Isolation of Neural Stem/Progenitor Cells from the Periventricular Region of the Adult Rat and Human Spinal Cord

Summary

The adult mammalian spinal cord contains neural stem/progenitor cells (NSPCs) that can be isolated and expanded in culture. This protocol describes the harvesting, isolation, culture, and passaging of NSPCs generated from the periventricular region of the adult spinal cord from the rat and from human organ transplant donors.

Abstract

Adult rat and human spinal cord neural stem/progenitor cells (NSPCs) cultured in growth factor-enriched medium allows for the proliferation of multipotent, self-renewing, and expandable neural stem cells. In serum conditions, these multipotent NSPCs will differentiate, generating neurons, astrocytes, and oligodendrocytes. The harvested tissue is enzymatically dissociated in a papain-EDTA solution and then mechanically dissociated and separated through a discontinuous density gradient to yield a single cell suspension which is plated in neurobasal medium supplemented with epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and heparin. Adult rat spinal cord NSPCs are cultured as free-floating neurospheres and adult human spinal cord NSPCs are grown as adherent cultures. Under these conditions, adult spinal cord NSPCs proliferate, express markers of precursor cells, and can be continuously expanded upon passage. These cells can be studied in vitro in response to various stimuli, and exogenous factors may be used to promote lineage restriction to examine neural stem cell differentiation. Multipotent NSPCs or their progeny can also be transplanted into various animal models to assess regenerative repair.

Introduction

NSPCs are multipotent cells committed to the neural lineage that can self renew and readily expand in vitro. We refer to these cells as a mixed population of neural stem/progenitor cells since they display properties of self-renewing multipotent stem cells and more restricted progenitors. NSPCs are found in both the fetal and adult brain and spinal cord^1,2. In the adult, NSPCs are normally quiescent and reside within specific niches including the subventricular zone lining the lateral ventricles^2-4, and the periventricular region surrounding the central canal of the spinal cord^5,6.

Typically, NSPCs ....

Protocol

All animal procedures are approved by the Animal Care Committee of the University Health Network, Toronto ON Canada, in accordance with the policies established in the Guide to the Care and Use of Experimental Animals prepared by the Canadian Council on Animal Care. For the harvesting of human spinal cord tissue, approval was obtained from the University Health Network Research Ethics Board and from the Trillium-Gift of Life Foundation which oversees organ donation in Ontario, Canada.

1. Preparation of Dissection Buffers and Culture Media

1. For the isolation of rat spinal cord, prepare 100 ml dissection buffer (1x PBS + 0.6% gluco....

Results

Adult rat spinal cord cells grown in suspension culture in EFH medium will form small neurospheres (colonies of undifferentiated cells) within 1 week of initial plating. In primary cultures, most of the cells plated will die and growth factor-responsive stem cells will proliferate and are selected for in the EFH medium. By passage 3, there will be numerous free-floating neurospheres about 100 µm in diameter (Figure 2A). Neurospheres are round and phase-bright, and under high magnification, cilia-like mic.......

Discussion

During the dissection of the rat spinal cord tissue care should be taken not to damage the spinal cord while performing the laminectomy. It is easier to isolate the periventricular tissue when the spinal cord segments are intact. The tissue segments should be fully immersed in dissection buffer and the overlying meninges and white matter can be cut away as longitudinal strips with microscissors. Alternatively, fine tissue forceps can be used to peel the white matter away.

For the isolation pro.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
1x PBS	Life Technologies	#10010023	Dissection buffer
1x HBSS	Life Technologies	#14175095	Dissection buffer
D-glucose	Sigma	# G-6152	Prepare 30% glucose stock solution for dissection buffer and hormone mix
Penicillin-Streptomycin	Life Technologies	#15140-148	Dissection buffer and culture medium
Neurobasal-A	Life Technologies	#10888-022	Culture medium
L-glutamine, 200 mM	Life Technologies	#25030-081	Culture medium
B27	Life Technologies	#12587010	Culture medium
DMEM	Life Technologies	#11885084	Hormone mix
F12	Life Technologies	#21700-075	Hormone mix
NaHCO3	Sigma	# S-5761	Prepare 7.5% NaHCO3 stock solution for hormone mix
HEPES	Sigma	#H9136	Prepare 1M HEPES stock solution for hormone mix
Insulin	Sigma	#I-5500	Hormone mix
Apo-transferrin	Sigma	#T-2252	Hormone mix
Putrescine	Sigma	# P7505	Hormone mix
Selenium	Sigma	#S-9133	Hormone mix
Progesterone	Sigma	#P-6149	Hormone mix
EGF, mouse	Sigma	#E4127	Prepare 100 μg/ml stocks in B27 and aliquot; EFH medium
EGF, human recombinant	Sigma	#E9644	Prepare 100 μg/ml stocks in B27 and aliquot; EFH medium
bFGF, human recombinant	Sigma	#F0291	Prepare 100 μg/ml stocks in B27 and aliquot; EFH medium
Heparin, 10,000 U	Sigma	#H3149	Prepare 27.3 mg/ml stocks in hormone mix and aliquot; EFH medium
Papain dissociation kit	Worthington Biochemicals	#LK003150	Contains EBSS, papain, DNase, ovomucoid protease inhibitor with BSA
Sodium Pentobarbital	Bimeda – MTC Animal Health Inc	DIN 00141704
Tissue Forceps: Addisons	Fine Science Tools	#11006-12	Serrated standard tip; micro-tip also available
Fine Forceps: Dumont #4	Fine Science Tools	#11241-30
Microscissors	Fine Science Tools	#15024-10	Round-handled Vannas
Rongeurs	Bausch & Lomb	N1430
10 mm Petri dishes	Nunc	1501
T25 Culture flasks	Nunc	156367
40 μm nylon cell strainer	VWR	CA21008-949
6 well plates	Nunc	CA73520-906
Matrigel, growth factor reduced (100x)	Corning	354230	Thaw according to directions and freeze aliquots; use diluted at a ratio of 40 μl Matrigel: 1 ml SFM