CXCL12 mediates mouse neural progenitor cell (NPC) migration and polarization. (A–D): Mouse NPCs were seeded on cover-glasses coated with bovine serum albumin (BSA) stripes (green) without CXCL12 (A, BSA stripes, vehicle group) or with CXCL12 (B, BSA/ CXCL12 stripes). Cells were stained with nestin (white) and 4′,6-diamidino-2-phenylindole (blue). The quantification of stripe assay were shown as (C) (percent of total cells on stripes to total cell number) and standardized to migration index as (D) (ratio of cell number on stripes to cell number off stripes). (E): NPCs on transwell insert were incubated in the presence of CXL12 as indicated concentration and quantified. *, p <0.05. (F–I): NPC polarity change was also determined through immunochemistry technique with cells seeded on BSA stripes (F, G) and BSA/CXCL12 stripes (H, I). NPCs were seeded for 10 minutes before the staining. Scale bar =60 μm (A, B), 20 μm (E, G), 10 μm (F, H). Abbreviations: BSA, bovine serum albumin; DAPI, 4′,6-diamidino-2-phenylindole.