We thank Castle Raley at the George Washington University Genomics Core for RNA analyses and Q2 Lab Solutions for RNA sequencing analyses. This work was supported by the National Institute of Neurological Disorders and Stroke [grant number F31NS117085] and the Vivian Gill Research Endowment to Dr. Robert H. Miller. Figure 1 was created with BioRender.com.

All animal care and experimental procedures were conducted following the approval of the Animal Care and Use Committee at The George Washington University School of Medicine and Health Sciences (Washington, D.C., USA; IACUC#2021-004). The study utilized male and female C57BL/6J wild-type (WT) mice aged 10 weeks to 5 months, which were sourced from a commercial supplier (see Table of Materials) and housed at The George Washington University. An overview of the protocol workflow is presented in Figure 1.
1. Preparation of the spinal cord
<ol>
	<li>Anesthetize the animals using Avertin (12.5 mg/mL of 2,2,2-Tribromoethanol and 2.5% 2-methyl-2-butanol in sterile water) (see Table of Materials). Confirm the absence of a response to toe and tail pinches in the mice.</li>
	<li>Perform cardiac perfusion with cold 1x Dulbecco&#39;s phosphate-buffered saline (DPBS) to remove peripheral blood mononuclear cells.
	<ol>
		<li>Place the animal on a shallow tray and make a lateral incision to expose the pleural cavity. Insert a 23 G perfusion needle connected to a peristaltic pump (see Table of Materials) into the left ventricle and activate the pump. Once cold DPBS flows through the heart, create a small incision in the right atrium. 
		&#8203;NOTE: A faster perfusion rate is preferred in this step to enhance cell viability. Blood should be flushed out in under 1 min. Clearing of the liver indicates successful perfusion.</li>
	</ol>
	</li>
	<li>Decapitate the animal using large scissors and remove the spinal column14. Submerge it in cold 1x DPBS with Ca2+/Mg2+/0.2% glucose in a Petri dish on ice for tissue rinsing.</li>
	<li>Starting now, ensure that all steps are conducted in a sterile environment.&#160;Use hydraulic extrusion14 to isolate the entire spinal cord. Employ an 18 G needle and a 10 mL syringe filled with cold 1x DPBS with Ca2+/Mg2+/0.2% glucose. Transfer the spinal cord to a Petri dish placed on ice packs containing sufficient cold 1x DPBS with Ca2+/Mg2+/0.2% glucose to submerge the entire tissue.</li>
	<li>Carefully remove&#160;the meninges under a microscope within a laminar flow hood. Transfer the spinal cord to an empty Petri dish on ice packs, and using a No. 10 blade surgical scalpel, cut the entire spinal cord into 2-3 mm sections.</li>
</ol>
2. Enzymatic cell dissociation
<ol>
	<li>Add Enzyme mix 1 and Enzyme mix 2 from the commercially available Adult Brain Dissociation Kit following the manufacturer&#39;s protocol (see Table of Materials). Swirl the enzymes in the dish several times to ensure uniform coating of the spinal cord, then incubate at 37 &#176;C for 30 min. Every 5 minutes, gently swirl the dish to prevent tissue clumping and facilitate even distribution of reagents.</li>
	<li>Remove the dish from the incubator and add 350 &#181;L of 0.46 mg/mL DNAse I in Minimal Essential Medium (MEM) (see Table of Materials). Mix by gently swirling.</li>
	<li>Add 1 mL of cold DMEM/0.5% Fetal Bovine Serum (FBS) and mix by gently swirling. Immediately transfer the entire contents to a 5 mL tube.</li>
</ol>
3. Mechanical cell dissociation
<ol>
	<li>Using a P1000 pipette, gently triturate the tissue three times, ensuring that tissue pieces are drawn up each time to further dissociate the tissue. Then, using a plugged 9&#34; glass Pasteur pipette, gently triturate five more times, ensuring no bubbles are generated during the process.</li>
	<li>Place the 5 mL tube upright and allow the tissue to settle at the bottom for 30 s. Once the tissue has settled, draw up the supernatant using a P1000 pipette and pass it through a 30 &#181;m filter into a 15 mL conical tube.</li>
	<li>To the same 5 mL tube with the remaining tissue, add 1 mL of cold DMEM/0.5% FBS. Using a Pasteur pipette, gently triturate three times.</li>
	<li>Allow the tissue to settle at the bottom for 30 s, then pass the supernatant through a 30 &#181;m filter and collect it into the same 15 mL tube as before. Repeat step 3.3 and step 3.4 once more.</li>
	<li>Centrifuge the filtered cell suspension at 300 x g for 10 min at room temperature (RT). Carefully remove and discard the resulting supernatant using a vacuum aspirator.</li>
</ol>
4. Myelin removal
<ol>
