Research On The Effects And Mechanism Of Wenban Formula Stabilizing Atherosclerotic Plaque In Rabbits

Objective:To investigate the effects of Wenban Formula (WBF) in the atherosclerotic plaque and explore its possible mechanism of stabilizing atherosclerotic plaque.Methods:In this research rabbits were fed with high-fat diet to establish atherosclerotic model.56 rabbits were divided into four groups randomly:normal control group、model group、simvatatin-treated group and WBF-treated group, with 14 rabbits in each group. After 12 weeks the atherosclerotic model was builded. The rabbits were given drugs, and the dosage is administrated according to the method of converting the body surface area of rabbit to human being. Simvastatin-treated group and WBF-treated group were given drug with dosage of 0.98mg/kg.d、4.24g/kg.d respectively, while normal control group and model group were given cool boiled water with corresponding volume by intragastric administration. All rabbits were killed 8 weeks later. Blood serum was obtained to test the level of total cholesterol(TC)、triglyeride(TG)、high-density lipoprotein cholesterol(HDL-C)、low-density lipoprotein cholesterol(LDL-C) and high sensitive C-reactive protein (hs-CRP). Aortic pathological section was taken and stained by HE. Then the plaque area、lipid core area、intima and tunica media thickness、the fibrous cap thickness were observed by light microscope, and intima thickness/tunica media thickness ratio and the fibrous cap thickness /lipid core ratio were calculated. The positive area of MMP2、IL-6、CD34、VEGF、endostatin in the aortic plaque were observed by immunohistochemical method, while the VEGFmRNA and endostatin-mRNA by in situ hybridization technique.Results:1. After treatment, the level of serum TC、TG and LDL-C in WBF-treated group were significantly lower than those of the model group (p<0.01), but the variance of the level of HDL-C have no statistical significance in all groups.2、Aortic pathological section with HE staining being detected by ordinary light microscope,the result showed that the decreased area of fatty streak and spot in aortic tunica intima in WBF-treated group exceeded those of the model group, so were the decreased thickness of aortic tunica intima and accumulation of foam cells.3、Compared with model group, the plaque area、lipid core area、 intima thickness and intima thickness/tunica media thickness ratio in WBF-treated group were decreased significantly (p<0.01); while the fibrous cap thickness and the fibrous cap thickness/lipid core area ratio increased obviously (p<0.01).4、The collagen positive area with Masson and MMP2 positive area with immunohistochemical methods in WBF-treated group appeared to be decreased more significantly than those of model group(p<0.01).5、WBF could reduce obviously the level of serum hs-CRP and IL-6 postive area in the atherosclerotic plaque(p<0.01).6、Compared with model group, WBF could decrease CD34、VEGF and VEGFR-2 postive area significantly except for the endostatin (p<0.01) in the atherosclerotic plaque.7、VEGFmRNA postive area in the atherosclerotic plaque of WBF-treated group became smaller than that of model group(p<0.01).The endostatin-mRNA positive area also became smaller but with no significant statistical difference between them.8、Pearson test showed that there was a negative correlation between the fibrous cap thickness/lipid core area radio and IL-6、CD34 postive area in the atherosclerotic plaque respectively in all groups(p<0.01or p<0.05); and there was a positive correlation between IL-6 and CD34 postive area in the atherosclerotic plaque in all groups. 9、Pearson test showed there was a positive correlation between CD34 and VEGF postive area in the atherosclerotic plaque in all groups. And there was also a positive correlation between VEGF and VEGFR-2 in normal control group、model group and simvatatin-treated group (p<0.05). VEGF and VEGFR-2 in WBF-treated group appeared to be related somehow but with no statistical significance.Conclusion:1、WBF could reduce the level of lipid and plaqe area、intima thickness and intima thickness/tunica media thickness ratio, and improve the pathohistologics of arterioselerosis in atherosclerotic model rabbits.2、WBF could decrease the lipid core area; increase the fibrous cap thickness and the fibrous cap thickness/lipid core area ratio; inhibit the collagen hyperplasia and lessen degradation of extracellular matrix in fibrous cap, therefore it could improve the internal structure and stabilize plaque to some extent.3、There was a negative correlation between the stability of plaque and inflammatory factor, angiogenesis respectively.4、WBF could stabilize and regress plaque to some extent. The mechanism may include regulating blood lipid、reducing degradation of extracellular matrix in fibrous cap and inhibiting the inflammation reaction and angiogenesis in the atherosclerotic plaque.