抗β2糖蛋白Ⅰ抗体加速载脂蛋白E基因敲除小鼠动脉粥

Anti-β2GP I antibodies accelerate the formation of atherosclerosis in high fat diet fed ApoE deficientmice

目的探讨抗β2糖蛋白Ⅰ（β2GPⅠ）抗体对载脂蛋白E基因敲除（ApoE－/－）小鼠动脉粥样硬化形成的影响。 方法SPF级雄性ApoE－/－小鼠24只，6～8周龄，体重20～23 g，分为正常饮食对照组、高脂饮食对照组、高脂饮食＋抗β2GPⅠ抗体组和高脂饮食＋同源对照IgG组，每组6只。饲养期间每2周记录小鼠体重1次，根据分组每周腹腔注射抗β2GPⅠ抗体（100 μg/只）或同源对照IgG （100 μg/只）1次。饲养16周时利用小动物核磁共振（MRI）仪观察颈动脉脂质沉积情况；采集小鼠眼球血，乙二胺四乙酸抗凝后检测血浆总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDL－C）和高密度脂蛋白胆固醇（HDL－C）的水平，计算动脉粥样硬化指数（AI）；处死小鼠分离血管，苏木精伊红（HE）染色观察颈动脉近分叉处管腔狭窄情况，并计算其面积。 结果（1）各组小鼠体重监测结果：实验过程中，各组小鼠体重均有不同程度增长，至饲养第16周以高脂饮食对照组增长最为明显，与其他各组比较差异均有统计学意义（P均〈0.05），而高脂饮食＋抗β2GPⅠ抗体组和高脂饮食＋同源对照IgG组与正常饮食对照组比较差异均无统计学意义。（2）各组小鼠血脂的检测结果：饲养第16周时，高脂饮食对照组、高脂饮食＋抗β2GPⅠ抗体组和高脂饮食＋同源对照IgG组小鼠血浆TC和LDL－C水平均高于正常饮食对照组（P均〈0.05），而高脂饮食各组间差异均无统计学意义。而HDL－C水平仅高脂饮食对照组高于正常饮食对照组。TG水平各组间差异均无统计学意义。高脂饮食＋抗β2GPⅠ抗体组小鼠AI高于其他各组（P均〈0.05）。（3）各组小鼠颈动脉管腔脂质沉积、管壁厚度、管腔狭窄程度及颈动脉斑块面积的检测结果：饲养16周，MRI可见高脂饮食＋抗β2GPⅠ抗体组小鼠颈动脉管腔周围白色脂质沉积较其余各组明显。同时，小鼠颈动脉切片HE染色发现，高脂饮食＋抗β2GPⅠ抗体组小鼠颈动脉管腔出现狭窄，其斑块面积占整个管腔百分比为（37.545±1.351）%，明显大于正常饮食对照组[（1.235±0.460）%]、高脂饮食对照组[（11.635±2.751）%]和高脂饮食＋同源对照IgG组[（11.815±2.623）%], P均〈0.01。高脂饮食＋抗β2GPⅠ抗体组小鼠颈动脉斑块面积为[（3.121±0.124）×10^4 μm2]，明显大于正常饮食对照组[（0.094±0.015）×10^4 μm2]、高脂饮食对照组[（1.309±0.147）×10^4 μm2]和高脂饮食＋同源对照IgG组[（1.027±0.228）×104 μm2], P均〈0.01。

ObjectiveTo investigate the effects of anti-β2 glycoprotein Ⅰ（β2GPⅠ） antibody on atherosclerosis in ApoE deficient mice. MethodsA total of 24 male ApoE deficient mice of specific pathogen free level（six to eight-week old）were divided into normal control group, high fat diet group, high fat diet with anti-β2GPⅠ group, high fat diet with homologous control antibody group （n=6 each group）. During the feeding period, mice were weighed every 2 weeks and were intraperitoneally injected with anti-β2GPⅠIgG （100 μg/per） and homologous control IgG （100 μg/per） according to grouping once a week. At the 16th week, the carotid arterial lipid deposition was observed by small animal magnetic resonance imaging, and blood samples were collected from internal vein of eyeball and the concentrations of TC, TG, HDL-C and LDL-C in plasma were measured after EDTA anticoagulant treatment. AI was calculated. The mice were then sacrificed and carotid arteries were removed, hematoxylin-eosin staining was used to observe the atherosclerotic lesions near the bifurcation of carotid artery and to calculate lesion size. Results（1） The body weight of mice was significantly higher in the high fat diet group compared to other 3 groups（all P〈0.05）, which was similar among high fat diet＋ anti-β2GPⅠantibody group, high fat diet＋ homologous control IgG group and normal diet control group （P〉0.05）. （2） After 16 weeks, plasma concentrations of TC and LDL-C in high fat diet group, high fat diet＋ anti-β2GPⅠantibody group and high fat diet＋ homologous control IgG group were significantly higher than in normal diet group （all P〈0.05）, there was no significant difference among high fat diet groups. The level of HDL-C was significantly higher in high fat diet control group than in normal diet control group. The concentration of TG was similar among groups. However, the value of AI in high fat＋ anti-β2GPⅠ antibody group was significantly higher than in other groups （all P〈0.05）. （3） After 16 weeks, magnetic resonance imaging revealed that mice in high fat diet＋ anti-β2GPⅠ antibody group had more obviously lipid deposition in the carotid arteries, it was significantly higher than that in the other groups, and the cross sections of carotid arteries stained with HE also demonstrated obviously carotid lumen stenosis and the percentage of carotid plaque area to carotid artery was （37.545±1.351）% in the high fat diet＋ anti-β2GPⅠ antibody group, it was significantly higher than normal diet group （（1.235±0.460）%）, high fat diet control group（（11.635±2.751）%） and high fat diet＋ homologous control IgG group （（11.815±2.623）%）, all P〈0.01. In high fat diet＋ anti-β2GPⅠ antibody group, the area of carotid plaque was （3.121±0.124）×104 μm2, it was also significantly higher than normal diet group （（0.094±0.015）×10^4 μm2）, high fat diet control group （（1.309±0.147）×10^4 μm2） and high fat diet＋ homologous control IgG group （（1.027±0.228）×10^4μm2）, all P〈0.01. ConclusionAnti-β2GPⅠ antibody can promote atherosclerotic plaque formation in high fat diet fed ApoE deficient mice.