Adult spinal cord mixed cultures were first developed using rats with grant support from an NIH/NIDA R01 award (PI De Leo) and an NIH T32 training grant (PI Green). These methods were further adapted for mouse spinal cords with support from the following grants: NIH/NIDA 5K01DA023503 (PI Cao), NIH/NINDS 5R21NS066130 (PI Cao), and NIH/NIGMS P20GM103643 (PI Meng). The authors would also like to thank Dr. Alejandro M. S. Mayer, Department of Pharmacology, Chicago College of Osteopathic Medicine, for his technical help in obtaining microglia-rich mixed glial cells.

The following protocol was approved by the Institutional Animal Care and Use Committee (IACUC) at the University of New England. The following protocol is for preparing glial cultures from 4 adult mouse spinal cords.
1. Preparation of Solutions in a Culture Hood under Aseptic Conditions
<ol>
	<li>Prepare culture media: complete Dulbecco&#39;s modification of Eagle&#39;s media (cDMEM) containing DMEM (with 4.5 g/L glucose), 10% Fetal Bovine Serum (FBS), 2 mM L-glutamine, 100 IU/mL penicillin, 100 mg/mL streptomycin, 250 ng/mL Amphotericin B, and 50 &#181;M 2-mercaptoethanol (2-ME; see 1.1.1). Mix and filter sterilize all other components and then add FBS. Store the culture media at 4 oC.
	<ol>
		<li>Prepare 50 mM 2-ME/phosphate-buffered saline (PBS) stock solution: add 100 &#181;L of concentrated 2-ME (14.3 M) into 28.6 mL of 1x PBS, and filter sterilize (the solution can be stored at 4 oC for several months). Use 1 mL of 2-ME stock solution for every 1,000 mL of culture media.</li>
	</ol>
	</li>
	<li>Preparation of the density gradient media
	<ol>
		<li>Prepare a stock isotonic density gradient media solution (e.g., 100% Percoll) from 1 part 10x regular sterile PBS and 9 parts sterile stock density gradient media (e.g., Percoll).</li>
		<li>Dilute the 100% density gradient media (made in 1.2.1) with regular 1x sterile PBS to make a 20% density gradient media (e.g., 10 mL of 100% density gradient media with 40 mL of 1x PBS) and store it at 4 oC. Bring the 20% density gradient media to room temperature (RT) before preparing the cell culture.</li>
	</ol>
	</li>
	<li>Preparation of solutions from the papain dissociation system 
	NOTE: The papain dissociation system can be identified in the Materials Table. Other similar dissociation kits (including those assembled in-house) can also be used. All components must be sterile.
	<ol>
		<li>Add 32 mL of Earle&#39;s Balanced Salt Solution (EBSS) to the ovomucoid inhibitor mixture (powder).</li>
		<li>Add 5 mL of EBSS to one papain vial (powder). Place the papain vial in a 37 oC water bath for 10 min or until the papain is dissolved.</li>
		<li>Add 500 &#181;L of EBSS to one DNase vial (powder). Mix gently.</li>
		<li>Add 250 &#181;L of the DNase solution (above) to the papain vial.</li>
		<li>Calculate the total amount of the above papain/DNase mixture needed (approximately 800 &#181;L of papain/DNase mixture per mouse spinal cord) and transfer the needed mixture into a 50 mL tube for tissue digestion (step 3.2). Store the leftover in the original vial at 4 &#176;C for at least two weeks.</li>
		<li>Keep all components from the kits on ice until needed.</li>
	</ol>
	</li>
	<li>Prepare spinal cord collection tubes: one sterile 15 mL tube with 5 mL of Hank&#39;s balanced Salt Solution (HBSS; from the papain dissociation system,&#160;for collecting spinal cords) and one sterile 15 mL tube with 1x PBS (for filling up the 5 mL syringe, see step 2.4). In addition, prepare one sterile petri dish (35 mm or 60 mm) with 5 mL of HBSS and keep it in the culture hood.</li>
</ol>
2. Spinal Cord Collection
NOTE: All equipment must be sterile. Perform the collection in a designated area approved by the IACUC.
<ol>
	<li>Obtain the following tools for harvesting mouse spinal cords: straight sharp/blunt 18-cm surgical scissors, a 12-cm standard scalpel (#3 solid), carbon steel sterile scalpel blades #10, a small animal decapitator, 12-cm standard curved forceps, and a sterile 20G needle attached to a 5-mL&#160;syringe.</li>
	<li>Euthanize the animal with CO2 and disinfect the mouse head and the back region with 70% ethanol (EtOH).</li>
	<li>Decapitate animal with the decapitator. Make a middle longitudinal incision on the lower back to expose the muscle layer. Make a clean transection through the vertebrate column at the hip level (also cutting through the muscle layer that covers the vertebrate column) with the sterile straight surgical scissors (18 cm).</li>
	<li>Place the animal on a sheet of fresh disposable wipe. Carefully insert the 20 G needle (attached to a 5 mL syringe filled with sterile 1x PBS (step 1.4)) into the spinal column towards the rostral side. Hold the animal down tightly and push the syringe quickly. The whole spinal cord should come out from the cervical end. Collect the spinal cord into the 15 mL tube containing HBSS.</li>
	<li>Repeat step 2.4 for the rest of the mice. Between each animal, disinfect all used instruments with 70% EtOH. 
	NOTE: Typically, a single 12-well plate can be established for every 4 mouse spinal cords (see 4.3).</li>
</ol>
3. Preparation of the Single Cell Suspension
