Fig. 2.

Representative lung parenchyma specimens, investigated by both Light (H&E) and Electron microscopy - TEM (a, d, g, l, o and b–c, e–f, h–i, m–n, p–q, respectively), from control (a–c), AgNO₃- (d–i) and AgNP-treated (l–q) rats, 7 days after i.t. instillation. The physiological pulmonary structure is clearly preserved in control animals (a–c). Differently, selected structural alterations evidenced in pulmonary parenchyma of both AgNO₃- and AgNPs-treated rats are presented. Collapsed alveoli characterized by wall thickening and micro haemorrhagic foci, along with bronchiolar distortion (d, g and l); bronchus-associated lymphoid nodules adjacent to granulomatous formation in peribronchiolar area (l and o); markedly degraded pulmonary structure, with diffuse presence of collagen fibres (e–f), with detail of activated monocyte (insert in e); damaged lung parenchyma with several activated eosinophil granulocytes (h), characterized by the presence of cytoplasmic phagosomes, collagen fibres and residual bodies (i); thickened alveolar wall stuffed with inflammatory cells (m); early and late apoptosis (n); type II pneumocytes (PII) packed with vacuolized multi-vesicular bodies, activated lymphocyte in a vessel (p), and collagen fibril bundles (insert in p); pulmonary thrombus, together with necrosis (q). Light microscopy magnification: 20x (a, l, and o); 40 x (d and g). Electron Microscopy original magnification: x 5,000 (b–c, e–f, h, m–n, p–q); x 12,000 (i); x 20,000 (insert in p).