The severity of elastin degradation is semiquantified, as previously described (grade 1, no degradation; grade 2, mild degradation; grade 3, severe degradation; and grade 4, presence of aortic rupture) [12 (link)].
Briefly, the aortic sections were deparaffinized and hydrated in H2O and then incubated with primary antibodies against Mac-3 (1 : 100 dilution, BD, 550292), MCP-1 (1 : 500 dilution, Servicebio, G11199), VCAM-1 (1 : 200 dilution, Servicebio, G13336), MMP-2 (1 : 6000 dilution, Servicebio, GB11130), and MMP-9 (1 : 1000 dilution, Servicebio, GB11132) at 4°C overnight, followed by incubation with the corresponding secondary antibody for 1 h at 37°C. Then, the sections were dehydrated and images were obtained by a Nikon microscope equipped with a CCD camera. Immunostaining data of each section was randomly selected and measured by 2 different investigators in a blinded manner using the image analysis software (Image-Pro Plus, EPIX Vision).