Fig. 1

Enhanced microglial response in the spinal cord dorsal horn of collagen-immunised (CI) rats. Ionized calcium-binding adapter molecule 1 (Iba-1) immunoreactivity in the lumbar dorsal horn of control and CI rats on day 13 post-injections (a). Co-localization of Iba-1 (red) and phospho-p38 (green) immunoreactivity (yellow) in the dorsal horn (b). Quantification of Iba-1 (a) and phospho-p38/Iba-1 (b) in the dorsal horn. Scale bars = 100 μm. In a and b, values are the mean ± SEM of 5–4 rats per group. ***p < 0.001, **p < 0.01, *p < 0.05 versus controls; two-way ANOVA, post hoc Tukey’s test. Time course of mechanical hypersensitivity associated to collagen immunization (panel c left), which significantly correlates with the time course of the microglial response (panel c right). Time course of hind paw swelling associated to collagen immunization (panel d left), which does not correlate with the time course of the microglial response (panel d right). In c and d, values are the mean ± SEM of 8 rats per group: ***p < 0.001, *p < 0.05 versus controls; two-way RM-ANOVA, post hoc Tukey’s test. In correlations studies in c and d, data were analysed with a Pearson correlation