Figure 1.

Central fluid percussion injury does not result in focal brain damage, but does precipitate diffuse axonal injury in the thalamus of both rats and micro pigs 1 day following injury. Representative photographs of the gross (A,C) micro pig and (B,D) rat brain 1 day following cFPI. The top panels are dorsal and ventral views of the entire brain 1 day post-injury while panels (C) and (D) represent 5 mm thick coronal sections at the level of the rostral thalamus in the (C) micro pig and (D) rat. The boxes indicate the regions of analysis of microglia process convergence in the thalamus of both species. Diffuse cFPI also did not result in cell damage/death. Hematoxylin and eosin staining reveled no square wave cellular damage in the thalamus of either the (E) micro pig or (F) rat thalamus at 1 day following cFPI. Amyloid precursor protein (APP) immunohistochemistry in the (G) micro pig and (H) rat thalamus, however, demonstrated diffuse axonal injury (arrows) 1 day following cFPI. Insets (e–h) depict higher magnification images of panels (E–H), respectively. Note that the cFPI model employed did not result in contusion, hematoma formation or square wave cell damage/death, however did demonstrate diffusely distributed axonal injury, consistent with diffuse injury. Scale bar A–D: 1 mm; E–H: 100 um; e–h: 50 um.