Effect of Qingre Quyu Granule (清热祛瘀颗粒) on stabilizing plaques in the brachiocephalic artery of apolipoprotein E deficient mice

Objective： To investigate the effect of Qingre Quyu Granule （清热祛瘀颗粒, QRQYG） on stabilizing vulnerable plaques in apolipoprotein E （ApoE） defficient mice. Methods： Seventy-two male ApoE defficient mice were given a high-fat diet from 6 weeks of age. At the 16th week, all the mice were randomized into 3 groups： the QRQYG group, the simvastatin group, and the control group. Sixteen weeks after administration of 0.9 g/kg QRQYG, 3 mg/kg simvastatin or 10 mg/kg sodium chloride per day to the respective groups, the animals were euthanized. The pathological morphologic changes in the vulnerable plaques were evaluated, the matrix metalloprotease-9 （MMP-9） expression was measured by immunohistofluorescence, the soluble intercellular adhesion molecule 1 （ICAM-1） was determined by ELISA, the nuclear factor kappaB （NF-κB） subunit p65 was measured by quantitative RT-PCR, and, finally, thrombospondin-1 （TSP-1） was determined by the immunohistochemical method. Results： The plaque cross-sectional area in the brachiocephalic artery （23.7%, P0.01）, the lipid core of the plaque （43.1%±3.1%）, and the number of buried ？brotic caps of the plaque were significantly decreased in the QRQYG group compared to the control group （both P0.01）; furthermore, the thickness of the ？brotic cap of the plaque increased and the intra-plaque hemorrhage of the plaque decreased. The serum soluble ICAM-1 （27.1±5.1 μg/mL）, the protein expression of MMP-9 and TSP-1 and the p65 mRNA expression increased in the QRQYG group in comparison with the control group （P0.05 or P0.01）. Conclusion： QRQYG could stabilize the vulnerable plaque through inhibition of the inflammatory response.