Note: Perform steps 3 and 4 in a culture hood to keep everything sterile.
<ol>
	<li>Transfer all spinal cords into the HBSS-containing petri dish (step 1.4). Cut each of the spinal cords into many fine, small pieces with sterile scissors and forceps. Transfer the spinal cord tissue to the 50-mL&#160;conical tube containing the prepared papain/DNase enzyme mixture (step 1.3.5) using sterile forceps or a 10 mL pipette (avoid adding HBSS to the enzyme mixture, as this will further dilute the prepared enzyme solution and may result in decreased performance of the enzyme).</li>
	<li>Vortex the tube gently to mix. Incubate the tube at 37 oC for 1 h in an incubator/shaker with orbital shaking at 150 rpm.</li>
	<li>Vortex the tube again and vigorously triturate the enzyme solution with the tissue using a 5 mL pipette to promote further dissociation.</li>
	<li>Transfer the cell suspension into a 15-mL&#160;tube and centrifuge at 300 x g for 5 min at RT.</li>
	<li>During centrifugation, mix 2.7 mL EBSS with 300 &#181;L of reconstituted albumin-ovomucoid inhibitor solution (1.3.1) in a sterile tube. Add 150 &#181;L of the DNase solution (step 1.3.3).</li>
	<li>Following centrifugation, remove the supernatant and resuspend the cell pellet with the solution prepared above (step 3.5). Vortex well to break the cell pellet.</li>
	<li>Add 3 mL of reconstituted albumin-ovomucoid inhibitor solution (step 1.4.1) to the cell suspension. Centrifuge cells at 70 x g for 6 min at RT. Remove the supernatant (which contains membrane fragments).</li>
</ol>
4. Further Removal of Myelin from the Single Cell Suspension
<ol>
	<li>Add 8 mL of 20% density gradient media (prepared in step 1.2.2) into the tube containing the cell pellet, vortex gently to disrupt the pellet, and centrifuge the cells at 800 x g for 30 min at RT without braking. Carefully remove the top layer of debris (mostly myelin) and the supernatant, but keep the pellet.</li>
	<li>To remove remnants of the density gradient, wash the cells by resuspending the cell pellet with 8 mL of a diluted cDMEM (1 part cDMEM and 2 parts HBSS). Centrifuge the cells at 400 x g for 10 min at 4 oC. Remove the supernatant and wash the cells again with the diluted cDMEM (above) in the same manner. Keep the cells on ice until seeding them.</li>
	<li>Remove the supernatant and resuspend the cell pellet in culture media (cDMEM supplied with 2-ME (prepared in step 1.1)). For one 12-well plate, use 3 mL x 4 (number of mice used) + 2 mL = 14 mL media. This will ensure that there is sufficient cell suspension for the entire plate (12 wells) and will provide for extra wells that can be used to determine the average cell number per well and the microglial content of the culture. If other types of culture vessels will be used, calculate the total volume of needed culture media proportionally.</li>
	<li>Add 1 mL of the cell suspension into each well of a 12-well plate.</li>
	<li>Incubate the cells at 35.9 oC with 5% CO2.</li>
	<li>Change the media (remove old media via aspiration) on D 1 and then every 3 - 4 d thereafter (typically change the media on D: 1, 4, 8, and 11, and then use the cells on day 12). 
	NOTE: On day 1, the culture may contain significant amounts of debris due to the residue myelin from the spinal cord tissue; thus, changing the media on day 1 is recommended (please see the Discussion for more information). Cultures are ready for treatment between D 12 - 14. Cells usually are 80% confluent at D&#160;12 and can be near 100% confluent by D 14. Typically, on D 12, there are about 100,000 cells per well in a 12-well plate.</li>
</ol>
<img alt="Figure 4" src="/files/ftp_upload/54801/54801fig4.jpg" /> 
Figure 2: Representative images of mixed glial cells at different times after the establishment of the mixed glia culture. Primary spinal cord mixed glia were prepared from adult C57Bl/6 mice. Representative images show the progress of the glial culture after plating. At day 1, some cells are attached to the culture plate, but they are still mostly round. There are also many floating cells and significant debris. At day 4, the majority of the cells are attached to the culture plate. Cells appear ramified with visible processes. Cells are sporadically distributed and cultures are about 20-30% confluent at this time. At day 8, cultures are between 50-60% confluent. Some areas of the cultures have large patches of cells. Other areas of the cultures have sparse growth of cells. Some cells within the patches take on a &#8220;square-like&#8221; appearance. At day 12, cultures are at or above 80% confluent (about 90% confluent in the image shown here). Cell are in the log phase of growth at this time and between days 12-14 is the optimal time for using the glia cells for experiments. <a href="http://cloudfront.jove.com/files/ftp_upload/54801/54801fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="7">
	<li>Examine the microglial content using cells from the extra wells (step 4.3) via standard fluorescence-activated cell sorting (FACS) staining protocol11 using the combination of anti-mouse-CD45 and anti-mouse CD11b monoclonal antibodies. CD45+CD11b+ cells are identified as microglia.</li>
</ol>

