Transplanted type-1 astrocytes facilitate repair of demyelinating lesions by host oligodendrocytes in adult rat spinal cord.
The ethidium bromide model of demyelination/remyelination provides a system for studying the interactions between demyelinated axons, host glia and transplanted glia. The injection of 0.1% ethidium bromide in isotonic saline into the white matter of the spinal cord produces a glia-free demyelinating lesion which is subsequently remyelinated by Schwann cells and, to a lesser extent, oligodendrocytes. the in vitro description of an oligodendrocyte progenitor isolated from the adult CNS, together with the recognized role of type-1 astroctyes in controlling the developmental programme of perinatal O-2A progenitors, suggested the possibility that transplanted type-1 astrocytes may potentiate oligodendrocyte remyelination of the ethidium bromide lesion. Purified type-1 astrocyte cultures were prepared by removing cells of the oligodendrocyte lineage using a combination of exposure to cytosine arabinoside and complement-mediated immunocytolysis. Following transplantation of purified type-1 astrocyte cultures into ethidium bromide lesions, a significant increase in the extent of oligodendrocyte remyelination was achieved. Because the purified type-1 astrocyte cultures had no demonstrable oligodendrocyte-generating potential it was concluded that the additional oligodendrocytes appearing in the type-1 astrocytes transplanted lesion were of host origin. These results indicate that type-1 astrocytes can facilitate repair of demyelinating lesions by host oligodendrocytes. The possible mechanisms whereby this facilitation occurs are discussed.
Franklin
R J
RJ
Department of Clinical Veterinary Medicine, University of Cambridge, UK.
Crang
A J
AJ
Blakemore
W F
WF
D000818:Animals; D001253:Astrocytes / Q000502:physiology / Q000637:transplantation*; D002450:Cell Communication / Q000502:physiology; D003711:Demyelinating Diseases / Q000601:surgery*; D009836:Oligodendroglia / Q000502:physiology*; D051381:Rats; D013118:Spinal Cord Diseases / Q000601:surgery*