CD34⁺ cell transplantation in 24-week-old animals. (A–C) On day 35 after cell transplantation, the brains were evaluated. Compared with poststroke mice treated with CD34^– cells (A), animals transplanted with CD34⁺ cells (B) showed an increase in area occupied by the left cortex. Significant cortical regeneration was induced by CD34⁺ cells transplantation (C). (D and E) Compared with CD34^– cell transplantation (D), increased evidence of activated vasculature was observed in animals receiving CD34⁺ cells (E), as detected with mouse specific anti-CD13 antibody. (F–H) Migration of NPCs (small NeuN⁺ nuclei migrating toward the cortex) was observed in poststroke mice treated with CD34^– cells (F) and with CD34⁺ cells (G). However, a significant increase in migrating NPCs was induced by CD34⁺ cell transplantation (H). (I and J) A thin layer of migrating PSA-NCAM⁺ NPCs was observed at the ischemic edge of the cortex in animals treated with CD34^– cells (I), compared with a much thicker layer in those receiving CD34⁺ cells (J). Scale bars: 2 mm (A), 0.1 mm (D and I), and 0.4 mm (F). n = 4 in each group; *P < 0.05 versus CD34^– cells.