Figure 8.

Association between mechanical threshold and the indices of the sub-epidermal nerve plexus and nerve terminals in the third and fifth toe tips. (A,B) Index of plexus length in the toe tips is associated with the mechanical threshold. The CCI-mild group showed mechanical hypersensitivity at 7 d when indexed by the third toe tip and at both 7 and 14 d when indexed by the fifth toe tip. The CCI-moderate group, indexed by either the third or the fifth toe tip, showed mechanical hypersensitivity at both 7 and 14 d after CCI surgery. The CCI-severe group, whether indexed by plexus length in the third or fifth toe tip, showed mechanical hypersensitivity only at 14 d. (C,D) The index of the number of nerve terminals in the toe tips is associated with mechanical threshold. The CCI-mild group showed mechanical hypersensitivity when indexed by number of terminals in the third or fifth toe at 7 d but not at 14 d. The CCI-moderate group indexed by the third toe showed mechanical hypersensitivity at 7 d, while the group indexed by the fifth toe showed hypersensitivity at both 7 and 14 d. The CCI-severe group, whether indexed by the third or the fifth toe, showed hypersensitivity at both 7 and 14 d. * p < 0.05, ** p < 0.01 and *** p < 0.001, compared to the sham group.