FIGURE 5.

GRPs promoted axonal regeneration. GRPs stimulated significant ingrowth of SMI-312+ axons into the lesion (a–a”). On the contrary, in the control animals that received fibroblast transplantation, a high density of SM1–312+ axons were located in the intact spinal cord directly adjacent to the lesion site; however, we observed almost no growth of SM1–312+ axons across the lesion-intact interface (b). Orientation of all images in panels a–a” and B: D = dorsal, V = ventral, R = rostral, C = caudal. Compared with fibroblasts, GRPs significantly increased both the number of SMI-312+ axons profiles (c) and the density of these SMI-312+ axons (d) within the lesion site. Confocal imaging shows that most of these SMI-312+ fibers in the lesion extended along AP+/GFAP+ cells (e: Red = AP, blue = GFAP, green = SMI-312), demonstrating that axons regenerated along transplant-derived astrocytes within the lesion site. Arrowheads in e”‘–e”“ denote SMI-312+ host axons growing along AP +/GFAP+ transplant-derived astrocytes. Arrowheads in e–e” denote AP+/GFAP+ transplant-derived astrocytes. Scale bars: 50 μm (a,b), 10 μm (e)