Figure 1

White matter injury and OL-like cell loss in EC at 72 h in Timp-3 KO and WT mice. A. Representative regions from the nonischemic and the ischemic EC at 24 and 72 h. Iba-1 (microglia/macrophage) and GFAP (astrocyte) were both stained with DAB and counterstained with cresyl violet acetate (CVA). The intact linear rows of dark-staining nuclei by CVA were formed by OL-like cells (arrows) in nonischemic ECs at 24 and 72 h, as well as in ischemic ECs at 24 h. Ischemic EC shows massive DAB-positive glial cells at 72 h. A marked loss of CVA positive cells was seen in ischemic EC in WT mouse compared with that in KO mouse. Scale bars = 50 μm. B. Stereological counting of OL-like cells in ischemic EC at 24 and 72 h reperfusion shows OL-like counts were similar at 24 h between Timp-3 KO and WT ischemic. A significant loss of OL-like cells occurred at 72 h in the WT ischemic EC compared to KO ischemic and to the WT nonischemic EC (p < 0.01 and 0.05, respectively, n = 6). From 24 to 72 h, OLs in ischemic KO EC remained unchanged. The brain cartoon shows location of regions used for OL counting (shaded areas). CC: corpus callosum; EC: external capsule. Micrographic image shows Iba-1 and GFAP (arrows) visualized by DAB in higher magnification. C. TUNEL assay demonstrates apoptotic cell death in ischemic EC at 72 h reperfusion. TUNEL-positive cells were seen in ischemic WT EC. Scale bar = 100 μm. D. Distribution of neuronal degeneration in ischemic hemispheres in Timp-3 KO and WT mice at 24 and 72 h of reperfusion following 90 min transient MCAO. Coronal sections were stained for degenerating neurons using Fluoro-Jade (FluoJ). Number of FluoJ-positive cells was much greater in WT than in KO at both tiom points. La-ctx: lateral cortex, stri: striatum, pcf: piriform cortex. Scale bar = 100 μm.