Synergistic effects of ChABC, GF and daily exercise enhance the collateral sprouting of the CST axons in the injured spinal cord.

<p>(<b>A–L</b>) Images of the BDA-labeled CST at 5, 9 and 11 mm rostral to the lesion are depicted in different experimental groups after unilateral injections of BDA into the sensorimotor cortex (Ai-Li). Inverted images were generated from the boxed region depicted in A–L for better visualization. BDA labeling was unilateral, so only contralateral CST is labeled. To correct for inter-animal variations in the BDA labeling efficiency, the intensity value of the BDA labeled collaterals in the gray matter were normalized to the intensity of BDA labeled fibers of the main CST. (<b>M</b>) Quantification of the areas depicted in Ai-Li at various distances revealed an increase in BDA density in the combined ChABC+GFs/trained treatment group compared to all other groups at 5 and 9 mm distances. Comparison of BDA-labeled collaterals among different injured groups also showed an increase in the density of BDA-labeled CST fibers in the ChABC+GFs/untrained group that was significantly higher than both vehicle treated groups at 5 mm rostral point to the SCI epicenter (*p<0.05, Two-way ANOVA, Holm-Sidak <i>post hoc</i>, N = 3–5).