Rapid migration of grafted cortical astrocytes from suspension grafts placed in host thoracic spinal cord

The cerebral cortices from 14-day gestation rat embryos were prelabeled with Phaseolus vulgaris leucoagglutin (PHAL) and homografted as a cell suspension into host thoracic spinal cord. Animals were sacrificed at 7, 14, 21 and 30 days postimplantation (DPI). Paraffin sections of cervical, thoracic and lumbar spinal cord were double-labeled for the presence of glial fibrillary acidic protein (GFAP) a specific marker for astrocytes, and PHAL, utilized as a marker for graft-derived cells. PHAL-GFAP positive cells were found throughout the thoracic spinal cord at all time periods, indicating that grafted astrocytes migrated along all 3 axes of the host spinal cord (rostral-caudal, dorsal-ventral and left-right). At 30 DPI, graft-derived astrocytes were found in host cervical and lumbar spinal cord. There appeared to be a minimal delay in the onset of migration.