Figure 1

Cathepsin L drives intimal hyperplasia and macrophage infiltration. (A) Arterial enzyme activity for cathepsin L was measured by a fluorescence-based assay and normalized to tissue extract protein concentration at indicated time points following wire injury. Cathepsin L activity of the injured and uninjured carotid arteries from wild-type mice are displayed (n = 4 at each time point). (B,C) Common carotid arteries were injured by a 0.4 mm guide wire plus external carotid artery ligation and harvested 28 d after surgery. Frozen tissues were sectioned. Representative hematoxylin and eosin stained sections of carotid arteries from wild-type mice (n = 6) and cathepsin L^−/− mice (n = 6) are shown. The ratios of intima and media area and vessel medial size were quantified by planimetry at 28 d. The white arrows indicate internal elastic lamina. The black arrows indicate luminal side of the artery. (D) Mouse carotid arteries that were immunostained for macrophage markers (CD68-positive cells) 3 d after injury. The number of CD68-positive cells was defined as the percentage of total cells within a given area that stained positive for CD68. Representative hematoxylin and eosin stained and immunofluorescent-stained sections are shown. Data represent the means ± SEM. *P <0.05, **P <0.01 versus respectively controls. Scale bar represents 100 µm.