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. Author manuscript; available in PMC: 2013 May 1.
Published in final edited form as: Exp Neurol. 2011 Dec 29;235(1):162–173. doi: 10.1016/j.expneurol.2011.12.037

Figure 4. Quantification of axons bridging across a C3 lesion site filled with bone marrow stromal cells in animals that received pre- or post-conditioning lesions, infusions of mesopram or db-cAMP injections.

Figure 4

(A) Pre-conditioning lesions in combination with Lenti-NT-3 gene transfer (7 day Pre-CL+Lenti-NT-3) significantly increased the number of axons crossing a C3 dorsal funiculus lesion compared to animals that received only Lenti-NT-3, only Lenti-GFP, or a combination of Lenti-GFP/conditioning lesions (7 day Pre-CL-Lenti-GFP). The number of axons crossing the rostral host graft interface (0 µm) or a virtual line 50, 100, 200, 400, 800, 1200 and 1600 µm beyond the lesion site was quantified in a series of 1 out of 7 sections. (ANOVA followed by Fischer’s posthoc analysis *** p<0.001, ** p<0.01 comparing 7 day Pre-CL+Lenti-NT-3 to all other groups). (B) Axonal bridging after 1- or 7-day post-conditioning lesions in combination with Lenti-NT-3 gene transfer. The number of bridging axons in animals that received post-conditioning lesions 1 day after central lesions is not significantly different at any distance examined from animals that received pre-conditioning lesions 7 day before central lesions. Priming neurons by peripheral lesions 7 days after spinal cord lesions resulted in significantly fewer axons bridging beyond the lesion site. Data from pre-conditioned animals in combination with Lenti-NT-3 from (A) are included for clarity. (ANOVA followed by Fischer’s posthoc testing **p<0.01; * p<0.05). (C, D) Increases in cAMP levels result in only short-distance axon growth beyond the lesion. (C) Animals received infusions of the phosphodiesterase inhibitor mesopram starting one week prior to C3 dorsal column lesions, BMSC grafts, and Lenti-NT-3 or Lenti-GFP injections. Infusions of mesopram without NT-3 delivery failed to result in any axonal bridging; the combination of mesopram infusion with Lenti-NT-3 delivery did not further increase the number of bridging axons compared to Lenti-NT-3 delivery alone. Animals with Lenti-NT-3 injections alone, quantified in (A), are included for comparison. (D) Injections of dibutyryl-cAMP into L4 and L5 DRGs one day after spinal cord lesions and Lenti-NT-3 delivery increase axonal bridging only up to 100 µm beyond the rostral host/graft interface, when compared to animals injected with PBS and Lenti-NT-3 as controls (unpaired t-test *p<0.05). Data represent raw counts in one out of seven sections.