A Critical Role for Proinflammatory Behavior of Smooth Muscle Cells in Hemodynamic Initiation of Intracranial Aneurysm
Figure 5
Localization of MMP expression during IA initiation.
(A,B) The BT was stained for MMP-2 and -9 (top, red) and smooth-muscle actin, SMA, (middle, green) 5 days after CCA ligation. Ovals mark zones of IEL loss (determined from Van Giessen staining in adjacent sections), which showed the highest MMP intensity. High-magnification overlays of MMP and SMA staining in these zones (bottom) show both MMP-2 and -9 directly overlapping SMA (yellow or orange regions; arrowheads) and in large perinuclear patches entirely encircled by SMA-positive cytoplasm (arrows). (C) Quantitation of MMP-2 and -9 intensity in the media in areas of IEL loss compared to neighboring zones with intact IEL shows significantly higher intensity in areas of aneurysmal damage (n = 12; * indicates p<0.05). Scale bars = 50 µm.