Quantitative evaluation of atherosclerotic plaques and intraplaque neovascularization using contrast-enhanced ultrasound after treatment with atorvastatin in rabbits

IntroductionThis study is supposed to investigate the value of contrast-enhanced ultrasound (CEUS) in quantitative evaluation of atherosclerotic plaques and intraplaque neovascularization after treatment with atorvastatin (ATV) in rabbits.Material and methodsForty-five New Zealand white rabbits were enrolled to construct the rabbit model of AS. All rabbits were assigned into the control, AS group and ATV groups (n = 15 individually). The AS plaque formation and relative parameters were observed and calculated by CEUS respectively. Total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were measured. Serum levels of matrix metalloproteinase-3 and 9 (MMP-3/9) and high-sensitivity C-reactive protein (hs-CRP) were examined by ELISA. The histological changes plaques, maximal plaque thickness (MPT), plaque area (PA) and corrected plaque area (PA/CVA) were evaluated by HE staining. Immunohistochemistry (IHC) was used to measure the positive protein expressions of VEGF, FVIII-Rag, MMP-3, CD40L and F8. The correlation between CEUS parameters with ELISA and IHC was analyzed by the Spearman correlation analysis.ResultsAt the 8th week, no plaque and new blood vessel were observed in the control group. The ATV group showed more plaques and new blood vessels, and lower IMT, plaque thickness and area than the AS group. The PI and RI were significantly increased in the AS and ATV groups compared to the control group. PI, RI. Plaque EI and its ratio in plaque and arterial lumen of the ATV group were lower than those in the AS group. Compared with the control group, the AS and ATV groups had higher serum levels of TC, TG, LDL, MMP-3, MMP-9 and hs-CRP, and higher AI. However, compared with AS group, serum levels of TC, TG, LDL and AI fell in ATV group. In comparison of the AS group, serum levels of MMP-3, MMP-9 and hs-CRP, MPT, PA and PA/CVA, and the positive expressions of VEGF, FVIII-Rag, MMP-3, CD40L and F8 were significantly reduced in the ATV group. The AS and ATV groups showed a positive correlation of EI in the plaque and its ratio in the plaque and arterial lumen with F8 protein expression, MMP-3 and MMP-9.ConclusionIn conclusion, our results indicated that ATV stabilizes atherosclerotic plaques and reduces intraplaque neovascularization in a rabbit model with AS, which can be characterized using CEUS.