Figure 3.

Distribution and identity of parenchymal perivascular CM-DiI⁺ cells. These samples are stained at the 5 day time point. (a) The majority of parenchymal CM-DiI⁺ cells were located along vessels that are labelled with Alexa-633, which specifically labels larger arterioles (>20 µm). Both longitudinally and transversely cut vessels with surrounding CM-DiI⁺ cells were labelled with Alexa-633. Scale bar represents 50 µm (top row) or 20 µm (bottom row). (b) CM-DiI⁺ cells (red) express relatively low levels of Iba-1 (green). Note the co-localization of CM-DiI with Iba-1 immunolabelling, along the direction of the dotted arrow. Scale bar represents 40 µm. (c) All CM-DiI⁺ cells (red) were also involved in uptake of FITC-dextran (green). Note the co-localization of CM-DiI with FITC-dextran labelling, along the direction of the dotted arrow. Scale bar represents 40 µm. The perivascular location, low expression of Iba-1 (relative to surrounding microglia) and uptake of FITC-dextran indicate these cells are perivascular macrophages. Data are representative of n = 5 independent experiments.