Representative histological features of airway in a guinea pig allergic asthma model. A) Low-power micrograph (10x) from the lungs of control and experimental guinea pigs showing bronchi. B) Area of smooth muscle layer and C) lamina propria of bronchioles (white bars) and bronchi (black bars), adjusted by the basement membrane (BM) perimeter, as measured by automated morphometry. Bars and vertical lines are mean ± SE of n = 6 per group. *P < 0.01 (unpaired Student’s t-test).