Figure 2.

Histological evaluation of lungs of surviving intranasally ricin-exposed and antitoxin-treated mice. Mice were intranasally intoxicated with 2LD₅₀ (7 µg/kg) ricin. Antitoxin was administered at 24 h PE. Sham group was administered PBS instead of either ricin or antitoxin. At 30 days PE, lungs were harvested, and histological staining was conducted. Lung H&E staining of (A,B) sham mice and (C,D) ricin + antitoxin-treated mice. (A,C) Magnification ×2; (B,D) magnification ×20. Scale bar 500 (A,C) and 50 (B,D) µm, n = 3 per group. Dashed areas represent focal damage: intensive cell infiltration and alveolar epithelial disruption; black thick and thin arrows show platelet aggregates and occasional inflammatory cellular depositions, respectively; blue arrows show edema. (E) Histological severity score. Data are expressed as means ± SEM. *** p < 0.001.