兔定位性动脉粥样硬化发病机制的实验研究

目的 探讨定位性动脉粥样硬化模型中动脉粥样硬化的发病机制及各因素间内在联系.方法 将48只新西兰白兔随机分成两组：对照组6只给予基础饲料＋假手术,模型组42只饲以1％胆固醇、6％猪油的高脂饲料8周,进食高脂饲料后1周行髂动脉球囊内膜剥脱术.酶学法测定三酰甘油（TG）、总胆固醇（TC）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）水平;放免法测定血浆内皮素（ET）、血栓素B2（TXB2）、6-酮-前列腺素F1α（6-Keto-PGF1α）水平;硝酸还原法测定血清一氧化氮（NO）水平;免疫比浊法测定二磷酸腺苷（ADP）诱导的最大血小板聚集率（MPA）.8周时进行髂动脉造影,处死对照组及部分模型组动物行光镜检查.使用SPSS 19.0统计软件进行配对或非配对t检验,并进行多元线性回归分析,相关分析采用Pearson检验.结果 模型组中所有髂动脉都有不同程度（15％～100％）的狭窄,平均（61.47±28.10）％,对照组未见明显狭窄.与对照组TG：（0.96±0.78） mmol/L,TC：（1.89 ±0.60） mmol/L,LDL-C：（0.85 ±0.42） mmol/L,ET：（297.55 ±44.67）ng/L,MPA：（33.72 ±6.35）％,TXB2：（68.55±8.90）ng/L,TXB2/6-Keto-PGF1α：19.67±3.38]相比,血清或血浆TG 、TC、LDL-C、ET、MPA、TXB2和TXB2/6-Keto-PGF1α比值在模型组中均显著增高TG：（4.61 ±2.15） mmol/L,TC：（40.49±9.53） mmol/L,LDL-C：（36.96±8.17） mmol/L,ET：（386.78±52.92）ng/L,MPA：（48.10±7.25）％,TXB2：（184.14±27.51）ng/L,TXB2/6-Keto-PGF1α：85.75±37.50],差异有高度统计学意义（P＜0.01）,除TG外上述指标血清或血浆浓度均分别与髂动脉最大狭窄程度（MSD）呈正相关（P＜0.05）;而与对照组HDL-C：（0.64±0.18）mmol/L,NO：（71.83±3.81） μmol/L,6-Keto-PGF1α：（361.11±71.69）ng/L,NO/ET比值：23.30±0.76]比较,血清或血浆HDL-C、NO、6-Keto-PGF1α以及NO/ET比值在模型组均显著减少HDL-C：（0.33±0.19）mmol/L,NO：（51.43±11.10）μmol/L,6-Keto-PGF1α：（240.20±67.53）ng/L,NO/ET比值：13.45±3.15],差异有高度统计学意义（P＜0.01）,均与髂动脉MSD呈负相关（P＜0.05）.多元线性回归分析显示,MSD与血浆TXB2和ADP诱导的MPA相关（R2=0.804,P=0.015）.组织病理学检查显示,内膜明显增厚,粥样斑块形成.结论 高脂饮食及内皮损伤成功复制定位性动脉粥样硬化模型,通过血小板分泌及聚集功能变化而发挥作用,体现了脂质浸润学说、内皮损伤学说、血栓学说在动脉粥样硬化形成中存在一定的内在联系.

Experimental study on the pathogenesis of focal atherosclerosis in rabbits

degrees of stenosis ranging from 15％ to 100％,with the average of （61.47 ± 28.10） ％ in model group,but no Objective To investigate the pathological mechanism of atherosclerosis and internal relations among various factors in focal atherosclerotic model.Methods 48 New Zealand white rabbits were randomly divided into two groups：control group was given standard diet and sham operation （n=6）,model group was given an atherogenic diet with 1％cholesterol and 6％ pig oil for 8 weeks and balloon endometrial stripped in iliac artery was done 1 week after atherogenie diet （n=42）.Before and after 8 weeks of dietary intervention,bood samples were collected for enzymatic measurement of serum triglyceride （TG）,total cholesterol （TC）,low-density lipoprotein cholestrol （LDL-C） and high-density lipoprotein cholestrol （HDL-C）.Plasma endothelin （ET）,thromboxane B2 （TXB2）,6-keto-prostaglandin F1α （6-keto-PGF1α） were detected by radioimmunoassy.Serum nitric oxide （NO） was measured by nitrate reductase,and maximal platelet aggregation （MPA） rate following adenosine diphosphate （ADP） activation in vitro was assessed by immunoprecipitation.At the end of the dietary intervention,iliac artery quantitative angiography was made and iliac arteries in control and partial model group （n=6） were examined by light microscopy.Paired or unpaired t test,multiple linear regression analysis and Pearson correlation analysis were carried out by SPSS 19.0.Results All iliac arteries had various obvious stenosis in control group.Compared with control group TG：（0.96±0.78） mmol/L,TC：（1.89±0.60） mmol/L,LDL-C：（0.85±0.42） mmol/L,ET：（297.55±44.67） ng/L,MPA：（33.72±6.35） ％,TXB2：（68.55±8.90） ng/L,TXB2/6-Keto-PGF1α：19.67±3.38],serum or plasma TG,TC,LDL-C,ET,TXB2 concentration and the ratio of TXB2 to 6-keto-PGF1α significantly increased in model group TG：（4.61±2.15） mmol/L,TC：（40.49±9.53） mmol/L,LDL-C：（36.96±8.17） mmol/L,ET：（386.78±52.92） ng/L,MPA：（48.10±7.25） ％,TXB2：（184.14±27.51） ng/L,TXB2/6-Keto-PGF1α：85.75±37.50],with statistically significant differences （P ＜ 0.01）,and had positive relation to the maximal stenotic degree （MSD） except TG for all rabbit iliac arteries,respectively （P ＜ 0.05）.In contrast,compared with control group HDL-C：（0.64±0.18） mmol/L,NO：（71.83±3.81） μ mol/L,6-Keto-PGF1α：（361.11±71.69） ng/L,the ratio of NO to ET：23.30±0.76],serum or plasma HDL-C,NO,6-keto-PGF1α levels and the ratio of NO to ET significantly decreased in model group HDL-C：（0.33±0.19） mmol/L,NO：（51.43±11.10） μmol/L,6-Keto-PGF1α：（240.20±67.53） ng/L,the ratio of NO to ET：13.45±3.15],with statistically significant differences （P ＜ 0.01）,and negatively related to the MSD for all rabbit iliac arteries,respectively （P ＜ 0.05）.Multiple linear regression revealed that plasma TXB2 level and ADP-induced MPA rate contributed to the MSD （R2=0.804,P=0.015）.Histopathologic examination showed endometrium obvious thickening,atheromatous plaque had formed.Conclusion Focal atherosclerotic model in rabbit iliac artery is successfully replicated by combination an atherogenic diet with endothelial dedutation through platelet function changes of secretion and aggregation within a short period of time,which also reveals the intrinsic relations among lipid infiltration,endothelial injury and thrombogenicity during atherosclerotic progression.