Fig. 4.

Peritumoral astrocytes re-enter the cell cycle, do not undergo apoptosis or express C3d. a. Confocal image of Aldh1l1-eGFP + astrocytes co-labeled with the proliferation marker Ki67 in the cortical gray matter surrounding a Jx22 glioma revealed that a subpopulation of peritumoral astrocytes proliferated. White arrowhead points to a Aldh1l1-eGFP Ki67 double-positive astrocyte. b. Quantitative analysis of the percentage of Aldh1l1-eGFP Ki67 double-positive astrocytes among all astrocytes. c. Quantitative analysis of the number of Aldh1l1-eGFP + cells per mm3 in Sham, peritumoral area and contralateral. Difference in the astrocytic density was not detected (a,b,c n = 10 glioma, 5 sham). d. Confocal image of Aldh1l1-eGFP + brain slice labeled with cleaved-caspase-3 antibody, an apoptotic marker, shows a lack of Aldh1l1-eGFP astrocytes co-labeled with cleaved-caspase-3. Some GBM22 glioma cells label positive for cleaved-caspase-3. White arrows point a cleaved-caspase-3+ tumor cell and a Aldh1l1-eGFP + astrocyte without cleaved-caspase-3 labelling. e. Confocal images of Aldh1l1-eGFP + brain slices co-labeled with two different C3d antibodies (left and right), a marker for neurotoxic astrocytes demonstrates a lack of C3d labeling in Aldh1l1-eGFP-positive astrocytes. High magnification panels show increased immunoreactivity within the tumor mass and at the border that appears to be unspecific and in between Aldh1l1-eGFP + astrocytes (d,e n = 3).