Wisping axons are associated with loose ECM made up of canonically inhibitory and permissive proteins. Axons were labeled with 3A10 (B-D, G-H, S-T, V) or the axon tracer (F, J-L, N-P, R) and are shown in magenta. Each ECM protein is shown in green, and nuclei are blue. (A-D) Chondroitin sulfate proteoglycan (CSPG) expression in the intact spinal cord (A, cross-section) and in wisping stage regenerates (B-D). (B) is a longitudinal section. (C) and (D) are cross-sections through the terminal vesicle (C), and axons wisping into the injury site (D) from the same animal. Schematic longitudinal sections of the spinal cord in the upper right corner of (C) and (D) show where the section is in relationship to the injury site. (E-V) Similarly, the expression of tenascin-C (E-H), FN (I-L), Collagen XII (M-P), laminin (Q-T), and pigment (U, V) is shown. (W) A section adjacent to the one shown in (B) treated with chondroitinase ABC (chABC) before incubation with the CS-56 antibody. (X) A section adjacent to the one shown in (E) treated only with secondary antibody; the primary antibody was omitted. D, dorsal; V, ventral; R, rostral; C, caudal. Scale bar: 200 μm (A-X).