Effects of ventral root reimplantation and lithium on the axonal regeneration of avulsed motoneurons as revealed by retrograde FG-labeling at 20 weeks post-reimplantation. Representative micrographs of ipsilateral C7 (A-E) and C8 (F-J) spinal cross sections showing FG-labeled motoneurons present in the ipsilateral ventral horns of animals in the normal control (A, F), Av + PBS (B, G), Av + Li (C, H), Re + PBS (D, I), and Re + Li (E, J) subgroups. Scale bar = 100 μm. (K-L): The number of regenerated motoneurons in reimplanted treated animals was significantly higher than those without reimplantation treatment both in C7 (K) and C8 (L) ventral horns. *p < 0.05 compared to the normal subgroup, #p < 0.05 compared to the Av + PBS subgroup, and ^p < 0.05 compared to the Av + Li subgroup.