Effect of Angiotensin II Type 1 Receptor Antagonist, Losartan on Inflammatory Factor in Atherosclerotic Rabbits

BACKGROUND: Atherosclerosis is a progressive disease characterized by the accumulation of lipids and fibrous elements in the large arteries which now has become the pre-eminent health problem worldwide. OBJECTIVES: To investigate the effect and mechanism of Losartan intervention on atherosclerosis in rabbits fed with high-cholesterol diet. MATERIALS AND METHODS: 32 New Zealand rabbits were randomly divided into three groups: control group, high-cholesterol group and Losartan group. The level of weights, serum lipid levels and inflammatory factors, such as IL-6 and hs C-reactive protein were detected before the Losartan intervention and two months after the Losartan intervention respectively. The content of AngII was detected on later stage of the experiment. Pathological examination of the iliac arteries was performed to measure the thickness of endothelium and media. RESULTS: After the atherosclerosis model was established, the level of the serum lipids, hs CRP and IL-6 of rabbits in high-cholesterol group and Losartan group increased significantly in comparison with control group(P < 0.05), but there was no statistical difference between the two groups (P > 0.05). After the Losartan intervention, the levels of serum hs CRP and IL-6 were higher in high-cholesterol group and Losartan group in comparison with control group (P < 0.05), and they were significantly lower in Losartan group than high-cholesterol group (P < 0.05). Serum lipids levels of rabbits in high-cholesterol group and Losartan group also increased significantly in comparison with control group (P < 0.05), but there was no statistical difference between them (P > 0.05). Ratio of endothelium thickness to the media thickness was higher in high-cholesterol group and Losartan group in comparison with control group (P < 0.05), and the ratio in Losartan group was significantly lower than high-cholesterol group (P < 0.05). Content of Angiotensin was higher in high-cholesterol group and Losartan group compared to control group, and there was no statistical difference between them. CONCLUSIONS: The effect of Losartan on atherosclerosis is to prevent the development of atherosclerosis by inhibiting inflammatory process and may not be related to the lipid metabolism.