(A) Double immunofluorescence for S100A4 (red channel) and ecto-5′nucleotidase (5′NT, green channel) and (B) for S100A4 (red channel) and α-SMA (green channel); nuclei in B are stained by DAPI. (A) 3-mm-thick cryostat section of renal cortex (rat); the thick arrow points to a 5′NT-positive interstitial fibroblast; S100A4-positive cells (thin arrows) are seen inside capillaries. Scale bar: ~10 mm. Reproduced with permission from Histochemistry and Cell Biology (15). (B) Renal cortex after 4 days of ureteral obstruction (rat); no cellular colocalization of S100A4 and α-SMA. G, glomerulus. Inset: S100A4-positive cells, showing strong cytoplasmic and weak nuclear staining; the shape of the cells is reminiscent of migrating lymphocytes. Scale bars: ~100 mm; inset, ~10 mm. Reproduced with permission from Histochemistry and Cell Biology (17).