Ag NWs produced foreign body reactions at Days 7 & 21 post instillation. H & E-stained tissue sections recovered at 7 (A, C, & E) or 21 (B, D, F) days post exposure to sham control (A-B), S-Ag NWs (C-D), or L-Ag NWs (E-F). All panels are Brightfield microscopy images of representative tissues from rats instilled with a single dose of sham control or Ag NWs at 0.5 ml/kg (Day 7), or 1.0 ml/kg (Day 21). Broken arrows indicate multi-nucleated Langhans cells (C-D), or granulomas (E-F). Scale bar is 50 μm.