脂蛋白相关磷脂酶A_2与兔易损斑块的相关性研究

Relationship between Lp-PLA_2 and vulnerable atherosclerotic plaque in rabbits

目的:建立易损斑块动物模型,观察探讨脂蛋白相关磷脂酶A2(Lp-PLA2)、超敏C反应蛋白(hs-CRP)、基质金属蛋白酶(MMP-9)在易损斑块中的表达规律。方法:实验新西兰雄兔48只随机分为对照组、稳定斑块组、p53基因组和p53+药物组。对照组假手术后普通饲料喂养;稳定斑块组、p53基因和p53+药物组行腹主动脉球囊拉伤后高脂喂养12周,p53基因和p53+药物组于10周末行腹主动脉斑块形成处转染人野生型p53基因重组腺病毒载体,p53+药物组于12周末给与中国圆斑蝰蛇毒和组胺药物触发斑块破裂。4组兔于实验第1d和处死前检测Lp-PLA2、hs-CRP、MMP-9、HDL、LDL、VLDL血清指标,处死后取腹主动脉斑块处病理标本并做局部原位杂交、免疫组织化学分析。结果:稳定斑块组、p53基因组和p53基因+药物触发组血清Lp-PLA2、MMP-9第12周末明显高于对照组和实验第1d(P<0.05);p53基因组和p53基因+药物触发组血清Lp-PLA2及hs-CRP水平明显高于对照组和稳定斑块组,差别显著(P<0.05);p53基因+药物触发组与p53基因组比较血清Lp-PLA2、hs-CRP、MMP-9水平均差别明显(P<0.05)。第12周末,病理结果示4组兔分别为正常动脉血管、稳定粥样硬化斑块、易损斑块、破裂斑块模型,在p53基因组和p53基因+药物触发组纤维帽厚度明显低于稳定斑块组(P<0.05);p53基因+药物触发组斑块破裂、血栓形成明显高于p53基因组。血清Lp-PLA2与斑块纤维帽厚度呈明显负相关性(r=-0.710,P<0.01),hs-CRP、MMP-9与纤维帽厚度无明显相关关系(P>0.05)。结论:在已建立的动脉粥样硬化动物易损斑块模型上,动脉血清与组织Lp-PLA2、hs-CRP、MMP-9的表达规律表明,Lp-PLA2与斑块的不稳定性相关性好,结合hs-CRP、MMP-9检测可更好阐释斑块的性质;为发现易损斑块并预测斑块稳定性提供了基础实验依据。

AIM：To explore the expressive role of lipoprotein-associated phospholipase A2,high sensitive C-reactive protein and matrix metalloproteinase-9 in vulnerable atherosclerotic plaques in a rabbit model. METHODS： Forty eight New Zealand white male rabbits were randomly divided into 4 groups （12 rabbits each）： control group,stable plaque group,p53 group,and p53＋drug group. Rabbits in control group were fed with a regular diet and underwent sham operation. Rabbits in stable plaque group,p53 group and p53＋drug group underwent balloon induced arterial wall injury and then were fed on a diet with 1% cholesterol. The animals were all fed for 3 months,then the rabbits in p53 group and p53＋drug group underwent Ad5-CMV p53 transfection at 10th week. Before killed,the animals in p53＋drug group underwent pharmacological triggering with Russell＇s viper venom （RVV） and histamine to induce the rupture of the atherosclerotic plaques. At the 1st day and before sacrifice,the serum was collected for measuring Lp-PLA2,hs-CRP,MMP-9,HDL,LDL and VLDL. The expressions of Lp-PLA2,hs-CRP and MMP-9 in tissues were determined by the methods of hybridization and immunohistochemistry. RESULTS： At the end of 12th week,the serum and tissue levels of Lp-PLA2 and MMP-9 in stable plaque group,p53 group and p53＋drug group were significant different from those in control group and in each group at the first day （P〈0.05）. The serum levels of Lp-PLA2 and hs-CRP in p53 group and p53＋drug group were significantly higher than those in control group and stable group （P〈0.05）. The serum levels of Lp-PLA2,hs-CRP and MMP-9 were all significantly different between p53 group and p53＋drug group （P〈0.05）. At the end of 12th week,pathological results showed that 4 groups were normal artery,stable plaque,vulnerable plaque and rupture plaque,respectively. The fabric cap was thicker in plaque groups than that in normal group （P〈0.05）. The rupture and formation of thrombus were more significant in p53＋drug group than those in p53 group. The serum level of Lp-PLA2 had negative interrelated relationship with fabric cap in plaque groups （r=-0.710,P〈0.01）,and hs-CRP,MMP-9 had no interrelated relationships with fabric cap in plaque groups. CONCLUSION： Base on the successful establishment of the atherosclerotic plaque animal model,serum Lp-PLA2 shows better interrelated relationships to plaques stability. Combination with hs-CRP and MMP-9,we can exactly evaluate the nature of plaques.