3,4.
A unique feature of this technique is that it allows you to study different parts of the brain such as hippocampus or cerebellum in their original structure, providing a big advantage over dissociated cultures in which all the cellular organization and neuronal networks are disrupted. In the case of the cerebellum it is even more advantageous because it allows the study of Purkinje cells, extremely difficult to obtain as dissociated primary culture. This method can be used to study certain developmental features of the cerebellum in vitro, as well as for electrophysiological and pharmacological experiments in both wild type and mutant mice.
The method described here was designed to study the effect of apoptotic stimuli such as Fas ligand in the developing cerebellum, using TUNEL staining to measure apoptotic cell death. If TUNEL staining is combined with cell type specific markers, such as Calbindin for Purkinje cells, it is possible to evaluate cell death in a cell population specific manner. The Calbindin staining also serves the purpose of evaluating the quality of the cerebellar cultures.

Watch this Scientific Journal Video about Organotypic Cerebellar Cultures: Apoptotic Challenges and Detection at JoVE.com

Organotypic Cerebellar Cultures: Apoptotic Challenges and Detection

This method describes the generation of organotypic cerebellar cultures and the effect of certain apoptotic stimuli on the viability of different cerebellar cell types.

Organotypic cultures of neuronal tissue were first introduced by Hogue in 1947 1,2 and have constituted a major breakthrough in the field of neuroscience. ...

organotypic-cerebellar-cultures-apoptotic-challenges-and-detection

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18.1K Views.  The Salk Institute for Biological Studies. This method describes the generation of organotypic cerebellar cultures and the effect of certain apoptotic stimuli on the viability of different cerebellar cell types. 

Video: Organotypic Cerebellar Cultures: Apoptotic Challenges and Detection

Organotypic Hippocampal Slice Cultures

The hippocampus, a component of the limbic system, plays important roles in long-term memory and spatial navigation 1. Hippocampal neurons can modify the strength of their connections after brief periods of strong activation. This phenomenon, known as long-term potentiation (LTP) can last for hours or days and has become the best candidate mechanism for learning and memory 2. In addition, the well defined anatomy and connectivity of the hippocampus 3 has made it a classical model system to study synaptic transmission and synaptic plasticity4.
As our understanding of the physiology of hippocampal synapses grew and molecular players became identified, a need to manipulate synaptic proteins became imperative. Organotypic hippocampal cultures offer the possibility for easy gene manipulation and precise pharmacological intervention but maintain synaptic organization that is critical to understanding synapse function in a more naturalistic context than routine culture dissociated neurons methods.
Here we present a method to prepare and culture hippocampal slices that can be easily adapted to other brain regions. This method allows easy access to the slices for genetic manipulation using different approaches like viral infection 5,6 or biolistics 7. In addition, slices can be easily recovered for biochemical assays 8, or transferred to microscopes for imaging 9 or electrophysiological experiments 10.

We describe a method to prepare organotypic hippocampal slices that can be easily adapted to other brain regions. Brain slices are laid on porous membranes and culture media is allowed to form an interface. This method preserves the gross architecture of the hippocampus for up to 2 weeks in culture.

The hippocampus, a component of the limbic system, plays important roles in long-term memory and spatial navigation 1. Hippocampal neurons can modify the ...