	<li>Remove myelin using the debris removal solution (DRS) provided in the Adult Brain Dissociation Kit following the manufacturer&#39;s protocol. After debris removal, add 5 mL of cold DMEM/0.5% FBS to the cell pellet and gently invert the tube three times. Centrifuge the cell suspension at 300 x g for 10 min at room temperature (RT). 
	NOTE: If the cells will be used for in vitro studies and will remain in culture, pre-warmed DMEM/0.5% FBS should be used instead.</li>
	<li>Discard the supernatant and resuspend the cell pellet in 1 mL of DPBS/0.5% FBS (cold for RNA studies and warm for in vitro assays). Count the cells and assess viability using Trypan Blue. 
	NOTE: Cell suspensions from multiple animals may be combined to increase cell concentration.</li>
	<li>Wash the cells by adding DPBS/0.5% FBS up to a total volume of 5 mL. Centrifuge the suspension at 300 x g for 10 min at room temperature and discard the supernatant using a pipette.</li>
</ol>
5. Microglia and astrocyte isolation
<ol>
	<li>Label the cells with anti-CD11b or anti-ACSA-2 microbeads following the manufacturer&#39;s protocol (see Table of Materials).</li>
	<li>Sort the cells by positive selection using the MS columns according to the manufacturer&#39;s instructions (see Table of Materials). After sorting, centrifuge the sorted cells at 300 x g for 10 min and discard the supernatant.</li>
</ol>
6. Plating cells for in vitro assays
NOTE: If cells will not be plated and will be used immediately for RNA analysis, proceed to step 8.
<ol>
	<li>Resuspend the cells in 1 mL of warm DMEM/0.5% FBS. Count the cells and assess their viability using a hemacytometer (see Table of Materials).</li>
	<li>Adjust the cell concentration to 75,000 cells per 50 &#181;L. Add 50 &#181;L of the cell suspension to each Poly-L-lysine-coated coverslip11 in a 24-well plate.</li>
	<li>Incubate at 37 &#176;C for 2 h to allow the cells to adhere to the coverslip.</li>
	<li>Carefully add 450 &#181;L of warm DMEM/5% FBS/Penicillin-Streptomycin (Pen-Strep, see Table of Materials) to each well.</li>
	<li>After 3 days, replace half of the media with 250 &#181;L of warm DMEM/5% FBS/Pen-Strep. For maintenance, completely replace the media with 500 &#181;L of warm DMEM/5% FBS/Pen-Strep every 4-5 days.</li>
</ol>
7. Immunohistochemistry
NOTE: It is best to perform immunohistochemistry analyses after at least 3 days when the media has been replaced at least once. This ensures debris has been removed and cells have completely adhered to the coverslip.
<ol>
	<li>Remove the media and label the cells with anti-mouse mAb O4 (1:100) (see Table of Materials) in warm DMEM/5% FBS/10% normal goat serum (NGS) for 15 min at room temperature (RT) or at 37 &#176;C. 
	NOTE: Skip this step and proceed to step 7.3 if the cells will not be labeled with O4.</li>
	<li>Gently rinse the coverslips by dipping them into warm DMEM/5% FBS three times. Add goat anti-mouse 594 IgM (1: 300) (see Table of Materials) in warm DMEM/5% FBS/10% NGS and incubate at RT for 15 min in the dark. Gently rinse three times in warm DMEM/5% FBS.</li>
	<li>Fix the cells with cold 5% acetic acid/methanol for 15 min at 4 &#176;C. Wash three times with 1x PBS, then label with the appropriate antibody: anti-rabbit GFAP (1: 500), anti-mouse GFAP (1: 500), or anti-rabbit Iba1 (1: 500) in 1% Triton-X100/10% NGS in 1x DPBS (see Table of Materials). Incubate for 1 h at RT. 
	NOTE: Keep coverslips in the dark if they have already been stained with O4.</li>
	<li>Gently rinse three times with PBS. Label with the appropriate secondary antibody: anti-mouse 594 IgG (1: 500), anti-rabbit 488 IgG (1: 500) (see Table of Materials). Incubate for 30 min at RT in the dark.</li>
	<li>Gently rinse three times with PBS. Counterstain with DAPI (1: 1000) for 1 min at RT. Rinse three times with PBS, add mounting medium (see Table of Materials), and mount coverslips onto slides.</li>
</ol>
8. RNA extraction
NOTE: Ideally, there should be at least 100,000 cells to extract sufficient RNA for analysis. If necessary, cells from 2-3 spinal cords may be combined.
<ol>
	<li>Extract RNA using a commercially available RNA isolation kit following the manufacturer&#39;s protocol (see Table of Materials). For each wash step with the RW1 wash buffer provided in the kit, leave the cells in the wash buffer for an additional 2 min.</li>
	<li>Remove any remaining genomic DNA using DNase I according to the manufacturer&#39;s instructions (see Table of Materials). Incubate with DNase at RT for 15 min, then wash with RW1 buffer.</li>
	<li>To increase RNA yield, prior to elution, incubate the samples in RNAse-free water at RT for 10 min. Assess RNA integrity and quantity using a bioanalyzer15 (see Table of Materials).</li>
</ol>

