高脂诱导五指山小型猪动脉粥样硬化模型的建立及Lp-PLA_2的表达调控

Establishment of a Wuzhishan minipig model of atherosclerosis induced by high fat/cholesterol diet and regulation of Lp-PLA_2 expression

目的高脂诱导建立五指山小型猪动脉粥样硬化(AS)模型,观察脂蛋白相关磷脂酶A_2(Lp-PLA_2)在AS模型血浆和斑块中的表达变化。方法将10只五指山小型猪随机分为正常对照(Ctr)组4只饲喂普通饲料、AS模型(AS model)组6只饲喂高脂饲料,连续造模24周。造模24周时,空腹取前腔静脉血测定总胆固醇(TC)、低密度脂蛋白(LDL-C)、高密度脂蛋白(HDL-C)、甘油三酯(TG)、C-反应蛋白(CRP)、Lp-PLA_2活性和成分的变化,并取主动脉进行油红O染色以及取腹主动脉血管行HE染色和IL-6免疫组化染色,观察血管脂质沉积和斑块病理以及IL-6蛋白表达变化。采用RT-PCR和Western Blot法观察腹主动脉组织中Lp-PLA_2mRNA和蛋白的表达情况。结果与正常对照组比,AS模型组体重、体质量指数(BMI)、TC、LDL-C、HDL-C、CRP、Lp-PLA_2活性和成分均显著升高(P<0.05,P<0.01),同时主动脉脂质沉积明显(P<0.01)和AS斑块形成,腹主动脉组织中Lp-PLA_2mRNA和蛋白表达以及IL-6蛋白表达均显著升高(P<0.05)。结论长期高脂饮食24周能诱发五指山小型猪AS,且Lp-PLA_2在参与血管炎症和AS斑块形成中发挥了关键作用。

Objective To establish a Wuzhishan minipig model of atheroselerosis （AS） induced by high fat/choles- terol diet, and observe the changes of expression of lipoprotein associated phospholipase A2 （ Lp-PLA2 ） in plasma and plaques. Methods 10 Wuzhishan minipigs were randomly divided into 2 groups： The normal control （ Ctr, n = 4） group was fed with normal diet, and AS model （n = 6） group fed with high fat/cholesterol diet for 24 weeks. After the modeling for 24 weeks, the changes of total cholesterol （TC）, low density lipoprotein （LDL-C）, high density lipoprotein （HDL-C）, triglyc- eride （TG） , C-reactive protein （CRP） , Lp-PLA2 activity and composition were detected. The changes of vascular lipid dep- osition and plaques were assessed by pathology using oil red O staining and HE staining, respectively, and immunohistochem- ical staining for IL-6 protein expression. Moreover, the expression of Lp-PLAz mRNA determined by RT-PCR and protein by Western blot were observed in the abdominal aortic tissues. Results Compared with the control group, the body weight, body mass index （BMI） , TC, LDL-C, HDL-C, CRP, Lp-PLA2 activity and composition and aortic lipid deposition were significantly increased, and AS plaque formation was observed in the AS model group （P 〈 0.05, P 〈 0. 01 ）. The expression of Lp-PLA2mRNA and protein and IL-6 protein in abdominal aortic tissues were also significantly increased （P 〈 0.05）. Con- clusions Long-term high fat/cholesterol diet feeding for 24 weeks can induce atherosclerosis in Wuzhishan minipigs, and Lp-PLA2 plays a key role in the vascular inflammation and plaque formation.