Evaluation of Axonal Transportation by Retrograde Tracer in SCI Mice after Treatment
(A) A schematic diagram of muscle and spinal cord for the experiment of retrograde transportation by FluoroRuby (retrograde tracer). At 5 days after injection of FluoroRuby into the hamstring at the injured side, histological evaluation of spinal cord was performed at the injured site (L1 spinal level) and their proximal (Th13 spinal level) and distal sites (L2 spinal level) in 4-week SCI mice. (B) FluoroRuby stain (red) in spinal cord sections at the injured site and their proximal and distal sites from CTR, M1, and M2 groups. White squares in the distal site (L2 level) show anterior horns in spinal cord sections under low magnification and were enlarged in the right upper corner under high magnification. White squares in the proximal site (Th13 level) show anterior horns in spinal cord sections under low magnification and were enlarged in the right panels under high magnification. Scale bars, 200 μm. (C) Bar graphs show the number of FluoroRuby (FR)-positive neuronal cells per each spinal cord section at distal and proximal sites of injury from CTR, M1, and M2 group mice. Error bars showed means + SD (n = 3 in each group). *p < 0.05. n.s., not significant.