Figure 5.

Interferon regulatory factor-5 deficiency reduced the frequency of plaque rupture and reduced both necrotic core and CDC11c plaque area in an inducible plaque rupture model. (A) Schematic figure of the common location of plaques ruptures identified in the area between the cast and ligation. (B) Computed tomography (CT) with contrast agent demonstrated that the blood flow was diminished, but not interrupted, after partial ligation proximal to the bifurcation of the carotid artery. Red indicates a high blood flow and blue and green indicate a lower blood flow. (C) No difference in total plaque area, intima/media ratio based on haematoxylin and eosin, was seen when comparing ApoE  ^−/− and ApoE  ^−/−  Irf5  ^−/− carotid lesions. (D) Plaque rupture frequencies are reduced in ApoE  ^−/−  Irf5  ^−/− mice compared with ApoE  ^−/− mice. Representative images of haematoxylin and eosin stained cross-sections of the right carotid artery 4 days after cast placement in the intra-cast region of (left) and ApoE  ^−/−  Irf5  ^−/− mice (right). Scale bars, 100 μm. The left insert demonstrates a rupture, characterized by the loss of continuity of the fibrous cap with invasion of thrombus into the plaque tissue and at the right insert a non-ruptured plaque in ApoE  ^−/−  Irf5  ^−/−. P indicates plaque tissue and T indicates thrombus. Scale bars insert, 50 μm. Scale bar, 100 μm. (E–G) Representative images of cross-sections of carotid arteries after the cast with respective staining and quantification. (E) The sections were stained with haematoxylin and eosin for plaque and necrotic core size (necrotic cores are indicated with a dotted line). A decrease in necrotic core size was observed in the interferon regulatory factor-5-deficient group. (F) CD68 was used to identify macrophages and (G) CD11c. Unless mentioned otherwise, all quantifications are shown as a percentage of the cross-sectional plaque size. All values are expressed as median and interquartile range. Scale bar, 100 μm; n = 16–17.