Fig. 2.

Aging leads to loss of distal nerve and neuropathy. A Mechanical allodynia in 6, 12, and 21 month-old mice (n = 6/group). B Thermal hyperalgesia in 6, 12, and 21 month-old mice (n = 6/group). Distal nerve quantification in 6 and 24 month-old mice, IENF C and SBNP D (n = 3–5/group). E Representative images of paw plantar skin of 6 and 24 month-old mice used for IENF quantification. PGP9.5 positive nerve fibers stain brown. Black arrows indicate intra-epidermal nerve fibers and arrowheads indicate dermal nerves. All images were obtained at 40 × magnification. All data are Mean ± SEM. *p < 0.05, **p < 0.005, ***p < 0.0005, ****p < 0.00005