Fig. 4.
Effects of locally applied fluticasone (“FLUT”) on pain behaviors and on sensory neuron excitability measured on postoperative day (POD) 3. Fluticasone treatment significantly reduced the mechanical hypersensitivity induced by dorsal root ganglion inflammation (LID) at all time points (A). Fluticasone also reduced responses to light brush strokes and acetone (B, C). **P < 0.01; ***P < 0.001, significant effect of drug treatment on the indicated day (two-way repeated-measures ANOVA with Bonferroni post-test). N = 6 (LID + FLUT group) or 7 (LID group) rats per group. Cells recorded in isolated whole dorsal root ganglia, 3 days after inflammation, showed increased excitability and spontaneous activity (SA) compared with normal cells. SA was increased by LID, and this effect was blocked by fluticasone (D). Fluticasone also reduced hyperexcitability as measured by rheobase (E) and threshold (F). N = 94 cells from three animals in LID POD3 group, 94 cells from four animals in LID plus FLUT group. Data from normal cells replotted from previous figure for comparison. *P < 0.05; ***P < 0.001, significant difference between normal and LID groups; #P < 0.05, significant difference between LID and LID plus local fluticasone (one-way ANOVA with Bonferroni post-test or Kruskal–Wallis test with Dunn multiple comparison post-test). PWT = paw withdrawal threshold.