Probing the influence of myelin and glia on the tensile properties of the spinal cord.
Although glia have been historically classified as the structurally supporting cells of the central nervous system, their role in tissue mechanics is still largely unstudied. The influence of myelin and glia on the mechanical properties of spinal cord tissue was examined by testing embryonic day 18 chick embryo spinal cords in uniaxial tension following disruption of the glial matrix using either ethidium bromide (EB) or an antibody against galactocerebroside (alphaGalC) in the presence of complement. Demyelination was confirmed by myelin basic protein immunoreactivity and quantified using osmium tetroxide staining. A substantial loss of astrocytes and oligodendrocytes concurrent with demyelination was observed following EB injection but not alphaGalC injection. No morphological changes were observed following injection of saline or IgG with complement as controls for EB and alphaGalC. Demyelinated spinal cords demonstrated significantly lower stiffness and ultimate tensile stress than myelinated spinal cords. No significant differences were observed in the tensile response between the two demyelinating protocols. The results demonstrate that the glial matrix provides significant mechanical support to the spinal cord, and suggests that myelin and cellular coupling of axons via the glial matrix in large part dictates the tensile response of the tissue.
Shreiber
David I
DI
Department of Biomedical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA. shreiber@rci.rutgers.edu
Hao
Hailing
H
Elias
Ragi A I
RA
D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001369:Axons / Q000378:metabolism; D002642:Chick Embryo; D004867:Equipment Design; D004996:Ethidium / Q000494:pharmacology; D005699:Galactosylceramides / Q000378:metabolism; D007074:Immunoglobulin G / Q000378:metabolism; D008954:Models, Biological; D009186:Myelin Sheath / Q000378:metabolism / Q000502:physiology*; D009457:Neuroglia / Q000378:metabolism*; D009836:Oligodendroglia / Q000378:metabolism; D013116:Spinal Cord / Q000378:metabolism*; D013314:Stress, Mechanical; D013718:Tensile Strength
D005699:Galactosylceramides; D007074:Immunoglobulin G; C002454:galactocerebroside; D004996:Ethidium