Fig. 1

Activation of A1/A2 subtype astrocyte and expression of KLF4 on astrocyte following focal cerebral ischemia. A Images show the dual-IF staining for C3 with GFAP, S100A10 with GFAP, and KLF4 with GFAP in ischemic penumbra from sham operated mice (control) or mice at day 2, 4, 7 and 14 post-ischemia. Scale bar = 100 µm (inserts = 30 μm). B Quantification of A1-subtype (C3 + GFAP +) astrocyte, A2-subtype (S100A10 + GFAP +) astrocyte and KLF4 on astrocyte (KLF4 + GFAP +) expressions. Results are expressed as the mean ± standard deviation of the number of positive events per field of view, and the data were analyzed by one-way ANOVA (n = 8 per experimental group). Note that cerebral ischemia induced a strong increase in the number of A1 astrocytes in the penumbra, with the effect reaching maximal level at day 14 post-ischemia. However, the expression of A2 astrocyte decreased at day 2 post-ischemia, but then increased by 4–14-day post-ischemia, peaking at day 7, and declining at day 14. While the expression of KLF4 on astrocyte increased slightly during the first 2-day post-ischemia, but then increased significantly by day 4, and reached a maximum at day 7, before declining at day 14. *P < 0.05, ***P < 0.001 compared with control