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	<li>Gaskin, D. J., Richard, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+economic+costs+of+pain+in+the+United+States.">The economic costs of pain in the United States.</a> J Pain. 13 (8), 715-724 (2012).</li><li>Ji, R. R., Berta, T., Nedergaard, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glia+and+pain:+Is+chronic+pain+a+gliopathy?.">Glia and pain: Is chronic pain a gliopathy?.</a> Pain. 154 (01), S10-S28 (2013).</li><li>Ni, M., Aschner, M., Maines, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neonatal+rat+primary+icroglia:+isolation,+culturing+and+selected+applications.">Neonatal rat primary icroglia: isolation, culturing and selected applications.</a> Curr Protoc Toxicol. , (2010).</li><li>Cao, L., Fei, L., Chang, T. T., DeLeo, 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=Induction+of+interleukin-1beta+by+interleukin-4+in+lipopolysaccharide-treated+mixed+glial+cultures:+microglial-dependent+effects.">Induction of interleukin-1beta by interleukin-4 in lipopolysaccharide-treated mixed glial cultures: microglial-dependent effects.</a> J Neurochem. 102 (2), 408-419 (2007).</li><li>Malon, J. T., Maddula, S., Bell, H., Cao, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Involvement+of+calcitonin+gene-related+peptide+and+CCL2+production+in+CD40-mediated+behavioral+hypersensitivity+in+a+model+of+neuropathic+pain.">Involvement of calcitonin gene-related peptide and CCL2 production in CD40-mediated behavioral hypersensitivity in a model of neuropathic pain.</a> Neuron Glia Biol. 7 (2-4), 117-128 (2011).</li><li>Blasi, E., Barluzzi, R., Bocchini, V., Mazzolla, R., Bistoni, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immortalization+of+murine+microglial+cells+by+a+v-raf+/+v-myc+carrying+retrovirus.">Immortalization of murine microglial cells by a v-raf / v-myc carrying retrovirus.</a> J Neuroimmunol. 27 (2), 229-237 (1990).</li><li>Bocchini, V., 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=An+immortalized+cell+line+expresses+properties+of+activated+microglial+cells.">An immortalized cell line expresses properties of activated microglial cells.</a> J Neurosci Res. 31 (4), 616-621 (1992).</li><li>Alliot, F. O., Marty, M. C., Cambier, D., Pessac, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+spontaneously+immortalized+mouse+microglial+cell+line+expressing+CD4.">A spontaneously immortalized mouse microglial cell line expressing CD4.</a> Dev Brain Res. 95 (1), 140-143 (1996).</li><li>Alliot, F. O., Pessac, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Astrocytic+cell+clones+derived+from+established+cultures+of+8-day+postnatal+mouse+cerebella.">Astrocytic cell clones derived from established cultures of 8-day postnatal mouse cerebella.</a> Brain Res. 306 (1-2), 283-291 (1984).</li><li>Malon, J. 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M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+a+short-term+in+vitro+exposure+to+the+marine+toxin+domoic+acid+on+viability,+tumor+necrosis+factor-alpha,+matrix+metalloproteinase-9+and+superoxide+anion+release+by+rat+neonatal+microglia.">Effect of a short-term in vitro exposure to the marine toxin domoic acid on viability, tumor necrosis factor-alpha, matrix metalloproteinase-9 and superoxide anion release by rat neonatal microglia.</a> BMC Pharmacol. 1, 7 (2001).</li><li>Lawson, L. J., Perry, V. H., Dri, P., Gordon, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterogeneity+in+the+distribution+and+morphology+of+microglia+in+the+normal+adult+mouse+brain.">Heterogeneity in the distribution and morphology of microglia in the normal adult mouse brain.</a> Neuroscience. 39 (1), 151-170 (1990).</li><li>Rock, R. B., 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=Role+of+Microglia+in+Central+Nervous+System+Infections.">Role of Microglia in Central Nervous System Infections.</a> Clin Microbiol Rev. 17 (4), 942-964 (2004).</li><li>Yang, I., Han, S. J., Kaur, G., Crane, C., Parsa, A. 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The authors have nothing to disclose.

It is critical to perform all steps-including the media changing schedule-in a consistent manner in order to obtain reproducible results between experiments. The following steps are particularly critical in obtaining excellent quality adult mixed glia.
The enzymatic digestion is an important aspect of this protocol. It is crucial that the tissue pieces are well-digested in order to obtain a single cell suspension. However, over-digestion will result in significantly fewer cells. Each lab needs...

