Histograms showing an increase in the density of sensory and sympathetic nerve fibers in the geriatric arthritic knee joint. The length of calcitonin gene-related peptide (CGRP+, A) sensory nerve fibers, neurofilament 200 kDa (NF200+, B) sensory nerve fibers, tyrosine hydroxylase (TH+, C) postganglionic sympathetic nerve fibers and growth-associated protein-43+ (GAP-43+, D) nerve fibers undergoing sprouting in the synovium were obtained by manually tracing the nerve fibers in a determined volume of synovium. Bars represent the mean of at least three mice ± SEM. *P < 0.05 versus mice that received intraarticular injections of saline.
Jimenez-Andrade and Mantyh Arthritis Research & Therapy 2012 14:R101 doi:10.1186/ar3826