Multi-electrode Array Recordings of Neuronal Avalanches in Organotypic Cultures

The cortex is spontaneously active, even in the absence of any particular input or motor output. During development, this activity is important for the migration and differentiation of cortex cell types and the formation of neuronal connections1. In the mature animal, ongoing activity reflects the past and the present state of an animal into which sensory stimuli are seamlessly integrated to compute future actions. Thus, a clear understanding of the organization of ongoing i.e. spontaneous activity is a prerequisite to understand cortex function. 
Numerous recording techniques revealed that ongoing activity in cortex is comprised of many neurons whose individual activities transiently sum to larger events that can be detected in the local field potential (LFP) with extracellular microelectrodes, or in the electroencephalogram (EEG), the magnetoencephalogram (MEG), and the BOLD signal from functional magnetic resonance imaging (fMRI). The LFP is currently the method of choice when studying neuronal population activity with high temporal and spatial resolution at the mesoscopic scale (several thousands of neurons). At the extracellular microelectrode, locally synchronized activities of spatially neighbored neurons result in rapid deflections in the LFP up to several hundreds of microvolts. When using an array of microelectrodes, the organizations of such deflections can be conveniently monitored in space and time. 
Neuronal avalanches describe the scale-invariant spatiotemporal organization of ongoing neuronal activity in the brain2,3. They are specific to the superficial layers of cortex as established in vitro4,5, in vivo in the anesthetized rat 6, and in the awake monkey7. Importantly, both theoretical and empirical studies2,8-10 suggest that neuronal avalanches indicate an exquisitely balanced critical state dynamics of cortex that optimizes information transfer and information processing.
In order to study the mechanisms of neuronal avalanche development, maintenance, and regulation, in vitro preparations are highly beneficial, as they allow for stable recordings of avalanche activity under precisely controlled conditions. The current protocol describes how to study neuronal avalanches in vitro by taking advantage of superficial layer development in organotypic cortex cultures, i.e. slice cultures, grown on planar, integrated microelectrode arrays (MEA; see also 11-14).

A robust way to study neuronal avalanches, i.e. scale-invariant spatio-temporal activity bursts, indicative of critical state dynamics in cortex. Avalanches emerge spontaneously in developing superficial layers of cultured cortex which allows for long-term measurements of the activity with planar integrated multi-electrode arrays (MEA) under precisely controlled conditions.

The cortex is spontaneously active, even in the absence of any particular input or motor output.  During development, this activity is important for the ...

Organotypic Slice Cultures of Embryonic Ventral Midbrain: A System to Study Dopaminergic Neuronal Development in vitro

The mouse is an excellent model organism to study mammalian brain development due to the abundance of molecular and genetic data. However, the developing mouse brain is not suitable for easy manipulation and imaging in vivo since the mouse embryo is inaccessible and opaque. Organotypic slice cultures of embryonic brains are therefore widely used to study murine brain development in vitro. Ex-vivo manipulation or the use of transgenic mice allows the modification of gene expression so that subpopulations of neuronal or glial cells can be labeled with fluorescent proteins. The behavior of labeled cells can then be observed using time-lapse imaging. Time-lapse imaging has been particularly successful for studying cell behaviors that underlie the development of the cerebral cortex at late embryonic stages 1-2. Embryonic organotypic slice culture systems in brain regions outside of the forebrain are less well established. Therefore, the wealth of time-lapse imaging data describing neuronal cell migration is restricted to the forebrain 3,4. It is still not known, whether the principles discovered for the dorsal brain hold true for ventral brain areas. In the ventral brain, neurons are organized in neuronal clusters rather than layers and they often have to undergo complicated migratory trajectories to reach their final position. The ventral midbrain is not only a good model system for ventral brain development, but also contains neuronal populations such as dopaminergic neurons that are relevant in disease processes. While the function and degeneration of dopaminergic neurons has been investigated in great detail in the adult and ageing brain, little is known about the behavior of these neurons during their differentiation and migration phase 5. We describe here the generation of slice cultures from the embryonic day (E) 12.5 mouse ventral midbrain. These slice cultures are potentially suitable for monitoring dopaminergic neuron development over several days in vitro. We highlight the critical steps in generating brain slices at these early stages of embryonic development and discuss the conditions necessary for maintaining normal development of dopaminergic neurons in vitro. We also present results from time lapse imaging experiments. In these experiments, ventral midbrain precursors (including dopaminergic precursors) and their descendants were labeled in a mosaic manner using a Cre/loxP based inducible fate mapping system 6.

Organotypic Slice Cultures of Embryonic Ventral Midbrain: A System to Study Dopaminergic Neuronal Development in vitro

A method to generate organotypic slices from the E12.5 murine embryonic midbrain is described. The organotypic slice cultures can be used to observe the behavior of dopaminergic neurons or other ventral midbrain neurons.

The  mouse is an excellent model organism to study mammalian brain development due  to the abundance of molecular and genetic data. However, the ...

