Fig. 4: Ferroptosis correlates with lung disease severity in a COVID-19 Syrian hamster model.

a 10-week-old male hamsters were inoculated with 10⁵ PFU SARS-CoV-2 and euthanized at several time points to examine lung tissue. Representative images showing H&E staining, IHC staining using anti-TfR1 antibody (clone H68.4), and TUNEL staining on SARS-CoV-2-infected hamster lung sections collected on 2, 4, 7, 14 days post infection (dpi). Scale bar = 50 μm. b The positive TfR1 stain area is normalized to the mock group. Data shown as mean ± SEM, n = 6 (mock), n = 7 (7 dpi), unpaired two-sided t test (p value indicated). c Injured area% and positive TfR1 area% in infected lungs (n = 24) were plotted and fitted with linear regression. R² = 0.5329. Mock and infected lung section were IF stained with anti-4-HNE antibody (clone HNEJ-1) and anti-FTL antibody. The mean intensities of (d), HNEJ-1 and (e), FTL were normalized to the mock group. Data shown as mean ± SEM, n = 6 for both groups, unpaired two-sided t test (p value indicated). f Representative images of FTL and 4-HNE stain on mock and infected hamster lung at 7 dpi. Nucleus is in blue, 4-HNE in red, and FTL in green. Scale bar = 20 μm.