Fig. 1
Effects of microglial activation state and exposure to myelin on inflammatory gene expression. a Myelin phagocytosis. Representative images showing myelin fragments inside primary rat microglia at 6 h after adding 25 μg/mL DiI-labeled myelin (red). Microglia were co-labeled with tomato lectin (TL, green) and the nuclear stain, DAPI (blue). Scale bar, 10 μm. Short arrows show peri-nuclear accumulation of myelin; long arrows show myelin in other cell regions. b, c Gene expression of inflammatory markers (b) and “ionized Ca2+ binding adapter molecule 1” (c Iba1; also known as AIF-1). Microglia were unstimulated (control, CTL) or stimulated for 24 h with 20 ng/mL IFN-γ and 50 ng/mL TNF-α (I + T) or 20 ng/mL IL-4, with or without a subsequent 6-h exposure to 25 μg/mL myelin (30 h total time after cytokine addition; plus or minus sign indicates presence/absence of myelin). Expression of each gene is shown as normalized mRNA counts (described in the “Methods” section). On the scatterplots, the mean ± SEM is indicated for six different microglia cultures. Data were analyzed by two-way ANOVA with Bonferroni’s post hoc test. The comparisons are as follows. Asterisk Between unstimulated microglia (CTL) and cells treated with I + T or IL-4. Dagger sign CTL versus activated cells in the presence of myelin. Number sign Effects of myelin within a particular activation state. One symbol p < 0.05, two symbols p < 0.01, three symbols p < 0.001