Figure 1.

Epidermal nerve innervation of glabrous skin and classification of sensory fibers derived from Wildtype (Wt) and Gla^−/0 mice. (A) Typical immunohistochemical stainings of cryopreserved glabrous skin section (20 µm) from the hind paw of adult Wt and Gla^−/0 mice, where the nuclei were stained with DAPI (top row) and nerve fibers with anti β-tubulin III (middle row). Images were merged to determine in which layer of the epidermis, based on the morphological shape of the epidermal nuclei, the nerve fibers ended and quantified. (B) In all epidermal layers, a reduced number of fibers are detected in Gla^−/0 glabrous skin. (C) The cell body diameter of cultured Gla^−/0 is increased compare with Wt nociceptors. Representative fluorescent images of cultured Wt (top panel) and Gla^−/0 nociceptor (lower panel) stained against β-III tubulin showed increased cell bodies of Gla^−/0 noceptors (scale bar 20 µm). The cell body diameter distribution profile (10 µm bins) of Gla^−/0 (n = 568) and Wt (n = 564) nociceptors showed a right shift of the Gla^−/0 nociceptor cell diameter compared with Wt (χ² test, p < 0.001). (D) Recorded conduction velocities (CVs) of nociceptive fibers from Wt and Gla^−/0 mice. The CV of C-fibers of Gla^−/0 is significantly increased compared Wt C-fibers (right panel), whereas the CV of Aδ-fibers is unchanged (left panel).