THE MIGRATION AND INTERMIXING OF DONOR AND HOST GLIA ON NITROCELLULOSE POLYMERS IMPLANTED INTO CORTICAL LESION CAVITIES IN ADULT MICE AND RATS

The fate of neonatal glia (mostly glial fibrillary acidic protein-posi tive astrocytes), cultured on nitrocellulose papers and implanted into cortical lesion cavities. was examined in adult mice and rats. In mic e, a Y-chromosome-specific probe and in situ hybridization techniques were used to identify male cells. Male-female grafts allowed visualiza tion of donor glia and their behaviour after transplantation; female-m ale grafts allowed an analysis of how host cells responded to the pres ence of the implants. There was substantial intermixing of cells, with many donor glia migrating away from the implants and host cells migra ting onto both sides of the nitrocellulose paper. In rats, donor glia were labelled with fluorescein-conjugated latex microspheres prior to transplantation on nitrocellulose polymers. The rat data were broadly consistent with those obtained from the mouse; moreover, immunohistoch emical studies in rats suggested that the majority of host cells migra ting onto the previously cell-coated papers were astrocytes. In a numb er of studies, glia-coated polymers have been used in an attempt to pr omote the regrowth of axons across lesion sites in the brain and spina l cord. The present work suggests that both transplanted and host glia may influence the regenerative growth seen in such implants.