Fig. 3

Quantitative morphometrical analysis of microglial activation during glioma growth reveals regional differences between core, border and control regions. Images from cortical regions implanted with glioma cells at 14 dpi. a Endogenous EGFP fluorescence in microglial cells (red arrowheads) in the tumor core in relation to (b) GL261 cells labeled with mCherry (white circle) were immunopositive for the microglial/macrophage marker Iba1 (c, red arrowheads). d–f) EGFP channel of representative slices showing morphological changes in microglia, from the non-inoculated region 1 (d) to the tumor regions 2 (e) and 3 (f). In (d), a set of parameters for morphometrical analysis of individual microglial cells is represented as follows. Blue filled in red outline: mean intensity value of Iba1 expression (g); End points, the ImageJ plugin processed Skeleton tags of all pixel/voxels in a skeleton image. All junctions were classified in different categories depending on their 26 neighbors. When they had less than 2 neighbors, they were counted as end-points voxels (h); Red contour: soma size measured in μm² (I); yellow contour: total perimeter length in μm (j). Data were expressed as mean ± SEM. (*p < 0.05 statistical significance, ANOVA one way followed by Tukey’s test). Scale bar: 20 μm