Abstract:Objective: To construct a rabbit model of abdominal aorta atherosclerosis by modified balloon injury and high-cholesterol diet, and evaluate the expression of immune clearance related proteins in early plaque. Methods: A total of 20 New Zealand rabbits were assigned randomly to 3 groups: sham, classical intervention, and modified intervention. The high-cholesterol diet and normal diet were given respectively to the intervention groups and the sham for one week, after which the model was constructed through the femoral artery. The sham group was given a general diet, anesthesia, skin cutting, isolated femoral artery and suture, but no balloon injury. For the classic intervention group, a balloon was inserted into the abdominal aorta, inflated and unidirectionally pulled 3 times. For the modified intervention group, the balloon was inserted, inflated and a bidirectionally pushed and pulled for 30-40 times. Following the intervention, the 2 intervention groups received high-cholesterol diet, while the sham group received normal diet for another 4 weeks. The intravascular ultrasound was performed to examine the abdominal aorta via the femoral artery, and the injured segments of abdominal aorta were sampled for further hematoxylin-eosin (HE, 苏木素-伊红染色) staining and immunohistochemistry study at the end of the study. Results: There was no significant difference in weight gain measured at 4 weeks post intervention among the 3 groups. The intravascular ultrasound demonstrated significant plaque hyperplasia and lumen stenosis in the modified intervention group. HE staining revealed varying degrees of intimal hyperplasia in all samples from both intervention groups. Compared to the classical intervention group, the modified intervention group exhibited significantly increased maximum intimal thickness (481.5 ± 81.94μm vs. 174.69 ± 53.76μm, P < 0.05) , mean intimal thickness (262.63 ± 53.04μm vs. 77.49 ± 18.02μm, P < 0.05) , higher intimal /media area ratio (1.57 ± 0.30 vs. 0.39 ± 0.14, P < 0.05) and severer vascular stenosis (52.13 ± 11.31% vs. 19.04 ± 5.90%, P < 0.05). The immunohistochemistry study revealed significantly enhanced macrophage infiltration in the modified intervention group compared with the classic group. Moreover, a higher expression of the anti-phagocytic protein CD47 in the proliferative intima was detected in the modified intervention group than the sham group. Conclusion: Our novel rabbit model of abdominal aorta atherosclerosis by modified balloon injury and high-cholesterol diet succeeded in accelerating early plaque development with enhanced stability and reliability. Significant necrotic cell clearance impairment in early plaque was detected in this novel model.