Chronic pain is a serious health problem that affects approximately 100 million adults in the United States, with an estimated annual cost of up to $635 billion1. Mounting evidence has indicated a significant contribution of spinal cord glial cells in the development of neuropathic pain, one of the most devastating kinds of chronic pain2. A proper in vitro culture system would help significantly in further investigating the roles of glial cells at the cellular and molecular levels.
Currently, the in vitro glial culture systems utilized by researchers include mainly glial cells derived from cortical tissues of neonatal mouse or rat brains and immortalized glial cell lines derived from neonatal mouse or rat primary glial cells. Neonatal cells contain significant numbers of undifferentiated cells that can be further differentiated into glial cells (mainly astrocytes and microglia), thus providing abundant cells for experimental usage3. However, our previous study has shown that neonatal brain glial cells responded significantly differently from adult spinal cord glial cells upon lipopolysaccharide (LPS) stimulation. For example, interleukin (IL)-4 displayed enhanced inhibitory effects on LPS-induced nitric oxide (NO) production in adult rat spinal cord glia compared to neonatal brain glia4. Furthermore, the profiles of chemokine production upon stimulation by a neuropeptide, calcitonin gene-related peptide (CGRP), are unarguably different between neonatal mouse brain glia (methods described in Ref. 5) and adult mouse spinal cord glia (Figure 1). Established cell lines are easy to use and maintain and can provide a large number of cells in a short time period. In general, immortalized cell lines are generated either using a virus-mediated immortalization system (such as the widely-used microglial cell line BV2)6, 7 or following the identification of spontaneous transformation (such as the astrocyte cell line C8-D1A and microglial cell line C8-B4)8, 9. Cell lines are excellent in studying the molecular characteristics of astrocytes and microglia individually; however, the results obtained from cell lines always require further validation in primary cells or in&#160;in vivo conditions. It should also be noted that there has not been a report of a glial cell line that is derived from a rodent spinal cord glia.
To help&#160;investigating&#160;the role of spinal cord glial cells in the development of neuropathic pain, a culture system that is derived from the adult mouse spinal cord has been developed by adapting a previously-reported method used to generate adult rat mixed glial cultures4, 5. The mouse spinal cord glial culture was further refined recently10 and is described in more detail in this article. Adult spinal cord mixed glial cultures can be established with a mouse from selected strains that fit the needs of the particular study, and cells can be maintained in culture for up to 21 d post initiation of the culture. This method can be used in neuropathic pain studies, as well as in investigations of various neurological diseases that involve pathological changes within the spinal cord, such as amyotrophic lateral sclerosis (ALS), human immunodeficiency virus (HIV)-associated sensory neuropathy, and multiple sclerosis (MS).

<table><tbody><tr><td>Dulbecco&amp;rsquo;s modification of Eagle&amp;rsquo;s media (DMEM) with 4.5 g/L glucose</td><td>Lonza</td><td>12-709F</td><td>The cDMEM media is a standard, widely used culture media. Individual researchers can decide where to purchase the DMEM and all other components used to make cDMEM media.</td></tr><tr><td>L-Glutamine (100x)</td><td>Lonza</td><td>17-605E</td><td>The L-glutamine is a standard, widely used component for various culture media. Individual researchers can decide where to purchase L-glutamine.</td></tr><tr><td>Antibiotic-Antimycotic Solution (100x)</td><td>Corning-Mediatech</td><td>30-004-CI</td><td>This is a combination of penicillin, streptomycin and Amphotericin formulated to contain 10,000 units/mL penicillin G, 10 mg/mL streptomycin sulfate and 25 &amp;micro;g/mL amphotericin B. Individual researchers can decide where to purchase individual components.</td></tr><tr><td>2-mercaptoethanol (2-ME)</td><td>Sigma-Aldrich</td><td>M3148</td><td>A BioReagent, suitable for cell culture, molecular biology and electrophoresis.</td></tr><tr><td>Papain dissociation system</td><td>Worthington Biochemical Corporation</td><td>LK003150</td><td>Individual components of this kit can be purchased separately.&amp;nbsp;</td></tr><tr><td>Percoll</td><td>GE Health Care</td><td>17-0891-01</td><td>Percoll is sold as sterile solution. Undiluted Percoll can be re-autoclaved if needed.</td></tr><tr><td>Lab-line incubator/shaker&amp;nbsp;</td><td>Barstead/Lab-line</td><td>MaxQ4000&amp;nbsp;</td><td>This is the incubator/shaker we have currently. Other types of shakers can be used instead.</td></tr><tr><td>Lipopolysaccharides, &lt;em&gt;Salmonella Minnesota&lt;/em&gt; Re595</td><td>Sigma-Aldrich</td><td>L-9764</td><td>Other strains of LPS can also induce glial responses. The magnitude of the responses though, may vary.</td></tr><tr><td>Mouse IL-6 DuoSet ELISA&amp;nbsp;</td><td>R&amp;amp;D Systems</td><td>DY406</td><td>Each individual Researcher can select the ELISA kit he or she prefers.</td></tr><tr><td>Mouse TNF-alpha DuoSet ELISA</td><td>R&amp;amp;D Systems</td><td>DY410</td><td>Each individual Researcher can select the ELISA kit he or she prefers.</td></tr><tr><td>Mouse IP-10 (CXCL10) DuoSet ELISA</td><td>R&amp;amp;D Systems</td><td>DY466</td><td>Each individual Researcher can select the ELISA kit he or she prefers.</td></tr><tr><td>Mouse MCP-1 (CCL2) ELISA Opteia set</td><td>BD Biosciences</td><td>555260</td><td>Each individual Researcher can select the ELISA kit he or she prefers.</td></tr><tr><td>Mouse chemokine Q-Plex</td><td>Quansys Biosciences</td><td>120251MS</td><td>This product was not available for in-house assay at the time. Instead, we sent out samples to the manufacturer for analysis.</td></tr><tr><td>APC-anti-mouse-CD45 (clone 30-F11)</td><td>eBioscience</td><td>17-0451</td><td>Antibody of the same clone but from other vendors can be used.</td></tr><tr><td>FITC-anti-mouse-CD11b (clone M1/70)</td><td>eBioscience</td><td>11-0112</td><td>Antibody of the same clone but from other vendors can be used.</td></tr><tr><td>Accuri C6 flow cytometer</td><td>BD Biosciences</td><td>BD Accuri C6&amp;nbsp;</td><td>Each individual Researcher can use any flow cytometer he or she prefers.</td></tr><tr><td>FlowJo software</td><td>Tree Star, Inc.</td><td>FlowJo7.6.5</td><td>Each individual Researcher can use any analysis software he or she prefers.</td></tr></tbody></table>

