Epithelial injury. (a) Asthmatic mice show the shrinkage of bronchial epithelia (arrow) with pyknotic nucleus and marginated heterochromatin. Normal airways (b) show thin and regular intercellular space as compared to that of asthmatic airways. (c) Widening of intercellular space; cc, clara cells; asm, airway smooth muscle; cec, ciliated epithelial cells; n, nucleus; c, cilia. Arrows in (b) and (c) indicate the intercellular space between adjacent bronchial epithelia. Images are at 880X magnification.