Figure 6

Microscopic features of the lung from male Syrian hamsters intranasally inoculated with 1 × 10⁶ PFU of SARS-CoV-2 (n = 3 per group). A Consolidations of lung parenchyma at various degrees were shown after SARS-CoV-2 infection. Prominent alveolar wall thickening was observed from 4 dpi with perivascular inflammatory cell infiltration. Consolidation was the most severe at 8 dpi. These severe proliferative lesions became relatively moderate at 12 and 16 dpi. H&E. Scale bars, 100 μm. B Microscopic changes of the bronchiolar epithelium, lumen, submucosa, and peribronchiolar region. Exudates with inflammatory cells and cell debris were observed in the bronchiolar lumen at 4 dpi. These damages of the epithelium such as cilia loss, vacuolation, and proliferation were various following the infection. H&E. Scale bars, 100 μm; Insert: higher magnification. C Histopathology scoring of the lung. Data are presented as means ± SD. Microscopic lesions of lung showed significant differences in 4 and 8 dpi groups than the control group (P < 0.01). The most severe lesion was observed at 8 dpi among infection groups (P < 0.01). No significant differences in lesion were observed among 2, 4, 12, and 16 dpi groups.