Abstract:

Objective       To explore inhibitory actions of polyinosinic acid on expression of lectin-like oxidized low-density lipoprotein receptor-1 and its antiatherogenic role in atherosclerotic rabbits. MethodsThirty male New Zealand white rabbits were randomly divided into five groups: the control group, the hypercholesterol group, the poly Ⅰgroup, the fluvastatin group and the association group(n=6). Except for the control group, the other groups were strainedwith a balloon in the abdominal aortic under general anesthesia induced by 3% sodium pentobarbital. Then, they were fed with polyinosinic acid(polyⅠ), fluvastatin, or hypercholesterol .12 weeks later, rabbits were sacrificed and the abdominal aortas were pathologically studied. Expressions of LOX-1 mRNA and protein in the vascular tissue were determined by immunohistochemistry and reverse transcription- polymerase chain reaction(RT-PCR), respectively. Results         Pathological changes of abdominal aortas: ① In the control group , ascular intima endothelial cells were intact and had no obvious lipid deposition. ② In the hyper-cholesterol group, vascular intima endothelial cells fell off and atheromatous plaque formation were identified. Under the fibrous cap, large numbers of amorphous necrotic disintegrating products could be found with large amounts of cholesterol clefts, foam cells and lymphocytes. ③  In the fluvastatin group, some endothelial cells fell off. Beneath the vascular intima, there were scattered and irregular plaques with a small amount of foam cells. ④ In the poly Ⅰ group, some endothelial cells fell off and there were a lot of foam cells, as well as inflammatory cells,  below the fibrous cap. ⑤ In the association group, there was obviously weaker atherosclerosis than in the hypercholesterol group. The ascular intima slightly thickened, and there were a few foam cells,  with the smooth muscle tidily ranked. There were high  expressions of  LOX-1 protein and mRNA in the vascular tissues of the hyper-cholesterol group, but rarely in the control group. Expression of LOX-1 protein and mRNA in both the fluvastatin group and association group were significantly lower than that in the hypercholesterol group(P＜0.01). Expressions of LOX-1 protein and mRNA between the hyper-cholesterol group and polyⅠgroup showed no significance(P＞0.05). Conclusion       Poly Ⅰ may have a role in resist ance of atherosclerosis, but it does not posses an obvious function to reduce expressions of LOX-1 protein and mRNA. Fluvastatin can significantly inhibit the development of atherosclerosis and expressions of LOX-1 protein and mRNA.

Key words: Atherosclerosis; Oxidized low density lipoprotein; Lectin-like oxidized low-density lipoprotein receptor-1; Fluvastatin; Polyinosinic acid; Ribbit