Chemotherapy-induced sensory neuropathy.

Peripheral sensory neuropathy induced by PTX was performed using previously reported methods (23, 24). Male 15.5-week-old C57BL/6J mice received PTX (Taxol, 25 mg/kg by tail vein injection, every 48 hours for a total of 3 doses; Sigma-Aldrich, T7402). Thermal sensation was assessed using the IITC Plantar Analgesia Meter 400 (IITC Life Science). Paw withdrawal latency was performed before and after treatment according to the Hargreaves method (24). Two weeks after the final dose (at 18 weeks of age), cyclic end-loading was performed as outlined above to induce a stress fracture. Animals were sacrificed 7 and 14 days thereafter, and bilateral forelimbs were isolated and analyzed as outlined below. In addition, intraepidermal nerve fiber loss was confirmed in a medial footpad biopsy from the left hind limb on the basis of previously reported methods (23, 24). Briefly, 50-μm-thick cryosections of the skin biopsy site were analyzed by immunohistochemical staining for the pan-axonal marker protein gene product (PGP) 9.5 (Bio-Rad) or calcitonin gene–related peptide (CGRP).