preparation of primary mixed glial cultures from adult mouse spinal cord tissue

It has been well-accepted that spinal cord glial responses contribute significantly to the development of neuropathic pain. Tremendous information regarding glial activities at the cellular and molecular levels has been obtained through in vitro cell culture systems. The in vitro systems utilized, mainly include primary glia derived from neonatal brain cortical tissue and immortalized cell lines. However, these systems may not reflect the characteristics of spinal cord glial cells in vivo. In order to further investigate the roles of spinal cord glial cells in the development of peripheral nerve injury-induced neuropathic pain using a culture system that better reflects the in vivo condition, our laboratory has developed a method to establish primary spinal cord mixed glial cultures from adult mice. Briefly, spinal cords are collected from adult mice and processed through papain digestion followed by myelin removal with a density-gradient medium. Single cell suspensions are cultured in complete Dulbecco&#39;s modified Eagle media (cDMEM) supplemented with 2-mercaptoethanol (2-ME) at 35.9 oC. These culture conditions were optimized specifically for the growth of mixed glial cells. Under these conditions, cells are ready to be used for experimentation between 12 - 14 d&#160;(cells are usually in log phase during this time) after the establishment of the culture (D 0) and can be kept in culture conditions up to D 21. This culture system can be used to investigate the responses of spinal cord glial cells upon stimulation with various substances and agents. Besides neuropathic pain, this system can be used to study glial responses in other diseases that involve pathological changes of spinal cord glial cells.

This method can be used to prepare mixed glial cells from both mice and rats. The average total cell number per well in a 12-well plate on D 12 post-initiation of the culture should be relatively stable, with around 100,000 cells per well when cells are derived from mouse spinal cords. Glial cells obtained from this method can be used in experiments that are designed to examine adult spinal cord glial responses upon administration of substances and agents of interest. Figure 3&#16...

Watch this Scientific Journal Video about Preparation of Primary Mixed Glial Cultures from Adult Mouse Spinal Cord Tissue at JoVE.com

Preparation of Primary Mixed Glial Cultures from Adult Mouse Spinal Cord Tissue

The development of neuropathic pain involves pathological changes of spinal cord glial cells. A reliable glial culture system derived from adult spinal cord tissue and designed for studying these cells in vitro is lacking. Therefore, we show here how&#160;to establish primary mixed glial cultures from adult mouse spinal cord tissue.

It has been well-accepted that spinal cord glial responses contribute significantly to the development of neuropathic pain. Tremendous information ...

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10.6K Views.  University of New England.  De ontwikkeling van neuropatische pijn omvat pathologische veranderingen van het ruggenmerg gliacellen. Een betrouwbare gliale kweeksysteem afgeleid van volwassen ruggenmerg weefsel en is ontworpen voor het bestuderen van deze cellen in vitro ontbreekt. Daarom zien we hier hoe je primaire gemengde gliale culturen van volwassen muis ruggenmerg weefsel vast te stellen. 

Video: Preparation of Primary Mixed Glial Cultures from Adult Mouse Spinal Cord Tissue

Primary Microglia Isolation from Mixed Glial Cell Cultures of Neonatal Rat Brain Tissue

