Fig. 7.

Analysis of retrogradely-labeled motoneurons. (A) Representative optical slice of correctly (red) and incorrectly (green) labeled motoneuronal cell bodies in cross-sections from spinal cords within the lumbar enlargement. Inset shows that fluorescently tagged retrograde labels were restricted to the motoneuron-rich ventral horn ipsilateral to the injured side. Longer exposure times were used to enhance autofluoresence in order to visualize the spinal cord structure in the inset. The higher magnification image shows distinguishable cell bodies used for motoneuron counts. Scale bars represent 100 μm. (B) Statistical analysis revealed significantly more correctly labeled motoneurons in all collagen-treated versus saline treated groups. Within hydrogel-treated conditions, groups containing coupled HNK-1 peptide resulted in significantly more correctly labeled motoneurons than groups without coupled HNK. No statistically significant differences were found between PSA and non-PSA containing collagen-treated animals, number of incorrectly labeled motoneurons, and total number of motoneurons. An asterisk (*) represents statistically significant differences compared to saline treated groups in number of correctly labeled motoneurons. A double asterisk (**) represents statistically significant differences of HNK- and PSA/HNK-coupled hydrogels compared to saline, native, scrambled peptide-coupled, and PSA-coupled in number of correctly projecting motoneurons. Means are reported +/− standard error. Differences were considered significant at p < 0.05 using one-way analysis of variance. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)