Figure 7.

ChABC treatment degrades CSPGs at the site of spinal cord injury and promotes regeneration of YFP-labeled fibers. Sagittal section of the naive (A) and injured (B–I) YFP-H mouse spinal cord shows that crush injury to the dorsal columns (B) disrupts the main descending CST projection (long arrows) and the ascending dorsal column projection (arrowheads), leaving the ventral tracts intact (short arrows). At the injury epicenter (asterisks), C-4-S immunolabeling of degraded matrix CSPGs (red) is absent in penicillinase-treated animals (C), but both intrathecal (D) and intracerebroventricular (E) delivery of ChABC results in extensive digestion of CSPGs within the lesion site, the surrounding scar and extending rostrocaudally in white matter tracts (arrowheads). Low (F, H)- and high (G, I)-power images show that the lesion epicenter is devoid of YFP-labeled fibers in penicillinase-treated animals (F, G). In contrast, after IT ChABC treatment, numerous small YFP-labeled fibers are apparent (H, I) indicating regenerative growth of lesioned YFP-labeled axons into the modified scar. Scale bars: 500 μm (A–E), 100 μm (F, H), 20 μm (G, I).