Microglia account for approximately 12% of the total cellular population in the mammalian brain. While neurons and astrocytes are considered the major cell types of the nervous system, microglia play a significant role in normal brain physiology by monitoring tissue for debris and pathogens and maintaining homeostasis in the parenchyma via phagocytic activity 1,2. Microglia are activated during a number of injury and disease conditions, including neurodegenerative disease, traumatic brain injury, and nervous system infection 3. Under these activating conditions, microglia increase their phagocytic activity, undergo morpohological and proliferative change, and actively secrete reactive oxygen and nitrogen species, pro-inflammatory chemokines and cytokines, often activating a paracrine or autocrine loop 4-6. As these microglial responses contribute to disease pathogenesis in neurological conditions, research focused on microglia is warranted.
	Due to the cellular heterogeneity of the brain, it is technically difficult to obtain sufficient microglial sample material with high purity during in vivo experiments. Current research on the neuroprotective and neurotoxic functions of microglia require a routine technical method to consistently generate pure and healthy microglia with sufficient yield for study. We present, in text and video, a protocol to isolate pure primary microglia from mixed glia cultures for a variety of downstream applications. Briefly, this technique utilizes dissociated brain tissue from neonatal rat pups to produce mixed glial cell cultures. After the mixed glial cultures reach confluency, primary microglia are mechanically isolated from the culture by a brief duration of shaking. The microglia are then plated at high purity for experimental study.
	The principle and protocol of this methodology have been described in the literature 7,8. Additionally, alternate methodologies to isolate primary microglia are well described 9-12. Homogenized brain tissue may be separated by density gradient centrifugation to yield primary microglia 12. However, the centrifugation is of moderate length (45 min) and may cause cellular damage and activation, as well as, cause enriched microglia and other cellular populations. Another protocol has been utilized to isolate primary microglia in a variety of organisms by prolonged (16 hr) shaking while in culture 9-11. After shaking, the media supernatant is centrifuged to isolate microglia. This longer two-step isolation method may also perturb microglial function and activation. We chiefly utilize the following microglia isolation protocol in our laboratory for a number of reasons: (1) primary microglia simulate in vivo biology more faithfully than immortalized rodent microglia cell lines, (2) nominal mechanical disruption minimizes potential cellular dysfunction or activation, and (3) sufficient yield can be obtained without passage of the mixed glial cell cultures.
	It is important to note that this protocol uses brain tissue from neonatal rat pups to isolate microglia and that using older rats to isolate microglia can significantly impact the yield, activation status, and functional properties of isolated microglia. There is evidence that aging is linked with microglia dysfunction, increased neuroinflammation and neurodegenerative pathologies, so previous studies have used ex vivo adult microglia to better understand the role of microglia in neurodegenerative diseases where aging is important parameter. However, ex vivo microglia cannot be kept in culture for prolonged periods of time. Therefore, while this protocol extends the life of primary microglia in culture, it should be noted that the microglia behave differently from adult microglia and in vitro studies should be carefully considered when translated to an in vivo setting.

Isolating primary microglia from the cellular heterogeneity of the brain is essential to investigate their role in both physiological and pathological conditions. This protocol describes a mechanical isolation and mixed cell culture technique that provides high yield and high purity, viable primary microglial cells for in vitro study and downstream applications.

Microglia account for approximately 12% of the  total cellular population in the mammalian brain. While neurons and astrocytes are considered  the major ...

Immunology and Infection

Derivation of Glial Restricted Precursors from E13 mice

This is a protocol for derivation of glial restricted precursor (GRP) cells from the spinal cord of E13 mouse fetuses. These cells are early precursors within the oligodendrocytic cell lineage. Recently, these cells have been studied as potential source for restorative therapies in white matter diseases. Periventricular leukomalacia (PVL) is the leading cause of non-genetic white matter disease in childhood and affects up to 50% of extremely premature infants. The data suggest a heightened susceptibility of the developing brain to hypoxia-ischemia, oxidative stress and excitotoxicity that selectively targets nascent white matter. Glial restricted precursors (GRP), oligodendrocyte progenitor cells (OPC) and immature oligodendrocytes (preOL) seem to be key players in the development of PVL and are the subject of continuing studies. Furthermore, previous studies have identified a subset of CNS tissue that has increased susceptibility to glutamate excitotoxicity as well as a developmental pattern to this susceptibility. Our laboratory is currently investigating the role of oligodendrocyte progenitors in PVL and use cells at the GRP stage of development. We utilize these derived GRP cells in several experimental paradigms to test their response to select stresses consistent with PVL. GRP cells can be manipulated in vitro into OPCs and preOL for transplantation experiments with mouse PVL models and in vitro models of PVL-like insults including hypoxia-ischemia. By using cultured cells and in vitro studies there would be reduced variability between experiments which facilitates interpretation of the data. Cultured cells also allows for enrichment of the GRP population while minimizing the impact of contaminating cells of non-GRP phenotype.

This protocol outlines the derivation of Glial Restricted Precursors from fetal spinal cords and maintained in vitro either for transplantation or for the study of oligodendrocytic lineage.

This is a protocol for derivation of glial restricted precursor (GRP) cells from the spinal cord of E13 mouse fetuses. These cells are early precursors ...

Culturing Microglia from the Neonatal and Adult Central Nervous System

Microglia are the resident macrophage-like cells of the central nervous system (CNS) and, as such, have critically important roles in physiological and pathological processes such as CNS maturation in development, multiple sclerosis, and spinal cord injury. Microglia can be activated and recruited to action by neuronal injury or stimulation, such as axonal damage seen in MS or ischemic brain trauma resulting from stroke. These immunocompetent members of the CNS are also thought to have roles in synaptic plasticity under non-pathological conditions. We employ protocols for culturing microglia from the neonatal and adult tissues that are aimed to maximize the viable cell numbers while minimizing confounding variables, such as the presence of other CNS cell types and cell culture debris. We utilize large and easily discernable CNS components (e.g. cortex, spinal cord segments), which makes the entire process feasible and reproducible. The use of adult cells is a suitable alternative to the use of neonatal brain microglia, as many pathologies studied mainly affect the postnatal spinal cord. These culture systems are also useful for directly testing the effect of compounds that may either inhibit or promote microglial activation. Since microglial activation can shape the outcomes of disease in the adult CNS, there is a need for in vitro systems in which neonatal and adult microglia can be cultured and studied.

We outline methods for the efficient and quick isolation/culture of viable microglia from the neonatal cerebral cortex and adult spinal cord. The dissection and plating of cortical microglia can be accomplished within 90 minutes, with the subsequent microglial harvest taking place ~ 10 days following the initial dissection.