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

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P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Astrocytes+are+necessary+for+blood-brain+barrier+maintenance+in+the+adult+mouse+brain.">Astrocytes are necessary for blood-brain barrier maintenance in the adult mouse brain.</a> Glia. 69 (2), 436-472 (2021).</li><li>Badimon, A., 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=Negative+feedback+control+of+neuronal+activity+by+microglia.">Negative feedback control of neuronal activity by microglia.</a> Nature. 586, 417-423 (2020).</li><li>Yanuck, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microglial+phagocytosis+of+neurons:+diminishing+neuronal+loss+in+traumatic,+infectious,+inflammatory,+and+autoimmune+CNS+disorders.">Microglial phagocytosis of neurons: diminishing neuronal loss in traumatic, infectious, inflammatory, and autoimmune CNS disorders.</a> Front Psychiatry. 10, 712 (2019).</li><li>Xu, Y. J., Au, N. P. B., Ma, C. H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+and+phenotypic+diversity+of+microglia:+implication+for+microglia-based+therapies+for+alzheimer&#8217;s+disease.">Functional and phenotypic diversity of microglia: implication for microglia-based therapies for alzheimer&#8217;s disease.</a> Front Aging Neurosci. 14, 896852 (2022).</li><li>Song, S., 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=Microglial-oligodendrocyte+interactions+in+myelination+and+neurological+function+recovery+after+traumatic+brain+injury.">Microglial-oligodendrocyte interactions in myelination and neurological function recovery after traumatic brain injury.</a> J Neuroinflammation. 19 (1), 246 (2022).</li><li>Butler, C. A., 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=Microglial+phagocytosis+of+neurons+in+neurodegeneration,+and+its+regulation.">Microglial phagocytosis of neurons in neurodegeneration, and its regulation.</a> J Neurochem. 158 (3), 621-639 (2021).</li><li>Voskuhl, R. R., 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=Reactive+astrocytes+form+scar-like+perivascular+barriers+to+leukocytes+during+adaptive+immune+inflammation+of+the+CNS.">Reactive astrocytes form scar-like perivascular barriers to leukocytes during adaptive immune inflammation of the CNS.</a> J Neurosci. 29 (37), 11511-11522 (2009).</li><li>Bordon, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MAFG+activity+in+astrocytes+drives+CNS+inflammation.">MAFG activity in astrocytes drives CNS inflammation.</a> Nature Reviews Immunology. 20, 205 (2020).</li><li>Agalave, N. M., Lane, B. T., Mody, P. H., Szabo-Pardi, T. A., Burton, 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=Isolation,+culture,+and+downstream+characterization+of+primary+microglia+and+astrocytes+from+adult+rodent+brain+and+spinal+cord.">Isolation, culture, and downstream characterization of primary microglia and astrocytes from adult rodent brain and spinal cord.</a> J Neurosci Methods. 340, 108742 (2020).</li><li>Kerstetter, A. E., Miller, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+culture+of+spinal+cord+astrocytes.">Isolation and culture of spinal cord astrocytes.</a> Methods in Molecular Biology. 814, 93-104 (2012).</li><li>Hersbach, B. A., Simon, T., Masserdotti, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+direct+neuronal+reprogramming+of+mouse+astrocytes.">Isolation and direct neuronal reprogramming of mouse astrocytes.</a> J Vis Exp. (185), 64175 (2022).</li><li>Nikodemova, M., Watters, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+isolation+of+live+microglia+with+preserved+phenotypes+from+adult+mouse+brain.">Efficient isolation of live microglia with preserved phenotypes from adult mouse brain.</a> J Neuroinflammation. 9, 147 (2012).</li><li>Richner, M., Jager, S. B., Siupka, P., Vaegter, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydraulic+extrusion+of+the+spinal+cord+and+isolation+of+dorsal+root+ganglia+in+rodents.">Hydraulic extrusion of the spinal cord and isolation of dorsal root ganglia in rodents.</a> J Vis Exp. (119), e55226 (2017).</li><li>Davies, J., Denyer, T., Hadfield, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioanalyzer+chips+can+be+used+interchangeably+for+many+analyses+of+DNA+or+RNA.">Bioanalyzer chips can be used interchangeably for many analyses of DNA or RNA.</a> Biotechniques. 60 (4), 197-199 (2016).</li><li>Ahn, J. J., Islam, Y., Miller, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+type+specific+isolation+of+primary+astrocytes+and+microglia+from+adult+mouse+spinal+cord.">Cell type specific isolation of primary astrocytes and microglia from adult mouse spinal cord.</a> J Neurosci Methods. 375, 109599 (2022).</li><li>Pan, J., Wan, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methodological+comparison+of+FACS+and+MACS+isolation+of+enriched+microglia+and+astrocytes+from+mouse+brain.">Methodological comparison of FACS and MACS isolation of enriched microglia and astrocytes from mouse brain.</a> J Immunol Methods. 486, 112834 (2020).</li><li>Neuschulz, A., 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=A+single-cell+RNA+labeling+strategy+for+measuring+stress+response+upon+tissue+dissociation.">A single-cell RNA labeling strategy for measuring stress response upon tissue dissociation.</a> Mol Syst Biol. 19, 11147 (2023).</li><li>CB, S., 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=One+brain-all+cells:+a+comprehensive+protocol+to+isolate+all+principal+cns-resident+cell+types+from+brain+and+spinal+cord+of+adult+healthy+and+EAE+mice.">One brain-all cells: a comprehensive protocol to isolate all principal cns-resident cell types from brain and spinal cord of adult healthy and EAE mice.</a> Cells. 10 (3), 1-25 (2021).</li></ol>

