The nerve morphological parameters of the 2 M (n=6), 4 M (n=6) and 8 M (n=6) groups. A: The number of myelinated axons, most of regenerated collaterals reinnervated the distal tibial nerve, the ratio of total regenerated axon numbers to proximal peroneal nerve axon numbers was 3.95±0.10, 4.06±0.19 and 3.87±0.23, respectively. *P < 0.05; B: The myelin sheath thickness; C: The axon diameter; D: The axon area. B-D: *P < 0.05 versus 8 M, #P < 0.05 versus 4 M. (Bars=SD).