FIGURE 4.

Characterization of glucose-regulated protein (GRP78)-positive cells in lesioned striatum on day 7 after 3-nitropropionic acid injection. (A) Triple-labeling of GRP78, Iba1, and GFAP showing that the lesion core (right side of the broken line) is devoid of GFAP immunoreactivity, but is evenly filled with Iba1-positive cells, nearly all of which express GRP78. The boxed areas in the peri-lesional area and the lesion core are enlarged in the corresponding panels B–D. (B) In the peri-lesional area, evident GRP78 immunoreactivity is observed in reactive astrocytes (arrowheads) and activated microglia (arrows). (C,D) In the lesion core, intense GRP78 expression is observed in the vascular profiles (asterisks) and in activated microglia/macrophages (arrows). (E) Quantitative temporal analysis showing that the number of GRP78-positive microglia/macrophages increases progressively over a 7-day period after lesion induction. Note that the number of GRP78-positive microglia/macrophages is significantly higher in the lesion periphery than in the epicenter on day 3. The data are expressed as the mean ± standard error of the mean. ^∗∗∗P < 0.001 vs. saline-treated controls. Cell nuclei are stained with 4′,6-diamidino-2-phenylindole. Scale bars represent 50 μm for A; and 20 μm for B–D.