Table 2.

Frequencies of morphological findings in the lungs of mice in noninfectious and infectious models

Morphological findings in the lungs of male mice	Unilateral intrabronchial administration of the GC + LPS mixture, male ICR mice	Infection of male hACE2 mice with SARS-CoV-2
Peribronchial mononuclear/neutrophil infiltration	+  +  +	–
Perivascular mononuclear/neutrophil infiltration	+  +  +	–
Hyalin-like membranes	–	+  +
Microcirculatory disorders—congestion, stasis, aggregation of red blood cells, and microthromboses	+	+  +  +
Transudate in the lumen of pulmonary acini	+  +	+  +
Infiltration of alveolar walls with mononuclear cells / neutrophils	+  +  +	+
Infiltration of the alveolar lumen with mononuclear cells/neutrophils	+  +  +	+

Sign severity is assessed using semiquantitative scores where “–” means a missing sign, “ + ” a minimal or mild sign, “ +  + ” a moderate sign, and “ +  +  + ” a severe sign