Figure 3.

Fluorescent microscopy of GFAP-labeling in the peri-lesion area and corresponding contralateral hemisphere. At 1 day after FPI (A,B), there is only a minimal astrocyte reaction in the peri-lesion area in the ipsilateral cortex (B). Note in the inset image, the elongated appearance of these astrocytes oriented toward the lesion emanating from the area of the corpus callosum, or possibly the underlying lateral ventricle. This morphology, coupled with the minimal astrocytic staining in the peri-lesion area, is indicative of the early stages of astrocyte activation. In the corresponding contralateral hemisphere, minimal GFAP-labeling is observed. At 3 days post-FPI (C,D), a robust number of GFAP-labeled cells with an activated appearance are observed in the peri-lesion area (D). Only minimal GFAP-labeling is observed in the contralateral hemisphere at this timepoint (C). At 7 days post-FPI (E,F), the appearance of GFAP-labeled astrocytes with an activated appearance is decreased relative to the 3-day timepoint. In the corresponding contralateral hemisphere at 7 days post-FPI, there appears to be diminished GFAP-labeling relative to 1 and 3 days, as well as sham and naïve mice (data not shown). At 30 days post-FPI (G,H), a sizable population of GFAP-labeled astrocytes is observed in both the contralateral (G) and ipsilateral (H) hemispheres. In both hemispheres, the labeling is quite robust in layers I–IV and VI, but conspicuously absent in layer V. Scale bar in (A) = 50 μm for all images.