Temporal progressive antigen expression in radial glia after contusive spinal cord injury in adult rats.

Abstract

In the development of the CNS, radial glial cells are among the first cells derived from neuroepithelial cells. Recent studies have reported that radial glia possess properties of neural stem cells. We analyzed the antigen expression and distribution of radial glia after spinal cord injury (SCI). Sprague-Dawley rats had a laminectomy at Th11-12, and spinal cord contusion was created by compression with 30 g of force for 10 min. In the injury group, rats were examined at 24 h and 1, 4, and 12 weeks after injury. Frozen sections of 20-microm thickness were prepared from regions 5 and 10 mm rostral and caudal to the injury epicenter. Immunohistochemical staining was performed using antibodies to 3CB2 (a specific marker for radial glia), nestin, and glial fibrillary acidic protein (GFAP). At 1 week after injury, radial glia that bound anti-3CB2 MAb had spread throughout the white matter from below the pial surface. From 4 weeks after injury, 3CB2 expression was also observed in the gray matter around the central canal, and was especially strong around the ependymal cells and around blood vessels. In double-immunohistochemical assays for 3CB2 and GFAP or 3CB2 and nestin, coexpression was observed in subpial structures that extended into the white matter as arborizing processes and around blood vessels in the gray matter. The present study demonstrated the emergence of radial glia after SCI in adult mammals. Radial glia derived from subpial astrocytes most likely play an important role in neural repair and regeneration after SCI.