Effects of CatK expression on the airway smooth muscle cells. (A) Representative immunofluorescence staining of small airways from 2 months old WT and Ctsk-/- mice (original magnification, ×200). Smooth muscle cell layer thickness and cell area in lung sections from mice of various ages are depicted in panels B and C. (D) Representative image and band intensity analysis data of immunoblots show increased expression in α-actin and vimentin in 2 months old WT and Ctsk-/- mice. Morphometry and image analysis were processed using Openlab software and Chemigenius system, respectively. A/Pbm means the staining area divided by the perimeter of airway basement.