Fig. 4.

CST sprouting rostral to SCI in NgR(310)ecto-transgenic mice. (A) Transverse sections rostral to lesion display a similar degree of dorsal CST labeling in both wild-type and NgR(310)ecto-transgenic mice. These transverse sections were obtained 5 mm rostral to a dorsal over-hemisection site from eight wild-type (WT) mice and 16 transgenic gfap∷ngr-ecto mice as indicated. The midline is to the left and dorsal is up in all sections. Also note the increased density of ectopic sprouts lateral to the dCST in the transgenic animals. The bottom row illustrates the dCST pattern at the same level of the spinal cord in transgenic mice without spinal injury. Note that there is little dCST sprouting, similar to the injured control and distinct from the injured transgenic mice. Mouse identifying number is at the bottom right of each panel. (B) Schematic of transverse spinal cord section illustrating the dCST and the location of the high magnification images in C and D. (C and D) BDA-labeled CST fiber in gray matter adjacent to the dCST from a wild-type mouse (C) and gfap∷NgR(310)ecto mouse (D). (E) Ectopic CST fibers outside of the dCST and dlCST and ≥100 µm in length are counted from transverse sections 5–7 mm rostral to over-hemisection. Means ± SEM are reported from 7 to 9 determinations. The indicated values in the presence of the inhibitor were statistically different from control binding without inhibitor (**P ≤ 0.01; Student’s t test).