The Analysis of Purkinje Cell Dendritic Morphology in Organotypic Slice Cultures

Purkinje cells are an attractive model system for studying dendritic development, because they have an impressive dendritic tree which is strictly oriented in the sagittal plane and develops mostly in the postnatal period in small rodents 3. Furthermore, several antibodies are available which selectively and intensively label Purkinje cells including all processes, with anti-Calbindin D28K being the most widely used. For viewing of dendrites in living cells, mice expressing EGFP selectively in Purkinje cells 11 are available through Jackson labs. Organotypic cerebellar slice cultures cells allow easy experimental manipulation of Purkinje cell dendritic development because most of the dendritic expansion of the Purkinje cell dendritic tree is actually taking place during the culture period 4. We present here a short, reliable and easy protocol for viewing and analyzing the dendritic morphology of Purkinje cells grown in organotypic cerebellar slice cultures. For many purposes, a quantitative evaluation of the Purkinje cell dendritic tree is desirable. We focus here on two parameters, dendritic tree size and branch point numbers, which can be rapidly and easily determined from anti-calbindin stained cerebellar slice cultures. These two parameters yield a reliable and sensitive measure of changes of the Purkinje cell dendritic tree. Using the example of treatments with the protein kinase C (PKC) activator PMA and the metabotropic glutamate receptor 1 (mGluR1) we demonstrate how differences in the dendritic development are visualized and quantitatively assessed. The combination of the presence of an extensive dendritic tree, selective and intense immunostaining methods, organotypic slice cultures which cover the period of dendritic growth and a mouse model with Purkinje cell specific EGFP expression make Purkinje cells a powerful model system for revealing the mechanisms of dendritic development.

We present a protocol that permits to view and to quantitatively asses the morphology of the dendritic tree of individual Purkinje cells grown in organotypic cerebellar slice cultures. This protocol is intended to promote studies on the mechanisms of Purkinje cell dendritic development.

Purkinje cells are an attractive model system for studying dendritic development, because they have an impressive dendritic tree which is strictly ...

Organotypic Slice Cultures to Study Oligodendrocyte Dynamics and Myelination

NG2 expressing cells (polydendrocytes, oligodendrocyte precursor cells) are the fourth major glial cell population in the central nervous system. During embryonic and postnatal development they actively proliferate and generate myelinating oligodendrocytes. These cells have commonly been studied in primary dissociated cultures, neuron cocultures, and in fixed tissue. Using newly available transgenic mouse lines slice culture systems can be used to investigate proliferation and differentiation of oligodendrocyte lineage cells in both gray and white matter regions of the forebrain and cerebellum. Slice cultures are prepared from early postnatal mice and are kept in culture for up to 1 month. These slices can be imaged multiple times over the culture period to investigate cellular behavior and interactions. This method allows visualization of NG2 cell division and the steps leading to oligodendrocyte differentiation while enabling detailed analysis of region-dependent NG2 cell and oligodendrocyte functional heterogeneity. This is a powerful technique that can be used to investigate the intrinsic and extrinsic signals influencing these cells over time in a cellular environment that closely resembles that found in vivo.

A technique to study NG2 cells and oligodendrocytes using a slice culture system of the forebrain and cerebellum is described. This method allows examination of the dynamics of proliferation and differentiation of cells within the oligodendrocyte lineage where the extracellular environment can be easily manipulated while maintaining tissue cytoarchitecture.

NG2 expressing cells (polydendrocytes, oligodendrocyte precursor cells) are the fourth major glial cell population in the central nervous system. During ...

The Analysis of Neurovascular Remodeling in Entorhino-hippocampal Organotypic Slice Cultures

Ischemic brain injury is among the most common and devastating conditions compromising proper brain function and often leads to persisting functional deficits in the affected patients. Despite intensive research efforts, there is still no effective treatment option available that reduces neuronal injury and protects neurons in the ischemic areas from delayed secondary death. Research in this area typically involves the use of elaborate and problematic animal models. Entorhino-hippocampal organotypic slice cultures challenged with oxygen and glucose deprivation (OGD) are established in&#160;vitro models which mimic cerebral ischemia. The novel aspect of this study is that changes of the brain blood vessels are studied in addition to neuronal changes and the reaction of both the neuronal compartment and the vascular compartment can be compared and correlated. The methods presented in this protocol substantially broaden the potential applications of the organotypic slice culture approach. The induction of OGD or hypoxia alone can be applied by rather simple means in organotypic slice cultures and leads to reliable and reproducible damage in the neural tissue. This is in stark contrast to the complicated and problematic animal experiments inducing stroke and ischemia in vivo. By broadening the analysis to include the study of the reaction of the vasculature could provide new ways on how to preserve and restore brain functions. The slice culture approach presented here might develop into an attractive and important tool for the study of ischemic brain injury and might be useful for testing potential therapeutic measures aimed at neuroprotection.

