Measurement of neurotrophic factors in the spinal cord tissue. A–F, The concentration of BDNF (A, D), NT-3 (B, E), and GDNF (C, F) in the spinal cord tissue was measured by ELISA. One-centimeter-long spinal cord tissue blocks were collected from both the epicenter (A–C) and the caudal (D–F) regions 3 weeks after injury, and were processed separately for ELISA analysis. *p < 0.05, **p < 0.01, and **p < 0.001 compared with the sham-operated animals; ¶p < 0.05 and ¶¶p < 0.01 compared with the injury-alone (PBS) group; #p < 0.05 and ###p < 0.001 compared with the indicated groups by one-way ANOVA followed by Tukey's post hoc analysis. n = 7 animals per group.