Ag NW instillation produced epithelial sloughing in bronchiolar regions. Panels are Brightfield microscopy images of the most severe responses in H & E-stained tissue sections, from rats instilled with a single dose of 1.0 ml/kg sham control (A, B, C), L-Ag NWs (D-E), or S-Ag NWs (F). Images show tissues at Days 1, 7, and 21 days post exposure to sham control (A-C, respectively), Days 1 and 7 post exposure to L-Ag NWs (C & D, respectively), and Day 21 post exposure to S-Ag NWs (F). Solid arrows indicate sloughed epithelial cells. Scale bar is 50 μm.