Figure 3.

The isolated astrocytes express the classical markers of reactive astrocytes. A, Relative expression of reactive astrocyte genes in the GeneChip profiles from astrocytes isolated from healthy and injured brains is graphed over the course of 1 week. By 1 d after injury, GFAP and vimentin (Vim) are induced to similar degrees between MCAO and LPS reactive astrocytes. Nestin (Nes) is induced in MCAO reactive astrocytes but not LPS reactive astrocytes. GFAP and vimentin expression remains elevated over the course of 1 week after injury. In contrast, nestin expression is transient, decreasing to baseline levels by day 7 after injury. Error bars represent SEM. B–Q, Immunofluorescence for reactive astrocyte markers was performed on 10 μm fixed cryosections from the brains of Aldh1l1-eGFP mice that had undergone control surgeries (B, F), MCAO (C–E, G–I), saline injection (J, N), or LPS injection (K–M, O–Q). eGFP is expressed in and marks astrocytes. B, J, F, N, Reactive astrocyte markers are minimally expressed (vimentin; B, J) or not expressed (nestin; F, N) in healthy tissue. D, E, L, M, Vimentin expression is seen in astrocytes of the MCAO lesion penumbra strongly at 7 d (D, E) after injury and in astrocytes of the LPS-treated cortex after 7 d (L, M). H, I, MCAO penumbra astrocytes express nestin 7 d after injury. White stars indicate MCAO core regions in which astrocytes have lost GFP expression. O–Q, Nestin is not expressed in the LPS-treated cortex. Scale bars: B–D, F–H, J–L, N–P, 50 μm; E, I, M, Q, 200 μm.