FIGURE 4.

The elimination of microglia by PLX5622 treatment results in correspondingly reduced Fascin-1 expression, disorganized astrocytic and fibrotic scars, and scattered macrophages in the injured spinal cord at 14 days. (A) Representative fluorescence images of Fascin-1 (Red) and CX3CR1 (Green) immunostaining showing a consistent reduction in Fascin-1 expression with the elimination of microglia after treatment with PLX5622 compared to vehicle (control). The asterisks indicate the lesion epicenter. Scale bar: 500 μm. (B) Representative immunofluorescence images of Fascin-1 (Red) and GFAP (Green), Fascin-1 (Red) and Mac2 (Green), Fascin-1 (Red) and PDGFRβ (Green) at the lesion sites of mice treated with vehicle (control) or PLX5622. After the elimination of microglia using PLX5622, the compact GFAP⁺ astrocytic scars and PDGFRβ⁺ fibrotic scars are disrupted, with clusters of Mac2⁺ macrophages spreading outside of the lesion core. The asterisks indicate the lesion epicenter. The dotted lines delineate the boundary around the lesion core. Scale bar: 500 μm. (C) Quantification of the number of Fascin-1⁺ CX3CR1⁺ microglia in the control and PLX5622 groups (n = 3 per group). The results are expressed as the mean ± SEM. ****p < 0.0001. (D) Percentage of surviving Fascin-1⁺ or CX3CR1⁺ cells in the PLX5622 groups relative to that the untreated control groups (n = 3 per group).