None

The isolation of pure, viable primary cells is paramount for investigating the structure and function of specific cell types. In the adult mouse, particularly in the spinal cord, this task poses significant challenges, as existing protocols are often not tailored to the adult spinal cord10,17. This protocol presents an efficient and cost-effective method applicable to various downstream applications, including cell culture, flow cytometry, histology, and transcri...

Astrocytes and microglia are versatile glial cells that play vital roles in the central nervous system (CNS), encompassing responsibilities such as regulating neuronal function, contributing to CNS development, maintaining the blood-brain barrier, and participating in other critical processes1,2,3,4. Besides their role in maintaining homeostasis, these glial cells also play a pivotal part in injury and repair mechanisms. Microglia are well-known for their phagocytic, inflammatory, and migratory capabilities following insults or injuries5,6,7. Astrocyte responses in disease are equally diverse, encompassing contributions to inflammation, the formation of glial scars, and the compromise of the blood-brain barrier8,9. Although our understanding of the detrimental and reparative roles of microglia and astrocytes in the CNS has grown, the inherent heterogeneity in both their structure and function necessitates robust tools for studying them in various contexts.
Gaining further insight into the roles of microglia and astrocytes in health and disease requires a combined approach of in vivo and in vitro investigations. In vivo techniques leverage the intricate crosstalk between glial cells and neurons within the CNS, while in vitro methodologies prove valuable when assessing single-cell functions or responses under specific stimuli. Each method offers unique advantages; in vitro studies are essential for understanding the specific roles of these cell types without direct or indirect input from neighboring cells. Additionally, in vitro assays utilizing immortal cell lines present certain benefits, including the ability to proliferate indefinitely, cost-efficiency, and ease of maintenance. However, it&#39;s important to note that primary cells more closely mimic normal physiological responses compared to cell lines. This physiological relevance is crucial in functional assays and transcriptomic analyses.
One of the challenges in obtaining primary cells, particularly from the adult mouse spinal cord, lies in the quantity and viability of the samples. The adult spinal cord, being smaller than the brain and containing a significant amount of myelin, poses unique difficulties. While there are several published protocols detailing the isolation of pure, viable glial cells from neonatal animals or the adult mouse brain10,11,12,13, these methodologies may not be suitable for studying diseases and injuries specific to the spinal cord. In this protocol, we offer a comprehensive procedure to efficiently isolate pure, viable microglia and astrocytes from the adult mouse spinal cord, facilitating downstream applications in cell culture and transcriptomic analyses. This protocol has been successfully employed to isolate these cells from adult mice aged 10 weeks to 5 months, demonstrating its utility across various contexts, including studies involving conditional knockout mice, drug responses, developmental research, and age-related models.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>2,2,2-Tribromoethanol</td>
			<td>Sigma Aldrich</td>
			<td>T48402</td>
			<td></td>
		</tr>
		<tr>
			<td>24 well tissue culture plate</td>
			<td>Avantor</td>
			<td>10861-558</td>
			<td></td>
		</tr>
		<tr>
			<td>2-Methyl-2-butanol, 98%</td>
			<td>Thermo Fisher</td>
			<td>A18304-0F</td>
			<td></td>
		</tr>
		<tr>
			<td>4&#39;,6-Diamidino-2-Phenylindole, Dihydrochloride</td>
