Figure 2

MMP12 mediates age-dependent arterial stiffening.

Aortas were isolated from male wild-type and MMP12-null mice of different ages. (A) The samples were analyzed by real-time qPCR. Results show mean + SD; n = 2 with each independent experiment representing a pool of 4 aortas. The levels of each mRNA in the 2-month arteries were set to 1.0. (B) Cross sections of aortic roots from 2 (n = 7), 6 (n = 8) and 12 (n = 8) month-old male wild-type mice were stained for SMA (green) and MMP12 (red). Scale bar = 50 μm. (C) AFM of aortas from 2–18 month-old wild-type (n = 4) and MMP12-null (n = 4) mice. The bar graph shows mean + SE. (D) In situ elastase activity in cross sections of aortic roots from 6 and 12 month-old wild-type and MMP12-null mice. Scale bar = 50 μm. (E) Quantification of results in panel D from wild-type (n = 6) and MMP12-null (n = 8) mice. The bar graph shows mean + SE. All p values are from two-tailed Mann-Whitney tests.