Hypoxia inducible factors regulate infectious SARS-CoV-2, epithelial damage and respiratory symptoms in a hamster COVID-19 model
Fig 4
SARS-CoV-2 RNA and pathology in the nasal tract and lung.
(A) Sections from the left lung and nasal cavity were stained with H&E to analyse histopathological changes and with RNA in-situ hybridisation (ISH) to detect SARS-CoV-2 RNA using probes specific for the viral Spike (S) transcript. Representative images from each treatment group are shown. Lung lesions consisted of multifocal broncho-interstitial pneumonia (*) with mild to moderate necrosis of the bronchiolar epithelium (arrows and H&E inserts) (see S5 Fig). ISH shows abundant viral RNA in the nasal cavity epithelia that associates with mild to moderate necrosis (inserts) and within the airway epithelia and areas of inflammation. Scale bar = 100μm. (B) Nasal cavity was assessed for the presence and severity of lesions using a semi-quantitative scoring system from H&E-stained sections. SARS-CoV-2 RNA in the olfactory epithelium or exudates was quantified using the following scoring system: 0 = no positive staining; 1 = minimal; 2 = mild; 3 = moderate and 4 = abundant staining. (C) Lung pathology was assessed for the presence and severity of lesions using a semi-quantitative scoring system from H&E-stained sections. Digital image analysis calculated the area of lung airway and parenchyma staining for viral RNA. Statistical analysis was performed using a one-way ANOVA, p<0.05 = *, p<0.01 = **. N = 5 animals for vehicle and N = 6 animals for each treatment group.