Objectives To assess the aorta elastic properties in the procession of atherosclerosis by ultra-high frequency ultrasound, and to detect whether there was a relationship between the aorta elastic properties and the severity of atherosclerotic plaque.
Methods Mice deficient for the ApoE with high-cholestrol diet (Apo E−/−) were studied as an age-dependent model of atherosclerosis. At 10, 20, 30 and 40 weeks of age, the blood pressure in the ascending aorta was measured by catheter, and the aorta mechanical properties were assessed by measuring aortic elastic modulus and pulse transit time of the ascending aorta with ultrahigh frequency ultrasound. The plaque burden was assessed by high-frequency ultrasound and Masson’s trichrome stain, separately.
Results Elastic modulus of the aorta (EAo) significantly increased from 10 to 40 wks of age, and there was also an age-dependent decrease in PTT in Apo E−/− mice. Vessel thickness at the lesion-prone sites of the lesser curvature of the aorta and the proximal brachiocephalic artery increased with age, consistent with the Masson’s trichrome staining which showed age-dependent worsening of atherosclerosis in the mice model. There was a statistically relationship between the aorta mechanical properties and the severity of plaque.
Conclusions With the progression of atherosclerosis and the increased plaque burden, aorta mechanical properties deteriorated in Apo E−/− mice. Ultra-high ultrasound was a potential tool for assessment of plaque burden and aorta mechanical properties in mouse model.