Induction and Characterization of Atherosclerosis in New Zealand White Rabbits Using a High-Cholesterol Diet: A Cardiovascular Disease Model

Abstract

Atherosclerosis constitutes the main pathological basis of cardiovascular disease, which is the major cause of death in the world. The use of NZW rabbits on a high-cholesterol diet (HCD) is an established preclinical model; however, the dynamics of disease development on a dose-response scale at levels of systemic, vascular, and molecular levels have not been fully elucidated. To establish and characterize atherosclerosis in NZW rabbits using graded HCD exposure, and to determine the reversibility of disease parameters upon normalizing the diet. Thirty-two NZW male rabbits were randomly divided into four groups (n=8): Control (standard diet), 0.5% HCD, 1% HCD (both for 12 weeks) and Recovery group (1% HCD for 12 weeks followed by 4 weeks of standard diet). Parameters of serum lipids, liver enzymes, and inflammatory markers (hs-CRP, IL-6, TNF-α) were assayed sequentially. Hemodynamics were assessed through tail-cuff sphygmomanometry. Vascular imaging included B-mode ultrasound measurement of carotid intima-media thickness (cIMT) and magnetic resonance imaging (MRI) to determine aortic wall thickness. Expression analysis of the selected genes (LOX-1, ICAM-1, NF-κB, eNOS) was performed using RT-qPCR, and expression of proteins (PCSK9 and ox-LDL-R) was analyzed using Western blotting. Severe hypercholesterolemia (total cholesterol increased up to 19 times compared to the control), high inflammatory markers, worsening hemodynamic state, and 2.2-fold cIMT increase was observed in the 1% HCD group by the 12th week. LOX-1, ICAM-1, NF-κB and PCSK9 expressions increased significantly in aorta, while the level of eNOS decreased. All findings had a dose-dependent effect. Reversal of the diet resulted in partial biochemical and molecular normalization, but not in structural regression. Thus, the 1% HCD NZW rabbit model is a reliable model of human atherosclerosis with the ability to mimic its multifaceted pathophysiology.