Figure 7: (a)–(c) Immunohistochemical evidence for TLR-4 expression within atherosclerotic plaque of aortic sinuses from control apoE-/- (top) and CMS (bottom) apoE-/- mice. 5  m frozen sections of the apoE-deficient mouse aortic root were fixed with acetone for 5 minutes at room temperature and then immunostained with Rabbit antimouseTLR4 antibody ( ). Rabbit IgG was used as a negative control. (a)–(c) represent TLR-4 expression within aortic sinus of apoE-/- mice exposed to normal condition (control) or CMS for 0 week, 4, and 12 weeks, respectively (brown staining); (d) represents rabbit IgG staining for negative control. In (a) there is minimal immunoreactivity to TLR-4 in nonatherosclerotic aortic sinus of apoE-/- mouse (magnification   400).