Figure 5

Midkine enhances the migration of microglia cells. The migration assay was performed with filters coated with midkine (MK) or poly-D-lysine (PDL) on the lower surface at 10 μg/ml. Microglia cells (1x10⁵ cells in 100 μl 0.3% BSA/RPMI1640) prepared from WT (filled bars) or MKKO (open bars) newborn mice were added to the upper chamber of a Chemotaxicell, and incubated for 4 h. Ten fields (x 400 magnification) per filter were counted to determine the number of migrated cells. (1 field corresponds to 1/160 of the entire surface of the filter). The values are the mean ±S.E. per field. n = 3. *P < 0.0001, **P < 0.001.