			<td>Invitrogen</td>
			<td>D1306</td>
			<td>1:1000</td>
		</tr>
		<tr>
			<td>45% glucose solution</td>
			<td>Corning</td>
			<td>25-037-CI</td>
			<td></td>
		</tr>
		<tr>
			<td>5 mL capped tubes</td>
			<td>Eppendorf</td>
			<td>30122305</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic acid</td>
			<td>Sigma-Adlrich</td>
			<td>A6283</td>
			<td></td>
		</tr>
		<tr>
			<td>Adult Brain Dissociation Kit</td>
			<td>Miltenyi</td>
			<td>103-107-677</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-ACSA2 Microbead Kit</td>
			<td>Miltenyi</td>
			<td>130-097-679</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Iba1</td>
			<td>Wako</td>
			<td>019-1974</td>
			<td></td>
		</tr>
		<tr>
			<td>Bioanalyzer</td>
			<td>Agilent Technologies</td>
			<td>G2939BA</td>
			<td></td>
		</tr>
		<tr>
			<td>C57BL/6J wild-type (WT) mice&#160;</td>
			<td>Jackson Laboratories</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>CD11b (Microglia) MicroBeads</td>
			<td>Miltenyi</td>
			<td>130-093-634</td>
			<td></td>
		</tr>
		<tr>
			<td>Celltrics 30 &#181;m filter</td>
			<td>Sysmex Partec</td>
			<td>04-004-2326</td>
			<td></td>
		</tr>
		<tr>
			<td>Counting Chamber (Hemacytometer)</td>
			<td>Hausser Scientific Co</td>
			<td>3200</td>
			<td></td>
		</tr>
		<tr>
			<td>Deoxyribonuclease I from bovine pancreas</td>
			<td>Sigma Aldrich</td>
			<td>D4527-40KU</td>
			<td></td>
		</tr>
		<tr>
			<td>Distilled water</td>
			<td>TMO</td>
			<td>15230001</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM/F12</td>
			<td>Thermo Fisher</td>
			<td>11320074</td>
			<td></td>
		</tr>
		<tr>
			<td>DNase for RNA purification</td>
			<td>Qiagen</td>
			<td>79254</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s phosphate-buffered saline</td>
			<td>Thermo Fisher</td>
			<td>14040117</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum</td>
			<td>Thermo Fisher</td>
			<td>A5209401</td>
			<td></td>
		</tr>
		<tr>
			<td>GFAP antibody (mouse)</td>
			<td>Santa Cruz</td>
			<td>sc-33673</td>
			<td>1:500</td>
		</tr>
		<tr>
			<td>GFAP antibody (rabbit)</td>
			<td>Dako</td>
			<td>Z0334</td>
			<td>1:500</td>
		</tr>
		<tr>
			<td>Goat anti-mouse 594 IgG</td>
			<td>Invitrogen</td>
			<td>a11032</td>
			<td>1:500</td>
		</tr>
		<tr>
			<td>Goat anti-mouse 594 IgM</td>
			<td>Invitrogen</td>
			<td>a21044</td>
			<td>1:300</td>
		</tr>
		<tr>
			<td>Goat anti-Rabbit 488 IgG</td>
			<td>Invitrogen</td>
			<td>a11008</td>
			<td>1:500</td>
		</tr>
		<tr>
			<td>Iba1 antibody (rabbit)</td>
			<td>Wako</td>
			<td>019-1974</td>
			<td>1:500</td>
		</tr>
		<tr>
			<td>MACS Separator</td>
			<td>Miltenyi</td>
			<td>130-042-303</td>
			<td></td>
		</tr>
		<tr>
			<td>Masterflex C/L Pump System</td>
			<td>Thermo Fisher</td>
			<td>77122-22</td>
			<td></td>
		</tr>
		<tr>
			<td>MEM</td>
			<td>Corning</td>
			<td>15-015-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Sigma-Adlrich</td>
			<td>439193</td>
			<td></td>
		</tr>
		<tr>
			<td>Mounting Medium</td>
			<td>Vector Laboratories</td>
			<td>H-1000-10</td>
			<td></td>
		</tr>
		<tr>
			<td>MS Columns</td>
			<td>Miltenyi</td>
			<td>130-042-401</td>
			<td></td>
		</tr>
		<tr>
			<td>O4 Antibody</td>
			<td>R&#38;D</td>
			<td>MAB1326</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin</td>
			<td>Gibco</td>
			<td>15070063</td>
			<td></td>
		</tr>
		<tr>
			<td>Plugged 9&#34; glass pasteur pipette</td>
			<td>VWR</td>
			<td>14672-412</td>
			<td></td>
		</tr>
		<tr>
			<td>RNeasy Plus Micro Kit</td>
			<td>Qiagen</td>
			<td>74034</td>
			<td></td>
		</tr>
		<tr>
			<td>Royal-tek Surgical scalpel blade no. 10</td>
			<td>Fisher scientific</td>
			<td>22-079-683</td>
			<td></td>
		</tr>
		<tr>
			<td>Small Vein Infusion Set, 23 G x 19 mm</td>
			<td>Kawasumi</td>
			<td>D3K2-23G</td>
			<td></td>
		</tr>
	</tbody>
</table>

