Fig. 5

Growth-associated protein 43 (GAP-43)–positive intraepidermal nerve fibres (IENFs) in paw and back skin and their correlation. Numbers of IENFs per millimetre epidermis immunopositive for GAP-43 in control rats, acute antigen-induced arthritis (AIA) rats, and chronic AIA rats (a–c). Numbers of IENFs marked by antibodies against GAP-43 increased significantly in the left paw pad skin (ipsilateral) and in lumbar back skin from paraspinal right (contralateral) in the acute and chronic state of AIA, compared with immunized-only controls (a, c). GAP-43–positive IENFs were significantly increased in the right paw pad skin (contralateral) in the acute state of AIA but not in the chronic state (b). Numbers of IENFs positive for GAP-43 per millimetre of left paw pad skin correlated to those of lumbar back skin (d). R = 0.6023, p = 0.0014; *p < 0.05, **p < 0.01, ***p < 0.001