The Transplantation of Glial Cells into Areas of Primary Demyelination

Abstract

Injection of ethidium bromide into the white matter of the spinal cord produces a lesion in which demyelinated axons lie in a glial-free environment (Graça and Blakemore, 1986). This lesion therefore provides a system in which one can examine interactions between axons and glia which are involved in the reconstruction of a CNS environment around axons. By injecting glial cell cultures of differing composition it is possible to examine the ability of different cell types to influence repair and, in so doing, reveal aspects of their biology which may be difficult to document using other systems. It also provides a useful system in which to examine in-vivo,conclusions drawn from in-vitro investigations. For example, the importance of a stable extracellular matrix to the myelinating Schwann cell established by tissue culture studies (Bunge and Bunge, 1978; 1983), was well illustrated when Schwann cells were introduced into ethidium bromide lesions made in X-irradiated spinal cord of the cat (Blakemore and Crang, 1985). In these experiments it was found that myelin sheath formation following Schwann cell/axon contact only occurred in areas where there was collagen.