FIGURE 3.

Characterization of glucose-regulated protein (GRP78)-positive cells in lesioned striatum on day 3 after 3-nitropropionic acid injection. (A) Triple-labeling of GRP78, NeuN, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) showing that neuronal GRP78 expression is evident in the perilesional area, while GRP78 is virtually absent in dying or dead neurons in the lesion core. The two broken lines indicate the borders of three areas: the peri-lesional area, lesion periphery, and epicenter. The corresponding boxed areas in the lesion periphery and epicenter in A are enlarged in B, C. (B,C) In both the lesion periphery (B) and the epicenter (C), both TUNEL-positive (arrows) and TUNEL-negative (arrowheads) neurons show negligible immunoreactivity. Notably, in the lesion periphery, intense GRP78 expression is localized within the vascular profiles (asterisks in B) and presumptive activated microglia (open arrowheads in B), while no specific GRP78 expression is detectable in the epicenter. (D) Triple-labeling of GRP78, Iba1, and GFAP showing that the lesion core can be divided into two areas: the core periphery, which is heavily infiltrated by activated microglia, and the epicenter, which is devoid of Iba1-positive microglia. Notably, GFAP immunoreactivity is absent in both the periphery and the epicenter. (E,F) Higher-magnification views of the corresponding boxed areas in D. (E) In the peri-lesional area, GRP78 expression can be observed in reactive astrocytes (arrows) and activated microglia (arrowheads). (F) In the lesion periphery, intense GRP78 expression is visible in almost all Iba1-positive cells. Cell nuclei are stained with 4′,6-diamidino-2-phenylindole. Scale bars represent 50 μm for A D; and 20 μm for B, C, E, F.