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.

The methods outlined in this protocol enable the isolation of pure and viable microglia and astrocytes from the adult mouse spinal cord, facilitating various downstream applications, including in vitro functional or histological assays and RNA analysis.
A successful isolation for in vitro studies will result in continuous cell proliferation over several days. Adult cells exhibit a slower proliferation rate compared to cells isolated from neonatal animals, and some debris may ...

Watch this Scientific Journal Video about Isolation of Glial Cells from the Adult Mouse Spinal Cord at JoVE.com

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.

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 ...

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Research

JoVE Journal

Neuroscience

1.6K Views.  The George Washington University School of Medicine. 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.

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

Dissection and Culture of Commissural Neurons from Embryonic Spinal Cord

Commissural neurons have been widely used to investigate the mechanisms underlying axon guidance during embryonic spinal cord development. The cell bodies of these neurons are located in the dorsal spinal cord and their axons follow stereotyped trajectories during embryonic development. Commissural axons initially project ventrally towards the floorplate. After crossing the midline, these axons turn anteriorly and project towards the brain. Each of these steps is regulated by the action of several guidance cues. Cultures highly enriched in commissural neurons are ideally suited for many experiments addressing the mechanisms of axon pathfinding, including turning assays, immunochemistry and biochemistry. Here, we describe a method to dissect and culture commissural neurons from E13 rat dorsal spinal cord. First, the spinal cord is isolated and dorsal strips are dissected out. The dorsal tissue is then dissociated into a cell suspension by trypsinization and mechanical disruption. Neurons are plated onto poly-L-lysine-coated glass coverslips or tissue-culture dishes. After 30 hours in vitro, most neurons have extended an axon. The purity of the culture (Yam et al. 2009), typically over 90%, can be assessed by immunolabeling with the commissural neuron markers DCC, LH2 and TAG1 (Helms and Johnson, 1998). This neuronal preparation is a useful tool for in vitro studies of the cellular and molecular mechanisms of commissural axon growth and guidance during spinal cord development.

This video demonstrates a method to dissect and culture commissural neurons from E13 rat dorsal spinal cord. Dissociated commissural neurons are useful to study the cellular and molecular mechanisms of axon growth and guidance.

Commissural neurons have been widely used to investigate the mechanisms underlying axon guidance during embryonic spinal cord development. The cell bodies ...

