Reduced survival of PCK rats due to aortic dissection. (A) Survival rate of WT (n = 30) and PCK rats (n = 33) following surgery to induce IAs. Dotted lines indicate rats killed at the end of the experiment. (B) Representative image of an aortic arch from a PCK rat that prematurely died 3 weeks post-surgery. Scale bar, 3 mm. Arrow indicates the site of dissection. (C) Martius Scarlet blue staining of an aortic arch section of a WT rat that prematurely died 6 weeks post-surgery. Nuclei are stained in brown, fibrin in red, erythrocytes and fresh fibrin in yellow, and white blood cells and collagen in blue. Scale bar, 1 mm. Grey (D) and black (E) panels are magnifications showing the vessel wall deterioration and the infiltration of blood into the vessel wall. Scale bar, 0.1 mm. (F) Victoria blue staining of an aortic arch section from a PCK rat killed 4 weeks post-surgery illustrating the three locations at which elastic architecture was studied. Scale bar, 1 mm. Aao, ascending aorta; DAo, descending aorta; BCT, brachiocephalic trunk; LCCA, left common carotid artery; LSA, left subclavian artery. (G) Representative Victoria blue staining images of Stages 1, 2, and 3. (H and I) Classification of the elastic architecture downstream of the LSA in the aortic arch (location indicated in D) of five control WT and five control PCK rats (H) and five WT and four PCK rats killed 4 weeks post-surgery (I). Yellow, Stage 1; orange, Stage 2; and dark red, Stage 3. Fisher’s exact test. ****P < 0.0001.