Activated microglia inhibit neurite outgrowth and induce growth cone collapse in vitro.

<p><i>A</i>, Relative length of neurites of cortical neurons, neurons stimulated by LPS, and neurons co-cultured with BMDM, BMDM stimulated by LPS, microglia, or activated microglia stimulated by LPS (n = 3). <i>B</i>–<i>D</i>, Representative figures of neurons (TuJ1, green, <i>B</i>), neurons co-cultured with unactivated microglia (<i>C</i>), and neurons co-cultured with activated microglia (<i>D</i>). Scale bar: 20 µm. <i>E</i>, Collapse assay (n = 3). <i>F</i>–<i>H</i>, Representative figures of growth cones (phalloidin staining, red) of a neuron (<i>F</i>), a neuron co-cultured with unactivated microglia (<i>G</i>), and a neuron co-cultured with activated microglia (<i>H</i>). Scale bar: 10 µm. Data are represented as mean ± SEM. *<i>p</i><0.01 (one-way ANOVA followed by Tukey-Kramer test).