Pericytes are activated around glioma.

<p>(A) Low magnification photomicrograph of a normal rgs5^GFP/+ mouse brain, scale bar is 500 μm. (B) Under normal conditions, quiescent GFP positive pericytes showed a flat morphology with a small cell body (arrows), scale bar is 20 μm. (C) However, in response to a GL261 glioma, the number of GFP positive pericytes within the cerebral cortex was significantly increased, both in the ipsilateral and contralateral hemisphere, compared to a normal mouse brain without tumor (n = 3, mean ± SEM, ***, p<0.001, ANOVA). (D) Low magnification photomicrograph of a representative GL261 tumor (dashed) in the rgs5^GFP/+ mouse brain, scale bar as in A. Pericytes showing a morphology consistent with activated pericytes were found in the cerebral cortex both in the (E) ipsilateral and (F) contralateral hemisphere, scale bars as in B. (G) Low magnification photomicrograph of a representative GL261 tumor (dashed) in the rgs5^GFP/+ mouse brain showing the SVZ (arrows), scale bar as in A. Activated pericytes are present (H) in the SVZ ipsilateral to the tumor but not (I) in the SVZ contralateral to the tumor, scale bar is 50 μm. (J) The morphology of the GFP positive pericytes inside the tumor was different compared to the pericytes in the cortex, with either (K) a flattened cell body with elongated processes (arrows) or (L) a prominent cell body with tuft-like processes (arrow). Scale bar in J as in H and scale bars in K-L as in B.