Microglia are the resident macrophage-like cells of the central nervous system (CNS) and, as such, have critically important roles in physiological and ...

Dissection and Isolation of Murine Glia from Multiple Central Nervous System Regions

The methods presented here demonstrate laboratory procedures for the dissection of four different regions of the central nervous system (CNS) from murine neonates for the isolation of glial subpopulations. The purpose of the procedure is to dissociate microglia, oligodendrocyte progenitor cells (OPCs), and astrocytes from cortical, cerebellar, brainstem, and spinal cord tissue to facilitate further in vitro analysis. The CNS region isolation procedures allow for the determination of regional heterogeneity among glia in multiple cell culture systems. Rapid CNS region isolation is performed, followed by the mechanical removal of meninges to prevent meningeal cell contamination of glia. This protocol combines gentle tissue dissociation and plating on a specified matrix designed to preserve cell integrity and adherence. Isolating mixed glia from multiple CNS regions provides a comprehensive analysis of potentially heterogenous glia while maximizing the use of individual experimental animals. Additionally, following dissociation of regional tissue, mixed glia are further divided into multiple cell types including microglia, OPCs, and astrocytes for use in either single cell type, cell culture plate inserts, or co-culture systems. Overall, the demonstrated techniques provide a comprehensive protocol of broad applicability for careful dissection of four individual CNS regions from murine neonates and includes methods for the isolation of three individual glia cell types to examine regional heterogeneity in any number of in vitro cell culture systems or assays.

Here we present a protocol for in vitro isolation of multiple glial cell populations from a mouse CNS. This method allows for the segregation of regional microglia, oligodendrocyte precursor cells, and astrocytes to study the phenotypes of each in a variety of culture systems.

The methods presented here demonstrate laboratory procedures for the dissection of four different regions of the central nervous system (CNS) from murine ...

Primary Microglia Isolation from Postnatal Mouse Brains

Microglia are the mononuclear phagocytes in the central nervous system (CNS), which play key roles in maintaining homeostasis and regulating the inflammatory process in the CNS. To study the microglial biology in vitro, primary microglia show great advantages compared to immortalized microglial cell lines. However, microglia isolation from the postnatal mouse brain is relatively less efficient and time-consuming. In this protocol, we provide a quick and easy-to-follow method to isolate primary microglia from the neonatal mouse brain. The overall steps of this protocol include brain dissection, primary brain cell culture, and microglia isolation. Using this approach, researchers can obtain primary microglia with high purity. In addition, the harvested primary microglia were able to respond to the lipopolysaccharides challenge, indicating they retained their immune function. Collectively, we developed a simplified approach to efficiently isolate primary microglia with high purity, which facilitates a wide range of microglial biology investigations&#160;in vitro.

Primary cell culture is one of the primarily used approaches for studying microglial biology in vitro. Here, we developed a method for simple and rapid microglia isolation from the mouse postnatal day 1 (P1) to P4.

Microglia are the mononuclear phagocytes in the central nervous system (CNS), which play key roles in maintaining homeostasis and regulating the ...

Coculturing AdMSCs and Glia to Reduce Prion-Induced Inflammation

Adipose-Derived Mesenchymal Stromal Cells Co-Cultured with Primary Mixed Glia to Reduce Prion-Induced Inflammation

Mesenchymal stromal cells (MSCs) are potent regulators of inflammation through the production of anti-inflammatory cytokines, chemokines, and growth factors. These cells show an ability to regulate neuroinflammation in the context of neurodegenerative diseases such as prion disease and other protein misfolding disorders. Prion diseases can be sporadic, acquired, or genetic; they can result from the misfolding and aggregation of the prion protein in the brain. These diseases are invariably fatal, with no available treatments.
One of the earliest signs of disease is the activation of astrocytes and microglia and associated inflammation, which occurs prior to detectable prion aggregation and neuronal loss; thus, the anti-inflammatory and regulatory properties of MSCs can be harvested to treat astrogliosis in prion disease. Recently, we showed that adipose-derived MSCs (AdMSCs) co-cultured with BV2 cells or primary mixed glia reduce prion-induced inflammation through paracrine signaling. This paper describes a reliable treatment using stimulated AdMSCs to decrease prion-induced inflammation.
A heterozygous population of AdMSCs can easily be isolated from murine adipose tissue and expanded in culture. Stimulating these cells with inflammatory cytokines enhances their ability to both migrate toward prion-infected brain homogenate and produce anti-inflammatory modulators in response. Together, these techniques can be used to investigate the therapeutic potential of MSCs on prion infection and can be adapted for other protein misfolding and neuroinflammatory diseases.

Author Spotlight: Insight Into Advances in Prion Diseases Research

Adipose-derived mesenchymal stromal cells (AdMSCs) have potent immunomodulatory properties useful for treating diseases associated with inflammation. We demonstrate how to isolate and culture murine AdMSCs and primary mixed glia, stimulate AdMSCs to upregulate anti-inflammatory genes and growth factors, assess migration of AdMSCs, and co-culture AdMSCs with primary mixed prion-infected glia.

Mesenchymal stromal cells (MSCs) are potent regulators of inflammation through the production of anti-inflammatory cytokines, chemokines, and growth ...

