2.2 Histology
Thoracic aorta sections were fixed in 4% paraformaldehyde, then embedded in paraffin. Morphological characteristics of thoracic aorta were assessed by hematoxylin-eosin (H&E) staining. The media thickness (MT) of thoracic aorta was defined as the region between the internal and external elastic laminae. The MT/lumen diameter (LD) represented the level of VR. Thoracic aorta fibrosis was assessed by Masson’s trichrome staining. Collagen volume fraction (CVF) was quantified by measuring the ratio of blue fibrotic area to total thoracic aorta area.