Apoptotic cells line the margins of a blast-induced cortical tear without evidence of a vascular remnant. A section from a 3×−acute exposure rat was labeled for TUNEL (A), immunostained for α-smooth muscle actin (B, α-SMA) and counterstained with DAPI (C). Merged images are shown in panel (D). A tear lined by apoptotic cells that resembles a vessel is visible in panel (A). However while TUNEL-positive cells (arrows in panel A) are seen at the margins of the tear, no staining for α-SMA is apparent at the edges of the lesion (arrows in panel B). Scale bar: 200 μm.