Efficient Extraction of Astrocytes and Microglia from the Adult Mouse Spinal Cord

Isolation of Pure Astrocytes and Microglia from the Adult Mouse Spinal Cord For In Vitro Assays and Transcriptomic Studies

Astrocytes and microglia play pivotal roles in central nervous system development, injury responses, and neurodegenerative diseases. These highly dynamic cells exhibit rapid responses to environmental changes and display significant heterogeneity in terms of morphology, transcriptional profiles, and functions. While our understanding of the functions of glial cells in health and disease has advanced substantially, there remains a need for in vitro, cell-specific analyses conducted in the context of insults or injuries to comprehensively characterize distinct cell populations. Isolating cells from the adult mouse offers several advantages over cell lines or neonatal animals, as it allows for the analysis of cells under pathological conditions and at specific time points. Furthermore, focusing on spinal cord-specific isolation, excluding brain involvement, enables research into spinal cord pathologies, including experimental autoimmune encephalomyelitis, spinal cord injury, and amyotrophic lateral sclerosis. This protocol presents an efficient method for isolating astrocytes and microglia from the adult mouse spinal cord, facilitating immediate or future analysis with potential applications in functional, molecular, or proteomic downstream studies.

Author Spotlight: Isolation of Glial Cells from the Adult Mouse Spinal Cord 

This protocol outlines the isolation of purified astrocytes and microglia from the adult mouse spinal cord, facilitating subsequent applications such as RNA analysis and cell culture. It includes detailed cell dissociation methods and procedures designed to enhance both the quality and yield of isolated cells.

Astrocytes and microglia play pivotal roles in central nervous system development, injury responses, and neurodegenerative diseases. These highly dynamic ...

 Primary Microglia and Neuron Co-Culture Protocol for CNS Interaction Studies

Generating and Co-culturing Murine Primary Microglia and Cortical Neurons

Microglia are tissue-resident macrophages of the central nervous system (CNS), performing numerous functions that support neuronal health and CNS homeostasis. They are a major population of immune cells associated with CNS disease activity, adopting&#160;reactive phenotypes that potentially contribute to neuronal injury during chronic neurodegenerative diseases such as multiple sclerosis (MS). The distinct mechanisms by which microglia regulate neuronal function and survival during health and disease remain limited due to challenges in resolving the complex in vivo interactions between microglia, neurons, and other CNS environmental factors. Thus, the in vitro approach of co-culturing microglia and neurons remains a valuable tool for studying microglia-neuronal interactions. Here, we present a protocol to generate and co-culture primary microglia and neurons from mice. Specifically, microglia were isolated after 9-10 days in vitro from a mixed glia culture established from brain homogenates derived from neonatal mice between post-natal days 0-2. Neuronal cells were isolated from brain cortices of mouse embryos between embryonic days 16-18. After 4-5 days in vitro, neuronal cells were seeded in 96-well plates, followed by the addition of microglia to form the co-culture. Careful timing is critical for this protocol as both cell types need to reach experimental maturity to establish the co-culture. Overall, this co-culture can be useful for studying microglia-neuron interactions and can provide multiple readouts, including immunofluorescence microscopy, live imaging, as well as RNA and protein assays.

Author Spotlight: In Vitro Co-Culture Model for Studying Microglia-Neuronal Interactions in Disease Conditions

This protocol describes a microglia-neuronal co-culture established from primary neuronal cells isolated from mouse embryos at embryonic days 15-16 and primary microglia generated from the brains of neonatal mice at post-natal days 1-2.

Microglia are tissue-resident macrophages of the central nervous system (CNS), performing numerous functions that support neuronal health and CNS ...

Obtaining a Mixed Oligodendrocyte and Astrocyte Culture From Adult Mouse Neural Stem Cells

Source: Baldassarro, V. A. <a href="https://app.jove.com/v/61988">High-Content Screening Differentiation and Maturation Analysis of Fetal and Adult Neural Stem Cell-Derived Oligodendrocyte Precursor Cell Cultures.</a> J. Vis. Exp. (2021)
This video demonstrates a detailed protocol for isolating the lateral ventricle walls from the adult mouse brain and performing enzymatic tissue dissociation to obtain single cells. These cells are then subjected to specific culture conditions that selectively enhance the proliferation of neural stem cells and promote their differentiation into co-cultures of oligodendrocytes and astrocytes.

All procedures involving sample collection have been performed in accordance with the institute&#39;s IRB guidelines.
1. Solutions and reagents

	Prepare ...

JoVE Encyclopedia of Experiments

Neuronal Culture Techniques

Primary Neuronal Culture

Obtaining a Mixed Glial Cell Culture from a Neonatal Mouse Brain

Source: Sarkar, S. et al., <a href="https://app.jove.com/v/55364">Rapid and Refined CD11b Magnetic Isolation of Primary Microglia with Enhanced Purity and Versatility.</a> J. Vis. Exp. (2017)
The video demonstrated the method of isolating and culturing cells from a neonatal mouse brain. It involved enzymatic and mechanical dissociation of the brain, followed by culturing in growth media lacking neuronal growth factor to obtain a mixed glial population.

All procedures involving animal samples have been reviewed and approved by the appropriate animal ethical review committee. 
1. Growing of Mixed Glial ...

Preparation of Primary Mixed Glial Cultures from Adult Mouse Spinal Cord Tissue

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