Spinal Cord Electrophysiology II: Extracellular Suction Electrode Fabrication

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

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

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

Production of RNA for Transcriptomic Analysis from Mouse Spinal Cord Motor Neuron Cell Bodies by Laser Capture Microdissection

Preparation of high-quality RNA from cells of interest is critical to precise and meaningful analysis of transcriptional differences among cell types or between the same cell type in health and disease or following pharmacologic treatments.&#160;In the spinal cord, such preparation from motor neurons, the target of interest in many neurologic and neurodegenerative diseases, is complicated by the fact that motor neurons represent &#60;10% of the total cell population.&#160;Laser capture microdissection (LMD) has been developed to address this problem.&#160;Here, we describe a protocol to quickly recover, freeze, and section mouse spinal cord to avoid RNA damage by endogenous and exogenous RNases, followed by staining with Azure B in 70% ethanol to identify the motor neurons while keeping endogenous RNase inhibited.&#160;LMD is then used to capture the stained neurons directly into guanidine thiocyanate lysis buffer, maintaining RNA integrity.&#160;Standard techniques are used to recover the total RNA and measure its integrity.&#160;This material can then be used for downstream analysis of the transcripts by RNA-seq and qRT-PCR.

High-quality total RNA has been prepared from cell bodies of mouse spinal cord motor neurons by laser capture microdissection after staining spinal cord sections with Azure B in 70% ethanol.&#160;Sufficient RNA (~40-60 ng) is recovered from 3,000-4,000 motor neurons to allow downstream RNA analysis by RNA-seq and qRT-PCR.

Preparation of high-quality RNA from cells of interest is critical to precise and meaningful analysis of transcriptional differences among cell types or ...

A Procedure for Implanting a Spinal Chamber for Longitudinal In Vivo Imaging of the Mouse Spinal Cord

Studies in the mammalian neocortex have enabled unprecedented resolution of cortical structure, activity, and response to neurodegenerative insults by repeated, time-lapse in vivo imaging in live rodents. These studies were made possible by straightforward surgical procedures, which enabled optical access for a prolonged period of time without repeat surgical procedures. In contrast, analogous studies of the spinal cord have been previously limited to only a few imaging sessions, each of which required an invasive surgery. As previously described, we have developed a spinal chamber that enables continuous optical access for upwards of 8 weeks, preserves mechanical stability of the spinal column, is easily stabilized externally during imaging, and requires only a single surgery. Here, the design of the spinal chamber with its associated surgical implements is reviewed and the surgical procedure is demonstrated in detail. Briefly, this video will demonstrate the preparation of the surgical area and mouse for surgery, exposure of the spinal vertebra and appropriate tissue debridement, the delivery of the implant and vertebral clamping, the completion of the chamber, the removal of the delivery system, sealing of the skin, and finally, post-operative care. The procedure for chronic in vivo imaging using nonlinear microscopy will also be demonstrated. Finally, outcomes, limitations, typical variability, and a guide for troubleshooting are discussed.

A Procedure for Implanting a Spinal Chamber for Longitudinal In Vivo Imaging of the Mouse Spinal Cord

In this video, we describe a procedure for implanting a chronic optical imaging chamber over the dorsal spinal cord of a live mouse. The chamber, surgical procedure, and chronic imaging are reviewed and demonstrated.

Studies in the mammalian neocortex have enabled unprecedented resolution of cortical structure, activity, and response to neurodegenerative insults by ...

Two-photon Imaging of Cellular Dynamics in the Mouse Spinal Cord

Two-photon (2P) microscopy is utilized to reveal cellular dynamics and interactions deep within living, intact tissues. Here, we present a method for live-cell imaging in the murine spinal cord. This technique is uniquely suited to analyze neural precursor cell (NPC) dynamics following transplantation into spinal cords undergoing neuroinflammatory demyelinating disorders. NPCs migrate to sites of axonal damage, proliferate, differentiate into oligodendrocytes, and participate in direct remyelination. NPCs are thereby a promising therapeutic treatment to ameliorate chronic demyelinating diseases. Because transplanted NPCs migrate to the damaged areas on the ventral side of the spinal cord, traditional intravital 2P imaging is impossible, and only information on static interactions was previously available using histochemical staining approaches. Although this method was generated to image transplanted NPCs in the ventral spinal cord, it can be applied to numerous studies of transplanted and endogenous cells throughout the entire spinal cord. In this article, we demonstrate the preparation and imaging of a spinal cord with enhanced yellow fluorescent protein-expressing axons and enhanced green fluorescent protein-expressing transplanted NPCs.

A new ex vivo preparation for imaging the mouse spinal cord. This protocol allows for two-photon imaging of live cellular interactions throughout the spinal cord.

