The effects of ventral root reimplantation and lithium on the axonal regeneration in the median nerves at 40 mm distal to the reimplantation site at 20 weeks post-reimplantation. Figures 4A-E and a-e: A large of number of myelinated axons were present in the normal median nerve (A-a). However, the decreased presence of nerve fibers and obvious nerve atrophy were observed in both the Av + PBS (B-b) and Av + Li (C-c) subgroups. In both the Re + PBS (D-d) and Re + Li (E-e) subgroups, a small amount of uneven size nerve fibers re-appeared and were scattered in location. Scale bar = 100 μm. Figures 4F-J: The frequency distribution of myelinated fiber diameters in the normal control (F), Av + PBS (G), Av + Li (H), Re + PBS (I) and Re + Li (J) subgroups were estimated. Figures 4K-L: The results of statistical analysis of the mean number (4K) and diameter (4L) of the median nerve were summarized. The results showed that the Av + PBS subgroup showed the lowest values and the Re + Li subgroup showed the highest values among the treated subgroups. *p < 0.05 compared to the normal subgroup, #p < 0.05 compared to the Av + PBS subgroup, ^p < 0.05 compared to the Av + Li subgroup, and △p < 0.05 compared to the Re + PBS subgroup.