载脂蛋白CⅢ通过增加氧化应激及内质网应激水平促进动脉粥样硬化病变

Apolipoprotein CⅢ Promotes Atherosclerosis by Increasing Oxidative Stress and Endoplasmic Reticulum Stress

目的构建载脂蛋白CⅢ(Apo CⅢ)转基因小鼠,并与动脉粥样硬化易感的低密度脂蛋白受体(LDLR)敲除小鼠杂交,获得Apo CⅢ转基因+LDLR缺陷(Apo CⅢ+LDLR^(―/―))小鼠模型,开展Apo CⅢ对动脉粥样硬化影响及潜在机制的研究。方法 Apo CⅢ+LDLR^(―/―)小鼠与LDLR^(―/―)小鼠喂饲高脂饲料3个月,检测其血浆甘油三酯、总胆固醇、脂质过氧化产物和还原性谷胱甘肽水平。对小鼠的全主动脉和主动脉窦进行油红O染色及二氢乙啶染色,并提取主动脉的RNA和蛋白,分析相关基因的表达。结果 Apo CⅢ+LDLR^(―/―)小鼠喂饲高脂饲料后血浆甘油三酯水平明显高于LDLR^(―/―)小鼠,但总胆固醇水平差别不明显。主动脉全长和主动脉窦的染色显示动脉粥样硬化斑块明显增加。Apo CⅢ+LDLR^(―/―)小鼠血浆脂质过氧化产物8-异前列腺素和丙二醛水平明显升高,抗氧化物质还原性谷胱甘肽水平明显降低。对其主动脉进行二氢乙啶染色发现,动脉内活性氧水平明显增加。主动脉内氧化应激和内质网应激相关基因的mRNA和蛋白表达明显升高。提示Apo CⅢ可能通过增加动脉内的氧化应激和内质网应激,从而促进动脉粥样硬化斑块形成。结论 Apo CⅢ具有促动脉粥样硬化的作用,其机制可能与整体氧化应激水平的升高以及动脉壁氧化应激、内质网应激水平的增加有关。

Aim To construct the apolipoprotein CⅢ（ Apo CⅢ） transgenic mice,and to hybridize with low density lipoprotein receptor（ LDLR） knockout mice susceptible to atherosclerosis; To obtain the Apo CⅢ transgene ＋ LDLR defect（ Apo CⅢ ＋ LDLR^―/―） mice model; To study the effect of Apo CⅢ on atherosclerosis and its potential mechanism.Methods Apo CⅢ ＋ LDLR^―/―mice and LDLR^―/―mice were fed with high fat diet for 3 months. Plasma triglyceride,total cholesterol,lipid peroxidation products（ 8-isoprostane,malondialdehyde） and glutathione levels were detected. The whole aorta and aortic sinus of the mice were stained with oil red O and dihydroethidium（ DHE）. The RNA and protein in aorta were extracted and the expressions of related genes were analyzed. Results After feeding high fat diet,plasma triglyceride level in Apo CⅢ ＋ LDLR^―/―mice was apparently higher than that in LDLR^―/―mice,but there was no significant difference in total cholesterol levels. Whole aorta and aortic sinus dyeing showed a significant increase of atherosclerotic plaque. Plasma lipid peroxidation products（ 8-isoprostane,malondialdehyde） increased significantly and antioxidant glutathione reduced significantly in Apo CⅢ ＋ LDLR^―/―mice. Aortic DHE staining showed that the level of reactive oxygen species increased significantly. The mRNA and protein expressions of the genes related to oxidative stress and endoplasmic reticulum stress were significantly increased in the aorta. The results prompted that Apo CⅢ could increase arterial oxidative stress and endoplasmic reticulum stress,thereby promoting the formation of atherosclerotic plaque.Conclusion Apo CⅢ has the role of promoting atherosclerosis,and its mechanism may be related to the increases of overall oxidative stress level and arterial wall oxidative stress,endoplasmic reticulum stress level.