Two-photon (2P) microscopy is utilized to reveal cellular dynamics and interactions deep within living, intact tissues. Here, we present a method for ...

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.

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 ...

Spinal Cord Neurons Isolation and Culture from Neonatal Mice

We present a protocol for the isolation and culture of spinal cord neurons. The neurons are obtained from neonatal C57BL/6 mice and are isolated on postnatal day 1-3. A mouse litter, usually 4-10 pups born from one breeding pair, is gathered for one experiment, and spinal cords are collected individually from each mouse after euthanasia with isoflurane. The spinal column is dissected out and then the spinal cord is released from the column. The spinal cords are then minced to increase the surface area of delivery for an enzymatic protease that allows for the neurons and other cells to be released from the tissue. Trituration is then used to release the cells into solution. This solution is subsequently fractionated in a density gradient to separate the various cells in solution, allowing for neurons to be isolated. Approximately 1-2.5 x 106 neurons can be isolated from one litter group. The neurons are then seeded onto wells coated with adhesive factors that allow for proper growth and maturation. The neurons take approximately 7 days to reach maturity in the growth and culture medium and can be used thereafter for treatment and analysis.

This study presents a technique for the isolation of neurons from WT neonatal mice. It requires the careful dissection of the spinal cord from the neonatal mouse, followed by the separation of neurons from the spinal cord tissue through mechanical and enzymatic cleavage.

We present a protocol for the isolation and culture of spinal cord neurons. The neurons are obtained from neonatal C57BL/6 mice and are isolated on ...

Characterization and Isolation of Mouse Primary Microglia by Density Gradient Centrifugation

Microglia, the resident immune cells in the brain, are the first responders to inflammation or injury in the central nervous system. Recent research has revealed microglia to be dynamic, capable of assuming both pro-inflammatory and anti-inflammatory phenotypes. Both M1 (pro-inflammatory) and M2 (pro-reparative) phenotypes play an important role in neuroinflammatory conditions such as perinatal brain injury, and exhibit differing functions in response to certain environmental stimuli. The modulation of microglial activation has been noted to confer neuroprotection thus suggesting microglia may have therapeutic potential in brain injury. However, more research is required to better understand the role of microglia in disease, and this protocol facilitates that. The protocol described below combines a density gradient centrifugation process to reduce cellular debris, with magnetic separation, producing a highly pure sample of primary microglial cells that can be used for in vitro experimentation, without the need for 2-3 weeks culturing. Additionally, the characterization steps yield robust functional data about microglia, aiding studies to better our understanding of the polarization and priming of these cells, which has strong implications in the field of regenerative medicine.

A protocol for the isolation of primary microglia from murine brains is presented. This technique aids in furthering the current understanding of neurological conditions. Density gradient centrifugation and magnetic separation are combined to produce sufficient yield of a highly pure sample. Furthermore, we outline the steps for characterization of microglia.

Microglia, the resident immune cells in the brain, are the first responders to inflammation or injury in the central nervous system. Recent research has ...

Laminectomy and Spinal Cord Window Implantation in the Mouse

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

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

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

Isolation of Adult Spinal Cord Nuclei for Massively Parallel Single-nucleus RNA Sequencing

Probing an individual cell&#39;s gene expression enables the identification of cell type and cell state. Single-cell RNA sequencing has emerged as a powerful tool for studying transcriptional profiles of cells, particularly in heterogeneous tissues such as the central nervous system. However, dissociation methods required for single cell sequencing can lead to experimental changes in the gene expression and cell death. Furthermore, these methods are generally restricted to fresh tissue, thus limiting studies on archival and bio-bank material. Single nucleus RNA sequencing (snRNA-Seq) is an appealing alternative for transcriptional studies, given that it accurately identifies cell types, permits the study of tissue that is frozen or difficult to dissociate, and reduces dissociation-induced transcription. Here, we present a high-throughput protocol for rapid isolation of nuclei for downstream snRNA-Seq. This method enables isolation of nuclei from fresh or frozen spinal cord samples and can be combined with two massively parallel droplet encapsulation platforms.

Here, we present a protocol to rapidly isolate high-quality nuclei from the fresh or frozen tissue for downstream massively parallel RNA sequencing. We include detergent-mechanical and hypotonic-mechanical tissue disruption and cell lysis options, both of which can be used for isolation of nuclei.

Probing an individual cell&#39;s gene expression enables the identification of cell type and cell state. Single-cell RNA sequencing has emerged as a ...