DIFFERENTIATION OF THE O-2A PROGENITOR-CELL LINE CG-4 INTO OLIGODENDROCYTES AND ASTROCYTES FOLLOWING TRANSPLANTATION INTO GLIA-DEFICIENT AREAS OF CNS WHITE-MATTER

The in vitro properties of the CG4 cell line have led to its increasin g use as a cell line with which to study the behaviour of the O-2A pro genitor cell. In this study we have examined the in vivo behaviour of the CG4 cell line following transplantation into areas of adult rat sp inal cord white matter which have been permanently depleted of glial c ells by the combination of local X-irradiation and direct injection of 0.1% ethidium bromide. Twenty-one days after transplantation, both my elin-forming oligodendrocytes and glial fibrillary acidic protein-posi tive astrocytes were identified within the lesion, indicating that the CG4 cell line has bipotential differentiation properties when introdu ced into a pathological environment consisting of demyelinated axons b ut devoid of oligodendrocytes or astrocytes. In this respect, the CG4 cell line resembles other glial progenitor cell lines that have been t ransplanted into similar lesions. In some areas of the lesion, remyeli nation was observed that was similar in extent to that achieved by gro wth factor-expanded populations of O-2A progenitor cells. The transpla nt origin of the cell types within the lesion was confirmed by retrovi ral incorporation of the lacZ marker gene, the expression of which all owed their identification by histochemistry. In conclusion, the in viv o properties of the CG4 cell line make it a highly suitable line with which to study the behaviour of O-2A progenitors following transplanta tion into normal and damaged CNS. (C) 1995 Wiley-Liss, Inc.