Figure 4

The microglial activation state affects invasion through the extracellular matrix (ECM). A) Microglia were plated on glass coverslips coated with fluorescent-labeled fibronectin, without (control) or after 10 ng/ml lipopolysaccharide (LPS) or 20 ng/ml IL4 treatment. The corresponding phase contrast images show cell locations and morphology. Scale bar, 20 μm. B) Microglia invasion through Matrigel™-coated 8 μm diameter holes in Transwell™ chambers. For each treatment, cells that had invaded to the underside of the filter after 24 hr were visualized and counted as in Figure 3B. Results are expressed as mean ± SEM for the number of individual cell cultures indicated on each bar. *P <0.05; **P <0.01. C) Chemotactic invasion. Either medium alone (solid bars) or the chemoattractant, 300 μM ATP (striped bars), was added to the lower well of the Transwell™ chamber. After 24 hr, cells were counted as in Figure 3C. Results were normalized to control invasion without ATP and reported as mean ± SEM for the number of individual cultures indicated. Statistical differences were determined using two-way ANOVA, followed by Bonferroni post-hoc tests. ### indicates effect of ATP; ††† indicates a difference between control and IL4-treatment. P <0.001.