Localization of increased tPA by heparin administration. (A) Immunofluorescence staining shows tPA increased at the border of the ischemic core (IC) at 6 hours after MCAO administration in heparin-treated WT mice. Double labeling of tPA (red; B, arrows) with rabbit anti-tPA and microglial (MICRO) cells (green; C, arrows) with rat antiF4/80, tPA (red; E), and astrocytes (ASTRO; green) (F) with rat anti-GFAP, tPA (green; H) with goat polyclonal antibody, and neuron (NEURO; I) with rabbit antineurofilament polyclonal antibody, tPA (green; K), and endothelial cells (ENDO; red) (L) with polyclonal rabbit anti-VWF in the ischemic border zone. Merged images indicate tPA was expressed in microglial cells (D, arrows) but not in astrocytes (G), neurons (J), or endothelial cells (M). Inset in panel D is 1.4-fold magnified cells from the area denoted by the arrowhead. Scale bars equal 300 μm (A), 5 μm (B-D), and 12.5 μm (E-M).