Table 2 Histopathology evaluation of SARS-CoV-2-infected K18 hACE2 transgenic C57BL/6 mice in Lung and Brain at 6 DPI.
From: Lethality of SARS-CoV-2 infection in K18 human angiotensin-converting enzyme 2 transgenic mice
DAY 6 | Lung | Brain |
|---|---|---|
K18 hACE2 | 5/6 showed moderate (20–60%) of the tissue had significant interstitial mixed neutrophilic and mononuclear inflammation expanding alveolar septal walls, prominently surrounding vascular structures and mildly filling alveolar spaces. Bronchioles were mostly spared of inflammation. 1/6 showed minimal interstitial mononuclear inflammation and occasionally rimming bronchiolar walls, airways were mostly empty and rare accumulation of pyknotic cellular debris noted in bronchiolar lumen and wall. Few alveolar spaces had minimal cellular debris admixed neutrophils and histiocytes. ~1–4% of the tissue involved. | 6/6 showed moderate (5–40%) mixed perivascular inflammation: mixed neutrophilic and mononuclear cell vasculitis in 2/6 or within the gray and white matter, within vascular walls and within meninges. (3/6). Areas of inflammation frequently had admixed necrotic cellular debris (5/6). Few neutrophils noted within the brain parenchyma interstitium (2/6). There were few individual glial cells and neuronal (hippocampus, or gray matter cortex) necrosis (3/6). Vasculitis was prominent (2/6). Some areas had swollen vacuolated neurons throughout gray matter (2/6). Few individual necrotic neurons within the hippocampus (1/6). |
Diagnosis | Pneumonia (4/6), diffuse or multifocal, lymphoplasmacytic, histiocytic, interstitial, mild-moderate (5/6), or marked (1/6), subacute. | Meningoencephalitis (2/6) or encephalitis (4/6), neutrophilic, multifocal, mild, subacute, with necrosis, vasculitis (5/6). |
