Figure 2

Immunohistochemical stainings of a human atherosclerotic plaque. The region inside the square in A, C, E, and G is amplified in B, D, F, and H, respectively. A and B, sections were double stained for calpain (proteolyzed α-fodrin, in blue) and TUNEL (in brown), showing colocalization of these two stainings. The arrows in B show cells staining positively for calpain and TUNEL. C and D, sections were incubated with anti-proteolyzed α-fodrin antibody. α-fodrin fragments, resulting from the presence of active calpain, are present in the core and shoulder regions of the plaques and in some scattered areas of the fibrous cap. This is also seen in A with the blue colour. In D, cells stained brown are positive for calpain activity (long arrow), whereas non-stained cells (short arrow) are not. E and F, negative control (primary antibody omitted). G and H, TUNEL staining for cell death (in brown). The arrow in H points to a dying cell, staining brown.