Figure 3

Effects of preconditioning nerve lesion on glial activation in lumbar spinal cord (L4-6), 1 week after partial ligation of the left sciatic nerve. (A) Activation of microglia in the ipsilateral dorsal and ventral horn of the spinal cord was significantly increased 7 days after PSNL in both preconditioned (crush-injured) and unconditioned (no crush) rats as compared to normal rats and to the contralateral uninjured side. Activation of microglia in the contralateral dorsal and ventral horn of the spinal cord was significantly increased only in the rats that underwent (2 weeks before) right tibial nerve crush injury. (B) Activation of astrocytes in the ipsilateral dorsal horn of the spinal cord was significantly increased 7 days after PSNL in both preconditioned (crush-injured) and unconditioned (no crush) groups as compared to normal rats. Astrocyte activation was significantly increased in the ventral horn of preconditioned rats (left tibial and left peroneal crush) as compared to normal rats. In the contralateral spinal cord, no significant differences were observed between the groups, except for the dorsal horn of preconditioned rats (left tibial crush) as compared to normal rats. Micrographs (right panel) show examples of immunoreactivity to IBA1 (microglia, in red) and GFAP (astrocytes, in green) in sides ipsilateral (left) and contralateral (right) to PSNL in both dorsal and ventral spinal cords of unconditioned rats. (n = 3 rats per group, *P < 0.05, ** P < 0.01, *** P < 0.001, two-way ANOVA followed by Bonferroni post-tests). Data are expressed as mean ± s.e.m. Scale bars represent 50 μm.