Astrocyte Hypertrophy Contributes to Aberrant Neurogenesis after Traumatic Brain Injury

Figure 3

GFAP-labeled cells in the dentate gyrus. In (a), a confocal micrograph from a sham mouse is shown to depict the normal appearance of a robust number of radial glial processes extending through the granule cell layer (GCL). In (b), a representative confocal micrograph of an FPI mouse shows a decrease in the number of radial glial-like processes extending through the GCL. In addition to the lack of radial glial processes extending through the GCL, note that several GFAP-labeled astrocytes from FPI mice displayed varying levels of activated morphology in the hilus (arrows). In (c), quantitative analysis of the number of radial glial processes extending through the granule cell layer reveals a significant decrease ( < 0.05) in FPI mice compared to sham mice. In (d), the sham micrograph from (a) is shown after thresholding, to depict the technique used for densitometric analysis of GFAP-labeling in the hilus. Once thresholded, the Image J software (NIH v.1.49) automates the counting of white pixels. In (e), the micrograph from the FPI mouse is shown after thresholding. In (f), densitometric analysis of GFAP-labeled astrocytes in the hilus revealed no significant differences between sham and FPI mice at 30 days after FPI. It is pertinent to note that the subgranular zone was excluded from this analysis (as shown in Figure 1) because the cells in this region have a different appearance than they do in the hilus. Scale bars in all images = 30 μm.

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