A protocol for entorhino-hippocampal organotypic slice cultures, which allows reproducing many aspects of ischemic brain injury, is presented. By studying changes of the neurovasculature in addition to changes in the neurons, this protocol is a versatile tool to study plastic changes in neural tissue after injury.

Ischemic brain injury is among the most common and devastating conditions compromising proper brain function and often leads to persisting functional ...

Selective Depletion of Microglia from Cerebellar Granule Cell Cultures Using L-leucine Methyl Ester

Microglia, the resident immunocompetent cells of the CNS, play multifaceted roles in modulating and controlling neuronal function, as well as mediating innate immunity. Primary rodent cell culture models have greatly advanced our understanding of neuronal-glial interactions, but only recently have methods to specifically eliminate microglia from mixed cultures been utilized. One such technique &#8211; described here &#8211; is the use of L-leucine methyl ester, a lysomotropic agent that is internalized by macrophages and microglia, wherein it causes lysosomal disruption and subsequent apoptosis13,14. Experiments using L-leucine methyl ester have the power to identify the contribution of microglia to the surrounding cellular environment under diverse culture conditions. Using a protocol optimized in our laboratory, we describe how to eliminate microglia from P5 rodent cerebellar granule cell culture. This approach allows one to assess the relative impact of microglia on experimental data, as well as determine whether microglia are playing a neuroprotective or neurotoxic role in culture models of neurological conditions, such as stroke, Alzheimer&#8217;s or Parkinson&#8217;s disease.

Microglia can influence neurons and other glia in culture by various non-cell autonomous mechanisms. Here, we present a protocol to selectively deplete microglia from primary neuronal cultures. This method has the potential to elucidate the role of microglial-neuronal interactions, with implications for neurodegenerative conditions where neuroinflammation is a hallmark feature.

Microglia, the resident immunocompetent cells of the CNS, play multifaceted roles in modulating and controlling neuronal function, as well as mediating ...

Investigating Functional Regeneration in Organotypic Spinal Cord Co-cultures Grown on Multi-electrode Arrays

Adult higher vertebrates have a limited potential to recover from spinal cord injury. Recently, evidence emerged that propriospinal connections are a promising target for intervention to improve functional regeneration. So far, no in vitro model exists that grants the possibility to examine functional recovery of propriospinal fibers. Therefore, a representative model that is based on two organotypic spinal cord sections of embryonic rat, cultured next to each other on multi-electrode arrays (MEAs) was developed. These slices grow and, within a few days in vitro, fuse along the sides facing each other. The design of the used MEAs permits the performance of lesions with a scalpel blade through this fusion site without inflicting damage on the MEAs. The slices show spontaneous activity, usually organized in network activity bursts, and spatial and temporal activity parameters such as the location of burst origins, speed and direction of their propagation and latencies between bursts can be characterized. Using these features, it is also possible to assess functional connection of the slices by calculating the amount of synchronized bursts between the two sides. Furthermore, the slices can be morphologically analyzed by performing immunohistochemical stainings after the recordings. 
Several advantages of the used techniques are combined in this model: the slices largely preserve the original tissue architecture with intact local synaptic circuitry, the tissue is easily and repeatedly accessible and neuronal activity can be detected simultaneously and non-invasively in a large number of spots at high temporal resolution. These features allow the investigation of functional regeneration of intraspinal connections in isolation in vitro in a sophisticated and efficient way.

Here we present a protocol that is based on spinal cord slices cultured on multi-electrode arrays to study functional regeneration of propriospinal connections in vitro.

Adult higher vertebrates have a limited potential to recover from spinal cord injury. Recently, evidence emerged that propriospinal connections are a ...

