Figure 3

Changes in sympathetic fiber innervation in the skin of naïve rats following MMP-2/9 inhibition. A and B represent confocal images of the rat’s glabrous hindpaw skin in vehicle-treated and MMP-2/9 inhibitor (MMP-2/9I.; 20 μg, i.pl.) injected rats, respectively, at the 2 week end point. Note an invasion of sympathetic fibers into the upper dermis (B), mimicking what we had previously observed in a model of inflammatory arthritis [35]. This fiber population was not normally found in control (vehicle-treated) animals as shown in A. Arrows in B indicate VMAT2-IR fibers in the upper dermis. The results in C are from all experimental groups and presented as the mean ± SEM. Inter-group differences were analyzed by ANOVA with a Dunnett’s post hoc test. *p < 0.05, **p < 0.01 indicates a significant difference as compared to glabrous skin sample of chronic vehicle-treated (V) naive rats. The dashed lines represent the dermal-epidermal junction.