Organotypic Hippocampal Slice Cultures As a Model to Study Neuroprotection and Invasiveness of Tumor Cells

In organotypic hippocampal slice cultures (OHSC), the morphological and functional characteristics of both neurons and glial cells are well preserved. This model is suitable for addressing different research questions that involve studies on neuroprotection, electrophysiological experiments on neurons, neuronal networks or tumor invasion. The hippocampal architecture and neuronal activity in multisynaptic circuits are well conserved in OHSC, even though the slicing procedure itself initially lesions and leads to formation of a glial scar. The scar formation alters presumably the mechanical properties and diffusive behavior of small molecules, etc. Slices allow the monitoring of time dependent processes after brain injury without animal surgery, and studies on interactions between various brain-derived cell types, namely astrocytes, microglia and neurons under both physiological and pathological conditions. An ambivalent aspect of this model is the absence of blood flow and immune blood cells. During the progression of the neuronal injury, migrating immune cells from the blood play an important role. As those cells are missing in slices, the intrinsic processes in the culture may be observed without external interference. Moreover, in OHSC the composition of the medium-external environment is precisely controlled. A further advantage of this method is the lower number of sacrificed animals compared to standard preparations. Several OHSC can be obtained from one animal making simultaneous studies with multiple treatments in one animal possible. For these reasons, OHSC are well suited to analyze the effects of new protective therapeutics after tissue damage or during tumor invasion. 
The protocol presented here describes a preparation method of OHSC that allows generating highly reproducible, well preserved slices that can be used for a variety of experimental research, like neuroprotection or tumor invasion studies.

Organotypic hippocampal slice cultures (OHSC) represent an in vitro model that simulates the in vivo situation very well. Here we describe a vibratome-based improved slicing protocol to obtain high quality slices for use in assessing the neuroprotective potential of novel substances or the biological behavior of tumor cells.

In organotypic hippocampal slice cultures (OHSC), the morphological and functional characteristics of both neurons and glial cells are well preserved. ...

Ex Utero Electroporation and Organotypic Slice Cultures of Embryonic Mouse Brains for Live-Imaging of Migrating GABAergic Interneurons

GABAergic interneurons (INs) are critical components of neuronal networks that drive cognition and behavior. INs destined to populate the cortex migrate tangentially from their place of origin in the ventral telencephalon (including from the medial and caudal ganglionic eminences (MGE, CGE)) to the dorsal cortical plate in response to a variety of intrinsic and extrinsic cues. Different methodologies have been developed over the years to genetically manipulate specific pathways and investigate how they regulate the dynamic cytoskeletal changes required for proper IN migration. In utero electroporation has been extensively used to study the effect of gene repression or overexpression in specific IN subtypes while assessing the impact on morphology and final position. However, while this approach is readily used to modify radially migrating pyramidal cells, it is more technically challenging when targeting INs. In utero electroporation generates a low yield given the decreased survival rates of pups when electroporation is conducted before e14.5, as is customary when studying MGE-derived INs. In an alternative approach, MGE explants provide easy access to the MGE and facilitate the imaging of genetically modified INs. However, in these explants, INs migrate into an artificial matrix, devoid of endogenous guidance cues and thalamic inputs. This prompted us to optimize a method where INs can migrate in a more naturalistic environment, while circumventing the technical challenges of in utero approaches. In this paper, we describe the combination of ex utero electroporation of embryonic mouse brains followed by organotypic slice cultures to readily track, image and reconstruct genetically modified INs migrating along their natural paths in response to endogenous cues. This approach allows for both the quantification of the dynamic aspects of IN migration with time-lapse confocal imaging, as well as the detailed analysis of various morphological parameters using neuronal reconstructions on fixed immunolabeled tissue.

Ex Utero Electroporation and Organotypic Slice Cultures of Embryonic Mouse Brains for Live-Imaging of Migrating GABAergic Interneurons

Here, we provide a low-cost and reliable method to generate electroporated brain organotypic slice cultures from mouse embryos suitable for confocal microscopy and live-imaging techniques.

GABAergic interneurons (INs) are critical components of neuronal networks that drive cognition and behavior. INs destined to populate the cortex migrate ...